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Item 7. Management’s Discussion and Analysis

2026-03-16 compared with 2025-03-06 · 470 added, 584 removed, 919 unchanged (53% of the section changed)

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We undertake no obligation to update forward-looking statements, which reflect events or circumstances occurring after the date of this Form 10-K.

We are a clinical-stage, oncology-focused biopharmaceutical company focused on developing novel, conditionally activated, masked biologics designed to be preferentially unmasked and activated in the tumor microenvironment.

We aim to build a commercial enterprise to maximize our impact on the treatment of cancer.

By pioneering a novel class of localized biologic drug candidates, powered by our PROBODY ® therapeutic technology platform, we are a leader in the field of masked, conditionally activated oncology therapeutics and have established biologics localization as a strategic area of research and development in the biopharmaceutical industry.

Our vision is to transform lives with safer, more effective therapies with the goal to address major unmet needs in oncology.

Our proprietary, versatile, multi-modality PROBODY technology platform is designed to enable conditional activation of potent masked biologic therapeutic candidates within the tumor microenvironment, while minimizing drug activity in healthy tissues and circulation.

Our platform is built on a strong foundation of tumor biology expertise, including deep knowledge of tumor-associated enzymes known as proteases.

Proteases are tightly controlled in normal tissues but often dysregulated and active in tumor microenvironments where they play important roles in cancer cell migration, invasion and metastasis.

Leveraging our deep scientific knowledge, we conceived of and constructed our PROBODY therapeutic platform which allows us to genetically engineer biologic therapeutic candidates to contain protease-cleavable masks.

Our masking strategy is designed to reduce binding of biologic therapeutics to their targets until the mask is removed by proteases in the tumor microenvironment, providing more selective targeting of the tumor.

We are employing our leading, masking platform technology to address some of the biggest challenges in oncology biologics research and development.

These include the validation of potential new targets for antibody-drug conjugates (“ADCs”), opening therapeutic window for novel T-cell engagers (“TCEs”) targeting solid tumors, and increasing the therapeutic index for immune modulators such as cytokines.

We are also exploring the potential for our PROBODY platform in preclinical research in areas outside of oncology, including in our collaboration with Moderna.

We have utilized our PROBODY therapeutic platform and masking technology to build a promising, broad pipeline of potential first-in-class and best-in-class clinical-stage molecules.

These are CX-2051, an investigational, conditionally activated ADC targeting epithelial cell adhesion molecule (“EpCAM”), CX-801, an investigational, masked version of interferon alpha-2b (“IFNα2b”) and CX-904, a conditionally activated, PROBODY ® TCE, targeting the epidermal growth factor receptor (“EGFR”) on tumor cells and the CD3 receptor on T cells.

Our current clinical-stage molecules address targets or mechanisms that have been previously validated as having anti-cancer activity but have been limited in their utilization due to systemic toxicities.

We have incorporated our significant, multi-modality masking, conditional activation expertise and clinical learnings to optimize predicted therapeutic index and the clinical potential of these promising agents through tumor localized, conditional activation.

CX-2051, a conditionally activated, PROBODY ADC, is directed toward the epithelial cell adhesion molecule (EpCAM).

High expression of EpCAM has been documented in many tumor types, including CRC.

The CX-2051 payload, a next generation topoisomerase-1 inhibitor payload licensed from AbbVie (formerly ImmunoGen), is tailored to specific EpCAM-expressing indications, including colorectal cancer, and includes a payload-antibody linker designed to drive bystander effect, contributing to anti-tumor activity.

The design of CX-2051 is intended to optimize the therapeutic index for the systemic treatment of EpCAM-expressing epithelial cancers where previous industry efforts targeting EpCAM have not been successful due to dose-limiting toxicities.

CX-2051 has demonstrated a wide predicted therapeutic index and strong preclinical activity and tolerability in multiple preclinical models, including colorectal cancer.

The IND for CX-2051 was allowed to proceed by the FDA in January 2024 and Phase 1 clinical initiation in EpCAM expressing solid tumors, including a primary initial focus in CRC commenced in April 2024.

As o f March 2025, the Phase 1 study has reached the seventh dose escalation cohort.

In Phase 1 dose escalation to date, CX-2051 has demonstrated a favorable tolerability profile and attained doses predicted to be therapeutically active.

In the Phase 1 study, EpCAM expression levels are being assessed retrospectively

and are anticipated to be high in the majority of CRC patients.

The CX-2051 Phase 1 study has reached the seventh dose level with CX-2051 initial Phase 1 data in advanced metastatic CRC expected in the first half of 2025.

CX-801 is our interferon ("IFN") alpha-2b PROBODY.

IFNα2b provides a potentially superior approach to activating anti-tumor immune responses than other cytokines.

CX-801 is a dually masked, conditionally activated version of IFNα2b that has the potential to become a cornerstone of combination therapy for a wide range of tumor types.

For a discussion related to the results of operations for 2024 compared to 2023, refer to Part II, Item 7, “Management's Discussion and Analysis of Financial Condition and Results of Operations - Comparison of Years Ended December 31, 2024 and 2023” in our Annual Report on Form 10-K for the year ended December 31, 2024 filed with the SEC on March 6, 2025.

We are a clinical-stage, oncology-focused biopharmaceutical company dedicated to developing innovative therapies to address major unmet need in oncology.

CytomX has led the field of conditionally activated, masked biologics through the development of its PROBODY technology platform.

This versatile, multi-modality platform is built on a strong foundation of tumor biology expertise, including deep knowledge of tumor-associated enzymes known as proteases.

CytomX’s experience and leadership with the PROBODY platform for over 15 years has led to a highly focused strategy for the application of its technology in product development that has resulted in a current pipeline of novel clinical-stage and pre-clinical stage programs.

In identifying and designing potential PROBODY therapeutics, we evaluate the following:

Drug targets that have been validated previously as having clinical anti-tumor activity, but have been limited in their utility due to expression and toxicity in healthy tissues.

• Indication:

The significance of the clinical unmet need that may be addressed if the target could be targeted systemically and unlocked through masking.

• Effector Mechanism:

the PROBODY platform is highly versatile and is being applied to a wide range of modalities including antibody drug conjugates (“ADCs”), T-cell engagers (“TCEs”), and cytokines.

In PROBODY therapeutic design, the goal is to align the selected indication with the most validated drug modality (e.g.

ADC, TCE) and cancer cell killing mechanism (e.g.

cytotoxic payload) to maximize the potential for clinical activity.

CytomX’s two current clinical programs, varsetatug masetecan (“Varseta-M”) and CX-801 are in Phase 1 clinical development and are examples of our focused program development strategy.

We aim to continue to advance our clinical pipeline towards later stage development and ultimately build a commercial enterprise to maximize our impact on the treatment of cancer.

Varsetatug Masetecan (Varseta-M)

Our most advanced clinical-stage program is Varseta-M, an investigational, conditionally activated antibody-drug conjugate (“ADC”) targeting epithelial cell adhesion molecule (“EpCAM”).

Varseta-M is initially focused on the lead indication of colorectal cancer (“CRC”).

Varseta-M is designed to bring the promise of ADCs, which have made a meaningful clinical difference in other solid tumors such as lung and breast cancer, to CRC by leveraging EpCAM as a potentially ideal CRC antigen to target this disease.

Varseta-M is a high affinity EpCAM antibody that is designed to preferentially bind EpCAM in the tumor microenvironment and minimize toxicities in healthy tissues, which have limited prior attempts in the field to target EpCAM systemically.

Varseta-M is armed with a topoisomerase-1 inhibitor payload.

Topoisomerase-1 inhibitors are known to have clinical activity in CRC, including irinotecan chemotherapy which is a standard component of the approved standard of care in CRC.

EpCAM is a high potential oncology target based on its documented high expression in many solid tumors, including CRC where it was first discovered due to its very high and uniform expression.

Historically, previous efforts across the drug development landscape to target this antigen systemically have been limited by dose-limiting toxicities.

For example, high affinity EpCAM antibodies were limited by pancreatitis and liver toxicities and discontinued.

However, EpCAM has been validated as a cancer target, including by the drug KORJUNY ® , which is approved for the treatment of malignant ascites in Europe.

KORJUNY ® , however, must be given directly into the peritoneum due to systemic toxicity, but its approval provides evidence that local delivery of an EpCAM therapeutic to the tumor can be effective.

The Varseta-M payload is a topoisomerase-1 inhibitor licensed from AbbVie (formerly ImmunoGen), tailored to have anti-tumor activity against EpCAM-expressing cancer types.

The payload-antibody linker is specifically designed to drive bystander killing of neighboring tumor cells, contributing to robust anti-tumor activity.

Overall, the design of Varseta-M seeks to establish a clinically meaningful therapeutic window for the systemic treatment of patients with EpCAM-expressing cancers, for the first time.

Varseta-M is designed to potentially address a broad range of EpCAM-expressing tumors, but is initially focused in CRC which is one of the largest unmet needs in oncology with over 1.9 million cases diagnosed annually around the world.

It is also a disease that is expected to grow and estimated that there will be over 3 million cases globally by 2040.

CRC is the second leading cause of cancer death worldwide and has a 5 year survival rate in the metastastic setting of only 13%.

CRC is also the leading cause of cancer death in the U.S.

for patients under the age of 50 and has been growing in incidence in younger patients over the last 3 decades.

Varseta-M clinical development is initially being focused on late-line metastatic CRC where there is significant unmet need and treatment options are highly inadequate.

In third line or later metastatic CRC, patients have typically progressed through multiple chemotherapy-based regimens.

Later stage treatment is limited to therapies that provide single digit percentage response rates, median progression free survival of 2 to 5.6 months and overall survival outcomes ranging from approximately 6 to 11 months.

It is estimated that there are more than 35,000 patients in the U.S.

with 3 rd line or later metastatic CRC, with the number expected to grow over the next decade.

While Varseta-M is initially being developed in late-line metastatic CRC, the program was developed with the vision to help a broad population of metastatic CRC patients, including those in the first- and second-line settings.

Given Varseta-M’s mechanism of action, our longer-term development vision is to make Varseta-M a core component of the CRC treatment landscape in earlier lines of therapy, consistent with the development strategy that has been employed for other solid tumor ADCs.

We plan to pursue combination strategies to progress this vision to move Varseta-M to earlier lines of therapy starting in 2026.

Additionally, given the broad solid tumor expression profile of EpCAM, Varseta-M has the potential to be an innovative new treatment option in a wide range of solid tumors.

High expression of EpCAM has been documented in other tumors such as gastric, gastroesophageal, pancreatic, ovarian, endometrial, non-small cell lung and triple negative breast cancers.

We plan to potentially initiate development in indications outside of CRC in the second half of 2026, with the ultimate vision to develop Varseta-M as a pan-tumor therapy.

Varsetatug Masetecan Development

The investigational new drug application (“IND”) for Varseta-M was allowed to proceed by the FDA in January 2024, and a Phase 1 clinical trial in patients with EpCAM-expressing solid tumors, with an initial focus on metastatic CRC, commenced in April 2024.

No pre-screening of CRC patients by EpCAM expression has been conducted due to the anticipated high and uniform EpCAM expression in CRC.

As of May 2025, the Phase 1 study had reached the seventh dose escalation level and had enrolled only mCRC patients.

In May 2025, we announced positive interim Phase 1 data as of an April 7, 2025 data cutoff in advanced metastatic CRC.

The data encompassed results from 25 CRC patients treated with Varseta-M at 5 dose levels ranging from 2.4 mg/kg to 10 mg/kg, administered every three weeks (“Q3W”).

The 2.4 mg/kg and 4.8 mg/kg doses were single patient dose escalation cohorts not anticipated to be therapeutically active.

At the 7.2 mg/kg, 8.6 mg/kg, and 10 mg/kg doses, 23 patients were treated, 18 of whom were efficacy evaluable, having had at least one post-baseline tumor assessment as of the data cutoff.

Patients enrolled in the study at the time of data cutoff had previously received a median of 4 prior lines of therapy and all patients had previously been treated with irinotecan.

64% of patients had liver metastases, 64% had KRAS mutations, and 96% were microsatellite stable.

Patients were not preselected based on EpCAM expression levels.

As of the data cutoff, 18 patients were efficacy-evaluable at doses of 7.2 mg/kg, 8.6 mg/kg, and 10 mg/kg Q3W.

Five of eighteen (28%) patients demonstrated confirmed partial responses per RECIST v1.1.

Three of seven (43%) efficacy evaluable patients at the dose of 10 mg/kg Q3W demonstrated confirmed partial responses per RECIST v1.1.

Seventeen of eighteen patients (94%) had disease control, defined as having an objective response or stable disease.

Preliminary median progression free survival (“PFS”) was 5.8 months as of the data cutoff with 10 of 18 patients remaining on study treatment.

As of the data cutoff, 25 patients were evaluable for safety.

Varseta-M was generally well-tolerated as of the data cutoff with manageable adverse events, with no dose limiting toxicities.

Most treatment related adverse events (“TRAEs”) were Grade 1 or Grade 2 in severity.

The most common reported TRAEs were diarrhea (18 patients, 5 Grade 3), nausea (11 patients, 1 Grade 3), vomiting (8 patients, No Grade 3), fatigue (8 patients, 1 Grade 3), anemia (5 patients, 3 Grade 3), hypokalemia (3 patients, 1 Grade 3), neutrophil count decrease (2 patients, 2 Grade 3) and neutropenia (2 patients, 1 Grade 3).

TRAEs included serious adverse events (“SAEs”) in 5 patients (1 Grade 2, 4 Grade 3).

The SAEs included Grade 3 Diarrhea (1 patient), Grade 3 Anemia (1 patient), Grade 3 colitis (1 patient), Grade 3 Diarrhea and Acute kidney injury (1 patient) and Grade 2 Asthenia (1 patient).

No Grade 4 or 5 TRAEs were observed as of the April 7, 2025 data cutoff.

No events of interstitial lung disease or febrile neutropenia were reported as of the data cutoff.

On August 13, 2025, we announced that a single Grade 5 treatment-related acute kidney injury occurred in a patient with a complex medical history, including having a solitary kidney.

The Grade 5 event was believed to be secondary to nausea, vomiting and

We reported the event to the FDA in accordance with regulatory requirements.

The CTMX-2051-101 Safety Review Committee reviewed the event and supported continued study execution.

Based on the positive interim Phase 1 dose escalation data in May 2025, dose expansions were initiated at the dose levels of 7.2 mg/kg, 8.6 mg/kg, and 10 mg/kg, administered Q3W and are currently ongoing.

Varsetatug Masetecan March 2026 Interim Data Update from Phase 1 Dose Expansions

In March 2026, we announced positive interim results from the ongoing Phase 1 dose expansions as of a January 16, 2026 data cutoff date.

As of the data cutoff, a total of 93 patients with late-line metastatic CRC had been enrolled in the study.

60 patients were enrolled across the Phase 1 expansion dose range of 7.2 mg/kg, 8.6 mg/kg, and 10 mg/kg of which 56 were efficacy evaluable as of the data cutoff.

Starting in October 2025, the expansion doses of 8.6 mg/kg and 10 mg/kg were prioritized for dose optimization utilizing optimized adverse event management guidelines and adjusted ideal body weight (AIBW) dosing.

20 patients had been enrolled in expanded dose optimization as of the January 16 th data cutoff towards an enrollment goal of 40 patients.

Patients enrolled in the study had previously received a median of 3 prior lines of therapy in the metastatic setting and 96% of patients had previously been treated with irinotecan.

76% of patients had liver metastases and 71% had KRAS mutations.

Patients were not preselected based on EpCAM expression levels.

All patients with evaluable tumor biopsies had high EpCAM levels as measured by immunohistochemistry.

As of the data cutoff, 56 patients were efficacy-evaluable at the expansion doses of 7.2 mg/kg, 8.6 mg/kg, and 10 mg/kg Q3W.

Median duration of follow-up across the efficacy-evaluable patient population was approximately 8 months.

Efficacy data across the Phase 1 Expansion doses are summarized below in Table 1.

Varseta-M Efficacy Summary by Phase 1 Expansion Dose

Confirmed Overall Response Rate (cORR)

Median Progression Free Survival (PFS)

Disease Control Rate (DCR)

At the 8.6 mg/kg dose, the confirmed response rate was 20% with an estimated median PFS of 6.8 months and at the 10 mg/kg dose, the confirmed response rate was 32% with an estimated median PFS of 7.1 months.

The disease control rate was 88% (49/56) across the expansion doses of 7.2 – 10 mg/kg.

The doses of 8.6 mg/kg and 10 mg/kg have been prioritized for further evaluation with the goal of selecting a dose or doses for a registrational study.

Dose optimization at 8.6 mg/kg and 10 mg/kg utilizing AIBW dosing and updated prophylaxis for adverse event management is ongoing.

At the doses of 11 mg/kg Q3W and 12 mg/kg Q3W, which were not expanded for further evaluation, the overall response rate was 30% (3/10).

As of the data cutoff, 93 patients were evaluable for safety including 80 patients across the expansion dose range of 7.2 mg/kg to 10 mg/kg.

Varseta-M’s safety profile was generally consistent with data presented in Phase 1 dose escalation.

Most TRAEs were Grade 1 or Grade 2 in severity.

No interstitial lung disease, febrile neutropenia or pancreatitis were observed.

The most common TRAE was diarrhea which was generally manageable and reversible.

In Phase 1 dose expansions starting in Q2 2025, prophylactic strategies for diarrhea management were investigated.

In dose optimization starting in Q4 2025, an updated prophylaxis regimen of anti-motility medication (loperamide or diphenoxylate/atropine) plus budesonide was implemented.

6 In the 20 patients receiving the updated prophylactic regimen at the Varseta-M expansion doses of 8.6 mg/kg and 10 mg/kg, Grade 3 diarrhea was 10%.

Overall, as of the January 16 th 2026 data cutoff, in the 80 patients treated at expansion and optimization doses ranging between 7.2 mg/kg to 10 mg/kg, the most common TRAEs were diarrhea (68 pts, 19 Gr 3), nausea (44 pts, 4 Gr 3), vomiting (29 pts, 3 Gr 3),

5 96% of patients with an evaluable biopsy had an H score by immunohistochemistry above 250 and all patients had H scores above 200.

6 Budesonide is a corticosteroid locally absorbed in the gastrointestinal (GI) tract.

7 8.6 mg/kg and 10 mg/kg dosed utilizing adjusted ideal body weight (AIBW).

8 Based on March 2, 2026 data snapshot.

fatigue (32 pts, 2 Gr 3), hypokalemia (21 pts, 13 Gr 3+), and anemia (13 pts, 6 Gr 3).

Serious treatment related adverse events (SAEs) in > 1 patient included diarrhea (4), vomiting (3), hypokalemia (3), dehydration (3), acute kidney injury (2), and colitis (2).

As previously reported on August 13, 2025, there was one treatment-related grade 5 acute kidney injury (AKI) in a patient treated at the 7.2 mg/kg dose.

The patient had a complex medical history including having a solitary kidney, and the AKI was determined to be secondary to Grade 3 nausea and Grade 2 diarrhea.

No other Grade 5 TRAEs have been reported as of the January 16 th 2026 data cutoff.

At the 11 mg/kg and 12 mg/kg doses, there were no dose limiting toxicities in dose escalation.

The most common TRAEs across the patients in the 11 mg/kg dose (n=8) and 12 mg/kg dose (n=3) were diarrhea (9 pts, 6 GR 3), nausea, (8 pts, 0 Gr 3), and vomiting (8 pts, 1 Gr 3).

Patients treated at the 11 and 12 mg/kg doses did not receive the optimized prophylactic regimen or adjusted ideal body weight dosing.

We plan to present additional Phase 1 Varseta-M data at a medical meeting in 2026 and aim to align with the FDA in 2026 on a potential registrational study designed for Varseta-M monotherapy in advanced late-line CRC.

Additionally, in the first quarter of 2026, a Phase 1 study of Varseta-M in combination with bevacizumab has been initiated, data from which is intended to inform potential Varseta-M development in earlier lines of CRC therapy.

Initial data from the combination study with bevacizumab is expected by the first half of 2027.

A Phase 1b/2 study in combination with bevacizumab and chemotherapy is expected to start by the end of 2026.

We also continue to evaluate additional non-CRC, EpCAM positive indications for potential Varseta-M development and anticipate initiating Phase 1 expansion cohorts in one or more additional indications in the second half of 2026.

In addition to Varseta-M, our pipeline includes CX-801, an investigational, masked version of interferon alpha-2b (“IFNα2b”), currently in a Phase 1 clinical trial.

CX-801 leverages a similarly focused application of the PROBODY technology platform in that it leverages a well validated and high potential mechanism that has been limited by systemic toxicity.

Interferon-alpha was one of the first immunotherapies approved, but has fallen out of broad use because of poor tolerability.

Like EpCAM, IFNα2b has also been validated as a localized therapy, including the approved therapy ADSTILADRIN ® for bladder cancer, which is a gene therapy encoding the protein IFNα2b that is administered directly into the bladder as a single agent, providing evidence that localized IFNα2b can be a powerful and effective therapy.

IFNα2b is also an attractive cytokine in that it is a potent and multi-faceted modulator of the immune system that also has direct anti-tumor cell killing effects, providing a potentially superior approach to activating anti-tumor immune responses compared with other cytokines such as IL-2, IL-12 or IL-15.

We have applied our significant masking and protein engineering expertise to the design of CX-801, which is a dually-masked, conditionally activated version of IFNα2b that is designed to be inactive in the periphery.

The dual masks on CX-801 include a peptide mask on the cytokine domain designed to limit binding in normal tissues as well as a steric Fc mask designed to further mitigate systemic activity as well as extend CX-801’s half-life.

For CX-801, we have also employed a focused initial development strategy in Phase 1, centered on the treatment of late-line melanoma where patient options are limited once they have typically progressed through earlier line checkpoint-based therapies.

With CX-801, our initial focus is to treat patients with CX-801 in the late-line setting to potentially re-activate the immune system and improve patient outcomes in combination with PD-1 inhibition.

Our ultimate vision for CX-801 is to potentially become a cornerstone of combination immunotherapy for a wide range of tumor types, including cancers beyond melanoma.

CX-801 Development

The IND for CX-801 was allowed to proceed by the FDA in January 2024, and in the third quarter of 2024 the first patient was dosed in the CX-801 Phase 1 dose escalation study in solid tumors.

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In Phase 1 dose escalation, the study will evaluate safety, translational biomarkers and signs of clinical activity for CX-801 monotherapy and in combination with KEYTRUDA ® .

In second quarter of 2024, CytomX announced a clinical collaboration with Merck to supply KEYTRUDA for evaluation of its combination with CX-801 in the Phase 1 study.

The Phase 1 study is currently in the fourth monotherapy dose escalation cohort where the dose of CX-801 exceeds the approved dose of the unmasked peginterferon alfa-2b (SYLATRON).

Initial Phase 1a translational data in advanced melanoma is expected in the second half of 2025.

In 2022, we advanced our first TCE into the clinic.

CX-904, which was partnered with Amgen, is a conditionally activated TCE against EGFR and CD3.

In preclinical studies, CytomX’s PROBODY EGFRxCD3 TCE demonstrated anti-tumor activity and better tolerability when compared to TCEs without PROBODY masking.

In May 2022, the first patient was dosed in a Phase 1 study evaluating CX-904 as a treatment for patients with advanced solid tumors.

On May 8, 2024, we reported initial Phase 1a data for CX-904 based on an April 16, 2024 data cutoff.

As of the data cutoff, the CX-904-101 study had enrolled 35 patients with advanced metastatic solid tumor types that are generally known to express EGFR, including pancreatic, CRC, non-small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), gastric, and esophageal cancers.

Patients enrolled in the study were heavily pre-treated and had a median of 4 prior lines of therapy.

19 patients were enrolled into initial non-step dosing cohorts with target doses ranging from 0.007 mg to 6 mg, and 16 patients were subsequently enrolled into step-dosing cohorts with target doses ranging from 5 mg to 10 mg and with tocilizumab prophylaxis.

As of the April 16, 2024 data cutoff, enrollment into a cohort with a target dose of 15 mg was ongoing.

As of the cutoff date, CX-904 demonstrated a favorable safety profile.

There were no observed cases of cytokine release syndrome (CRS) of any grade in step-dosing cohorts as of the cutoff date.

In non-step dosing cohorts, only Grade 1 CRS was observed in patients treated at the highest dose of 6 mg.

Overall, the most common treatment-related adverse events (TRAEs) were rash, arthralgia, arthritis, pruritis, and vomiting, the majority of which were low grade, being observed in 14 (40%), 13 (37%), 5 (14%), 5 (14%) and 5 (14%) of patients, respectively.

Grade 3 adverse events were tenosynovitis (n=1), arthralgia (n=2), arthritis (n=1), rash (n=1).

As of the April 16, 2024 data cutoff, 8 patients had measurable tumor reduction per RECIST 1.1, including 2 of 6 efficacy-evaluable patients (33%) with pancreatic cancer with confirmed partial responses.

All 6 efficacy-evaluable patients with pancreatic cancer achieved disease control (objective response or stable disease).

For the two patients with a confirmed partial response, one patient (6 mg target dose) achieved an 83% tumor reduction.

A second patient (5 mg target dose) with a confirmed response achieved a 51% tumor reduction and remained on study treatment as of the data cutoff.

In addition, a third pancreatic cancer patient maintained stable disease with no evidence of tumor growth through 3.5 months of study treatment, and remained on treatment as of the data cutoff.

Preliminary pharmacokinetic and pharmacodynamic data were consistent with the PROBODY TCE mechanism of action, including maintained masking in circulation, and CD8+ T-cell margination and tumor infiltration.

As of the end of 2024, the Phase 1 study of CX-904 had enrolled over 70 patients.

The 15 mg target step-dose level had been cleared and the maximum tolerated dose had not been reached.

Patient enrollment in 2025 had prioritized escalation to higher dose levels.

However, in March 2025, based on CX-904 clinical observations to-date as well as CytomX pipeline priorities, CytomX and Amgen jointly decided to not further develop the CX-904 program.

We are also continuously engaged in drug discovery efforts towards the generation of new clinical candidates across multiple modalities for the treatment of cancer, including additional ADCs, Cytokines, TCEs, and mRNAs reflecting the versatility of our PROBODY platform.

We do not have any products approved for sale, and we continue to incur significant research and development and general administrative expenses related to our operations.

In the second quarter of 2024, CytomX announced a clinical collaboration with Merck to supply KEYTRUDA for evaluation of its combination with CX-801 in the Phase 1 study.

The Phase 1 study is currently in the fourth monotherapy dose escalation cohort.

In May 2025, Phase 1 dose escalation enrollment of CX-801 in combination with KEYTRUDA ® (pembrolizumab) in advanced melanoma was initiated and is currently enrolling at the second dose level.

Phase 1 CX-801 monotherapy translational data in melanoma patients was presented at the Society of Immunotherapy of Cancer (“SITC”) 2025 Annual Meeting in November 2025, providing evidence that the CX-801 mechanism of action was working as designed.

As of the November 8, 2025 SITC presentation, CX-801 had been generally well tolerated and the translational data presented suggest consistently increased expression of interferon-stimulated genes in paired tumor biopsies.

Upregulation of immune checkpoint genes, including PD-1 and PD-L1, and activation of immune cell populations, was also observed, providing a rationale for evaluating the combination of CX-801 and pembrolizumab.

Pharmacokinetics (“PK”) analysis also demonstrated dose-proportional

exposure of CX-801, which remained predominantly in its intact (masked) form in circulation.Phase 1 clinical data from the CX-801 and KEYTRUDA ® combination dose escalation portion of the study are expected by the end of 2026.

Preclinical PROBODY Program and Platform

In addition to our clinical program focus on PROBODY ADCs such as Varseta-M and PROBODY cytokines such as CX-801, we view the field of masked biologics as having broad potential applicability across a range of therapeutic modalities, reflecting the versatility of our platform technology.

A key focus of our current work with collaboration partners is T-cell engaging bispecific therapies (“TCEs”) where we have significant ongoing efforts with partners such as Bristol Myers Squibb and Regeneron and maintain significant research expertise.

For example, at SITC 2025, we presented preclinical data for CX-908, a dually-masked PROBODY TCE targeting CDH3 and CD3.

CX-908 potently induced tumor regressions in established breast and lung cancer xenograft tumor models and demonstrated a 100-fold improvement in tolerability, including significantly reduced cytokine release vs.

an unmasked CDH3xCD3 molecule.

We view masking as a key strategy to widen a therapeutic window for TCEs and view strategic partnering in this area as an important way to extend the reach of the PROBODY platform.

We do not have any products approved for sale, and we continue to incur significant research and development as well as general and administrative expenses related to our operations.

As of December 31, 2025 and 2024, we had an accumulated deficit of $711.9 million and $691.6 million, respectively.

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Restructuring

On January 6, 2025, the Company announced a restructuring plan (the “2025 Restructuring Plan”) to streamline its organization and prioritize CX-2051 and its activities to support its research collaborations.

The restructuring plan will result in a reduction to its workforce by approximately 40% and is expected to be substantially completed in the first quarter of 2025.

On January 6, 2025, we announced a restructuring plan (the “2025 Restructuring Plan”) to streamline our organization and prioritize Varseta-M, CX-801 and our activities to support our research collaborations.

The restructuring plan resulted in a reduction of approximately 40% of our workforce and was substantially completed in the first quarter of 2025.

We recorded total restructuring charges of approximately $2.8 million, primarily related to one-time severance payments and other employee-related costs.

This includes $1.7 million of research and development expenses and $1.1 million of general and administrative expenses that were recorded for the year ended December 31, 2025.

Components of Results of Operations

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For the foreseeable future, we do not expect to generate any revenue from the sale of products unless and until such time as our product candidates have advanced through clinical development and obtained regulatory approval.

We expect that any revenue we generate in the foreseeable future will fluctuate from year to year as a result of the timing and amount of milestones and other payments from our collaboration agreements with Amgen, Astellas, Bristol Myers Squibb, Regeneron, Moderna and any other collaboration partners, and as a result of the fluctuations in the research and development expenses we incur in the performance of assigned activities under these agreements.

AbbVie, one of our previous collaboration partners, entered into a license agreement with Seagen Inc.

(“SGEN”) to license certain intellectual property rights.

As part of the collaboration agreement with AbbVie, we received a sublicense to these intellectual property rights and therefore paid SGEN sublicense fees.

These sublicense fees were treated as reductions to the transaction price and combined with the performance obligation to which they relate.

Milestone payments, when considered probable of being reached and when a significant revenue reversal would not be probable of occurring, are also recorded net of the associated sublicense fees and included in the transaction price.

We expect that any revenue we generate in the foreseeable future will fluctuate from year to year as a result of the timing and amount of milestones and other payments from our collaboration agreements with Astellas, Regeneron, Bristol Myers Squibb, Moderna and any other collaboration partners, and as a result of the fluctuations in the research and development expenses we incur in the performance of assigned activities under these agreements.

Research and Development Expenses

Our research and development expenses consist primarily of costs incurred to conduct research, such as the discovery and development of our product candidates, clinical development, including activities with third parties, such as contract research organizations (“CRO”) and contract development and manufacturing organizations (“CMO”), and the manufacture of drug products used in clinical trials, as well as the development of product candidates pursuant to our research, collaboration and license agreements.

Our research and development expenses consist primarily of costs incurred to conduct research, such as the discovery and development of our product candidates, clinical development, including activities with third parties, and contract development and manufacturing organizations (“CMO”), and the manufacture of drug products used in clinical trials, as well as the development of product candidates pursuant to our research, collaboration and license agreements.

Research and development expenses include personnel costs, including stock-based compensation expense, contractor services, laboratory materials and supplies, depreciation and maintenance of research equipment, and an allocation of related facilities costs.

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The process of conducting the necessary clinical research to obtain regulatory approval is costly and time-consuming.

actual probability of success for our product candidates may be affected by a variety of factors including:

The actual probability of success for our product candidates may be affected by a variety of factors including:

the safety and efficacy of our product candidates, early clinical data, investment in our clinical program, the ability of collaborators to successfully develop our licensed product candidates, competition, manufacturing capability and commercial viability.

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Allocated expenses primarily consist of rent expense related to our office and information technology related costs.

Interest Income

Interest income primarily consists of interest income from our cash equivalents and investments, and accretion of discounts or amortization of premiums on our investments.

Other Income (Expense), Net

Other income (expense), net consists primarily of gains and losses resulting from changes to currency exchange rates.

Income taxes are recorded in accordance with ASC 740 , Accounting for Income Taxes, or ASC 740 , which provides for deferred taxes using an asset and liability approach.

We recognize deferred tax assets and liabilities for the expected future tax consequences of events that have been included in our financial statements or tax returns.

We determine our deferred tax assets and liabilities based on differences between the financial reporting and tax bases of assets and liabilities, which are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse.

Valuation allowances are provided, if based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.

We also account for uncertain tax positions in accordance with the provisions of ASC 740 .

When uncertain tax positions exist, we recognize the tax benefit of tax positions to the extent that the benefit will more likely than not be realized.

The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances.

The state of California contested our tax position on revenue apportionment for upfront and milestone payments resulting from our collaboration and licensing agreements for the years 2017 and 2018.

We received a proposed assessment in September 2023 and filed a protest to contest the proposed assessment in November 2023.

We recorded an uncertain tax position of $4.1 million and $3.9 million in long term liabilities for the proposed tax assessment, penalties and interest through December 31, 2024 and 2023, respectively.

Comparison of Years Ended December 31, 2025 and 2024

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Total Revenue

The increase in revenue of $36.9 million for 2024 compared to 2023 was primarily due to:

• An increase in revenue under the BMS Agreement driven by higher percentage of completion of the existing targets.

The contractual research term under the BMS agreement concludes in the second quarter of 2025, at which point the performance obligation and corresponding revenue recognition are expected to be complete and BMS will be responsible for the future research and development of the collaboration programs;

• An increase in revenue under the Regeneron Agreement due to increased preclinical work and a higher percentage completion in the second full year of the collaboration which commenced preclinical research in 2023;

• An increase in revenue under the Moderna Agreement due to increased preclinical work and a higher percentage of completion in the second full year of the collaborations which commenced in 2023.

The $9.3 million of remaining Moderna deferred revenue is expected to be recognized by 2027, principally in 2026 and 2027 due to Moderna's budget considerations in 2025;

• An increase in revenue under the Astellas Agreement primarily driven by two milestone payments of $5.0 million each, triggered in March 2024.

One was related to the nomination of a second clinical candidate while the other was related to the milestone achievement of GLP toxicology study initiation for the first clinical candidate.

Astellas revenue in the first quarter of 2023 included the $5.0 million milestone for the first clinical candidate nomination achieved in the collaboration.

In the first quarter of 2025, Astellas initiated GLP toxicology studies for the second collaboration target nominated triggering a $5.0 million milestone payment to CytomX in the first quarter of 2025;

• A decrease in revenue under the Amgen Agreement primarily due to an increase in projected hours to completion.

In March 2025, Amgen terminated its license to the EGFR Product;

• A decrease in revenue under the AbbVie Agreement due to termination of the agreement in March 2023.

The decrease in revenue of $61.9 million for 2025 compared to 2024 was primarily due to:

• A decrease in revenue under the BMS Agreement driven by the completion of our performance obligations in the second quarter of 2025.

BMS is responsible for the future research and development of the ongoing collaboration programs;

• A decrease in revenue under the Astellas Agreement primarily driven by an increase in projected hours to completion for our performance obligation and higher preclinical milestone payments in 2024 compared to 2025.

In the first quarter of 2026, Astellas chose not to advance the remaining preclinical programs which will result in the completion of CytomX’s performance obligation by the second quarter of 2026;

• A decrease in revenue under the Regeneron Agreement driven by a primary focus on the lead preclinical program in 2025;

• A decrease in revenue under the Moderna Agreement due to a pause of the programs, driven by Moderna's budget considerations in 2025.

The remaining research and development activities are pending Moderna's budget considerations;

partially offset by;

• The recognition of all remaining deferred revenue under the Amgen Agreement resulting from Amgen terminating its license to the EGFR Product effective May 2025.

Operating Costs and Expenses

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CX-904 (EGFRxCD3)

CX-2051 (EpCAM)

CX-801 (IFNα2b)

CX-2029 (CD71)

Other wholly owned and partnered programs

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Total research and development expenses

Research and development expenses increased by $5.7 million for 2024, compared to 2023 primarily driven by

• a $5.0 million milestone payment to AbbVie (formerly ImmunoGen) in the current period, included in the general research and development expenses, for dosing the first patient for CX-2051 in Phase 1 under the ImmunoGen 2019 License Agreement;

• increase in manufacturing and clinical related activities for the CX-2051 program and clinical trial activities for the CX-904 program;

• increase in consulting expenses, offset by

• decrease in manufacturing activities and laboratory contract services for the CX-801 program and winding down of clinical study activities related to legacy programs, including CX-2029 and

• decrease in personnel related expenses.

Due to the 2025 Restructuring Plan to streamline the organization and reduce our workforce by approximately 40%, internal research and development costs are expected to be lower in 2025.

The decrease in research and development expenses of $14.7 million for 2025 compared to 2024 was primarily due to:

• reduced general research and development expenses as a result of the January 2025 restructuring;

• a reduction in CX-904 spend due to program deprioritization in 2025;

• a one-time milestone payment of $5.0 million to ImmunoGen in prior year;

partially offset by

• higher Varseta-M manufacturing and clinical spend;

• one-time restructuring expenses of $1.7 million which were primarily included in internal costs.

External research and development expenses are expected to be primarily focused on Varseta-M and CX-801 in 2026.

General and Administrative Expenses

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General and administrative

General and administrative expenses decreased by $0.3 million for 2024, compared to 2023 primarily due to lower personnel related expenses and lower rent as a result of partial sublease of the Company’s headquarters which started in March 2023, partially offset by higher professional services and consulting spend supporting areas including intellectual property and internal controls.

Due to the 2025 Restructuring Plan to streamline the organization and reduce our workforce by approximately 40%, general and administrative expenses are expected to be lower in 2025.

General and administrative expenses remained flat for 2025 compared to 2024, primarily driven by $1.1 million of one-time restructuring expenses partially offset by reduced personnel related expenses and legal and consulting related expenses.

Restructuring

During 2025, we recognized aggregate restructuring cost of approximately $2.8 million, primarily related to severance and benefits.

This included $1.7 million in research and development expenses and $1.1 million in general and administrative expenses.

The restructuring was substantially completed in the first quarter of 2025.

Interest Income and Other Income (Expense), Net

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Interest income decreased by $1.9 million during 2025 compared to 2024.

The decrease was primarily driven by lower interest rates and the lower cash and cash equivalents and short-term investments position as compared to 2023.

Year Ended December 31,

(in thousands)

Provision for income taxes

The $0.2 million tax provision represented the interest accrued for 2024, related to the proposed assessment received from the state of California for the years 2017 and 2018.

The $3.9 million tax provision for 2023 represented the uncertain tax position related to such proposed assessment, including penalties and interest through December 31, 2023.

The decrease was primarily driven by lower interest rates.

Liquidity and Capital Resources

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To date, we have financed our operations primarily through sales of our common stock in conjunction with the IPO, subsequent stock offerings and through our at-the-market offering, sales of our convertible preferred securities prior to our IPO, payments received under our collaboration agreements and proceeds from private placements of our common stock, warrants and pre-funded warrants.

In July 2023, we completed a private placement and issued pre-funded warrants to purchase an aggregate of 14,423,077 shares of common stock, accompanying Tranche 1 warrants to purchase up to 5,769,231 shares of common stock and accompanying Tranche 2 warrants to purchase up to 5,769,231 shares of common stock, at a combined price of $2.08 per share.

We received gross proceeds of approximately $30.0 million.

In March 2024, we achieved a clinical candidate milestone for a second collaboration target as well as the GLP toxicology studies milestone for the first collaboration target nominated in January 2023 under the Astellas Agreement;

We collected the two milestone payments totaling $10.0 million in April 2024.

In 2024, we sold 3,925,202 shares at a weighted average price of $1.8 per share under our at-the-market ("ATM") offering and received net proceeds of approximately $6.9 million after deducting the 3.0% sales commission and related issuance cost.

As of December 31, 2024, $56.2 million remained available for sale under the Sales Agreement.

On January 6, 2025, we announced the 2025 Restructuring Plan to streamline our organization and prioritize CX-2051 investment and activities to support our research collaborations.

The restructuring plan will result in a reduction to our workforce by approximately 40% and is expected to be substantially completed in the first quarter of 2025.

Based upon our current operating plan, we expect our existing capital resources will be sufficient to fund operations into the second quarter of 2026.

as a result, we collected the two milestone payments totaling $10.0 million in April 2024.

In the first quarter of 2025, we achieved the GLP toxicology studies for the second collaboration target nominated in March 2024 under the Astellas Agreement.

As a result, we collected the $5.0 million milestone payment in March 2025.

On January 6, 2025, we announced the 2025 Restructuring Plan to streamline our organization and prioritize Varseta-M investment and activities to support our research collaborations.

The 2025 Restructuring Plan resulted in a reduction to our workforce by approximately 40% and was substantially completed in the first quarter of 2025.

In February 2020, we initiated an at-the-market offering program (“ATM”) pursuant to a sales agreement with Jefferies, LLC (as amended on March 4, 2022 and August 9, 2024, the “Sales Agreement”).

In 2024, we sold 3,925,202 shares at a weighted average price of $1.82 per share under our ATM offering for net proceeds of approximately $6.9 million after deducting sales commissions and related issuance cost.

In 2025, we sold 4,872,861 shares at a weighted average price of $3.44 per share under our ATM offering for net proceeds of approximately $16.3 million after deducting sales commissions and related issuance cost.

In May 2025, we completed an underwritten public offering of 76,923,076 shares of common stock at a price of $1.30 per share and received net proceeds of approximately $93.4 million, after deducting underwriting discounts and commissions of $6.0 million and offering expenses of $0.6 million.

Based upon our current operating plan and liquidity requirements, we expect our existing capital resources will be sufficient to fund operations into the second quarter of 2027.

However, if the anticipated operating results are not achieved in future periods, our planned expenditures may need to be reduced in order to extend the time period over which the then-available resources would be able to fund the operations.

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As such, we may alter our expenditures as a result of contingencies such as the failure of one or all of our product candidates currently in clinical development, the acceleration of one or all of our product candidates in clinical development, the initiating of clinical trials for additional product candidates, the identification of more promising product candidates in our research efforts or unexpected operating costs and expenditures.

We will need to raise additional funds in the future.

We will need to raise additional capital to fund our operations in the future.

There can be no assurance, however, that such efforts will be successful;

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Cash Flows from Operating Activities

During the year ended December 31, 2024, cash used in operating activities was $86.2 million, which consisted of a net income of $31.9 million and non-cash charges of $8.3 million, adjusted by a net decrease of $126.4 million relating to the change of our net operating assets and liabilities, The non-cash charges primarily consisted of $7.7 million in stock-based compensation, $4.1 million in non-cash lease expense, $1.7 million in depreciation and amortization and $0.1 million impairment loss, partially offset by $5.3 million in net accretion of discounts on our investments.

The change in our net operating assets and liabilities was primarily due to:

• a net decrease of $118.3 million in deferred revenue resulting from the continued recognition of deferred revenue from existing and new customers;

• a decrease of $9.9 million in accounts payable, accrued and other long-term liabilities primarily due to timing of payments;

• an increase of $1.8 million in cash flows from accounts receivable, prepaid and other current assets primarily due to decrease in advance payments.

During the year ended December 31, 2023, cash used in operating activities was $$56.0 million, which consisted of a net loss of $0.6 million and a net decrease of $62.4 million relating to the change of our net operating assets and liabilities, offset by non-cash charges of $7.0 million.

The non-cash charges primarily consisted of $8.6 million in stock-based compensation, $3.7 million in non-cash lease expense and $2.1 million in depreciation, amortization, and impairment charges, offset by $7.4 million in net accretion of discounts on our investments.

The change in our net operating assets and liabilities was primarily due to:

• a net decrease of $89.0 million in deferred revenue resulting from the continued recognition of deferred revenue from existing and new customers;

• a decrease of $8.5 million in accounts payable, accrued and other long-term liabilities primarily due to decrease of payroll-related expenses, restructuring related expenses, and laboratory contract services;

• an increase of $32.6 million in cash flows from accounts receivable primarily related to the receipt of the $35.0 million upfront payment and prepaid research under the Moderna agreement entered into in December 2022.

• an increase of $2.5 million in cashflows from prepaid and other current assets primarily due to a decrease in advance payments to our third party manufacturing vendors and timing of payments.

Net cash used in operating activities of $75.6 million and $86.2 million for 2025 and 2024, respectively, was largely due to ongoing research and development activities and general and administrative expenses to support those activities.

Net loss for 2025 and net income for 2024 included, among other items, non-cash charges of stock-based compensation, non-cash lease expense, depreciation and amortization and impairment loss, partially offset by net accretion of discounts on short-term investments.

Cash Flows from Investing Activities

During year ended December 31, 2024, cash provided by investing activities was $99.7 million, which consisted of $255.5 million of proceeds from the maturities of short term investments partially offset by $155.5 million used in the purchase of short-term investments and $0.3 million of capital expenditures used to purchase property and equipment.

During year ended December 31, 2023, cash provided by investing activities was $150.7 million, which consisted of $424.8 million used in the purchase of short-term investments and $0.8 million of capital expenditures used to purchase property and equipment, partially offset by $275.0 million in proceeds received upon the maturity of marketable securities .

During the year ended December 31, 2025, net cash used in investing activities was $59.7 million, primarily due to increased purchases of short term investments following the funds received from our equity via the underwritten public issuance offering in May 2025 and from our ATM program.

These purchases were partially offset by proceeds from the maturities of marketable securities.

During the year ended December 31, 2024, net cash provided by investing activities was $99.7 million, primarily due to proceeds from the maturities of short term investments partially offset by purchases of short-term investments.

Cash Flows from Financing Activities

During the year ended December 31, 2024, cash provided by financing activities consisted of $6.9 million of net proceeds from issuance of common stock, net of issuance cost, and $0.6 million of proceeds from the exercise of stock options and employee stock purchases under the employee stock purchase plan (“ESPP”).

During the year ended December 31, 2023, cash provided by financing activities consisted of $29.7 million of net proceeds from issuance of pre-funded warrants and warrants and $0.6 million of proceeds from the exercise of stock options and employee stock purchases under the ESPP.

During the year ended December 31, 2025, net cash provided by financing activities of $110.4 million was primarily due to net proceeds from equity issuance via the underwritten public issuance offering in May 2025 and under our ATM program.

During the year ended December 31, 2024, net cash provided by financing activities of $7.5 million was primarily due to net proceeds from issuance of common stock, net of issuance cost.

Contractual Obligations

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License maintenance fees (3)

Milestone Payments (4)

Total contractual obligations

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The lease provides us with one option to extend the lease term for a period of five years at the then fair market rental value.

Financial Statements and Supplementary Data, Note 11 - “Leases" in the accompanying Notes to the financial statements for more information.

(2) We have minimum royalty obligations under the terms of certain exclusive licensed patent rights.

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Financial Statements and Supplementary Data, Note 9 - “License Agreement” in the accompanying Notes to the financial statements for more information.

Sublicense fees payable to UCSB for potential milestones that are probable to be earned by the Company in 2025 are not included.

(3) We have annual license maintenance fees under the terms of certain license agreement with UCSB and SGEN.

Financial Statements and Supplementary Data, Note 9 - “License Agreement” in the accompanying Notes to the financial statements for more information.

(4) We have development milestone payments under the terms of certain license agreements.

A development milestone is payable upon initiation of GLP toxicology studies for a nominated collaboration target, which we expect to occur in the first quarter of 2025.

Sublicense fees payable to UCSB for potential milestones that are probable to be earned by us in 2026 are not included.

(3) We have annual license maintenance fees under the terms of certain license agreement with UCSB.

Financial Statements and Supplementary Data, Note 9 - “License Agreement” in the accompanying Notes to the financial statements for more information.

We enter into agreements in the normal course of business with CROs for clinical trials and with vendors for pre-clinical studies and other services and products for operating purposes, which are cancelable at any time by us, generally upon 30 to 60 days prior written notice.

We enter into agreements in the normal course of business with vendors for clinical and pre-clinical studies and other services and products for operating purposes, which are cancelable at any time by us, generally upon 30 to 180 days with prior written notice.

These payments are not included in the above table of contractual obligations.

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There have been changes in estimates of research service periods and/or the related estimated FTE hours-to-completion of certain of our research development programs in each reporting period.

For example, changes in our estimated research service period resulted in recognition of higher total revenue of $27.4 million for certain programs in aggregate and lower total revenue of $9.5 million for other programs in aggregate, for 2024, as compared to the estimates in place at the end of 2023.

Such adjustments have impacted and will continue to impact the amounts and timing of our revenue recognized.

Such adjustment is accounted for on a prospective basis in our revenue recognition.

Changes in our

estimated research service periods resulted in recognition of higher total revenue of $13.8 million for 2025 as compared to the estimated research service periods in place at the end of 2024, and a decrease of net loss per share by $0.10 for 2025.

Any consideration payable to our customers is treated as a reduction to the transaction price and revenue, unless the payment to the customer is in exchange for distinct good and services.

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We record accrued liabilities for estimated costs of research, preclinical and clinical studies and contract manufacturing activities, which are a significant component of research and development expenses.

A substantial portion of our ongoing research and development activities is conducted by third-party service providers, including CROs.

Our contracts with CROs generally include pass-through costs, such as regulatory expenses, investigator fees, travel costs and other miscellaneous costs.

The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payments that do not match the periods over which materials or services are provided to us under such contracts.

A substantial portion of our ongoing research and development activities is conducted by third-party service providers.

We accrue the costs incurred under agreements with these third parties based on actual work completed in accordance with the respective agreements.

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We determine the estimated costs through discussions with internal personnel and external service providers as to the progress of stage of completion of the services and the agreed-upon fees to be paid for such services.

We make significant judgments and estimates in determining the accrual balance in each reporting period.

As actual costs become known, we adjust our accruals.

Although we do not expect our estimates to be materially different than the actual amounts incurred, such estimates for the status and timing of services performed relative to the actual status and timing of services performed may vary and could result in us reporting amounts that are too high or too low in any one period.

Our accrual is dependent, in part, upon the receipt of timely and accurate reporting from CROs and other third-party vendors.

Variations in the assumptions used to estimate accruals including, but not limited to, the number of patients enrolled, the rate of patient enrollment and the actual services performed, may vary from our estimates, resulting in adjustments to clinical trial expenses in future periods.

We make estimates in determining the accrual balance in each reporting period.

As actual costs become known, we adjust our accruals accordingly.

While we do not expect our estimates to differ materially from the actual amounts incurred, differences in the status and timing of services performed relative to vendor reporting and invoicing may result in modest period‑to‑period variability.

Our accruals depend, in part, on the timely and accurate reporting of services performed by third‑party vendors.

Differences between estimated and actual amounts, including but not limited to those related to patient enrollment levels, enrollment timing, and services performed, may result in adjustments to clinical trial expenses in future periods.

Uncertain Tax Position

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We recorded an uncertain tax position of $4.4 million in long term liabilities for the proposed tax assessment, penalties and interest through December 31, 2025.

Additional utilization of carryforward attributes and indirect federal tax effects of the assessment would result in a reduction in deferred tax assets of $5.1 million.

We filed a protest to contest the proposed

assessment in November 2023.

Additional utilization of carryforward attributes and indirect federal tax effects of the assessment would result in a reduction in deferred tax assets of $5.0 million as of December 31, 2025.

We filed a protest to contest the proposed assessment in November 2023.

Due to the ongoing nature of the examination and discussions with the state of California, we are unable to estimate a date by which this matter will be resolved.

Quantitative and Qualitat ive Disclosures about Market Risk

We are a smaller reporting company as defined by Rule 12b-2 of the Securities Exchange Act of 1934, or the Exchange Act, and are not required to provide the information under this item.

We are exposed to market risks in the ordinary course of our business.

These risks primarily relate to interest rate risks.

We had cash, cash equivalents and investments of $137.1 million and $100.6 million as of December 31, 2025 and 2024, respectively, which consists of bank deposits, money market funds and U.S.

Treasury securities.

Such interest-bearing instruments carry a degree of interest rate risk;

however, historical fluctuations of interest income have not been significant.

We do not enter into investments for trading or speculative purposes and have not used any derivative financial instruments to manage our interest rate exposure.

We have not historically been exposed to material risks due to changes in interest rates.

Based on our investment positions as of December 31, 2025, a hypothetical 100 basis point change in interest rates would not have a material effect in the fair value of the portfolio.

We are also exposed to foreign currency exchange risk related to foreign currency-based expenses.

To date, foreign currency transaction gains and losses have not been material to our financial statements.

We do not currently hedge our foreign currency exposure.

Financial Stateme nts and Supplementary Data

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Statements of Operations and Comprehensive Income (Loss)

Statements of Stockholders’ Deficit

Statements of Stockholders’ Equity (Deficit)

Statements of Cash Flows

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We have audited the accompanying balance sheets of CytomX Therapeutics, Inc.

(the Company) as of December 31, 2024 and 2023, the related statements of operations and comprehensive income (loss), stockholders’ deficit and cash flows for the years then ended, and the related notes (collectively referred to as the “financial statements”).

In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2024 and 2023, and the results of its operations and its cash flows for the years then ended, in conformity with U.S.

(the Company) as of December 31, 2025 and 2024, the related statements of operations and comprehensive income (loss), stockholders’ equity (deficit) and cash flows for each of the two years in the period ended December 31, 2025, and the related notes (collectively referred to as the “financial statements”).

In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2025, in conformity with U.S.

generally accepted accounting principles.

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Our responsibility is to express an opinion on the Company's financial statements based on our audits.

We are a public accounting firm registered with PCAOB and are required to be independent with respect to the Company in accordance with the U.S.

We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S.

federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

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Amounts received under these arrangements typically include nonrefundable upfront payments and license fees, research funding, milestone and other contingent payments for the achievement of defined collaboration objectives and certain preclinical, clinical, regulatory and sales-based events, as well as royalties on sales of any commercialized products.

Auditing the Company’s accounting for revenue from collaboration agreements was complex and required significant judgments primarily in evaluating estimates of the total expected inputs (hours) under the input method for revenue recognized over time.

Auditing the Company’s accounting for revenue from collaboration agreements required judgment primarily in evaluating estimates of the total expected inputs (hours) under the input method for revenue recognized over time.

How We Addressed the Matter in Our Audit

We obtained an understanding, evaluated the design and tested the operating effectiveness of the controls over the determination of the actual hours incurred for each performance obligation for the period, management’s estimate of the total expected hours to be incurred for each performance obligation, and the calculation and recognition of revenue for each performance obligation.

To test the recognition of revenue from collaboration agreements, our audit procedures included, among others, testing a sample of cash receipts, confirming a sample of receivables, reviewing management’s analysis for accuracy and completeness by agreeing data to the underlying contract, inspecting research or steering committee minutes, testing the application of the input method for the recognition of revenue, including testing the actual hours incurred and management’s estimate of the total hours to be incurred for each performance obligation for revenue recognized over time.

To test the recognition of revenue from collaboration agreements, our audit procedures included, among others, reviewing management’s analysis for accuracy and completeness by agreeing data to the underlying contract, inspecting research or steering committee minutes, and testing the application of the input method for the recognition of revenue, including testing the actual hours incurred and management’s estimate of the total hours to be incurred for each performance obligation for revenue recognized over time.

/s/ Ernst & Young LLP

We have served as the Company’s auditor since 2017.

San Jose, California

San Francisco, California

March 16, 2026

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Stockholders and the Board of Directors of CytomX Therapeutics, Inc.

To the Stockholders and Board of Directors of CytomX Therapeutics, Inc.

Opinion on Internal Control Over Financial Reporting

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(the Company) maintained, in all material respects, effective internal control over financial reporting as of December 31, 2025, based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the balance sheets of the Company as of December 31, 2024 and 2023, the related statements of operations and comprehensive income (loss), stockholders’ deficit and cash flows for the years then ended, and the related notes and our report dated March 6, 2025 expressed an unqualified opinion thereon.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the balance sheets of the Company as of December 31, 2025 and 2024, the related statements of operations and comprehensive income (loss), stockholders’ equity (deficit) and cash flows for each of the two years in the period ended December 31, 2025, and the related notes and our report dated March 16, 2026 expressed an unqualified opinion thereon.

Basis for Opinion

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/s/ Ernst & Young LLP

San Jose, California

San Francisco, California

March 16, 2026

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Operating lease right-of-use asset

Liabilities and Stockholders' Deficit

Liabilities and Stockholders' Equity (Deficit)

Current liabilities

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Operating lease liabilities - short term

Deferred revenues, current portion

Deferred revenue, current portion

Total current liabilities

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Commitments and contingencies (Note 10)

Stockholders' deficit

Stockholders' equity (deficit)

Convertible preferred stock, $ 0.00001 par value;

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Accumulated deficit

Total stockholders' deficit

Total liabilities and stockholders' deficit

Total stockholders' equity (deficit)

Total liabilities and stockholders' equity (deficit)

See accompanying notes to financial statements

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Other income (expense), net

Income before income taxes

Income (loss) before income taxes

Provision for income taxes

Net income (loss)

Deemed dividend on warrants

Net income (loss) attributable to common stockholders

Other comprehensive income (loss):

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Net income (loss) per share:

Shares used to compute net income (loss) per share

Weighted average common shares used to compute net income (loss) per share

See accompanying notes to financial statements

CYTOMX THERAPEUTIC, INC.

STATEMENTS OF STOCKHOLDERS' DEFICIT

STATEMENTS OF STOCKHOLDERS' E QUITY (DEFICIT)

(in thousands, except share and per share data)

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Income/(Loss)

Equity (Deficit )

Balance at December 31, 2023

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Issuance of common stock under the Employee Stock Purchase Plan

Issuance of pre-funded warrants and warrants, net of issuance cost

Issuance of common stock under the Open Market Sale Agreement, net of issuance cost

Exercise of pre-funded warrants

Stock-based compensation

Other comprehensive income

Other comprehensive loss

Balance at December 31, 2024

Exercise of stock options and release of RSUs

Issuance of common stock under the Employee Stock Purchase Plan

Issuance of common stock under the ESPP

Issuance of common stock under the Open Market Sale Agreement, net of issuance cost

Issuance of common stock in follow on offering, net of issuance cost

Exercise of pre-funded warrants

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Other comprehensive income

Deemed dividend on warrants

Balance at December 31, 2025

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Purchases of property and equipment in accounts payable and accrued liabilities

Supplemental disclosures of noncash financing items:

Deemed dividend on warrants

See accompanying notes to financial statements

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The Company is advancing potential first-in-class and best-in-class therapeutics created using its PROBODY ® therapeutic technology platform that could meaningfully improve outcomes for cancer patients.

Its proprietary and unique PROBODY technology platform is designed to enable “conditional activation” of masked antibody-based drugs in the tumor microenvironment across multiple therapeutic modalities.

Its proprietary and unique PROBODY technology platform is designed to enable “conditional activation” of masked drug candidates in the tumor microenvironment across multiple therapeutic modalities.

The Company is located in South San Francisco, California and was incorporated in the state of Delaware in September 2010.

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The Company considers all highly liquid investments purchased with original maturities of three months or less at the date of purchase to be cash equivalents.

Restricted cash represents a standby letter of credit issued pursuant to an office lease and value added tax return.

Restricted cash represents a standby letter of credit issued pursuant to office leases and value added tax return.

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that sum to the total of the amounts shown in the statements of cash flows:

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Expected cash inflows due to improvements in credit are recognized through a reversal of the allowance for credit losses subject to the total allowance previously recognized.

Interest receivable of $ 0.5 million and $ 22 thousand as of December 31, 2025 and 2024, respectively, primarily related to short term investments are included in p repaid expenses and other current assets.

In the event of impairment of any security, if management (i) has the intent to sell such security or (ii) will more-likely-than-not be required to sell such security before recovery of its amortized cost basis, such AFS debt security’s amortized cost basis will be written down to its fair value through earnings along with any existing allowance for credit losses.

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Impairment, if any, would be assessed using discounted cash flows or other appropriate measures of fair value.

During the years ended December 31, 2024 and 2023 , the Company recorded impairment loss of $ 0.1 million and $ 0 for long-lived assets.

During the years ended December 31, 2025 and 2024 , the Company recorded impairment loss of $ 0.4 million and $ 0.1 million for long-lived assets.

CYTOMX THERAPEUTICS, INC.

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The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

Most of the company's collaboration arrangements are related to delivering a combined performance obligation satisfied over time.

Revenue is recognized over the estimated research period using an input measure based on the actual full-time employee (“FTE”) hours incurred as a percentage of projected FTE hours for completing the performance obligation.

There have been changes in estimates of research service periods and/or the related estimated FTE hours-to-completion of certain of its research d evelopment programs in each reporting period.

Such adjustment is accounted for on a prospective basis in the Company's revenue recognition.

Changes in the estimated research service periods resulted in recognition of higher total revenue of $ 13.8 million for 2025 as compared to the estimated research service periods in place at the end of 2024, and a decrease of net loss per share by $ 0.10 for 2025.

Any consideration payable to the Company’s customers is treated as a reduction to the transaction price and revenue, unless the payment to the customer is in exchange for distinct good and services.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Comprehensive Income (Loss)

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The Company accrues for these costs based on factors such as estimates of the work completed and in accordance with agreements established with its third-party service providers under the service agreements.

The Company makes significant judgments and estimates in determining the accrued liabilities balance in each reporting period.

The Company makes judgments and estimates in determining the accrued liabilities balance in each reporting period.

As actual costs become known, the Company adjusts its accrued liabilities.

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The Company measures compensation expense for all stock-based payment awards, including employee stock options, restricted stock units (“RSUs”), and employee stock purchases related to Employee Stock Purchase Plan (“ESPP”) based on estimated fair values of the award at the grant date, and recognizes compensation expense over the requisite service vesting period.

Stock options forfeitures are accounted for in the period in which they occur.

Stock option forfeitures are accounted for in the period in which they occur.

To determine the fair value of a stock option award on the grant date, the Company uses the Black-Scholes option pricing model which consist of estimating variables such as the following.

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The Company elected the short-term lease recognition exemption.

The Company’s operating lease arrangement includes lease and non-lease components which are generally accounted for separately.

The Company’s operating lease arrangement includes lease and non-lease components which are accounted for as a single lease component.

The non-lease components generally refer to common area maintenance (“CAM” ) charges related to the premises.

Recent Accounting Pronouncements

In November 2024, the FASB issued ASU 2024-03, Disaggregation of Income Statement Expenses ("ASU 2024-03"), which enhances transparency in income statement disclosures.

ASU 2024-03 requires entities to disclose detailed information about specific components of income statement expenses, such as employee compensation, depreciation, and amortization, as well as other significant expense categories.

The objective is to provide financial statement users with greater insight into the nature and variability of expenses, improving their ability to analyze financial performance and make informed decisions.

This update applies to all entities, with public entities required to provide both quantitative and qualitative disclosures, while private entities may follow simplified disclosure requirements.

The amendments are effective for fiscal years beginning after December 15, 2025, with early adoption permitted.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740):

Improvements to Income Tax Disclosures (“ASU 2023-09"), which enhances transparency in income tax disclosures.

ASU 2023-09 require entities to disclose (1) specific categories in the rate reconciliation, (2) the income or loss from continuing operations before income tax expense or benefit (separated between domestic and foreign) and (3) income tax expense or benefit from continuing operations (separated by federal, state and foreign).

ASU 2023-09 requires entities to disclose (1) specific categories in the rate reconciliation, (2) the income or loss from continuing operations before income tax expense or benefit (separated between domestic and foreign) and (3) income tax expense or benefit from continuing operations (separated by federal, state and foreign).

ASU 2023-09 also requires entities to disclose their income tax payments to international, federal, state and local jurisdictions, among other changes.

The Company will adopt the ASU for its 2025 Form 10-K on a prospective basis.

The Company is evaluating the impact on its financial statements.

The Company has adopted this ASU as of December 31, 2025 on a prospective basis.

In November 2024, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2024-03, Disaggregation of Income Statement Expenses (“ASU 2024-03”), which enhances transparency in income statement disclosures.

ASU 2024-03 is effective for the annual reporting periods beginning after December 15, 2026 and for interim periods within annual reporting periods beginning after December 15, 2027 with early adoption permitted.

The Company expects to adopt this ASU during the year ended December 31, 2027 on a prospective basis and is currently evaluating the impact on its financial statements.

CYTOMX THERAPEUTICS, INC.

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Net Income (Loss) Per Share

Basic net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of shares of common stock outstanding for the period.

Basic net income (loss) per share is calculated by dividing the net income (loss) attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period.

Diluted net income (loss) per share is calculated using the weighted-average number of common shares outstanding, plus potential dilutive common stock during the period.

Diluted net loss per share is the same as basic net loss per share in the period when the effect of the potentially dilutive securities is anti-dilutive.

The pre-funded warrants are included in both the basic and diluted EPS calculation.

The pre-funded warrants were included in both the basic and diluted EPS calculation.

The following table presents the calculation of basic and diluted net income (loss) per share:

Year Ended December 31,

Net income (loss)

Net income (loss) attributable to common stockholders

Weighted-average common shares outstanding

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Common stock warrants

Total potentially dilutive weighted-average outstanding shares

Fair Value Measurements and Investments

In accordance with Accounting Standards Codification (“ASC”) 820-10, Fair Value Measurements and Disclosures, the Company determines the fair value of financial and non-financial assets and liabilities using the fair value hierarchy, which establishes three levels of inputs that may be used to measure fair value, as follows:

The Company determines the fair value of financial and non-financial assets and liabilities using the fair value hierarchy, which establishes three levels of inputs that may be used to measure fair value, as follows:

Inputs which include quoted prices in active markets for identical assets and liabilities.

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The Company’s financial instruments consist of Level I and Level II assets which consist primarily of highly liquid money market funds, some of which are included in restricted cash and U.S.

Treasury securities that are included in cash equivalent or short-term investments.

Treasury securities that are included in short-term investments.

Our Level II marketable securities are valued using third-party pricing sources, which can include observable market prices, interest rates and yield curves observable at commonly quoted intervals for similar assets as observable inputs for pricing.

The following tables set forth the fair value of the Company’s investments subject to fair value measurements on a recurring basis and the level of inputs used in such measurements:

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Treasury securities are less than a year.

Based on the scheduled maturities of our marketable securities, we determined that it was more likely than not that we will hold these marketable securities to maturity for a recovery of our cost basis.

Property and Equipment

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Depreciation and amortization expense was $ 1.2 million and $ 1.6 million for the years ended December 31, 2025 and 2024 , respectively.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Intangible Asset

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The amortization expense for each of the years ended December 31, 2025 and 2024 was $ 0.1 million.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

(in thousands)

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Legal and professional expenses

Restructuring expenses

Other accrued expenses

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Total revenue

AbbVie Ireland Unlimited Company

In April 2016, the Company and AbbVie entered into two agreements, a CD71 Co-Development and Licensing Agreement (the “CD71 Agreement”) and a Discovery Collaboration and Licensing Agreement (as amended and restated in June 2019, the “Discovery Agreement” and together with the CD71 Agreement the “AbbVie Agreements”).

Under the terms of the CD71 Agreement, the Company and AbbVie were co-developing a conditionally activated antibody-drug conjugate (“ADC”), CX-2029, against CD71, with the Company being responsible for preclinical and early clinical development.

AbbVie was to be responsible for later development and commercialization, with global late-stage development costs shared between the two companies.

Under the CD71 Agreement, t he Company has received in aggregate $ 100.0 million in upfront and milestone payments.

AbbVie had entered into a license agreement with Seattle Genetics, Inc.

(“SGEN”) to license certain intellectual property rights pursuant to which the Company was required to pay SGEN sublicense fees for certain milestone achievements and an annual maintenance fee.

These sublicense fees were treated as reductions to the transaction price and combined with the performance obligation to which they relate.

In March 2023, the Company announced that it would evaluate the potential next steps for CX-2029 following the decision from AbbVie, to not advance CX-2029 into additional clinical studies.

As a result of AbbVie’s decision, the 2016 CD71 License and Collaboration Agreement was terminated in May 2023 and the Company re-acquired full rights to CX-2029.

The Company has completed the performance obligation under the CD71 Agreement as of March 31, 2023 and recognized the related remaining deferred revenue of $ 4.0 million in the first quarter of 2023.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Under the terms of the Discovery Agreement, AbbVie received exclusive worldwide rights to develop and commercialize conditionally activated ADCs against up to two targets, one of which was selected in March 2017.

Under the Discovery Agreement, the Company received an upfront payment of $ 10.0 million for the first target in April 2016 and subsequently received an additional $ 10.0 million payment triggered by selection of the second target by AbbVie in June 201 9.

In December 2022, the research on the two discovery targets under the Discovery Agreement concluded with no plans to advance the discovery targets into clinical studies or to pursue new programs.

The Discovery Agreement was also terminated and all target rights have reverted back to CytomX.

In August 2023, the Company entered into a Transition Agreement (the “Transition Agreement”) with AbbVie Global Enterprises Ltd.

("AbbVie Global", an affiliate entity of AbbVie), pursuant to which the Company regained exclusive worldwide rights to develop CX-2029, a CD71-targeting conditionally activated antibody drug conjugate.

The Transition Agreement supersedes the CD71 Agreement that was terminated in May 2023, and grants certain intellectual property rights from AbbVie Global to enable the continued development of CX-2029 by the Company for all human and nonhuman diagnostic, prophylactic, and therapeutic uses.

Pursuant to the Transition Agreement, AbbVie Global is eligible to receive tiered sales royalties for CX-2029 ranging from the low-to-mid single digit percentages.

In the fourth quarter of 2023, the Company decided to not to make any further substantial investments in the CX-2029 program.

On September 29, 2017, the Company and Amgen, Inc.

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Concurrent with the Amgen Agreement, the Company and Amgen entered into a Share Purchase Agreement pursuant to which Amgen purchased 1,156,069 shares of the Company’s common stock at a price of $ 17.30 per share for total proceeds of $ 20.0 million.

In October 2021, CytomX and Amgen executed an amendment to the Amgen Agreement primarily to (1) extend the target selection date for Amgen to select its additional targets for research and development, and (2) reduce the total number of milestone events and increase the total amount of milestone payments for EGFR Products.

In each of May 2023 and March 2024, CytomX and Amgen executed an amendment to the Amgen Agreement to extend the target selection period for Amgen to select its additional targets, by March 31, 2025 based on the latest extension, for research and development as further discussed below.

Under the terms of the Amgen Agreement, as amended, the Company and Amgen were co-developing a conditionally activated T-cell engager (“TCE”) targeting epidermal growth factor receptor (the “EGFR Products”).

The Company was responsible for early-stage development of EGFR Products and Amgen was to be responsible for late-stage development and commercialization of EGFR Products.

Following potential advancement beyond early-stage development, the Company had the right to elect to participate financially in the global co-development of EGFR Products with Amgen, during which the Company would have been responsible for a certain percentage of the worldwide development costs for EGFR Products and Amgen would have been responsible for the rest of such costs (the “EGFR Co-Development Option”).

If the Company had exercised its EGFR Co-Development Option, the Company would have been entitled to share in somewhat less than 50 % of the profit and losses from sales of such EGFR Products in the U.S., subject to certain caps, offsets, and deferrals.

If the Company had chosen not to exercise its EGFR Co-Development Option, the Company would not have been responsible for any costs of later stage development.

The Company was also eligible to receive up to $ 460.0 million in development, regulatory, and commercial milestone payments for EGFR Products, and royalties in the low-double-digit to mid-teen percentage of worldwide commercial sales, provided that if the Company had exercised its EGFR Co-Development option, it would have received a profit and loss split of sales in the United States and royalties in the low-double-digit to mid-teen percentage of commercial sales outside of the United States.

In January 2022, the IND for the EGFR product (CX-904) was allowed to proceed by the U.S.

Food and Drug Administration (“F DA”) and the program progressed into Phase 1 dose escalation.

In March 2025, CytomX and Amgen jointly decided to not continue CX-904 development and Amgen terminated its license to the EGFR Products.

Following potential advancement beyond early-stage development, the Company had the right to elect to participate financially in the global co-development of EGFR Products with Amgen, during which the Company would have been responsible for a certain percentage of the worldwide development costs and entitled to certain percentage of profit sharing in the U.S., for EGFR Products.

In addition, the Company was also eligible to receive up to $ 460.0 million in development, regulatory, and commercial milestone payments for EGFR Products, and royalties in certain percentages of worldwide commercial sales.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Amgen als o had the right to select a total of up to three targets, including the two additional targets discussed below.

The Company and Amgen collaborate in the research and development of conditionally activated T-cell engaging bispecifics therapies directed against such targets.

Amgen has selected one such target (the “Amgen Other Product”).

If Amgen exercises its option within a specified period of time, it can select two such additional targets (the “Amgen Option Products” and, together with the Amgen Other Product, the “Amgen Products”).

Except with respect to preclinical activities to be conducted by CytomX, Amgen will be responsible, at its expense, for the development, manufacture, and commercialization of all Amgen Products.

If Amgen exercises all of its options and advances all three of the Amgen Products, CytomX is eligible to receive up to $ 950.0 million in upfront, development, regulatory, and commercial milestones and tiered high single-digit to low-teen percentage royalties.

In each of May 2023 and March 2024, CytomX and Amgen executed an amendment to the Amgen Agreement to extend the target selection period for Amgen to select its additional targets.

Amgen had the right to select a total of up to three targets, including the two additional targets.

The Company and Amgen collaborated in the research and development of conditionally activated T-cell engaging bispecifics therapies directed against such targets.

Amgen had selected one such target (the “Amgen Other Product”).

Except with respect to preclinical activities to be conducted by CytomX, Amgen would have been responsible, at its expense, for the development, manufacture, and commercialization of all Amgen Products.

T he Company concluded that, at the inception of the agreement and subsequent amendments, Amgen’s option to select the two additional targets is not a material right and does not represent a performance obligation of the agreement.

In January 2022, the IND for the EGFR product (“CX-904”) was allowed to proceed by the U.S.

Food and Drug Administration (“FDA”) and the program progressed into Phase 1 dose escalation.

In March 2025, CytomX and Amgen jointly decided to not continue CX-904 development and Amgen terminated its license to the EGFR Products.

As a result, all of the remaining deferred revenue of the EGFR product was recognized in the first quarter of 2025 due to Amgen terminating its license to the EGFR Product effective May 2025.

In April 2025, the Amgen Other Product was also terminated with 60 days written notice pursuant to the Amgen Agreement.

The Amgen research collaboration remains in effect with the current scope being the preclinical TCE that CytomX selected from Amgen’s preclinical pipeline further discussed below.

At the initiation of the collaboration, CytomX had the option to select from programs specified in the Amgen Agreement, an existing preclinical stage TCE product from the Amgen preclinical pipeline.

In March 2018, CytomX selected the program and this program is currently in preclinical development.

In March 2018, CytomX selected the program and this program, CX-908, a PROBODY ® T cell engager targeting CDH3 and CD3, is currently in preclinical development.

CytomX is responsible, at its expense, for converting this program to a conditionally activated TCE product, and thereafter, will be responsible for development, manufacturing, and commercialization of the product (“CytomX Product”).

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Furthermore, the Amgen Other Products are accounted for as a separate performance obligation from the EGFR Products as the nature of the services being performed is not the same and the value that Amgen can derive from one program is not dependent on the success of the other.

Concurrent with the execution of the Amgen Agreement, the Company entered into a sublicense agreement whereby the Company granted Amgen a sublicense of its rights to one patent family that it co-owns with UCSB, that is exclusively licensed to the Company under the UCSB Agreement covering PROBODY antibodies and other pro-proteins in the fields of therapeutics, in vivo diagnostics and prophylactics.

Concurrent with the execution of the Amgen Agreement, the Company entered into a sublicense agreement whereby the Company granted Amgen a sublicense of its rights to one patent family that it co-owns with UCSB, that is exclusively licensed to the Company under the UCSB Agreement covering certain conditionally activatable antibodies in the fields of therapeutics, in vivo diagnostics and prophylactics.

This sublicense was incremental to the patents, patent applications and know-how covering conditionally activated T-cell engaging bispecific molecules that were developed and owned by the Company and licensed to Amgen.

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To determine the standalone selling price, the Company used the discounted cash flow method by calculating risk-adjusted net present values of estimated cash flows.

The Company determined that the remaining potential milestone payments were fully constrained due to the uncertainty in achieving them as of December 31, 2024.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Of the $ 51.2 million total transaction price, the Company allocated $ 46.4 million to the EGFR Products performance obligation and $ 4.8 million to the Amgen Other Product performance obligations.

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In applying the input method of revenue recognition, the Company uses actual full-time employee (“FTE”) hours incurred relative to estimated total FTE hours expected to be incurred for each combined performance obligation over the research service period.

At the end of the second quarter of 2019, the Company determined that it would undertake additional testing and assessment of the molecules being evaluated under the EGFR project.

As a result, the estimated FTE hours-to-completion and research service period related to the EGFR project were increased to eight years .

In the second quarter of 2020, the Company completed the clinical candidate characterization phase and moved into the IND-enabling phase earlier than planned.

As a result, the estimated FTE hours-to-completion and research service period related to the EGFR project were decreased from eight to approximately seven years .

In the third quarter of 2022, the FDA initiated Project Optimus which is aimed to reform the dose

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

optimization and dose selection paradigm.

As a result, the estimated FTE hours-to-completion and research service period were increased by approximately an additional year.

The $ 4.8 million transaction price allocated to the Amgen Other Product performance obligation is recognized using estimated FTE hours-to-completion over the estimated research service period of six years .

The $ 4.8 million transaction price allocated to the Amgen Other Product performance obligation was recognized using estimated FTE hours-to-completion over the estimated research service period of six years .

The Company evaluates the measure of progress each reporting period using the input method and, if necessary, adjusts the measure of performance and related revenue recognition.

As of December 31, 2024 and 2023 deferred revenue related to the EGFR Products performance obligation was $ 9.7 million and $ 12.8 million , respectively.

Deferred revenue related to the Amgen Other Products performance obligation was immaterial as of December 31, 2024 and 2023.

As of June 30, 2025, the Company had completed its performance obligations related to the EGFR Products and the Amgen Other Products and recognized the remaining deferred revenue.

As of December 31, 2024, deferred revenue related to the EGFR Products performance obligation was $ 9.7 million and was immaterial for the Amgen Other Products.

Astellas Pharma Inc.

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In addition, Astellas had the right to expand the number of Additional Targets from three up to five (the “Expansion Option”) before the third anniversary of the effective date.

Furthermore, for a specified number of targets, at a pre-specified time prior to the initiation of the first pivotal study of a product against such target, the Company may elect to participate in certain development costs and share in the profits generated in the United States with respect to such product (“Cost Share Option”).

The Cost Share Option, if exercised, will also provide the option for the Company to co-commercialize such product in the United States.

The Company does not consider the Cost Share Option as a performance obligation at the inception of the agreement as participation is at the Company’s discretion.

Furthermore, for a specified number of targets, at a pre-specified time prior to the initiation of the first pivotal study of a product against such target, the Company had the option to elect to participate in certain development costs and share in the profits generated in the United States with respect to such product (“Cost Share Option”).

The Cost Share Option, if exercised, also provided the option for the Company to co-commercialize such product in the United States.

The Company had not considered the Cost Share Option as a performance obligation at the inception of the agreement as participation is at the Company’s discretion.

Pursuant to the Astellas Agreement, the consideration from Astellas was comprised of an upfront fee of $ 80.0 million and total potential contingent payments for development, regulatory and sales milestones of up to an aggregate of approximately $ 1.2 billion.

The Company is also entitled to tiered royalties from high-single digit to mid-teen percentage royalties from potential future sales.

Astellas is responsible for all preclinical research costs incurred by either party as set forth in the preclinical research plan and the Company will receive research and development service fees based on a prescribed FTE rate.

The Company determined that the license and expertise related to the development of product candidates should be combined with the research and development services and participation in the joint research committee as one combined performance obligation for each collaboration target.

The Company was also entitled to tiered royalties from high-single digit to mid-teen percentage royalties from potential future sales.

Astellas was responsible for all preclinical research costs incurred by either party as set forth in the preclinical research plan and the Company was entitled to receive research and development service fees based on a prescribed FTE rate.

The Company had determined that the license and expertise related to the development of product candidates should be combined with the research and development services and participation in the joint research committee as one combined performance obligation for each collaboration target.

The Company concluded, that at the inception of the agreement, Astellas’ Expansion Option for Additional Targets were not material rights and therefore not considered performance obligations.

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In applying the input method of revenue recognition, the Company uses actual FTE hours incurred relative to estimated total FTE hours expected to be incurred over the estimated research service period of each target.

In January 2023, the Company announced that it achieved a clinical candidate milestone under the Astellas Agreement which triggered a $ 5.0 million milestone payment to the Company which was fully recognized in the first quarter of 2023 as the Company had completed its related performance obligation of the first collaboration target which resulted in the clinical candidate nomination for further development.

In March 2024, the Company announced that it achieved the good laboratory practices ("GLPs") toxicology milestone for this candidate which triggered a $ 5.0 million milestone payment to the Company.

In January 2023, the Company achieved a clinical candidate milestone for the first collaboration target nomination under the Astellas Agreement which triggered a $ 5.0 million milestone payment to the Company which was fully recognized in the first quarter of 2023 as the Company had completed its related performance obligation.

In March 2024, the Company achieved the good laboratory practices ("GLPs") toxicology milestone for this candidate which triggered a $ 5.0 million milestone payment to the Company.

The $ 5.0 million milestone payment was fully recognized in the first quarter of 2024 as the Company had completed its related performance obligation of this first collaboration target.

Also, in March 2024, the Company announced that it achieved a clinical candidate milestone for a second collaboration target under the Astellas Agreement which triggered an additional $ 5.0 million milestone payment to the Company.

Also, in March 2024, the Company achieved a clinical candidate milestone for a second collaboration target nomination under the Astellas Agreement which triggered an additional $ 5.0 million milestone

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

$ 5.0 million milestone payment was fully recognized in the first quarter of 2024 as the Company had completed its related performance obligation of the second collaboration target which resulted in the clinical candidate nomination for further development.

In the first quarter 2025, Astellas initiated GLP toxicology studies for the second collaboration target nominated triggering a $ 5.0 million milestone payment to CytomX in the first quarter of 2025.

payment to the Company.

The $ 5.0 million milestone payment for this second nomination was fully recognized in the first quarter of 2024 as the Company had completed its related performance obligation.

In the first quarter of 2025, Astellas initiated GLP toxicology studies for the second collaboration target, triggering a $ 5.0 million milestone payment to CytomX.

The $ 5.0 million milestone payment was fully recognized in the first quarter of 2025 as the Company had completed its related performance obligation of this second collaboration target.

As of December 31, 2025 and 2024, deferred revenue relating to the Astellas Agreement was $ 8.6 million and $ 17.4 million , respectively.

The amount due from Astellas under the Astellas Agreement was $ 0.9 million and $ 1.1 million as of December 31, 2025 and 2024, respectively.

In the first quarter of 2026, Astellas chose not to advance the remaining preclinical programs which will result in the completion of CytomX’s performance obligation and recognition of the remaining deferred revenue by the second quarter of 2026.

Bristol Myers Squibb Company

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As such, the material rights were accounted for as part of the initial transaction price.

The Company received an upfront payment of $ 50.0 million from Bristol Myers Squibb in July 2014.

In January and December 2016, Bristol Myers Squibb exercised the option to select the third and fourth targets, and paid the Company $ 10.0

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

million and $ 15.0 million, respectively, pursuant to the terms of the BMS Agreement.

The Company received an upfront payment of $ 50.0 million from Bristol Myers Squibb in July 2014.

In January and December 2016, Bristol Myers Squibb exercised the option to select the third and fourth targets, and paid the Company $ 10.0 million and $ 15.0 million, respectively, pursuant to the terms of the BMS Agreement.

In December 2016, Bristol Myers Squibb selected a clinical candidate pursuant to the BMS Agreement, which triggered a $ 2.0 million pre-clinical milestone payment to the Company.

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Under the terms of Amendment 2, the period for target selection was extended and in 2022, all remaining targets were selected.

The Company will continue to collaborate with Bristol Myers Squibb to discover and conduct preclinical development of PROBODY therapeutics against targets selected by Bristol Myers Squibb over the estimated research period, which is projected to end in April 2025.

The Company continues to collaborate with Bristol Myers Squibb to discover and conduct preclinical development of PROBODY therapeutics against targets selected by Bristol Myers Squibb over the estimated research period, which is projected to end in April 2025.

Pursuant to Amendment 2, the Company was eligible to receive contingent payments for development, regulatory and sales milestones.

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There were no substantive changes to each party's performance obligations.

In March 2024, following a Bristol Myers Squibb corporate portfolio prioritization process, Bristol Myers Squibb notified CytomX that it does not intend to continue the development of BMS-986288 beyond the current Phase 2 study and terminated its collaboration license on the CTLA-4 target under the collaboration.

BMS-986288 was Bristol Myers Squibb’s leading next generation PROBODY CTLA-4 program that it had previously prioritized over BMS-986249, which was a PROBODY version of ipilimumab.

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The Company determined that it has no further obligations related to the target that was deprioritized and accounted for the reduction of the target as a modification and the related remaining unrecognized transaction price was reallocated to the remaining performance obligations.

The Company continues to be obligated to perform research work under Amendment 2 executed in February 2021 for multiple ongoing research programs for which CytomX’s research efforts on the programs are expected to be complete in April 2025.

As of December 31, 2024, the Company is eligible to receive approximately $ 1.3 billion in contingent payments for development, regulatory and sales milestones for the ongoing collaboration programs.

As of December 31, 2024, the Company has received in aggregate $ 297.0 million in upfront and milestone payments under the agreement.

T he Company has received in aggregate $ 297.0 million in upfront and milestone payments under the agreement.

T he Company's research efforts on all the ongoing programs were completed in April 2025 upon which the $ 11.6 million of remaining deferred revenue was fully recognized.

In May 2025, one collaboration target was also terminated with two months written notice pursuant to the BMS Agreement and two preclinical programs remain in development with Bristol Myers Squibb responsible for further advancement.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

The Company reevaluated the remaining potential milestone payments and determined that significant revenue reversal was probable as the achievement of such milestones was highly dependent on factors outside the Company’s control.

As a result, these payments continued to be fully constrained and were not included in the transaction price on December 31, 2024.

As of December 31, 2024 and 2023, deferred revenue relating to the BMS Agreement was $ 41.9 million and $ 119.9 million , respectively.

ModernaTX, Inc.

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In exchange, the Company received an upfront payment of $ 35.0 million in January 2023, including $ 5.0 million of prepaid research and development service fees.

The Company will continue to receive research and development service fees according to the preclinical research work plans based on a prescribed FTE rate and is eligible to receive up to approximatel y $ 1.2 billion i n future development, regulatory, and commercial milestone payments.

The Company will continue to receive research and development service fees according to the preclinical research work plans based on a prescribed FTE rate and is eligible to receive up to approximatel y $ 1.2 billion in future development, regulatory, and commercial milestone payments.

The Company is also eligible to receive tiered royalties from high-single digit to low-teen percentage rates of annual global net sales of any products that are commercialized under the Moderna Agreement.

7 unchanged sentences

In applying the input measure of revenue recognition, the Company uses actual FTE hours incurred relative to estimated total FTE hours expected to be incurred for the respective collaboration program over an estimated service period of four years .

Due to Moderna's budget considerations in 2025, the Company will continue its performance obligation primarily in 2026 and 2027.

Due to Moderna's budget considerations in 2025 , the Company's remaining activities for its performance obligation are currently paused pending future alignment with Moderna.

As of December 31, 2025 and 2024, deferred revenue relating to the Moderna Agreement was $ 9.3 million and $ 9.3 million , respectively.

The amount due from Moderna under the Moderna Agreement was $ 0.9 million and $ 0 as of December 31, 2024 and December 31, 2023, respectively.

The amount due from Moderna under the Moderna Agreement was $ 0 and $ 0.9 million as of December 31, 2025 and December 31, 2024, respectively.

Regeneron Pharmaceuticals, Inc.

4 unchanged sentences

Regeneron is responsible for funding the cost of preclinical research and discovery activities of both parties for all Licensed Products and for funding the cost of development, manufacturing and commercialization of all Licensed Products worldwide.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Pursuant to the Regeneron Agreement, the consideration from Regeneron is comprised of an upfront fee of $ 30.0 million, contingent payments for development and regulatory milestones and commercial milestone payments of up to an aggregate of approximately $ 0.8 billion.

2 unchanged sentences

In addition, the Company will receive research and development service fees based on a prescribed FTE rate.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

The Company determined that each collaboration program was a distinct performance obligation consisting of an exclusive research, development and commercialization license, research and development services and participation in the joint research committee.

7 unchanged sentences

The transaction price allocated to each performance obligation is recognized using an input measure.

In applying the input measure of revenue recognition, the Company uses actual FTE hours incurred relative to estimated total FTE hours expected to be incurred for the combined performance obligation over the estimated research service period of four years , which is projected to end in November 2026 .

In applying the input measure of revenue recognition, the Company uses actual FTE hours incurred relative to estimated total FTE hours expected to be incurred for each combined performance obligation over the estimated research service period of four years , which is projected to end in November 2026 .

As of December 31, 2025 and 2024, deferred revenue relating to the Regeneron Agreement was $ 10.5 million and $ 15.6 million , respectively.

11 unchanged sentences

However, the timing of revenue recognition could differ from the estimates depending on facts and circumstances impacting the various contracts, including progress of research and development, resources assigned to the contracts by the Company or its collaboration partners or other factors outside of the Company’s control.

• The $ 9.7 million of deferred revenue related to the Amgen EGFR Products is expected to be recognized until 2025 .

• The $ 8.6 million of deferred revenue related to the Astellas Agreement is expected to be recognized until 2026 .

• The $ 41.9 million of deferred revenue related to the BMS Agreement is expected to be recognized until the second quarter of 2025 .

• The $ 9.3 million of deferred revenue related to the Moderna Agreement is expected to be recognized primarily in 2026 and 2027 due to Moderna's budget considerations in 2025.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

• The $ 15.6 million of deferred revenue related to the Regeneron Agreement is expected to be recognized until 2026 .

• The $ 9.3 million of deferred revenue related to the Moderna Agreement, together with research and development service fees, are expected to be recognized pending alignment with Moderna's budget consideration.

• The $ 10.5 million of deferred revenue related to the Regeneron Agreement, together with research and development service fees, is expected to be recognized until 2026 .

License Agreement

UCSB Agreement

In August 2010, the Company entered into an exclusive, worldwide license agreement with University of California, Santa Barbara (“UCSB”), relating to the use of certain patents and technology relating to its core technology, including its therapeutic antibodies, and to certain patent rights the Company co-owns with UCSB covering PROBODY antibodies and other pro-proteins (the “UCSB Agreement”).

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

In August 2010, the Company entered into an exclusive, worldwide license agreement with University of California, Santa Barbara (“UCSB”), relating to the use of certain patents and technology, and to patent rights the Company co-owns with UCSB that cover certain conditionally activatable antibodies (the “UCSB Agreement”) .

Pursuant to the UCSB Agreement, the Company has annual minimum royalty obligations of $ 0.2 million under the terms of certain exclusive licensed patent rights.

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Otherwise, all remaining maintenance fees will become due immediately upon early termination of the agreement unless there is a material breach by UCSB.

In 2022, the Company incurred $ 0.1 million of sublicense fees triggered by the IND for the EGFR product and the dosing of the first patient of the EGFR program under the Amgen Agreement.

In 2023, the Company incurred $ 0.2 million of sublicense fees triggered by achieving the clinical candidate milestone under the Astellas Agreement.

In 2024, the Company incurred $ 0.6 million of sublicense fees triggered by achieving the GLP toxicology studies milestone for the first clinical candidate which was nominated by Astellas in 2023, as well as by achieving the clinical candidate nomination milestone for a second collaboration target under the Astellas Agreement.

In the first quarter 2025, the Company incurred $ 0.2 million of sublicense fees triggered by achieving the GLP toxicology studies milestone for the second clinical candidate which was nominated by Astellas in 2024.

In the first quarter of 2025, the Company incurred $ 0.2 million of sublicense fees triggered by achieving the GLP toxicology studies milestone for the second clinical candidate which was nominated by Astellas in March 2024.

During the years ended December 31, 2025 and 2024 , the Company incurred sublicense expenses of $ 1.1 million and $ 1.6 million, respectively, under the provisions of the UCSB Agreement.

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ImmunoGen is also entitled to royalties on product sales ranging from the mid-to-high single digits percentages.

In April 2024, the Company made a $ 5.0 million payment of the $ 35.0 million in potential clinical development milestone payments to AbbVie (formerly ImmunoGen) with respect to achieving the milestone of dosing the first patient for CX-2051 under the ImmunoGen 2019 License Agreement.

In April 2024, the Company made a $ 5.0 million payment of the $ 35.0 million in potential clinical development milestone payments to AbbVie (formerly ImmunoGen) with respect to achieving the milestone of dosing the first patient for Varseta-M under the ImmunoGen 2019 License Agreement.

Varseta-M, which is currently in Phase 1 development, is covered under the ImmunoGen License Agreement.

Seattle Genetics, Inc ("SGEN")

4 unchanged sentences

The Company terminated the Transition Agreement in the first quarter of 2025.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Commitments and Contingencies

Legal Proceedings

On March 4, 2020 , Vytacera Bio, LLC (“Vytacera”) filed a patent infringement lawsuit against the Company in the U.S.

District Court for the District of Delaware.

The lawsuit alleged that the Company's use, offers to sell, and/or sales of the PROBODY ® technology platform for basic research applications constituted infringement.

The complaint sought unspecified monetary damages.

In September 2022, the Company filed a motion to dismiss the case.

On October 17, 2024, the Court dismissed the case and on October 28, 2024, the Court ordered the case to be closed.

The Company is subject to claims and assessments from time to time in the ordinary course of business, but is not aware of any such matters, individually or in the aggregate, that will have a material adverse effect on the Company’s financial position, results of operations or cash flows.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Indemnifications

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In addition, the Company obtained a standby letter of credit (the “Letter of Credit”) in an amount of approximately $ 0.9 million, which may be drawn by the Landlord to be applied for certain purposes upon the Company’s breach of any provisions under the 2016 Lease.

The Company recorded the $ 0.9 million of cash securing the Letter of Credit as non-current restricted cash on its balance sheet as of December 31, 2024 and 2023.

Rent expense during the years ended December 31, 2024 and 2023 was $ 5.1 million and $ 5.1 million, respectively.

The Company recorded $ 0.9 million of cash securing the Letter of Credit as non-current restricted cash on its balance sheet as of December 31, 2025 and 2024.

Supplemental information related to leases are as follows:

4 unchanged sentences

Operating cash flows from operating leases

December 31, 2024

December 31, 2023

Weighted-average remaining lease term (in years)

2 unchanged sentences

Operating lease

December 31, 2025

December 31, 2024

(in thousands)

Operating lease cost

Variable lease cost

Sublease income

CYTOMX THERAPEUTICS, INC.

7 unchanged sentences

In March 2023, the Company entered into a sublease agreement for a portion of its existing office and laboratory space.

The sublease is classified as an operating lease whereby sublease income is recognized on a straight-line basis over the sublease term that expires on September 30, 2026.

For the year ended December 31, 2024 and 2023 , sublease income was $ 1.2 million and $ 0.9 million, respectively.

The sublease is classified as an operating lease whereby sublease income, which is included as an offset against operating lease cost, is recognized on a straight-line basis over the sublease term that expires on September 30, 2026.

In January 2026, the Company and the sublease tenant entered into a sublease termination agreement, resulting in an early termination of the sublease in February 2026.

Pursuant to the sublease termination agreement, the sublessee will pay an aggregate of $ 0.6 million as final settlement of the sublea se.

The $ 0.6 million was collected in January 2026.

In November 2025, the Company entered into a lease (the “2026 Lease”) of office and laboratory space located in Emeryville, California for the Company’s corporate headquarters.

The contractual commencement date for t he 2026 Lease will be October 1, 2026 .

The 2026 Lease will expire on December 31, 2029 , and the Company has two options to extend the term, each for an additional two years , at the then fair market rent as determined under the term of the 2026 Lease.

T he Company is not reasonably certain to exercise the options.

Under the terms of the lease, the Company is obligated to make aggregate future minimum lease payments totaling approximately $ 5.7 million over the lease term payable starting from January 2027 , exclusive of operating expenses and other common area charges.

The Company determined that the lease commencement date for accounting purpose is April 1, 2026, when the office and laboratory space is expected to be available for use by the Company to begin construction of its leasehold improvements.

December 31, 2025

(in thousands)

Future sublease income payments

Total sublease income payments

In February 2020, the Company entered into the Open Market Sale Agreement (as amended on each of March 4, 2022 and August 9, 2024, the “Sales Agreement”) with Jefferies LLC (“Jefferies”), to sell its common stock, at par value $ 0.00001 per share, with aggregate gross sales proceeds of up to $ 75,000,000 , from time to time upon the Company’s request, through an at-the-market ("ATM") offering under which Jefferies will act as sales agent.

Maturity of operating lease liabilities

Total undiscounted lease payments

In February 2020, the Company entered into the Open Market Sale Agreement (as amended on each of March 4, 2022 and August 9, 2024, the “Sales Agreement”) with Jefferies LLC (“Jefferies”), as sales agent, providing for the sale of up to $ 75,000,000 of its common stock, at par value $ 0.00001 per share, from time to time under an at-the-market (“ATM”) offering.

Pursuant to the Sales Agreement, Jefferies as the sales agent will receive a commission of 3.0 % of the gross sales price for shares of common stock sold under the Sales Agreement.

In April 2024, under the Sales Agreement, the Company sold 2,270,608 shares at an average price of $ 2.20 per share and received net proceeds of approximately $ 4.8 million after deducting the 3.0 % sales commission and related issuance cost.

In December 2024, the Company sold 1,654,594 shares at an average price of $ 1.3 per share under the ATM offering and received net proceeds of approximately $ 2.1 million after deducting the 3.0 % sales commission and related issuance cost.

In 2024, under the ATM program, the Company sold approximately 3.9 million shares at a weighted average price of $ 1.82 per share for net proceeds of approximately $ 6.9 million after deducting sales commissions and related issuance cost.

In the fourth quarter of 2025, the Company sold approximately 4.9 million shares at a weighted average price of $ 3.44 per share under the ATM program for net proceeds of approximately $ 16.3 million, after deducting sales commissions and related issuance cost.

In May 2025, the Company completed an underwritten public offering of 76,923,076 shares of common stock at a price of $ 1.30 per share.

The aggregate net proceeds received by the Company from the offering were approximately $ 93.4 million, after deducting underwriting discounts and commissions of $ 6.0 million and offering expenses of $ 0.6 million.

Longitude Venture Partners V, L.P.

(“LVPV”) acquired approximately 11.5 million shares of common stock through the underwritten public offering.

Longitude Capital Partners V, LLC (“LCPV”) is a general partner of LVPV.

A member of the Company’s board of directors serves as a managing director of LCPV, and therefore, LCPV is considered a related party of the Company.

The Company had no other significant related party transactions with LCPV.

In June 2023, the Company entered into an agreement with BVF Partners L.P.

(“BVF”) for a private placement and received an aggregate net proceeds of approximately $ 29.7 million in July 2023, after deducting issuance costs of approximately $ 0.3 million.

In the private placement, CytomX issued pre-funded warrants to BVF to purchase up to 14,423,077 shares of common stock, accompanying Tranche 1 warrants to purchase up to 5,769,231 shares of common stock and accompanying Tranche 2 warrants to purchase up to 5,769,231 shares of common stock, at a combined price of $ 2.08 per share.

(“BVF”) for a private placement (the “Private Placement Agreement”) and received an aggregate net proceeds of approximately $ 29.7 million in July 2023, after deducting issuance

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

costs of approximately $ 0.3 million.

In the private placement, the Company issued pre-funded warrants to BVF to purchase up to 14,423,077 shares of common stock, accompanying Tranche 1 warrants to purchase up to 5,769,231 shares of common stock and accompanying Tranche 2 warrants to purchase up to 5,769,231 shares of common stock, at a combined price of $ 2.08 per share.

The initial exercise price of the Tranche 1 and Tranche 2 warrants was $ 4.16 per share and $ 6.24 per share, respectively.

The public offering in May 2025 triggered an adjustment provision in the Tranche 1 and Tranche 2 warrants, pursuant to which the exercise prices were reduced to $ 2.73 and $ 3.77 per share, respectively.

As a result of the exercise price reduction adjustment, the Company recorded deemed dividend of $ 3.0 million as a down round adjustment for the warrants in additional paid-in-capital against retained earnings in 2025.

The deemed dividend is treated as a reduction to income available to common stockholders for the basic net income (loss) per share calculation.

However, the adjustment to net income (loss) is not required in periods when the warrants are out-of-the-money for the diluted net income (loss) per share calculation.

The Tranche 1 warrants expired without being exercised in July 2025 and the Tranche 2 warrants will expire in July 2026 .

In May 2024, BVF exercised its right to purchase 7.5 million shares of common stock through its pre-funded warrants at an exercise price of $ 0.00001 per share.

The following table summarizes the Company's warrants activities:

In May 2025, BVF exercised its right to purchase the remaining 6.9 million shares of common stock through its pre-funded warrants at an exercise price of $ 0.00001 per share.

The following table summarizes the Company's activities of outstanding warrants for the year ended December 31, 2024 and 2025:

Pre-funded Warrants

6 unchanged sentences

Balance at December 31, 2024

The pre-funded warrants will expire in July 2043 , while Tranche 1 and Tranche 2 warrants will expire in July 2025 and July 2026 , respectively.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Balance at December 31, 2025

In the May 2024 annual meeting of stockholders, the Company's authorized shares of common stock were approved to increase from 150,000,000 shares to 300,000,000 shares.

15 unchanged sentences

To date, stock options granted under the 2015 Plan generally vest over four years and vest at a rate of 25 % upon the first anniversary of the issuance date and 1/48 th per month thereafter.

The initial number of shares of common stock available for future issuance under the 2015 Plan was 2,444,735 .

Beginning on January 1, 2016 and continuing until the expiration of the 2015 Plan, the total number of shares of common stock available for issuance under the 2015 Plan will automatically increase annually on January 1 by 4 % of the total number of issued and outstanding shares of common stock as of January 1 of the same year.

As of December 31, 2024 and 2023 , 2,319,648 shares and 2,944,245 shares of common stock, respectively, were available for future issuance under the 2015 Plan.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

In June 2025, the Company’s stockholders approved the amendment and restatement of the 2015 Plan, among other things, to increase the aggregate number of shares of the Company’s common shares available for grant to approximately 6.3 million shares, remove the “ evergreen provision ” which provided an annual increase of shares under the Plan on January 1 of each calendar year by 4 % of the total number of issued and outstanding shares of common stock as of January 1 of the same year.

As of December 31, 2025 and 2024 , 5,191,986 sh ares and 2,319,648 shares of common stock, respectively, were available for future issuance under the 2015 Plan.

The 2019 Plan

4 unchanged sentences

During 2021, t he total number of shares of common stock available for issuance under the 2019 Plan has increased by 1,000,000 shares.

As of December 31, 2024 and 2023 , 1,658,672 and 1,725,656 shares, respectively, of common stock were available for future issuance under the 2019 Plan.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

In conjunction with the amendment of the 2015 Plan approved by the Company's stockholders in June 2025, the Company discontinued the 2019 Plan with respect to new equity awards.

All the remaining shares available for grant under the 2019 Plan were released and transferred to the 2015 Plan.

As of December 31, 2025 and 2024, no shares and 1,658,672 shares, respectively, of common stock were available for future issuance under the 2019 Plan.

The following table summarizes the Company's stock option activities :

8 unchanged sentences

The aggregate intrinsic values of options exercised, outstanding and exercisable were calculated as the difference between the exercise price of the options and the quoted market price of the underlying common stock as of December 31, 2025.

The Company recorded $ 3.9 million and $ 5.8 million of stock-based compensation expense related to the stock option plans for the years ended December 31, 2025 and 2024, respectively.

The options granted in the years ended December 31, 2025 and 2024 had weighted-average per share grant-date fair values of $ 1.41 and $ 1.21 , respectively.

As of December 31, 2025, the unrecognized compensation expense with respect to options granted was $ 7.3 million and is expected to be recognized over 2.58 years.

1 unchanged sentence

The following table summarizes the Company's TRSU activities:

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

(in thousands)

5 unchanged sentences

As of December 31, 2025 , the unrecognized compensation expense with respect to the TRSUs was $ 2.1 million which is expected to be recognized over 1.5 years.

The TSRUs generally vest ratably over two to four years.

The TRSUs generally vest ratably over two to four years.

Performance-based RSUs ("PSU")

In October 2021, the Company granted 435,000 PSUs to executive employees with an aggregated grant date fair value of $ 2.3 million.

Vesting for 50% of the PSUs granted will occur upon achievement of certain specific milestones within one year of the grant date ("2021-Tranche-1") and the remaining 50% will vest upon achievement of additional company objectives within two years of the grant date ("2021-Tranche-2").

In July 2022, the Company determined that the performance condition for 2021-Tranche-1 was met and recorded $ 1.0 million of stock-based compensation expense for the year ended December 31, 2022.

In September 2023, the performance condition for 2021-Tranche-2 was modified and the award was vested in September 2023.

As a result, the Company recorded $ 0.1 million of stock-based compensation expense for 2021-Tranche-2 for the year ended December 31, 2023.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

In August 2022, the Company granted 250,000 PSUs to executive employees with an aggregated grant date fair value of approximately $ 0.4 million.

Vesting for 50% of the PSUs granted was set to occur upon attaining certain specific milestones by December 2023 (“2022-Tranche-1”), and the remaining 50% was set to vest upon attaining certain specific milestones by December 2024 (“2022-Tranche-2”).

For the year ended December 31, 2022, the Company recorded $ 55,000 c ompensation cost for the Tranche-1 award.

In December 2023, the Company determined that the performance condition for 2022-Tranche-1 was satisfied and the award was vested in December 2023.

As a result, the Company recorded the remaining $ 128,000 c ompensation cost for the 2022-Tranche-1 award for the year ended December 31, 2023.

In August 2024, the Company determined that the performance condition for the 2022-Tranche-2 had been satisfied and the award was vested in August 2024.

As a result the Company recorded $ 77,000 and $ 106,000 stock-based compensation cost for 2022-Tranche 2 for the years ended December 31, 2024 and 2023, respectively.

In February 2023, the Company granted 760,000 PSUs to executive employees with an aggregated grant date fair value of approximately $ 1.9 million.

Vesting for 50% of the PSUs granted will occur upon attaining certain specific milestones by December 2024 (“2023-Tranche-1”), and the remaining 50% will vest upon attaining certain specific milestones by December 2025 (“2023-Tranche-2”).

As of December 31, 2024, the PSUs for 2023-Tranche-1 were cancelled as the related performance condition was not met by December 2024.

The Company determined that it is not probable that the performance condition will be satisfied for 2023-Tranche-2 and no compensation cost was recorded for these awards through December 31, 2024.

Vesting for 50% of the PSUs granted occurred upon attaining certain specific milestones by December 2024 (“2023-Tranche-1”), and the remaining 50% were set to vest upon attaining certain specific milestones by December 2025 (“2023-Tranche-2”).

As of December 31, 2024, the PSUs for 2023-Tranche-1 were canceled as the related performance condition was not met by December 2024.

The performance condition for 2023-Tranche-2 was determined to be satisfied in June 2025 and the 2023-Tranche-2 PSUs were fully vested.

As a result, the Company recorded $ 0.7 million compensation cost for the year ended December 31, 2025.

In January 2024, the Company granted 810,000 PSUs to executive employees with an aggregated grant date fair value of approximately $ 1.3 million.

Vesting for 50% of the PSUs granted will occur upon attaining certain specific milestones by December 2025 (“2024-Tranche-1”), and the remaining 50% will vest upon attaining certain specific milestones by December 2026 (“2024-Tranche-2”).

As of December 31, 2025, the PSUs for 2024-Tranche-1 were canceled as the related performance condition was not met by December 2025.

The Company determined that it is not probable that the performance conditions will be satisfied for 2024-Tranche-2 and hence no compensation cost was recorded for these awards through December 31, 2025.

In September 2025, the Company granted 413,350 PSUs to executive employees with an aggregated grant date fair value of approximately $ 1.2 million.

Vesting for one third of the PSUs granted will occur upon attaining a certain specific milestone (“2025-Tranche-1”), vesting for one third of the PSUs granted will occur upon attaining a certain specific milestone (“2025-Tranche-2”) on June 30, 2027 or later, and the remaining one third will vest upon attaining a certain specific milestone on June 30, 2028 or later (“2025-Tranche-3”).

The Company determined that it is not probable that the performance conditions will be satisfied for each of these tranches and hence no compensation cost was recorded for these awards through December 31, 2025.

5 unchanged sentences

Balance at December 31, 2025

As of December 31, 2024, the unrecognized compensation expense with respect to PSUs granted was $ 2.3 million and is expected to be recognized over 1.34 years.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

As of December 31, 2025, unrecognized compensation expense with respect to PSUs granted was $ 1.9 million, of which $ 1.5 million is expected to be recognized ov er approximately 1.6 years and $ 0.4 million will be recognized upon occurrence of the specific milestone.

Employee Stock Purchase Plan

3 unchanged sentences

The Company issued 207,528 and 383,346 shares of common stock under the ESPP in 2025 and 2024, respectively.

In June 2025, the Board of Directors approved an amendment and restatement of the ESPP to remove the expiration date of the plan and the annual increase of shares on January 1 of each calendar year as defined under the ESPP.

Shares available for future purchase under the ESPP were 348,824 shares and 556,352 shares at December 31, 2025 and 2024, respectively.

The compensation expense related to the ESPP was $ 0.3 million, $ 0.3 million for the years ended December 31, 2024 and 2023, respectively.

The compensation expense related to the ESPP wa s $ 0.2 million and $ 0.3 million for the years ended December 31, 2025 and 2024, respectively.

As of December 31, 2025, there was $0.1 million of unrecognized compensation cost related to the ESPP, which the Company expects to recognize over 5 months.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Stock Based Compensation

12 unchanged sentences

Expected term (in years)

Weighted average fair value

Weighted average grant date fair value

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Inco me Taxes

5 unchanged sentences

Provision for income taxes

The table reflects the ASU 2023-09, Income Taxes (Topic 740):

Improvements to Income Tax Disclosures (ASU 2023-09).

Basis of Presentation and Summary of Significant Accounting Policies — Recent Accounting Pronouncements” for additional information on the adoption of ASU 2023-09.

A reconciliation of the Company’s effective tax rate to the statutory U.S.

federal rate is as follows:

Years Ended December 31,

Year Ended December 31, 2025

(in thousands)

federal taxes at statutory rate

State tax, net of federal benefit

Research tax credits

Change in valuation allowance

Nondeductible items

Stock based compensation

Sec 162(m) limitation

Changes in unrecognized tax benefits

Deferred tax adjustment related to stock based compensation

A reconciliation of the Company’s effective tax rate to the statutory U.S.

federal rate, prior to the adoption of ASU 2023-09, is as follows:

Year Ended December 31,

federal taxes at statutory rate

State tax, net of federal benefit

Stock compensation

Change in valuation allowance

162(m) limitation

Sec 162(m) limitation

CYTOMX THERAPEUTICS, INC.

19 unchanged sentences

Management considered all available evidence, both positive and negative, including but not limited to our historical operating results, income or loss in recent periods, cumulative losses in recent years, forecasted earnings, future taxable income, and significant risk and uncertainty related to forecasts, and concluded the deferred tax assets are not more likely than not to be realized.

The net change in the total valuation allowance for the years ended December 31, 2024 and 2023 was a decrease of $ 13.4 million and an increase of $ 9.4 million, respectively.

The Company had net operating loss carryforwards for federal and state income tax purposes of approximately $ 294.3 million and $36.7 million, respectively, as of December 31, 2024 , available to reduce future taxable income.

Of the federal net operating loss carryforwards, $ 65.6 million will begin to expire in 2034 , if not utilized and $ 228.7 million will carried forward indefinitely.

The net change in the total valuation allowance for the years ended December 31, 2025 and 2024 was an increase of $ 25.2 million and a decrease of $ 13.4 million, respectively.

The Company had net operating loss carryforwards for federal and state income tax purposes of approxi mately $ 394.5 million and $ 56.9 million, respectively, as of December 31, 2025 , available to reduce future taxable income.

Of the federal net operating loss carryforwards, $ 65.6 million will begin to expire in 2034 , if not utilized an d $ 328.9 m illion will be carried forward indefinitely.

The state net operating loss carryforwards will begin to expire in 2032 , if not utilized.

The Company also has federal and state research and development tax credit carryforwards of $ 26.4 million and $ 15.0 million , respectively, as of December 31, 2025 available to reduce future income taxes.

The federal research and development tax credits will begin to expire in 2031 if not utilized.

The federal research and development tax credits will begin to expire in 2031 if n ot utilized.

The state research and development tax credits will carryforward indefinitely.

I nternal Revenue Code section 382 (“IRC Section 382”) places a limitation (the “Section 382 Limitation”) on the amount of taxable income that can be offset by net operating loss (“NOL”) carryforwards after a change in control (generally greater than 50 % change in ownership) of a loss corporation.

California has similar rules.

The Company has performed an IRC Section 382 analysis and determined there was an ownership change in 2017 that resulted in 382 limitations.

When an ownership change occurs, IRC Section 382 limits the use of NOLs and credits in subsequent periods based on the annual 382 limitations.

The annual 382 limitations may limit the full use of available tax attributes in one year but the identified ownership changes may not result in expiration of tax attributes for use prior to expiration of their respective carryforward periods.

Accordingly, none of the tax attributes have been reduced but limited the full use in 2018.

The Company has determined that, while an ownership change has occurred, the applicable limits would not impair the value or anticipated use of the Company’s federal and state net operating losses.

Although realization is not assured, management believes it is more likely than not that any limitation under IRC Section 382 will not impair the realizability of the deferred income tax assets related to federal and state net operating loss carryforwards .

The Company reviewed its stock ownership for the year ended December 31, 2024 and concluded no ownership changes occurred in current year which would result in a reduction of its net operating loss or in its research and development credits expiring unused.

If the additional ownership change occurs, the utilization of net operating loss and credit carryforwards could be significantly reduced.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Internal Revenue Code section 382 (“IRC Section 382”) places a limitation (the “Section 382 Limitation”) on the amount of taxable income that can be offset by net operating loss (“NOL”) carryforwards after a change in control (generally greater than 50 % change in ownership) of a loss corporation.

California has similar r ules.

When such ownership change occurs, IRC Section 382 limits the use of NOLs and credits in subsequent periods based on the annual Section 382 Limitation.

The Company performed an IRC Section 382 analysis and determined that there was no ownership change in 2025 which may result in a reduction of its NOLs or its research and development credits expiring unused.

A reconciliation of the beginning and ending unrecognized tax benefit amount is as follows (in thousands):

4 unchanged sentences

Balance at end of the year

Of the unrecognized tax benefits as of each of December 31, 2024 and 2023, approximately $ 2.3 mill ion, would affect the Company’s effective tax rate if recognized.

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Of the unrecognized tax benefits as of each of December 31, 2025 and 2024, approximately $ 2.3 million would affect the Company’s effective tax rate if recognized.

Penalties and interest of $ 1.0 million and $ 1.0 million, respectively, have been accrued for as of December 31, 2025.

6 unchanged sentences

The Company filed a protest to contest the proposed assessment in November 2023.

Due to the ongoing nature of the examination and discussions with the state of California, the Company is unable to estimate a date by which this matter will be resolved.

Due to the ongoing nature of the

examination and discussions with the state of California, the Company is unable to estimate a date by which this matter will be resolved.

Defined Contribution Plan

1 unchanged sentence

Employee contributions are voluntary and are determined on an individual basis subject to the maximum allowable under federal tax regulations.

During the years ended December 31, 2024 and 2023, the Company made contributions to the plan o f $ 0.6 m illion, $ 0.5 million, respectively.

Segment Disclosures

During the years ended December 31, 2025 and 2024, the Company made contributions to the plan o f $ 0.5 million and $ 0.6 m illion, respectively.

The Company operates as a single operating segment.

7 unchanged sentences

In addition to the revenue by collaborative partners disclosed in Note 8, the CODM reviews the following significant expenses in making decisions about the allocation of resources and assessing performance (in thousands):

CYTOMX THERAPEUTICS, INC.

Notes to Financial Statements

Year Ended December 31,

3 unchanged sentences

CX-904 (EGFRxCD3)

CX-2051 (EpCAM)

CX-801 (IFNα2b)

CX-2029 (CD71)

Other wholly owned and partnered programs

4 unchanged sentences

General and administrative expenses

Total operating expense

Income (loss) from operations

4 unchanged sentences

Net income (loss)

Subsequent Event

On January 6, 2025, the Company announced a restructuring plan to streamline its organization and prioritize CX-2051 (EpCAM PROBODY ® ADC) and its activities to support its research collaborations.

The restructuring plan will result in a reduction to its workforce by approximately 40 % and is expected to be substantially completed in the first quarter of 2025.

The Company estimates that it will incur aggregate restructuring charges of approximately $ 4.0 million, primarily related to one-time severance payments and other employee-related costs, which the Company expects will be substantially recor ded in the first quarter of 2025.

Changes in and Disagreements with Acco untants on Accounting and Financial Disclosure

Control s and Procedures

Evaluation of Disclosure Controls and Procedures.

The term “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act of 1934, as amended (the “Exchange Act”) refers to controls and other procedures of an issuer that are designed to ensure that information required to be disclosed by the issuer in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC’s rules and forms.

Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by an issuer in the reports that it files or submits under the Exchange Act is accumulated and communicated to the issuer’s management, including its Principal Executive and Principal Financial Officers, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

In designing and evaluating the disclosure controls and procedures, our management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and our management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

Our disclosure controls and procedures are designed to provide reasonable assurance of achieving their control objectives.

Our management, with the participation of our Principal Executive Officer and Principal Financial Officer, has evaluated the effectiveness of our disclosure controls and procedures as of December 31, 2024, the end of the period covered by this Annual Report on Form 10-K.

Based on that evaluation, the Company's Principal Executive Officer and Principal Financial Officer concluded that, as of December 31, 2024, our disclosure controls and procedures were effective at a reasonable assurance level.

Management’s Annual Report on Internal Control over Financial Reporting

Management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Exchange Act Rules 13a-15(f) and 15d-15(f).

Our internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of our assets;

(ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of the financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures are being made only in accordance with authorizations of our management and directors;

and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of our assets that could have a material effect on the financial statements.

Internal control over financial reporting is designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements prepared for external purposes in accordance with generally accepted accounting principles.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements.

Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Our management, with the participation of our Principal Executive Officer and Principal Financial Officer, conducted an evaluation of the effectiveness of our internal control over financial reporting based on the framework in Internal Control – Integrated Framework (2013 framework) issued by the Committee of Sponsoring Organizations of the Treadway Commission.

Based on our evaluation under the framework in Internal Control – Integrated Framework, the Company's Principal Executive Officer and Principal Financial Officer concluded that, as of December 31, 2024, our internal control over financial reporting was effective.

The effectiveness of our internal control over financial reporting as of December 31, 2024 has also been audited by Ernst & Young LLP, an independent registered public accounting firm, as stated in its report included in this Annual Report on Form 10-K.

Changes in Internal Control Over Financial Reporting

There was no change in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) that occurred during our fiscal quarter ended December 31, 2024, that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

Othe r Information

Trading Arrangements

During the three months ended December 31, 2024, none of our directors or officers (as defined in Rule 16a-1(f) under the Securities Exchange Act of 1934, as amended) adopted , terminated or modified a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K.

Termination of CX-2009 & CX-2029

On January 31, 2025, the Company sent formal notice of termination to AbbVie Global Enterprises Ltd.

(“AbbVie”) regarding the Transition Agreement dated August 22, 2023 between AbbVie and the Company (the “AbbVie Transition Agreement”) and the sublicense pertaining to CX-2029 under the AbbVie Transition Agreement.

The Company previously announced in 2023 that it would not significantly invest in further development and has now terminated AbbVie Transition Agreement.

Qn January 31, 2025, the Company sent formal notice of termination to ImmunoGen, Inc.

( “ImmunoGen”, now AbbVie) regarding the License Agreement dated February 16, 2016 between ImmunoGen and the Company (the “ImmunoGen License Agreement”) and the sublicense pertaining to CX-2009 under the Immunogen License Agreement.

The Company previously announced it would end development work of CX-2009 in 2022 and has now terminated ImmunoGen License Agreement.

2025 Executive Retention Program

To further incentivize the Company’s executive efforts critical to 2025 goals of the Company, and to recognize their continued commitment to the organization, the Board approved a 2025 cash incentive award program (the “Retention Program”) effective upon filing of the annual report on Form 10-K for the fiscal year 2024.

The Retention Program is conditioned on the achievement by the Company of $50 million of new capital from all sources by December 31, 2025, and continued employment by the Company as of the date of completion of the performance condition.

Under this Retention Program, Company executives will be eligible to receive a one-time cash payment equal to 50% of annual target bonus incentive of such executive upon the successful completion of this performance condition if employed on such date.

No retention awards will be earned or issued if the new capital condition is not met by December 31, 2025.

Executives did not earn and the Company did not pay annual cash bonus for 2024.

Disclosure Regarding Foreign Jurisdictions That Prevent Inspections

Directors, Executive Of ficers and Corporate Governance

The information required by this Item will be set forth in the Company’s proxy statement to be filed with the Securities and Exchange Commission within 120 days after the Company’s fiscal year end and is incorporated herein by reference.

We have adopted a code of business conduct and ethics that applies to all employees, including our Principal Executive Officer, Principal Financial Officer, Principal Accounting Officer or Controller, or persons performing similar functions.

The code of business conduct and ethics is available on our website at www.cytomx.com.

Amendments to, and waivers from, the code of business conduct and ethics that apply to any director, executive officer or persons performing similar functions will be disclosed at the website address provided above and, to the extent required by applicable regulations, on a Current Report on Form 8-K filed with the SEC.

We have adopted an insider trading policy (the “Corporate Securities Trading Policy”) governing the purchase, sale and other dispositions of our securities by our directors, officers and employees that we believe is reasonably designed to promote compliance with insider trading laws, rules and regulations, and any applicable listing standard s.

A copy of our Corporate Securities Trading Policy as Exhibit 19.1 to the Annual Report on Form 10-K for the year ended December 31, 2023 was filed with the SEC on March 11, 2024.

Executi ve Compensation

Security Ownership of Certain Beneficial Ow ners and Management and Related Stockholder Matters

Certain Relationships and Relate d Transactions and Director Independence

Principal Accou ntant Fees and Services

Exhibits and Financial Statement Schedules

(1) Financial Statements:

The financial statements required by Item 15(a) are filed as part of this Annual Report on Form 10-K under Item 8 “Financial Statements and Supplementary Data.”

(2) Financial Statement Schedules

The financial statement schedules required by Item 15(a) are omitted because they are not applicable, not required or the required information is included in the financial statements or notes thereto as filed in Item 8 of this Annual Report on Form 10-K.

(3) Exhibits.

Incorporated by Reference

Exhibit Description

Amended and Restated Certificate of Incorporation.

Amended and Restated Bylaws of CytomX Therapeutics, Inc,.

effective March 20, 2024.

Reference is made to exhibits 3.1 through 3.2.

Specimen Common Stock Certificate.

Registration Rights Agreement dated as of September 29, 2017 by and between CytomX Therapeutics, Inc.

and Amgen, Inc.

Description of Registrant’s Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934.

Form of Pre-Funded Warrant

Form of Tranche Warrant

2010 Stock Incentive Plan adopted on September 21, 2010 (“2010 Plan”).

Form of Stock Option Agreement under the 2010 Plan.

2011 Stock Incentive Plan, adopted on February 7, 2012, as amended (“2011 Plan”).

Form of Restricted Stock Award Agreement and Option Exercise Agreement under the 2011 Plan.

2015 Equity Incentive Plan (“2015 Plan”).

Form of 2015 Plan Option Agreement under the 2015 Plan.

Form of 2015 Plan Early Exercise Option Agreement

Form of 2015 Plan Restricted Share Unit Award Grant Notice and Agreement

2019 Employment Inducement Incentive Plan adopted on September 18, 2019 (“2019 Plan”).

Form of Stock Option Agreement under the 2019 Plan.

CYTOMX THERAPEUTICS, INC.

Employee Stock Purchase Plan.

Form of Indemnification Agreement by and between CytomX Therapeutics, Inc.

and each of its directors and each of its executive officers.

Employment Offer Letter Agreement between CytomX Therapeutics, Inc.

Phil, dated as of December 15, 2010.

Employment Offer Letter Agreement between CytomX Therapeutics, Inc.

and Jeffrey Landau dated as of March 13, 2021.

Amended and Restated Severance and Change of Control Agreement dated February 27, 2019, by and between CytomX Therapeutics, Inc.

and Sean McCarthy.

Amended and Restated Severance and Change of Control Agreement dated March 25, 2019, by and between CytomX Therapeutics, Inc.

and Lloyd Rowland.

Form of Amended and Restated Severance and Change of Control Agreement by and between CytomX Therapeutics, Inc.

and each of its executive officers other than Sean A.

Lease dated as of December 10, 2015, by and between CytomX Therapeutics, Inc.

and HCP Oyster Point III LLC.

Sublease Agreement dated as of March 24, 2023, by and between CytomX Therapeutics, Inc and Atomic AI, Inc.

Exclusive License Agreement dated as of August 19, 2010, by and between The Regents of the University of California and CytomX Therapeutics, Inc., as amended by Amendment No.

1 to Exclusive Agreement effective as of May 30, 2013 and Amendment No.

2 to Exclusive Agreement effective as of November 8, 2013.

Amendment No.3 to Exclusive License Agreement effective as of April 2, 2019, by and between CytomX Therapeutics, Inc.

and The Regents of the University of California.

Collaboration and License Agreement dated as of May 23, 2014, by and between CytomX Therapeutics, Inc.

and Bristol Myers Squibb Company.

Amendment to Extend Collaboration and License Agreement, dated March 17, 2017, by and between the Company and Bristol Myers Squibb.

Amendment No 2 to Collaboration and License Agreement, as amended, dated March 17, 2017, by and between the Company and Bristol Myers Squibb, effective as of February 22, 2021.

Amendment No 3 to Collaboration and License Agreement, dated May 23, 2014, by and between the Company and Bristol Myers Squibb Company, effective as of October 11, 2022.

Co-Development and License Agreement, dated April 21, 2016, by and between CytomX Therapeutics, Inc.

and AbbVie Ireland Unlimited Company.

First Amendment to the CD71 Co-Development and License Agreement by and between CytomX Therapeutics, Inc.

and AbbVie Ireland Unlimited Company, dated as of October 5, 2016.

Second Amendment to the CD71 Co-Development and License Agreement by and between CytomX Therapeutics, Inc.

and AbbVie Ireland Unlimited Company, effective as of March 31, 2017.

Third Amendment to the CD71 Co-Development and License Agreement by and between CytomX Therapeutics, Inc.

and AbbVie Ireland Unlimited Company, effective as of January 3, 2018.

Amended and Restated Discovery Collaboration and License Agreement, dated as of June 28, 2019, by and between CytomX Therapeutics, Inc., and AbbVie Ireland Unlimited Company.

Transition Agreement effective as of August 22, 2023 by and between CytomX Therapeutics, Inc., and AbbVie Global Enterprises Ltd.

Collaboration and License Agreement by and between CytomX Therapeutics, Inc.

and Amgen, Inc.

dated as of September 29, 2017.

Amendment No.

1 to the Collaboration and License Agreement, dated as of September 29, 2020, by and between CytomX Therapeutics, Inc.

and Amgen, Inc.

Amendment No.

2 to the Collaboration and License Agreement, dated as of October 27, 2021, by and between CytomX Therapeutics, Inc.

and Amgen, Inc.

Amendment No.

3 to the Collaboration and License Agreement, dated as of May 18, 2023, by and between CytomX Therapeutics, Inc.

and Amgen, Inc.

Amendment No.

4 to the Collaboration and License Agreement, dated as of March 28, 2024, by and between CytomX Therapeutics, Inc.

and Amgen, Inc.

Collaboration and License Agreement dated as of March 23, 2020, by and between CytomX Therapeutics, Inc.

and Astellas Pharma Inc.

License Agreement by and between CytomX Therapeutics, Inc.

and ImmunoGen Inc., dated as of February 12, 2016.

Collaboration and License Agreement dated as of November 16, 2022 by and between CytomX Therapeutics, Inc.

and Regeneron Pharmaceuticals, Inc.

Amendment No.1 to the Collaboration and License Agreement effective as of June 28, 2024 by and between CytomX Therapeutics, Inc.

and Regeneron Pharmaceuticals, Inc.

Collaboration and License Agreement dated as of December 30, 2022 by and between CytomX Therapeutics, Inc.

and ModernaTX, Inc.

Unit Purchase Agreement by and among the CytomX Therapeutics, Inc.

and certain accredited investors named therein, dated June 29, 2023.

Open Market Sale Agreement, dated as of February 27, 2020, by and between CytomX Therapeutics, Inc.

and Jefferies LLC.

Amendment No.

1 to Open Market Sales Agreement, dated as of March 4, 2022, by and between CytomX Therapeutics, Inc.

and Jefferies LLC.

Amendment No.

2 to Open Market Sales Agreement, dated as of August 9, 2024, by and between CytomX Therapeutics, Inc.

and Jefferies LLC.

Corporate Securities Trading Policy

Consent of Independent Registered Public Accounting Firm.

Power of Attorney (included on signature page)

Certification of Principal Executive Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

Certification of Principal Financial Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

Certification of Principal Executive Officer and Principal Financial Officer Pursuant to 18 U.S.C.

Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

Executive Compensation Clawback Policy

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Inline XBRL Taxonomy Extension Schema Document

Inline XBRL Taxonomy Extension Calculation Linkbase Document

Inline XBRL Taxonomy Extension Definition Linkbase Document

Inline XBRL Taxonomy Extension Label Linkbase Document

Inline XBRL Taxonomy Extension Presentation Linkbase Document

Cover Page Interactive Data File (formatted as inline XBRL and contained in Exhibit 101)

Confidential treatment has been granted for certain information contained in this exhibit.

Such information has been omitted and filed separately with the Securities and Exchange Commission.

Certain confidential portions of this exhibit have been omitted from this exhibit.

# Indicates management contract or compensatory plan.

** The certifications attached as Exhibit 32.1 that accompany this Annual Report on Form 10-K are not deemed filed with the Securities and Exchange Commission and are not to be incorporated by reference into any filing of CytomX Therapeutics, Inc.

under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, whether made before or after the date of this Annual Report on Form 10-K, irrespective of any general incorporation language contained in such filing.

Form 10-K Summary

Registrants may voluntarily include a summary of information required by Form 10-K under Item 16.

We have elected not to include such summary.

Pursuant to the requirements of Section 13 or 15(d) the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Notes to Financial Statements

Restructuring

On January 6, 2025, the Company announced a restructuring plan to streamline its organization and prioritize Varseta-M (EpCAM PROBODY ® ADC), CX-801 and its activities to support its research collaborations.

This plan resulted in a reduction of approximately 40 % of its workforce and was substantially completed in the first quarter of 2025.

The Company incurred total restructuring charges of $ 2.8 million, primarily related to one-time severance payments and other employee-related co sts.

This includes $ 1.7 million of research and development expenses and $ 1.1 million of general and administrative expenses that were recorded during the twelve months ended December 31, 2025.

The following is a summary of accrued restructuring costs as of December 31, 2025 (in thousands):

Severance and Benefits Costs

Stock Based Compensation

Restructuring cost recorded

Changes in estimates

Non-cash charges

Balance at December 31, 2025

Subsequent Event

In March 2026, Astellas chose to not advance the remaining preclinical programs under the alliance, resulting in a termination of the collaboration effective in the second quarter of 2026.

CytomX is currently assessing options to advance select targets previously covered under the Astellas collaboration as part of its ongoing research and development strategy.

CYTOMX THERAPEUTICS, INC.

March 6, 2025

McCarthy, D.Phil.

Chief Executive Officer and Chairman

(Principal Executive Officer)

/s/ Christopher W.

Christopher W.

Chief Financial Officer

(Principal Financial Officer and Principal Accounting Officer)

POW ER OF ATTORNEY

Each person whose individual signature appears below hereby authorizes and appoints Sean A.

and Lloyd Rowland and each of them, with full power of substitution and resubstitution, as his or her true and lawful attorney-in-fact and agent to act in his or her name, place and stead and to execute in the name and on behalf of each person, individually and in each capacity stated below, and to file any and all amendments to this Annual Report on Form 10-K and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorney-in-fact and agents full power and authority to do and perform each and every act and thing, ratifying and confirming all that said attorney-in-fact and agents or his substitute or substitutes may lawfully do or cause to be done by virtue thereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Chief Executive Officer and Director

March 6, 2025

McCarthy, D.Phil.

(Principal Executive Officer)

/s/ Matthew P.

March 6, 2025

/s/ Alan Ashworth

March 6, 2025

Alan Ashworth, Ph.D.

/s/ Elaine V.

March 6, 2025

/s/ Mani Mohindru

March 6, 2025

Mani Mohindru, Ph.D.

/s/ Halley E.

March 6, 2025

Zhen Su, M.D.

Changes in and Disagreements with Accoun tants on Accounting and Financial Disclosure

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 7. Management’s Discussion and Analysis