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Item 1. Business

2026-03-09 compared with 2025-03-13 · 209 added, 195 removed, 406 unchanged (50% of the section changed)

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until immediately prior to the Merger) changed its corporate name to Cartesian Therapeutics, Inc.

We are a clinical-stage biotechnology company pioneering mRNA cell therapy for the treatment of autoimmune diseases.

We leverage our proprietary technology and manufacturing platform to introduce one or more mRNA molecules into cells to enhance their function.

We are a late clinical-stage biotechnology company pioneering cell therapy for the treatment of autoimmune diseases.

We leverage our proprietary technology and manufacturing platform to introduce mRNA into cells to provide a therapeutic effect to patients suffering from a variety of autoimmune conditions.

Unlike DNA, mRNA degrades naturally over time without integrating into the cell’s genetic material.

Therefore, our mRNA cell therapies are distinguished by their capacity to be dosed repeatedly like conventional drugs, administered in an outpatient setting, and given without pre-treatment chemotherapy required with many conventional cell therapies.

In a placebo-controlled Phase 2b clinical trial in patients with myasthenia gravis, or MG, a chronic autoimmune disease that causes disabling muscle weakness and fatigue, we observed that our lead product candidate, Descartes-08, generated a deep and durable clinical benefit where we observed an average MG-ADL (Activities of Daily Living) reduction of 5.5 points at Month 4 with a third of patients achieving minimal symptom expression at Month 6 and 80% of participants reaching Month 12 maintained a clinically meaningful response.

Durability of response in MG is commonly measured over a period of 26 to 52 weeks, and maintenance of response over that period is considered durable.

Our cell therapies are designed to be dosed repeatedly like conventional drugs, administered in an outpatient setting and given without pre-treatment chemotherapy required with many conventional cell therapies.

Autoimmune diseases, where the immune system mistakenly attacks the body, are a family of more than 80 disorders.

Autoimmune diseases are typically treated with immunosuppressant medications, such as steroids.

These treatments must be administered continually and carry risks, including infection, osteoporosis, and metabolic disease.

Newer agents that block the complement pathway or inhibit the neonatal Fc receptor, or FcRn, must also typically be administered continually.

We believe there is a significant unmet need for outpatient treatments, completed over a short period of time, that provide deep, durable clinical benefit.

Cell therapies have the potential to provide this benefit, but conventional cell therapies that use DNA are associated with toxicities, including cytokine release syndrome, or CRS, neurotoxicity, transformation to cancer, and death.

Further, conventional cell therapies typically require pre-treatment with chemotherapy, which suppresses the immune system and increases the risk of infection, anemia, and neurotoxicity.

As a result, conventional DNA cell therapies typically require close monitoring in an inpatient setting, increasing the total cost of care and generally limiting their reach to only the sickest patients.

We believe our mRNA cell therapies have the potential to deliver deep, durable clinical benefit to a broad group of patients with autoimmune diseases because they can be administered over a short period of time, in an outpatient setting, and without pre-treatment chemotherapy.

We are leveraging our proprietary technology and manufacturing platform to develop mRNA cell therapies for autoimmune diseases.

Our mRNA CAR-T modality is a personalized approach that collects a patient’s T-cells and uses mRNA to introduce a chimeric antigen receptor, or CAR, into the cell.

The CAR redirects the T-cells to target and destroy pathogenic self-reactive cells.

The table below summarizes key information about our development pipeline.

Our lead product candidate, Descartes-08, is an autologous mRNA CAR-T directed against the B cell maturation antigen, or BCMA, that we are developing for the treatment of autoimmune diseases.

Descartes-08 has been granted Orphan Drug Designation and Regenerative Medicine Advanced Therapy, or RMAT, Designation by the FDA for the treatment of MG as well as a Rare Pediatric Disease Designation for the treatment of juvenile dermatomyositis.

Descartes-08 for the Treatment of MG

In July 2024, we reported topline results from a Phase 2b randomized, double-blind, placebo-controlled trial in patients with MG.

The trial achieved its primary endpoint with statistical significance in the pre-specified modified intent-to-treat, or mITT, efficacy population, with 71% (10/14) of patients treated with Descartes-08 observed to have 5-point or greater improvements in MG Composite, or MGC, score at Month 3 compared to 25% (3/12) of patients treated with placebo (p=0.018).

In addition, the trial also achieved its primary endpoint with statistical significance in the per-protocol population, with 69% (11/16) of patients treated with Descartes-08 observed to have 5-point or greater improvements in MGC score at Month 3 compared to 33% (5/15) of patients treated with placebo (p=0.048).

Consistent with previously reported results from the Phase 2a open-label portion of the trial, Descartes-08 responders experienced deep improvements across the MG severity scales at Month 3 (average MG-ADL (Activities of Daily Living) = -5.6;

QMG (Quantitative MG) = -5.0;

QoL-15r (Quality of Life Revised Scale) = -7.9).

A 2-point improvement in MG-ADL and 3-point improvement in MGC and QMG scales are considered “clinically meaningful” by expert consensus published in peer-reviewed journals.

The improvements seen at Month 3 persisted or further improved in patients evaluated at their Month 4 (n=5) and Month 6 (n=3) follow-up visits, as of the June 19, 2024 data cutoff date.

In December 2024, we reported updated results from this trial.

Deepening of responses was observed over time with participants included in the primary efficacy dataset who continued follow-up (n=12) experiencing an average MG-ADL reduction of 5.5 (±1.1) at Month 4.

At Month 4, particularly deep responses were observed in participants without prior exposure to biologic therapies (n=7), including complement or neonatal fragment crystallizable receptor inhibitors, with an average MG-ADL reduction of 6.6 (±1.5).

Responses were observed to further deepen at Month 6, with 33% (4/12) of participants in the primary efficacy dataset and 57% (4/7) of participants with no prior exposure to biologic therapy observed to have minimum symptom expression, defined as an MG-ADL score of 0 or 1.

Responses were observed to be durable through Month 12, with 80% (4/5) of evaluable participants from the primary efficacy dataset maintaining a clinically meaningful response, defined as a reduction in MG-ADL score of at least 2 points.

Of the two participants with no prior exposure to biologic therapy that reached Month 12, both maintained at least a clinically meaningful response, with one continuing to demonstrate minimum symptom expression.

Consistent with previously reported results from the Phase 2a open-label portion of the trial, Descartes-08 continued to be observed as well-tolerated, supporting outpatient administration without the need for lymphodepleting chemotherapy.

Consistent with previously reported data, Descartes-08 was observed to be well-tolerated across the safety dataset (n=36), and adverse events were transient and mostly mild.

Notably, there were no cases of CRS, and no cases of immune effector cell-associated neurotoxicity syndrome, or ICANS.

In addition, treatment with Descartes-08 was not observed to lead to a decrease in vaccine titers for common viruses and was not associated with increased rates of infection or hypogammaglobulinemia.

Within this data readout, we also announced updated trial results from a Phase 2a open-label trial of Descartes-08 in patients with MG from certain retreated patients.

Two participants were previously retreated, and experienced rapid improvement in clinical scores and maintained minimum symptom expression for up to one year after receiving a second

treatment cycle.

A third participant received a second treatment cycle and at the participant’s Month 2 visit, two weeks after the last Descartes-08 infusion, achieved a 4-point reduction in MG-ADL and 6-point reduction in MGC scores from baseline, without reports of CRS or ICANS.

The time course and magnitude of treatment response upon retreatment were similar to the time course and magnitude of treatment response observed when the participants were first treated.

Four of the seven remaining participants from the Phase 2a portion of the trial maintained clinically meaningful responses for at least one year following initial dosing.

We plan to commence our Phase 3 AURORA trial of Descartes-08 in patients with MG in the first half of 2025.

The randomized, double-blind, placebo-controlled Phase 3 AURORA trial is designed to assess Descartes-08 versus placebo (1:1 randomization) administered as six weekly outpatient infusions without preconditioning chemotherapy in approximately 100 participants with acetylcholine receptor autoantibody positive, or AChR Ab+, MG.

The primary endpoint will assess the proportion of Descartes-08 participants with an improvement in MG-ADL score of three points or more at Month 4 compared to placebo.

Secondary endpoints will assess safety and tolerability and the proportion of participants with a reduction of four points or more in MGC score, as well as improvements in other validated MG severity scales, including Quantitative MG, QMG, and MG Quality of Life Revised Scale, or MG-QoL-15R.

In January 2025, we received written agreement from the FDA under the Special Protocol Assessment, or SPA, process on the overall design of our planned AURORA trial.

The SPA agreement indicates that the FDA has determined that the proposed trial design is acceptable to support a future Biologics License Application, or BLA, for Descartes-08 in MG, subject to the ultimate outcome of the trial.

Descartes-08 for the Treatment of Other Autoimmune Diseases

We are also developing Descartes-08 for the treatment of other autoimmune diseases.

In July 2024, the first patient was dosed in our Phase 2 trial of Descartes-08 for the treatment of systemic lupus erythematosus, or SLE, a chronic autoimmune disease that causes systemic inflammation affecting multiple organ systems.

A data readout of this trial is expected in the second half of 2025.

In December 2024, we filed an amendment to the investigational new drug application, or IND, for a pediatric basket trial for juvenile dermatomyositis, or JDM, juvenile SLE, juvenile MG, anti-neutrophil cytoplasmic antibody-associated vasculitis, as well as other conditions.

Our Phase 2 basket trial in pediatric patients is expected to initiate in the second half of 2025.

The FDA has also granted Descartes-08 Rare Pediatric Disease Designation for the treatment of JDM.

The FDA grants Rare Pediatric Disease Designation for serious and life-threatening diseases that primarily affect children ages 18 years or younger and fewer than 200,000 people in the United States.

Under the FDA’s Rare Pediatric Disease Designation and priority review voucher programs, if Decartes-08 is approved for marketing in JDM, Cartesian may qualify for a priority review voucher that can be redeemed to receive priority review of a subsequent marketing application for a different product candidate.

Descartes-15 is our next-generation autologous anti-BCMA mRNA CAR-T.

In preclinical studies, we have observed Descartes-15 to be 10-fold more potent than Descartes-08.

We are testing the safety of Descartes-15 in an open label, single-arm Phase 1 trial in patients with relapsed/refractory multiple myeloma.

This trial remains ongoing with three patients dosed to date.

We expect that the Phase 1 trial data will inform our clinical development plan for Descartes-15 in autoimmune diseases.

Limitations of Current DNA-Based Cell Therapy Treatments in Autoimmune Disease

Conventional DNA cell therapies have been associated with CRS, neurological toxicities and Parkinsonism, infection, risk of secondary malignancy, and death.

The acute toxicities are from exponential amplification of the modified cell, and the pre-treatment chemotherapy administered to enable cell amplification.

Conventional DNA-engineered CAR-T cells are in clinical development for several autoimmune diseases.

DNA CAR-T cells are typically administered to patients in a subtherapeutic dose, which means that the cells must proliferate to reach therapeutic numbers in the body.

However, this proliferation is not controlled in magnitude or duration, varies from patient to patient, and can be unpredictable.

This proliferation occurs because the CAR gene is irreversibly integrated into the T-cell’s genome, causing a cascade in which every daughter cell carries the same CAR as the parent cells.

The resulting unconstrained proliferation frequently exceeds the toxicity threshold, leading to serious adverse events.

In November 2023, the FDA announced that it is investigating the risk of T-cell malignancies in approved DNA CAR-T cell immunotherapies.

The proliferation of DNA CAR-T cells has typically required pre-treatment chemotherapy, usually fludarabine and cyclophosphamide administered for several days before CAR-T cell treatment.

This chemotherapy is toxic, suppressing the immune system and increasing the risk of infection, anemia, and neurotoxicity.

Given these risks and requirements, conventional DNA cell therapies are administered under close monitoring in an inpatient setting, increasing their cost and limiting their reach to only the sickest patients.

These diseases are typically treated with immunosuppressant medications, such as steroids, biologics and non-steroidal agents such as methotrexate, CD19 directed therapies and intravenous immunoglobulin.

These treatments must be administered chronically and carry risks, including infection, osteoporosis and metabolic disease.

The treatment landscape within generalized myasthenia gravis, or MG, offers agents that block the complement pathway or inhibit the neonatal Fc receptor, or FcRn, that typically must be administered chronically.

Even with recent treatment advancements in the field of MG, we believe there remains a significant unmet need for outpatient treatments, administered over a short period of time, and can provide deep and durable clinical benefit.

Limitations of Current Biologic Treatments in Autoimmune Disease

Currently approved biologic therapies for MG, such as complement inhibitors and FcRn inhibitors have significantly improved treatment options, but they come with limitations such as incomplete response, immunosuppression risks, high treatment burden, lack of disease modification and potential for emerging resistance.

Not all patients with AChR+ MG respond adequately to currently approved biologics.

The variability in treatment response may be due to differences in disease mechanisms, with some patients having disease drivers beyond complement activation (for complement inhibitors) or immunoglobulin G, or IgG, reduction (for FcRn inhibitors).

Additionally, some individuals experience an initial improvement but later lose response, requiring adjustments in their treatment strategy.

Currently approved biologic therapies for MG, such as complement inhibitors and FcRn inhibitors have improved treatment options.

However, these therapies are still limited by incomplete response, chronic dosing required to mitigate symptoms, immunosuppression risks, high treatment burden and lack of disease modification.

Not all patients with acetylcholine receptor autoantibody positive, or AChR+ MG, the subtype currently being pursued in our Phase 3 AURORA trial, respond adequately to currently approved biologics.

We believe the variability in treatment response may be due to differences in underlying disease pathologies, with some patients having disease drivers beyond complement activation (for complement inhibitors) or immunoglobulin G, or IgG, reduction (for FcRn inhibitors).

Additionally, some patients experience an initial improvement but later lose response, requiring adjustments in their treatment strategy.

Biologic therapies used for MG can increase the risk of infections.

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Patients receiving FcRn inhibitors may also experience an increased risk of infections due to immunoglobulin depletion.

The long-term safety of these treatments remains an area of active study.

The long-term safety of these treatments remain an area of active study.

Currently approved biologic therapies require frequent infusions, which can be burdensome for patients.

Efgartigimod requires weekly infusions in repeated cycles, while eculizumab is administered every two weeks and ravulizumab every eight weeks.

While ravulizumab reduces the frequency of infusions compared to eculizumab, both of these treatments require ongoing maintenance, which may impact patient quality of life.

Efgartigimod (Vyvgart) and rozanolixizumab (Rystiggo) both require weekly infusions in repeated cycles, while zilucoplan (Zilbrysq) is administered daily, both nipocalimab-aahu (Imaavy) and eculizumab (Soliris) are administered every two weeks, ravulizumab (Ultomiris) every eight weeks for most body weights and inebilizumab-cdon (Uplizna) every six months following two initial doses.

While ravulizumab and inebilizumab-cdon each reduce the frequency of infusions compared to eculizumab, both of these

treatments require ongoing maintenance, which may impact patient quality of life.

Access to infusion centers or home infusion services further adds to the logistical challenges.

All existing biologic therapies for MG manage symptoms rather than addressing the root cause of the disease.

These treatments do not eliminate the underlying autoimmune process or autoreactive B and T cells, meaning patients typically require lifelong therapy.

While symptom control is critical, the need for continuous treatment highlights the unmet need for therapies that could induce long-term remission.

Finally, the effectiveness of complement inhibitors may vary among patients due to differences in complement system activity or genetic factors.

Some individuals may have upregulated alternative complement pathways or specific gene polymorphisms that reduce the efficacy of eculizumab and ravulizumab.

This variability underscores the importance of identifying biomarkers that could help predict response and guide personalized treatment strategies.

The majority of approved biologic therapies for the treatment of MG focus on the management of symptoms rather than addressing the root cause of the disease.

These treatments do not eliminate the underlying autoimmune process or autoreactive B and T cells, meaning patients typically require chronic lifelong therapy.

While symptom control is critical, the need for continuous treatment highlights the unmet need for therapies that can induce long-term remission and a precision immune reset.

Limitations of Current DNA-Based Cell Therapy Treatments in Autoimmune Disease

Compared to biologic therapies, cell therapies have increased potential to provide a deep and durable clinical benefit;

however, conventional DNA cell therapies have been associated with cytokine release syndrome, or CRS, neurological toxicities and Parkinsonism, infection, risk of secondary malignancy and death.

The acute toxicities are from exponential amplification of the modified cell and the pre-treatment chemotherapy administered to enable cell amplification.

Conventional DNA-engineered chimeric antigen receptor, or CAR, T-cells are in clinical development for several autoimmune diseases.

DNA CAR-T cells are typically administered to patients in a subtherapeutic dose, which means that the cells must proliferate to reach therapeutic numbers in the body.

However, this proliferation is not controlled in magnitude nor duration, varies from patient to patient, and can be unpredictable.

This proliferation occurs because the CAR gene is irreversibly integrated into the T-cell’s genome, causing a cascade in which every daughter cell carries the same CAR as the parent cells.

The resulting unconstrained proliferation frequently exceeds the toxicity threshold, leading to serious adverse events, or SAEs.

The proliferation of DNA CAR-T cells typically requires pre-treatment chemotherapy, usually fludarabine and cyclophosphamide, administered for several days before CAR-T cell treatment.

This chemotherapy is toxic, suppressing the immune system and increasing the risk of infection, anemia, and neurotoxicity.

Our Autoimmune Disease Solution

We believe that mRNA cell therapy has the potential to be a potent yet safer alternative to DNA cell therapy for treating autoimmune diseases.

As the data in our clinical trials indicates, the mRNA cell therapies we are developing have the potential to deliver deep and durable clinical benefits to many patients with autoimmune diseases because they can be administered over a short period of time, in an outpatient setting, and without pre-treatment chemotherapy.

These attributes may extend the reach and potential of mRNA cell therapy to a broader group of patients with autoimmunity.

mRNA CAR-T cells locate their target, become activated, and proliferate like DNA CAR-T cells.

However, because mRNA does not replicate and degrades naturally over time, the maximum number of mRNA molecules can be determined by the dose.

The actual number of mRNA molecules declines to zero over time.

The number of mRNA molecules determines the degree of CAR protein expression, and the persistence of the mRNA molecules determines the duration of mRNA CAR-T cell activity.

Thus, unlike DNA CAR-T cells, our mRNA CAR-T cells provide pharmacokinetic control.

In other words, a patient’s exposure to our cells is determined by the dose.

The time, course and duration of that exposure are substantially determined by

the nature of the mRNA we use.

Therefore, while DNA CAR-T therapies are administered at subtherapeutic levels, we can administer a therapeutic number of mRNA CAR-T cells and re-dose these cells over time, much like a conventional drug.

Because the mRNA cannot be replicated, we believe, and have thus far observed, that mRNA CAR-T cells do not cause the types of severe toxicity associated with DNA CAR-T cells.

Also, because mRNA CAR-T is dosed at a therapeutic dose and does not rely on cell proliferation to reach the therapeutic window, there is no need to administer pre-treatment chemotherapy.

As of December 31, 2024, we have administered Descartes-08 to over 100 patients suffering from one of MG, multiple myeloma, and other diseases in open-label trials on an outpatient basis, many at community clinics.

Descartes-08, our lead cell therapy product candidate, is an autologous CAR-T product targeting B-cell maturation antigen, or BCMA, in clinical development for the treatment of MG and myositis, specifically, moderate to severe multi-refractory dermatomyositis and antisynthetase syndrome.

In contrast to conventional DNA-based CAR T-cell therapies, our CAR-T administration has been observed to provide deep and durable benefits through 12 months, is designed to not require preconditioning chemotherapy, to be administered in the outpatient setting and does not carry the risk of genomic integration associated with cancerous transformation.

Descartes-08 has been granted Orphan Drug Designation and Regenerative Medicine Advanced Therapy, or RMAT, Designation by the FDA for the treatment of MG, and Rare Pediatric Disease Designation for the treatment of juvenile dermatomyositis, or JDM.

Based on efficacy and safety data observed in our clinical trials thus far, we believe our cell therapies have the potential to deliver deep and durable clinical benefit to a broad group of patients with autoimmune diseases after a single course of therapy.

We aim to provide a personalized approach to treating patients that begins with the collection of a patient’s cells which we then use to manufacture our cell therapy product candidates.

Once a patient’s cells have expanded in our process, we introduce mRNA to deliver a CAR into the cell.

Once the manufacturing process is complete, we send the product candidate back to the treating physician where they administer six weekly infusions of our cell therapy to the patient.

Descartes-08 is specifically designed to target and destroy the pathogenic, self-reactive cells that are the underlying cause of the autoimmune disease, with the goal of creating a precision immune reset for the patient.

The table below summarizes key information about our development pipeline.

As of December 31, 2025, we have administered Descartes-08 to over 100 patients suffering from one of MG, multiple myeloma, and other diseases in open-label and randomized placebo-controlled trials on an outpatient basis.

We have not observed product-related CRS, neurotoxicity or infection of any grade.

The most common product-related adverse events observed, headache, nausea, and fever, were self-limited and resolved within 72 hours of onset.

One participant with MG with a history of allergic reaction to biologics developed hives after the third infusion and was hospitalized for monitoring.

The patient’s hives resolved completely after a brief course of steroids.

The most common product-related adverse events, or AEs, observed, headache, nausea, and fever, were self-limited and resolved within 24 hours of onset.

Our Product Candidates

Descartes-08, our lead mRNA cell therapy candidate, is an autologous mRNA CAR-T product targeting BCMA in clinical development for generalized MG and SLE.

In contrast to conventional DNA-based CAR T-cell therapies, mRNA CAR-T administration is designed to not require preconditioning chemotherapy, can be administered in the outpatient setting, and does not carry the risk of genomic integration associated with cancerous transformation.

Descartes-08 has been granted Orphan Drug Designation and RMAT Designation by the FDA for the treatment of MG, and Rare Pediatric Disease Designation for the treatment of JDM.

Descartes-08 for the Treatment of MG

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Clinical Development

To date, we have completed the Phase 1/2 trial of Descartes-08 in MG, which consisted of a Phase 1b portion, a Phase 2a portion, and a Phase 2b portion.

To date, we have completed a Phase 1/2 trial of Descartes-08 in MG, which consisted of a Phase 1b portion, a Phase 2a portion, and a Phase 2b portion.

The primary objective of the Phase 1b portion of the trial was to determine the maximum tolerated dose of Descartes-08 for patients with MG.

We observed Descartes-08 to be well-tolerated by the three patients who participated in this portion of the trial with no CRS or other serious product-related adverse events.

We observed Descartes-08 to be well-tolerated by the three patients who participated in this portion of the trial with no CRS or other serious product-related AEs observed.

The primary objective of the Phase 2a portion of the trial was to determine the optimal dosing schedule for patients with MG using the highest dose level tested in Phase 1b (52.5 x106 cells/kg).

This portion of the trial was designed to assess the safety and preliminary efficacy of Descartes-08 when administered across three different treatment schedules (six doses given twice-weekly, once-weekly, or once-monthly).

This portion of the trial evaluated 11 patients with particularly advanced disease as assessed by both patient and clinician-reported outcomes.

This portion of the trial evaluated 11 patients with particularly advanced disease

as assessed by both patient and clinician-reported outcomes.

11 of the 14 patients included in the Phase 1b and Phase 2a portions of the trial were classified at screening to have Class III or IV disease, as defined by the Myasthenia Gravis Foundation of America, indicating they had moderate-to-severe weakness affecting their muscles.

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Follow-on results of the Phase 2b portion of the trial were presented in December 2024.

The trial reached its primary endpoint to assess the proportion of patients achieving a five-point or greater reduction in their MGC score at day 85.

The trial achieved its primary endpoint to assess the proportion of patients achieving a five-point or greater reduction in their MGC score at day 85.

Patients received six weekly infusions at the dose established in Phase 1b (52.5 x106 cells/kg).

The trial also involved a crossover component in which any patient originally assigned to placebo was given the opportunity to receive Descartes-08 after completing trial treatment.

In the Phase 2b trial, we observed a deepening of responses after Month 3 in the primary efficacy data set.

Two MG composite responders at Month 3 withdrew from the study before Month 4 for personal reasons (total number of participants at Month 4 and Month 6 was 12).

Of the 12 participants as of the readout date, eight had reached Month 9 follow-up and five had reached Month 12 follow-up, thus completing the trial.

Results of the study showed an average MG-ADL reduction of 5.5 points at Month 4 (chart below on the left) and an average MGC reduction of 7.1 for Descartes-08 treated patients (chart below on the right), both of which exceed the thresholds clinicians generally consider clinically meaningful, defined as a reduction in MG-ADL score of at least two points and a reduction in MGC score of at least three points.

Additionally, at Month 6, one third of all participants were observed to achieve minimal symptom expression.

This is consistent with what we observed in the Phase 2a trial, where deepest responses were observed to occur at Month 6 and Month 9.

Additionally, 80% of all participants who reached Month 12, including both responders and non-responders at Month 3, were observed to maintain clinically meaningful responses as measured by both MG-ADL and MGC.

We also observed that 57% of the participants with no prior exposure to biologic therapy, achieved minimal symptom expression at Month 6.

Of the two participants with no prior exposure to biologic therapy that reached Month 12, both were observed to maintain at least a clinically meaningful response with one continuing to maintain minimal symptom expression.

In April, 2025, we reported updated, 12-month data from this trial and published this data in Nature Medicine in January 2026.

Responses amongst this patient population without prior exposure to biologic therapies were observed to deepen through Month 12 with an average MG-ADL reduction of 7.1 (±1.9).

The deepest responses were observed as minimal symptom expression, or MSE, defined as an MG-ADL score of 0 or 1.

The tables below set forth the results observed.

33% (4/12) of participants in the primary efficacy dataset and 57% (4/7) of participants with no prior exposure to biologic therapy were observed to achieve MSE by Month 6 and maintained it through Month 12.

Responses were observed to be durable through Month 12, with 83% (10/12) of evaluable participants from the primary efficacy dataset maintaining a clinically meaningful response, defined as a reduction in MG-ADL score of at least 2 points.

Of the seven participants with no prior exposure to biologic therapy that reached Month 12, 100% maintained at least a clinically meaningful response.

The safety profile observed in the follow-up portion of the Phase 2b trial was in line with what we reported at the time of our top line data readout as well as the Phase 2a portion of the trial.

Of note, there was a Grade 2 upper respiratory infection reported in both the Descartes-08 and placebo groups.

There were no other new adverse events, or AEs, reported, including no hypogammaglobulinemia and other infections and no difference in vaccine titers between Descartes-08 and placebo.

There were no other new AEs reported after Month 3 follow-up, including no hypogammaglobulinemia and other infections and there was no difference in vaccine titers between Descartes-08 and placebo.

The table below summarizes the safety results observed.

We previously reported that there were three participants in the Phase 2a portion of the trial who were observed to have a response to Descartes-08, but then reverted to baseline, two patients one year after treatment and the other 1.5 years after treatment.

As previously reported, there were two participants who were retreated and experienced rapid improvements in clinical scores and maintained minimum symptom expression for up to one year after receiving a second treatment cycle.

The tables below set forth key findings from these patients.

The time course and magnitude of treatment response upon retreatment were similar to those seen when the participants were first treated.

Notably, in the one participant who completed their 12-month retreatment follow-up visit, the duration of response was observed to be longer than that patient’s initial response, and this patient had maintained minimum symptom expression at Month 12.

The third retreated participant, at their Month 2 visit, which was 2 weeks after their last Descartes-08 infusion, achieved a 4-point reduction in MG-ADL and 6-point reduction in MGC scores from baseline, without reports of CRS or ICANS.

The third retreated participant’s responses deepened from a 4-point MG-ADL reduction at Month 2 to a 9-point improvement in MG-ADL at Month 12 following retreatment.

In May 2025, we initiated our Phase 3 AURORA trial of Descartes-08 in patients with MG.

The primary endpoint will assess the proportion of Descartes-08 participants with an improvement in MG-ADL score of

three points or more at Month 4 compared to placebo.

Secondary endpoints will assess safety and tolerability and the proportion of participants with a reduction of four points or more in MG Composite, or MGC, score, as well as improvements in other validated MG severity scales, including QMG, and MG Quality of Life Revised Scale, or MG-QoL-15R.

In January 2025, we received written agreement from the FDA under the Special Protocol Assessment, or SPA, process on the overall design of our planned AURORA trial.

The complete trial design for AURORA is set forth below.

Descartes-08 for the Treatment of Myositis

Background Information About Myositis

Myositis is a rare set of pathogenic autoantibody-driven diseases characterized by inflammation and muscle weakness.

Myositis symptoms can range from mild to life-threatening and symptoms often include muscle weakness, joint or muscle pain, fatigue, swelling, trouble breathing or swallowing, and arrhythmia.

Myositis impacts approximately 80,000 people in the United States.

Based on strong mechanistic alignment with our existing clinical data in MG and SLE as well as the significant unmet need that remains, in November 2025 we announced the expansion of our development of Descartes-08 into myositis, specifically dermatomyositis and antisynthetase syndrome, a significantly underserved market with high unmet need.

The FDA accepted our investigational new drug application, or IND, in December 2025 for a clinical trial design which provides a potential opportunity for a single pivotal trial.

We expect to commence this trial in the first half of 2026.

Our randomized, double-blind, placebo-controlled Phase 2 trial in myositis is designed to assess Descartes-08 versus placebo (1:1 randomization) administered as six weekly outpatient infusions without preconditioning chemotherapy in up to 50 patients with moderate to severe multi-refractory dermatomyositis and antisynthetase syndrome.

The primary endpoint is expected to assess safety and efficacy of Descartes-08 compared to placebo added to standard of care in participants with myositis at Week 24.

We currently intend to conduct a blinded interim analysis through the Data Safety Monitoring Board, or DSMB, after ten patients are enrolled and reach the primary endpoint, at which point we may revise sample size assumptions to what could be necessary to support the trial becoming pivotal, pending FDA review.

The complete trial design for this trial is set forth below.

Descartes-08 for the Treatment of Juvenile Dermatomyositis

Background Information About Juvenile Dermatomyositis

Juvenile Dermatomyositis is a rare pediatric autoimmune disorder marked by pathognomonic skin rash and muscle inflammation affecting multiple organ systems including the joints, heart, lungs, kidneys, eyes, and gastrointestinal systems.

The symptoms of JDM can range from mild to life-threatening and symptoms often include fatigue, joint pain, muscle weakness and fever.

JDM impacts approximately 4,000 people in the United States.

Clinical Development

In December 2024, we filed an amendment to the IND for a pediatric basket trial including juvenile dermatomyositis, or JDM.

The initiation of the Phase 2 pediatric basket trial was announced in January 2026.

The FDA has also granted Descartes-08 Rare Pediatric Disease Designation for the treatment of JDM.

The FDA grants Rare Pediatric Disease Designation for serious and life-threatening diseases that primarily affect children ages 18 years or younger and fewer than 200,000 people in the United States.

Under the FDA’s recently renewed Rare Pediatric Disease Designation and priority review voucher programs, if Descartes-08 is approved for marketing in JDM, Cartesian may qualify for a priority review voucher that can be redeemed to receive priority review of a subsequent marketing application for a different product candidate.

Descartes-08 for the Treatment of Systemic Lupus Erythematosus

We are also developing Descartes-08 for the treatment of SLE, a chronic autoimmune disease that causes systemic inflammation which affects multiple organ systems.

In November 2025, we announced topline data from our Phase 2 trial in SLE, a chronic autoimmune disease that causes systemic inflammation which affects multiple organ systems.

We also announced a pause in further development of Descartes-08 in SLE, including further enrollment in the Phase 2 trial, in order to prioritize opportunities in MG and myositis.

Shortly thereafter we made a further decision to no longer pursue development of Descartes-08 in SLE.

The Phase 2 trial in SLE remains ongoing for follow-up only.

Background Information About Systemic Lupus Erythematosus

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SLE is the most common form of lupus, representing approximately 70% of lupus patients, and approximately three million adults worldwide are estimated to have SLE.

We recently initiated a multi-center open-label single-arm Phase 2 trial, for which we have received FDA IND allowance.

The primary objective of this trial is to evaluate the safety, tolerability, and manufacturing feasibility of Descartes-08 mRNA CAR-T cells administered as six once-weekly outpatient infusions of 52.5x106 cells/kg without pre-treatment chemotherapy in approximately 30 patients with SLE.

We also filed an amendment to the IND application with our Descartes-08 product candidate in pediatric autoimmune disease in December 2024.

This Phase 2 SLE trial of Descartes-08 remains ongoing and a preliminary data readout is expected in the second half of 2025.

Clinical Development

The Phase 2 open-label trial was designed to evaluate outpatient administration of Descartes-08 without preconditioning chemotherapy or integrating vectors for the treatment of patients with moderate or severe SLE refractory to immunosuppressant therapy.

The primary outcome measure assesses safety and tolerability, with secondary outcome measures assessing preliminary efficacy.

The complete trial design is set forth below.

The tables below set forth the results of the Phase 2 trial.

Initial data from the Phase 2 trial reported significant reduction in disease activity following initial Descartes-08 treatment with 100% of participants who reached Month 3 follow-up (n=3) achieving Lupus Low Disease Activity State, or LLDAS, response, defined by specific criteria that indicate low disease activity, improved patient outcomes, and sustained symptom improvement.

Disease remission reported as DORIS response was seen in 2 out of 3 participants at Month 3.

DORIS is defined as the Definition of Response in SLE indicating a clinical SLE Disease Activity Index, or SLEDAI-2K score of 0 and physician global assessment, or PGA, of less than 0.5.

We believe these results suggest that Descartes-08 may have clinical effect in the field of autoimmune disease broadly.

The tables below set forth the safety results from the Phase 2 trial.

In this trial, Descartes-08 continued to be observed as well-tolerated, supporting outpatient administration without the need for lymphodepleting chemotherapy.

AEs reported were transient and mostly mild, with no AEs above Grade 2 or SAEs and notably, there were no cases of CRS and no cases of immune effector cell-associated neurotoxicity syndrome.

Infusion-related fever and flu-like symptoms were the most common AEs, and all resolved within 24 hours.

No hypogammaglobulinemia or decrease in vaccine titers were observed and immunoglobulin levels were consistent with measurements at baseline.

We believe observations of correlative biomarkers support application of Descartes-08 in multiple autoimmune diseases.

In particular, we observed a statistically significant (p<0.01) decrease in proinflammatory cytokines associated with SLE pathogenesis (IL7, IL10, CCL20, ST1A1).

Additionally, significant decreases were observed in plasmacytoid dendritic cells, or pDCs, three months after receiving Descartes-08 in both MG and SLE patients, which we believe supports the expansion into myositis, given myositis’ known pDC correlation.

Descartes-15 is a next-generation, autologous anti-BCMA mRNA CAR-T.

Using our proprietary technology and manufacturing platform, we designed Descartes-15 to be more resistant than Descartes-08 to recycling of the CAR upon multiple antigen exposures.

We believe this is a particularly important feature to increase the durability of CAR expression on the surface of these cells.

We observed that Descartes-15 was 10-fold more potent than Descartes-08 in preclinical studies, as illustrated in the below charts.

In November 2023, we received IND allowance from the FDA to initiate the Phase 1 trial to test the safety of Descartes-15 in patients with multiple myeloma and dosing is underway in this trial.

The Phase 1 dose escalation trial is designed to assess the safety and tolerability of outpatient Descartes-15 administration in patients with multiple myeloma.

Following the Phase 1 dose escalation trial, we expect to subsequently assess Descartes-15 in autoimmune indications.

We observed that Descartes-15 was 10-fold more potent than Descartes-08 in preclinical studies.

In November 2025, we reported results from the Phase 1 dose escalation trial designed to assess safety and tolerability of outpatient administration of Descartes-15 in patients with multiple myeloma.

In this trial, no significant AEs or dose-limiting

toxicities were reported in any of the three participants.

The only Descartes-15-related adverse event was a grade 2 hypotension occurring after the first two infusions.

Despite favorable safety data observed in this trial, we have paused further development of Descartes-15 to prioritize opportunities for Descartes-08 in MG and myositis.

In-Vivo Development

Our current pipeline consists of autologous treatments for patients.

However, there have been recent advancements within the in-vivo space.

An in-vivo cell therapy treats disease by modifying a patient’s cells inside their body, rather than doing so via autologous means.

In-vivo treatment options create an opportunity for more convenient dosing with less frequent procedures.

As we advance our pipeline, we continue to evaluate the potential of enhanced delivery platforms for our cell therapies with multiple feasibility studies underway to explore the potential timing for optimizing in-vivo delivery of our assets currently in development.

Manufacturing

We have established wholly-owned internal manufacturing and research and development capabilities, which allow us to optimize processes rapidly and in an iterative manner.

We have established wholly-owned internal manufacturing and research and development capabilities, designed to allow us to optimize processes rapidly in an iterative manner and maintain control over the critical components of the supply chain.

Our main manufacturing facility is located in Frederick, Maryland, and operates under current good manufacturing practice, or cGMP.

This facility has sufficient capacity to support current clinical needs and can potentially transition to support commercial manufacturing of our maturing pipeline of innovative mRNA cell therapies for the treatment of autoimmune diseases.

We believe the Frederick facility will allow us to scale our wholly-owned, in-house cGMP manufacturing capabilities for late-stage clinical and commercial supply of our mRNA cell therapy product candidates, while continuing to maintain control over product quality and production.

We also maintain additional manufacturing space located in Gaithersburg, Maryland.

This facility has sufficient capacity to support current clinical needs and can potentially transition to support commercial manufacturing of our maturing pipeline of innovative cell therapies for the treatment of autoimmune diseases.

We believe the Frederick facility has the potential to allow us to scale our wholly-owned, in-house cGMP manufacturing capabilities for late-stage clinical and commercial supply of our cell therapy product candidates, while continuing to maintain control over product quality and production.

We manufacture Descartes-08 in-house and are typically able to process and release lots for infusion within approximately three weeks.

Our autologous cell therapy product candidates, including Descartes-08, are manufactured on a patient-by-patient basis.

We have optimized our manufacturing processes through over 200 cGMP runs.

We have optimized our manufacturing processes through over 200 cGMP runs across all of our current and prior programs.

Intellectual Property

Our success depends in part on our ability to obtain, maintain, protect, defend and enforce proprietary protection for our drug candidates and other discoveries, inventions, trade secrets and know-how that are critical to our business operations.

Our success depends in part on our ability to obtain, maintain, protect, defend and enforce proprietary rights for our product candidates and other discoveries, inventions, trade secrets and know-how that are critical to our business operations.

Our success also depends in part on our ability to operate without infringing, misappropriating or otherwise violating the proprietary rights of others, and in part on our ability to prevent others from infringing, misappropriating or violating our proprietary rights.

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285909, and Korean Patent No.

Our issued patents and any patents issuing from our pending applications are set to expire on various dates in 2040 through 2044.

Additionally, as of December 31, 2024, we had 13 patent applications pending worldwide, including three U.S.

applications, eight applications in ex-U.S.

jurisdictions, and 2 International (PCT) applications.

A patent granted on U.S.

Our issued patents and any patents issuing from our pending applications are set to expire on various dates ranging from 2040 to 2044.

Additionally, as of December 31, 2025, we had 24 patent applications pending worldwide, including seven U.S.

applications and seventeen applications in ex-U.S.

jurisdictions.

A patent granted from U.S.

Patent Application No.

18/654,279 will expire on March 13, 2040, a patent granted on U.S.

18/654,279 will expire on March 13, 2040, a patent granted from U.S.

Patent Application No.

17/919,092 will expire on April 15, 2041, and a patent granted on U.S.

17/919,092 will expire on April 15, 2041, a patent granted from U.S.

Patent Application No.

18/292,670 will expire on July 28, 2042, barring any potential patent term adjustment or terminal disclaimers.

patent applications are directed to compositions of matter, and U.S.

18/292,670 will expire on July 28, 2042, a patent granted from U.S.

Patent Application No.

18/292,670 is also directed to methods of use.

In addition, PCT/US2024/020251 was filed on March 15, 2024, a composition-of-matter and method-of-use PCT application, and any national stage application based on it will expire on March 15, 2044.

Also, PCT/US2024/020815 was filed on March 20, 2024, a composition-of-matter and method-of-use PCT application, and any national stage applications based on it will expire on March 20, 2044.

In addition, a patent granted on any of European patent application 20773688.5, AU 2020241428, CA 3199205, CN 202080020956.1, IN 202117036675, KR 2023-7034215, or MX/a/2021/011196 will expire March 2040 and a patent granted on European patent application 21789568.9 will expire April 2041.

All of these patent applications are composition-of-matter applications.

In addition, we had two registered marks protecting our brand and prospective products both domestically and internationally.

With respect to the legacy Selecta assets, as of December 31, 2024, we had (i) 102 issued patents worldwide, including 11 patents issued in the United States and 91 issued outside the United States, set to expire on various dates in 2032 through 2043, (ii) 65 patent applications pending worldwide, including 12 U.S.

19/166,014 will expire on March 15, 2044, and a patent granted from U.S.

Patent Application No.

19/166,759 will expire on March 20, 2044, excluding any potential patent term adjustments, patent term extensions, or terminal disclaimers.

patent applications are directed to compositions of matter, methods of use, and methods of manufacture.

In addition, a patent granted on any of foreign patent applications EP 20773688.5, AU 2020241428, CA 3199205, CN 202080020956.1, IN 202117036675, KR 2023-7034215, and MX/a/2021/011196 will expire March 2040, a patent granted on European patent application 21789568.9 will expire April 2041, and a patent granted on any of foreign patent application EP 24775468.2, AU 2024240255, BR112025019788-6, CA 3286127, CN 202480031788.4, JP 2025-554182, KR 10-2025-7034765, MX/a/2025/010878, and SG 11202506142T will expire March 2044.

All of these patent applications are composition-of-matter, methods-of-use, and/or methods-of-manufacture applications.

There are also two pending U.S.

provisional applications, and any patent ultimately claiming priority to one of these provisional applications will expire in or around 2046.

In addition, as of December 31, 2025, we had two registered marks protecting our brand and prospective products both domestically and internationally.

With respect to the legacy Selecta assets, as of December 31, 2025, we had (i) 294 issued patents worldwide, including 14 patents issued in the United States and 280 issued outside the United

States, set to expire on various dates in 2032 through 2040, (ii) 75 patent applications pending worldwide, including 13 U.S.

applications and 62 applications outside the United States and (iii) two registered marks.

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Unless we obtain a waiver from NCI, we must have licensed products and licensed processes manufactured substantially in the United States.

Prior to the first commercial sale, upon NCI’s request, we are obligated to provide NCI with commercially reasonable quantities of licensed products made through licensed processes to be used for in vitro research.

to the first commercial sale, upon NCI’s request, we are obligated to provide NCI with commercially reasonable quantities of licensed products made through licensed processes to be used for in vitro research.

Additionally, we must use reasonable commercial efforts to initiate a Phase 3 clinical trial of a licensed product by the fourth quarter of 2024, submit a BLA with respect to a licensed product by the fourth quarter of 2026, and make a first commercial sale of a licensed product by the fourth quarter of 2028.

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There is also a pending patent application which, if issued, will expire on March 15, 2033, but could also be subject to patent term adjustment and to any potential future terminal disclaimers.

NCI has the right to

terminate this agreement, after giving written notice and providing a cure period in accordance with its terms, if we are in default of a material obligation.

NCI has the right to terminate this agreement, after giving written notice and providing a cure period in accordance with its terms, if we are in default of a material obligation.

We have the unilateral right to terminate the agreement in any country or territory by giving NCI 60 days’ written notice.

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On June 11, 2020, we entered into a License and Development Agreement with Swedish Orphan Biovitrum AB (publ.), or Sobi, which was amended on October 31, 2023, or, as so amended, the Sobi License.

Pursuant to the Sobi License, we granted Sobi an exclusive, worldwide (except as to Greater China) license to develop, manufacture and commercialize a drug candidate known as SEL-212, which is currently in development for the treatment of chronic refractory gout.

Pursuant to the Sobi License, Sobi agreed to make milestone payments totaling up to $630.0 million to us upon the achievement of various development and regulatory milestones and, if commercialized, sales thresholds for annual net sales of SEL-212, and tiered royalty payments ranging from the low double digits on the lowest sales tier to the high teens on the highest sales tier.

Pursuant to the Sobi License, we granted Sobi an exclusive, worldwide (except as to Greater China) license to develop, manufacture and commercialize a drug candidate Nanoecapsulated Sirolimus plus Pegadricase, or NASP, formerly known as SEL-212, which is currently in development for the treatment of chronic refractory gout.

Pursuant to the Sobi License, Sobi agreed to make milestone payments totaling up to $630.0 million to us upon the achievement of various development and regulatory milestones and, if commercialized, sales thresholds for annual net sales of NASP, and tiered royalty payments ranging from the low double digits on the lowest sales tier to the high teens on the highest sales tier.

Any proceeds received from milestone payments or royalties relating to the Sobi License would be required to be distributed to holders of CVRs, net of certain deductions.

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Sobi may terminate the Sobi License for any reason upon 180 days’ written notice, whereby all rights granted under the Sobi License would revert back to us.

In addition, if Sobi were to terminate the Sobi License, we have the option to obtain a license to all patents and know-how necessary to exploit SEL-212 in existence as of the termination date from Sobi in return for making an equitable royalty payment to Sobi.

In addition, if Sobi were to terminate the Sobi License, we have the option to obtain a license to all patents and know-how necessary to exploit NASP in existence as of the termination date from Sobi in return for making an equitable royalty payment to Sobi.

The biotechnology and pharmaceutical industries are characterized by rapidly advancing technologies, intense competition, and a strong emphasis on proprietary products.

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Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies.

The key competitive factors affecting the success of any other cell therapy product candidates that we develop, if approved, are likely to be their efficacy, safety, convenience, price, the level of generic competition and the availability of reimbursement from government and other third-party payors.

Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products that are more effective, have fewer or less severe side effects, are more convenient or are less expensive than any products that we may develop.

The key competitive factors affecting the success of any other cell therapy product candidates that we develop, if approved, are likely to be their efficacy, durability of response, safety, convenience, price, the level of generic competition and the availability of reimbursement from government and other third-party payors.

Our competitors also may obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for ours.

In addition, our ability to compete may be affected in many cases by insurers or other third-party payors seeking to encourage the use of generic or biosimilar products.

Descartes-08 may compete with products of other companies in the MG market, including Argenx SE, UCB S.A., Johnson & Johnson, Alexion Pharmaceuticals, Inc.

Descartes-08 may compete with products of other companies in the MG market, including Amgen, Argenx SE, UCB S.A., Johnson & Johnson through its Janssen Pharmaceuticals, Inc.

subsidiary, AstraZeneca PLC through its Alexion Pharmaceuticals, Inc.

subsidiary, Kyverna Therapeutics, Inc.

and Cabaletta Bio, Inc.

Other companies developing CAR-T therapies include large, fully integrated pharmaceutical companies such as Novartis AG, Gilead Sciences, Inc., through its Kite Pharma, Inc.

subsidiary, Bristol-Myers Squibb Company, AstraZeneca PLC and Janssen Pharmaceuticals, Inc.

and biopharmaceutical companies such as Kyverna Therapeutics, Inc.

subsidiary, Bristol-Myers Squibb Company, and biopharmaceutical companies such as Kyverna Therapeutics, Inc.

and Cabaletta Bio, Inc.

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Government authorities in the United States, at the federal, state and local level, and in other countries, extensively regulate, among other things, the research, development, testing, manufacturing, quality control, approval, labeling, packaging, storage, record-keeping, promotion, advertising, distribution, post-approval monitoring and reporting, marketing and export and import of products such as those we are developing.

We believe our cell therapy product candidates are subject to regulation in the United States as “biologics” or “biological products.” We expect to seek approval of Descartes-08 through a single BLA reviewed by FDA’s Center for Biologics Evaluation and Research, or CBER.

We believe our cell therapy product candidates are subject to regulation in the United States as “biologics” or “biological products.” We expect to seek approval of Descartes-08 through a BLA reviewed by FDA’s Center for Biologics Evaluation and Research, or CBER.

Biological products are subject to regulation under the Federal Food, Drug, and Cosmetic Act, or the FD&C Act, and the Public Health Service Act, or the PHS Act, and other federal, state, local and foreign statutes and regulations.

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In response to a request for an SPA agreement, the FDA issues a letter to the sponsor indicating its agreement or non-agreement with elements of the proposed protocol.

substantial scientific issue essential to determining the safety or effectiveness of the drug after the testing has begun.

An SPA agreement documents the FDA’s concurrence with the adequacy and acceptability of specific critical elements of the protocol design, and the FDA may not change an SPA agreement once the trial is underway unless the sponsor or applicant agrees in writing or the FDA identifies a substantial scientific issue essential to determining the safety or effectiveness of the drug after the testing has begun.

Even if the sponsor conducts the trial in accordance with an SPA agreement and the trial meets its endpoints with statistical significance, there is no guarantee that the FDA will accept or approve a marketing application.

For example, the FDA could determine that the overall balance of risks and benefits for the product candidate is not adequate to support approval, or only justifies approval for a narrow set of clinical uses or approval with restricted distribution or other post-approval requirements or limitations.

In January 2025, we received written agreement under the SPA process on overall design of the our planned Phase 3 AURORA trial for Descartes-08 in MG.

The SPA agreement indicates that the FDA has determined that the proposed trial design is acceptable to support a future BLA for Descartes-08 in MG, subject to the ultimate outcome of the trial.

Post-approval clinical trials, sometimes referred to as Phase 4 clinical trials, may be conducted after initial marketing approval to gain additional experience from the treatment of patients in the intended therapeutic indication, particularly for long-term safety follow-up.

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One of the performance goals agreed to by the FDA under PDUFA is to review 90% of standard BLAs in 10 months from the filing date and 90% of priority BLAs in six months from the filing date, whereupon a review decision is to be made.

additional months are added to these timelines for new molecular entities.

The FDA does not always meet its PDUFA goal dates for standard and priority BLAs.

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Orphan product exclusivity also could block the approval of one of our products for seven years if a competitor obtains approval of the same biological product as defined by the FDA or if our product candidate is determined to be contained within the competitor’s product for the same indication or disease.

The scope of any eventual orphan exclusivity relative to the orphan designation is the subject of ongoing litigation and as such is uncertain and may change.

For example, under FDA regulations, a designated orphan product may not receive orphan exclusivity for a use that is broader than the indication for which it received orphan designation and FDA approval.

However, in 2021, the U.S.

Court of Appeals for the Eleventh Circuit in Catalyst Pharmaceuticals, Inc.

Becerra adopted a broader interpretation of the scope of orphan exclusivity.

The court in Catalyst held that orphan exclusivity blocks approval of another company’s application for the “same drug” for the “entire disease or condition” for which the drug is granted orphan designation, regardless of whether the product was approved only for a narrower use or indication.

Similarly, in 2025, the U.S.

District Court for the District of Columbia in Neurelis v.

Brenner adopted the same reasoning as the court in Catalyst to reach the same conclusion.

Although the FDA announced in January 2023 that it will not apply the Catalyst decision beyond the facts at issue in that case, neither a court of appeals nor FDA has addressed Neurelis and either Catalyst or Neurelis could serve as a precedent for future challenges to the FDA’s orphan product-related decisions.

Orphan exclusivity may be lost if the FDA later determines that the orphan designation request was materially defective or if the manufacturer is unable to ensure the availability of sufficient quantities of the drug to meet the needs of patients with the rare disease or condition, or if the manufacturer chooses to provide consent to FDA approval of other applications.

Descartes-08 has been granted Orphan Drug Designation for the treatment of MG.

Expedited Development and Review Programs

The FDA offers various programs, including the Fast Track program, Breakthrough Therapy designation, and the RMAT designation that are intended to expedite or facilitate the process for reviewing new biological products that meet certain criteria.

The FDA offers various programs, including the Fast Track program, Breakthrough Therapy designation, RMAT designation and the National Priority Voucher, or CNPV, program that are intended to expedite or facilitate the process for reviewing new biological products that meet certain criteria.

Specifically, new biological products are eligible for Fast Track designation if they are intended to treat a serious or life-threatening disease or condition and demonstrate the potential to address unmet medical needs for the disease or condition.

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As a condition of approval, the FDA may require that a sponsor of a biological product subject to accelerated approval perform adequate and well-controlled post-marketing clinical studies to confirm such benefit.

The Food and Drug Omnibus Reform Act of 2022, or FDORA, added the failure to conduct post-approval studies with due diligence or to submit timely progress reports on such studies to the list of prohibited acts under the FD&C Act, which means that any such failures, whether they result from a sponsor’s actions or the actions of third-parties, could provide the basis for enforcement actions.

In addition, the FDA currently requires as a condition for accelerated approval that promotional materials be submitted prior to use, which could adversely impact the timing of the commercial launch of the product.

In addition, under the provisions of The Food and Drug Safety and Innovation Act, or FDASIA, the FDA established a Breakthrough Therapy Designation which is intended to expedite the development and review of products that treat serious or life-threatening diseases or conditions.

In addition, under the provisions of The Food and Drug Safety and Innovation Act, or FDASIA, Congress and the FDA established a Breakthrough Therapy Designation which is intended to expedite the development and review of products that treat serious or life-threatening diseases or conditions.

A breakthrough therapy is defined as a drug that is intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development.

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Descartes-08 has been granted RMAT designation for the treatment of MG.

In 2025, the FDA also announced the opportunity for prescription drug and biological product companies to participate in the FDA Commissioner's CNPV pilot program.

Companies selected for the CNPV program will be issued a voucher entitling

the company to benefits including enhanced communications and rolling review to allow for a shortened review time.

CNPV does not change the standards for approval and may not necessarily expedite the development or approval process.

Post-approval Requirements

Rigorous and extensive FDA regulation of biological products continues after approval, particularly with respect to cGMP requirements.

Rigorous and extensive FDA regulation of biological products continues after approval.

Manufacturers of our products are required to comply with applicable requirements in the cGMP regulations, including quality control and quality assurance and maintenance of records and documentation.

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The FDA has approved a number of products under these provisions.

To our knowledge, the definition of “biosimilar” with regard to an mRNA-modified cell therapy has not been expressly stated in statute, regulation, or guidance, and has not been reviewed by a court.

To our knowledge, how the definition of “biosimilar” applies with regard to an mRNA-modified cell therapy has not been expressly stated in statute, regulation, or guidance, and has not been reviewed by a court.

The regulatory pathway for a biosimilar to one of our products thus remains somewhat uncertain.

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As a result, the ultimate impact, implementation and meaning of the BPCIA is subject to significant uncertainty.

For example, the FDA had previously required comparative clinical studies to support a demonstration of biosimilarity if there is residual uncertainty about whether there are clinically meaningful differences between the reference product and the proposed product.

However, in October 2025, the FDA issued a new draft guidance document that largely permits biosimilar applications without comparative efficacy studies, thus potentially increasing the risk of sooner biosimilar entry.

Government Regulation Outside of the United States

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The requirements and process governing the conduct of clinical studies, product licensing, pricing and reimbursement vary from country to country.

In all cases, the clinical studies are conducted in accordance with GCP and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

In all cases, the clinical studies must be conducted in accordance with GCP and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

In the European Economic Area, or EEA, which is composed of the 27 member states of the European Union, or EU, plus Norway, Iceland and Liechtenstein, medicinal products can only be commercialized after obtaining a Marketing Authorization, or MA.

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Normally, the pediatric clinical trials must be completed before the initial MA application for the relevant indication.

However, the EMA may grant a deferral of the studies in order not to delay the approval of the product in adults and the EMA may waive the requirement to conduct studies in certain circumstances, such as if the relevant condition does not occur in

If pediatric clinical trials are completed in accordance with an agreed PIP, the product will be entitled to a six-month extension of its supplementary protection certificate.

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For other countries outside of the EU, such as countries in Eastern Europe, Latin America or Asia, the requirements governing the conduct of clinical studies, product licensing, pricing and reimbursement vary from country to country.

In all cases, again, the clinical studies are conducted in accordance with GCP and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

cases, again, the clinical studies must be conducted in accordance with GCP and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

When conducting clinical trials in the EU, we must adhere to the provisions of the EU Clinical Trials Regulation (EU) No 536/2014.

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Violation of the federal Anti-Kickback Statute may also constitute a false or fraudulent claim for purposes of the federal civil False Claims Act.

Actions under the civil False Claims Act may be brought by the Department of Justice or as a qui tam action

by a private individual in the name of the government.

Actions under the civil False Claims Act may be brought by the Department of Justice or as a qui tam action by a private individual in the name of the government.

Many states also have similar fraud and abuse statutes or regulations that apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor.

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Member States may approve a specific price for a product or may instead adopt a system of direct or indirect controls on the profitability of the company placing the product on the market.

Other Member States allow companies to fix their own prices for products, but monitor and control prescription volumes and issue

guidance to physicians to limit prescriptions.

Recently, many countries in the EU have increased the amount of discounts required on pharmaceuticals and these efforts could continue as countries attempt to manage healthcare expenditures, especially in light of the severe fiscal and debt crises experienced by many countries in the EU.

Other Member States allow companies to fix their own prices for products, but monitor and control prescription volumes and issue guidance to physicians to limit prescriptions.

in light of the severe fiscal and debt crises experienced by many countries in the EU.

The downward pressure on health care costs in general, particularly prescription products, has become intense.

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• The IRA requires manufacturers to pay rebates for Medicare Part B and Part D drugs whose price increases exceed inflation.

• The IRA eliminates the so-called “donut hole” under Medicare Part D beginning in 2025 by significantly lowering the beneficiary maximum out-of-pocket cost and requiring manufacturers to subsidize, through a newly established manufacturer discount program, 10% of Part D enrollees’ prescription costs for brand drugs below the out-of-pocket maximum and 20% once the out-of-pocket maximum has been reached.

• The IRA eliminated the so-called “donut hole” under Medicare Part D by requiring manufacturers to subsidize, through a newly established manufacturer discount program, 10% of Part D enrollees’ prescription costs for brand drugs below the out-of-pocket maximum and 20% once the out-of-pocket maximum has been reached.

The IRA also significantly lowered the beneficiary maximum out-of-pocket cost under Medicare Part D.

• The IRA delays the rebate rule that would require pass through of pharmacy benefit manager rebates to beneficiaries

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The negotiated prices will be capped at a statutorily determined ceiling price.

There are certain statutory exemptions from the IRA’s Price Negotiation Program, such as for a drug that has only a single orphan drug designation and is approved only for an indication or indications within the scope of such designation.

There are certain statutory exemptions from the IRA’s Price Negotiation Program, such as for a drug that has only orphan drug designations and is approved only for an indication or indications within the scope of such designation.

The IRA’s Price Negotiation Program is currently the subject of legal challenges.

Manufacturers that fail to comply with the IRA may be subject to various penalties, including civil monetary penalties or a potential excise tax.

Manufacturers that fail to comply with the IRA may be subject to various penalties, including civil monetary penalties and a potential excise tax.

The IRA permits the Secretary of Health and Human Services, or the HHS Secretary, to implement many of the IRA’s provisions through guidance, as opposed to regulation, for the initial years.

The effect of the IRA is anticipated to have significant effects on the pharmaceutical industry and may reduce the prices pharmaceutical manufacturers can charge and reimbursement pharmaceutical manufacturers can receive for approved products, among other effects.

The IRA is anticipated to have significant effects on the pharmaceutical industry and may reduce the prices pharmaceutical manufacturers can charge and reimbursement pharmaceutical manufacturers can receive for approved products, among other effects.

The Trump Administration has issued Executive Orders relating to prescription drug pricing and letters to pharmaceutical manufacturers that direct drug manufacturers to, among other things, offer most favored nation, or MFN, pricing in Medicaid, offer MFN pricing for all newly launched drugs;

repatriate increased revenue from abroad to lower drug prices in the United States, and implement direct-to-consumer and direct-to-business distribution of their products at MFN pricing.

The Administration has warned that manufacturers that fail to make “significant progress” toward MFN pricing will face enumerated regulatory and enforcement consequences.

In September 2025, the Trump Administration began announcing deals with specific manufacturers to address its MFN goals.

In addition, other legislative changes have been proposed and adopted in the United States.

This included aggregate reductions of Medicare payments to providers of 2% per fiscal year, which went into effect on April 1, 2013, and, due to subsequent legislative amendments, will stay in effect through 2027 unless additional Congressional action is taken.

On January 2, 2013, the American Taxpayer Relief Act was signed into law, which, among other things, further reduced Medicare payments to several providers, including hospitals and imaging centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years.

The Trump Administration has discussed several changes to the reach and oversight of the FDA, which could affect its relationship with the biotechnology and pharmaceutical industries, transparency in decision making and ultimately the cost and

availability of prescription drugs.

These include aggregate reductions of Medicare payments to providers of 2% per fiscal year, which went into effect on April 1, 2013, and, due to subsequent legislative amendments, will stay in effect through 2032 unless additional Congressional action is taken.

Drug pricing is an active area for regulatory reform at both the federal and state levels, and additional significant changes to current drug pricing and reimbursement structures in the U.S.

2 unchanged sentences

Employees and Human Capital Resources

At Cartesian Therapeutics, we consider human capital to be an essential driver of our business and successful strategy creation and execution.

We consider human capital to be an essential driver of our business and successful strategy creation and execution.

Our people, driven by our collaborative, pioneering, and patient-focused culture, propel our business forward, strengthening us for long-term success.

14 unchanged sentences

We file electronically with the SEC our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, proxy statements and other information.

Our SEC filings are available to the public over the Internet at the SEC’s website at http://www.sec.gov.

Our SEC filings are available to the public at the SEC’s website at http://www.sec.gov.

We make available on our website at www.cartesiantherapeutics.com, free of charge, copies of these reports as soon as reasonably practicable after filing or furnishing these reports with the SEC.

11 unchanged sentences

We may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of our product candidates.

• Interim, top-line and preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data.

• Our product candidates may cause undesirable side effects or have other properties that could delay or prevent their regulatory approval, limit the commercial profile of an approved label, or result in significant negative consequences following marketing approval, if any.

• We have recorded a material amount of goodwill and indefinite-lived intangible assets in connection with the Merger.

We have, and may in the future, record impairment charges, which would adversely impact our financial position and results of operations.

• We expect to continue to grow our manufacturing capabilities and resources and we must incur significant costs to develop this expertise and/or rely on third-parties to manufacture our products.

3 unchanged sentences

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 1. Business