What changed in this filing

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Item 1. Business

2026-02-24 compared with 2025-02-25 · 308 added, 323 removed, 529 unchanged (54% of the section changed)

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In 2023, Regeneron initiated a technology transfer of the manufacturing process for ARCALYST drug substance, and we are working to qualify Samsung as our replacement CDMO.

In December 2024, we initiated a collaborative study agreement with The Mayo Clinic (together with Johns Hopkins University) to investigate the effects of ARCALYST in the treatment of cardiac sarcoidosis.

KPL-387 is an investigational, fully human immunoglobulin G2 monoclonal antibody that binds human interleukin-1 receptor 1 (“IL-1R1”), inhibiting IL-1α- and IL-1β-mediated signaling.

KPL-387 is an independently developed asset that we believe has the potential to further advance recurrent pericarditis treatment options for patients by providing the added convenience of monthly subcutaneous dosing with a liquid formulation.

In June 2024, we initiated a Phase 1 clinical trial of KPL-387 in normal healthy volunteers.

In February 2025, we announced our plan to initiate a Phase 2/3 clinical trial of KPL-387 in recurrent pericarditis in mid-2025.

We expect data from the Phase 2 portion of the trial in the second half of 2026.

KPL-387 is an independently developed asset that we believe may expand the recurrent pericarditis market and provide an additional treatment option for patients, with the potential to add the convenience of monthly subcutaneous self-administration with a liquid formulation.

In July 2025, we announced that the Phase 2 dose-focusing portion of the Phase 2/3 clinical trial of KPL-387 in recurrent pericarditis had begun recruiting.

We expect data from the Phase 2 portion of the trial in the second half of 2026 and plan to use the totality of the data to determine further development strategy.

In September 2025, we announced plans to conduct a supplemental Phase 2 transition to KPL-387 monotherapy dosing and administration study to evaluate the efficacy and safety of dosing regimens used to transition patients from standard therapies to KPL-387 monotherapy.

In October 2025, the FDA granted Orphan Drug Designation to KPL-387 for the treatment of pericarditis.

KPL-1161 is an independently developed, pre-clinical, Fc-modified immunoglobulin G2 monoclonal antibody that binds IL-1R1, inhibiting IL-1α- and IL-1β-mediated signaling.

KPL-1161 is a modified version of KPL-387 designed to have an increased drug half-life that we believe could support quarterly subcutaneous dosing.

We are currently conducting preclinical activities with respect to this asset, with an expectation to initiate a Phase 1 first-in-human clinical trial by the end of 2026.

Abiprubart is an investigational monoclonal antibody inhibitor of CD40-CD154 costimulatory interaction, which we believe to be an attractive approach to address multiple autoimmune disease pathologies.

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We previously announced a Phase 2b clinical trial of abiprubart in Sjögren’s Disease.

In February 2025, we announced our plans to discontinue development of abiprubart in the indication and explore strategic alternatives for the asset.

Mavrilimumab is an investigational monoclonal antibody inhibitor targeting granulocyte-macrophage colony stimulating factor receptor alpha (“GM-CSFRα”).

In 2017, we licensed exclusive worldwide rights in all indications to mavrilimumab from MedImmune, Limited, which has since been acquired by AstraZeneca PLC (“MedImmune”).

In February 2025, we announced our termination of our license agreement from MedImmune for convenience, effective in May 2025.

In addition, in February 2025, we provided written notice to Huadong that Huadong has not conducted material development activity with respect to mavrilimumab in the People’s Republic of China for a continuous period in excess of six months as required under the mavrilimumab Huadong Collaboration Agreement (as defined below).

Unless Huadong conducts material development activity within 60 days of the notice, the mavrilimumab Huadong Collaboration Agreement will terminate in April 2025.

In February 2025, we announced our plans to discontinue development of abiprubart in the indication and to explore strategic alternatives for the asset.

The following table summarizes our current products, product candidates and out-licensing arrangements:

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(2) The FDA granted Breakthrough Therapy designation to ARCALYST for recurrent pericarditis in 2019;

the FDA granted Orphan Drug exclusivity to ARCALYST in March 2021 for the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and pediatric patients 12 years and older.

the FDA granted Orphan Drug exclusivity to ARCALYST in March 2021 for the treatment of pericarditis, which includes the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and pediatric patients 12 years and older.

The European Commission granted Orphan Drug designation to ARCALYST for the treatment of idiopathic pericarditis in 2021.

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Kiniksa granted Huadong exclusive rights in the Asia Pacific Region, excluding Japan.

(4) The FDA granted Orphan Drug designation to KPL-387 for the treatment of pericarditis, which includes recurrent pericarditis, in October 2025.

Using a data-centric approach, our team considers a wide variety of metrics to drive informed capital allocation strategies and generate value from this pipeline, including by analyzing potential additional indications for our products and product candidates, being opportunistic in our business development activities to in-license or acquire programs, considering appropriate opportunities to partner or out-license our programs and conducting internal research to discover and develop molecules to expand our portfolio.

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Critical components of our business strategy include the following:

● Commercialize ARCALYST .

● Continuing to Execute on ARCALYST Commercialization .

We have invested in a talented and specialized cardiology sales team, complemented by a successful marketing strategy, to effectively reach patients and prescribers.

By expanding awareness and building the market for ARCALYST, we expect to increase disease awareness, secure patient access, and support our patients throughout their therapy.

● Advance Our Product Candidates Through the Development Process .

Using a data-driven approach, we evaluate development opportunities, possible indications and other factors to advance our portfolio of assets.

By expanding awareness and building the market for ARCALYST, we expect to increase disease awareness of recurrent pericarditis, improve our patients’ journeys to diagnosis and treatment, establish ARCALYST as a therapy to be used earlier and for the full duration of the disease, secure patient access and support our patients throughout their therapy.

● Advancing KPL-387 through Commercialization .

We believe KPL-387, our clinical-stage IL-1 inhibition therapy, is a potential new treatment option to address recurrent pericarditis patients’ needs and expand the overall IL-1 inhibition market for recurrent pericarditis.

Market research data demonstrate the demand for a drug with KPL-387’s potential for streamlined preparation, dosing frequency and patient-friendly administration.

We believe that advancing such a drug through the clinic and, if approved, into the market will further our mission of developing therapies for patients with critical unmet need.

● Maximizing the Potential of our other Developmental Assets .

We are advancing a number of other assets in our pipeline, including KPL-1161.

We use a data-first approach to guide our selection of indications and opportunities with an aim to maximize the potential of our portfolio.

We believe that each of our product candidates holds the potential to offer differentiated therapy to patients, and we aim to unlock that potential through innovative research and development.

● Explore Opportunities to Drive Value and Maximize the Potential of Our Existing Portfolio.

● Exploring Opportunities to Drive Value and Maximize the Potential of Our Existing Portfolio.

We have and may in the future seek collaborations, licenses and other strategic relationships to assist in advancing and expanding our current programs, as appropriate.

In addition, strategic out-licensing transactions may be used as a source of non-dilutive capital to support our commercial and clinical activities.

● Work to Identify, Discover, Acquire and Develop New Therapies.

● Working to Identify, Discover, Acquire and Develop New Therapies.

We evaluate a variety of factors for potential product candidates, technologies and discovery targets, including biologic rationale for addressing the disease, potential for regulatory approval, commercial viability, intellectual property position, prospects for favorable pricing and reimbursement and the impact of competition.

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We received Breakthrough Therapy designation from the FDA for ARCALYST for the treatment of recurrent pericarditis in 2019 , Orphan Drug designation from the FDA for ARCALYST for the treatment of pericarditis, which includes the treatment of recurrent pericarditis, in 2020 and FDA approval of ARCALYST for the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and children 12 years and older in March 2021.

Additionally, in 2021, the European Commission granted Orphan Drug designation to ARCALYST for the treatment of idiopathic pericarditis.

In 2022, we granted Huadong exclusive rights to develop and commercialize ARCALYST in the Asia Pacific region, excluding Japan.

In 2022, we granted Huadong exclusive rights to develop and commercialize ARCALYST in the Huadong Territory.

Mechanism of Action

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These data, together with clinical data from our pivotal Phase 3 clinical trial of ARCALYST, indicate that IL-1α and IL-1β play unique roles in recurrent pericarditis and other autoinflammatory diseases in which the pathology may be driven primarily by IL-1α.

Other literature published after the June 2022 completion of RHAPSODY corroborated these findings in larger populations of participants.

Other literature published after the June 2022 completion of the phase 3 clinical trial of ARCALYST corroborated these findings in larger populations of participants.

Beyond recurrent pericarditis, we believe there is potential for ARCALYST to address additional indications driven by IL-1α or IL-1β.

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Outside of our core target patient population, there are approximately 26,000 additional patients who are experiencing their first recurrence of the disease.

We have seen that, as we expand awareness about the disease and our therapy, healthcare professionals look to prescribe ARCALYST earlier in the disease’s natural history.

Further, data shows that one-third of patients with multiple recurrences continue to suffer from the disease at 5 years from their

first recurrence of the disease and one-quarter continue at 8 years.

We have seen that, as we expand awareness about the disease and our therapy, healthcare professionals look to prescribe ARCALYST earlier in the disease’s natural history, including prescriptions to biologic-appropriate patients in their first recurrence.

We expect that continuing to execute on this strategy will enable us to target this additional patient population more fully.

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Adverse events that may be caused by corticosteroids include glaucoma, fluid retention, hypertension, mood changes, memory changes, other psychological effects, weight gain and diabetes.

Since our commercial launch of ARCALYST, we have seen a shift in the treatment paradigm, with healthcare professionals prescribing ARCALYST’s targeted immunomodulation before using corticosteroids.

For these reasons, we believe that ARCALYST plays an important role in the effective treatment of recurrent pericarditis as a steroid-sparing therapy.

Clinical Trials

In June 2020, we reported results from RHAPSODY, our global, double-blind, placebo-controlled, randomized-withdrawal design, pivotal Phase 3 clinical trial of ARCALYST in subjects with recurrent pericarditis.

RHAPSODY met its prespecified primary and all major secondary efficacy endpoints with statistical significance.

Median [95% confidence interval (“CI”)] time to pericarditis recurrence for ARCALYST recipients in the randomized withdrawal period could not be estimated due to the low number of recurrences in the ARCALYST treatment arm.

The median time-to-recurrence for placebo recipients was 8.6 [4.0-11.7] weeks (Hazard Ratio = 0.04, p<0.0001).

ARCALYST recipients experienced a 96% reduction in risk of recurrent pericarditis events.

81% of ARCALYST recipients maintained clinical response at Week 16 of the randomized withdrawal period, compared to 20% of placebo recipients (p=0.0002).

Consistent results were observed at Week 8 and Week 24 and were also highly statistically significant (p<0.0001 and p=0.0022, respectively).

The proportion of ARCALYST recipients with absent or minimal pericarditis symptoms at Week 16 of the randomized withdrawal period was 81% compared to 25% for placebo recipients (p=0.0006).

Consistent results were observed at Week 8 and Week 24 and were also highly statistically significant (p<0.0001 and p=0.0002, respectively).

The percentage of trial days in which participants reported none/minimal pericarditis pain (NRS≤2) at Week 16 of the randomized withdrawal period (a secondary efficacy endpoint of the study) was 92% for ARCALYST recipients compared to 40% for placebo recipients (p<0.0001).

Finally, the time to treatment response (NRS≤2 and CRP≤0.5 mg/dL for ARCALYST recipients was 5.0 [95% CI:

Median time to ARCALYST monotherapy was 7.9 [95% CI:

7.0-8.1] weeks.

We believe these data show that ARCALYST demonstrates clinically meaningful outcomes associated with unmet medical need in recurrent pericarditis.

In November 2022, data from the long-term extension (“LTE”) portion of the RHAPSODY trial were presented, which demonstrated continued ARCALYST treatment beyond 18 months resulted in continued treatment response.

The median [maximum at end of LTE] duration of continuous ARCALYST therapy for all participants in RHAPSODY was 23 [35] months;

the median [maximum at end of LTE] duration of continuous ARCALYST therapy was 18 months [27] months for United States participants (n=45) and 29 [35] months for non-United States participants (n=29).

The annualized incidence of pericarditis recurrences while on therapy for all participants (n=74) during the first 18 months of the LTE portion of the trial was 0.04 events per participant-year (compared to 4.4 events per participant-year prior to study entry), none of which were associated with an elevation in C-Reactive Protein (CRP).

Participants (n = 52) were given the option at 18 months from their most recent pericarditis recurrence to continue or suspend ARCALYST treatment for observation.

There were 33 participants who elected to continue ARCALYST treatment, and the only recurrence in this group was associated with a treatment interruption of 4 weeks.

Of the participants who suspended treatment at 18 months (n=8), 75% (n=6) experienced pericarditis recurrences, all of which were associated with an elevation in CRP.

The median (interquartile range) time-to-event was 11.8 (3.7, Not-Estimable) weeks.

The 98% reduction in risk of recurrent pericarditis events in participants who continued ARCALYST treatment beyond 18 months (Hazard Ratio = 0.02, p<0.0001) was consistent with the results of the randomized withdrawal period.

Since our commercial launch of ARCALYST, we have seen a shift in the treatment paradigm, with an increasing number of healthcare professionals prescribing ARCALYST’s targeted immunomodulation before using corticosteroids.

Emblematic of this paradigm shift was the recently published American College of Cardiology Concise Clinical Guidance, which prioritized IL-1 inhibition therapy as a second-line treatment after failure of first-line therapy in the auto-inflammatory phenotype.

We believe this reflects a growing acceptance of ARCALYST as an effective, steroid-sparing therapy for patients with unmet need in this debilitating disease.

Clinical Trials and Collaborative Study Agreements

We have initiated a collaborative study agreement with The Mayo Clinic (together with Johns Hopkins University) to investigate the effects of ARCALYST in the treatment of cardiac sarcoidosis.

The study is a Phase 2 PROBE-design study to evaluate the efficacy and safety of ARCALYST over 24 weeks of treatment in patients with cardiac sarcoidosis.

The primary efficacy endpoint is change from baseline in number of segments with FDG uptake on cardiac FDG-PET scan at week 24.

The following graphic shows the trial design and primary and secondary efficacy endpoints in more detail:

Commercial Strategy for ARCALYST

Since our commercial launch of ARCALYST for the treatment of recurrent pericarditis in 2021, we have developed a focused and targeted commercial strategy.

Our specialty salesforce calls on high-volume accounts and prescribers.

Our salesforce is complemented by our medical affairs, payor and patient services teams who work to secure broad patient access to ARCALYST, educate communities, collaborate with patient advocacy groups and drive scientific understanding of recurrent pericarditis.

Further, we have established an efficient marketing effort intended to educate and raise awareness of recurrent pericarditis among prescribers and patients and promote ARCALYST as the first and only treatment for this debilitating disease.

Using these resources, our commercialization efforts are focused on four strategic imperatives to increase the uptake and adoption of ARCALYST as well as ensuring a positive patient experience.

Our specialty salesforce, which prioritizes calls on high-volume accounts and prescribers, is complemented by our medical affairs, payor and patient services teams who work to secure broad patient access to ARCALYST, educate communities, collaborate with patient advocacy groups and drive scientific understanding of recurrent pericarditis.

Using these resources, our commercialization efforts are focused on five strategic imperatives to increase the uptake and adoption of ARCALYST as well as ensuring a positive patient experience.

First, we are focused on increasing awareness of the disease and its impact on patients’ lives.

We believe disease awareness is essential to enable physicians to diagnose recurrent pericarditis earlier in its disease course and to treat the underlying disease, rather than to episodically manage individual flares.

Our sales and marketing teams work to educate patients and prescribers about the signs, symptoms, duration and treatment of the disease, and the impact that

recurrent pericarditis has on patients’ lives.

Our sales and marketing teams work to educate patients and prescribers about the signs, symptoms, duration and treatment of the disease, and the impact that recurrent pericarditis has on patients’ lives.

We have further partnered with each of NHL Hall-of-Famer Henrik Lundqvist and GRAMMY® Award-Winning Singer-Songwriter Carly Pearce as part of our Life DisRPted™ Campaign to drive awareness of recurrent pericarditis.

Second, we aim to secure broad patient access at a price that reflects ARCALYST’s value as the first and only FDA-approved therapy for recurrent pericarditis.

Second , we are working to improve the patient journey for those suffering from recurrent pericarditis.

For example, in 2024 we announced our sponsorship of the American Heart Association’s Addressing Recurrent Pericarditis initiative.

This initiative is designed to facilitate knowledge-sharing across a network of healthcare providers around the United States and streamline patient access to expert care.

The program currently collaborates with a number of pericardial disease centers, offering patients dedicated, expert care that is designed to shorten patients’ journeys to diagnoses.

Third, we are working to establish ARCALYST as a therapy to be used in recurrent pericarditis patients as soon as appropriate after diagnosis and for the full duration of the disease.

Evidence shows that, in part due to our educational efforts, prescribers are opting to prescribe ARCALYST earlier in the disease course, with real world evidence demonstrating that ARCALYST has increasingly become a second-line treatment for recurrent pericarditis, including after patients’ first recurrence.

In addition, patients and prescribers are opting to treat recurrent pericarditis for its full duration of disease.

This supports our overall mission to help patients lead meaningful lives with minimal flares for the full breadth of the disease’s natural history.

Fourth, we aim to secure broad patient access at a price that reflects ARCALYST’s value as the first and only FDA-approved therapy for recurrent pericarditis.

Helping to ensure affordability and access to treatment by patients is one of our core principles.

To this end, we offer a suite of programs to support affordability for eligible patients who are prescribed ARCALYST.

Third, we have built a robust patient support program to optimize patient experiences with ARCALYST and Kiniksa.

Fifth, we have built a robust patient support program to optimize patient experiences with ARCALYST and Kiniksa.

O ur Kiniksa OneConnect™ program offer s personalized treatment support for eligible patients prescribed ARCALYST.

This program is designed to ensure patients have a positive experience from initiating ARCALYST therapy through the end of their treatment.

Fourth, we are working to improve the patient journey for those suffering from recurrent pericarditis.

For example, in 2024 we announced our sponsorship of the American Heart Association’s Addressing Recurrent Pericarditis initiative.

This initiative is designed to facilitate knowledge-sharing across a collaborative network of healthcare providers around the United States and streamline patient access to expert care.

The participating healthcare sites offer patients dedicated, expert care and aim to shorten patients’ journeys to diagnoses.

Our Product Candidates

KPL-387 is an investigational, fully human immunoglobulin G2 monoclonal antibody that binds IL1-R1, inhibiting the signaling of both IL-1α and IL-1β cytokines.

KPL-387 is an independently developed asset that we believe has the potential to further advance recurrent pericarditis treatment options for patients with the potential to add the convenience of monthly subcutaneous dosing with a liquid formulation.

In June 2024, we initiated a Phase 1 clinical trial of KPL-387 in normal healthy volunteers and data from such study suggests that KPL-387 holds the potential for monthly subcutaneous dosing.

In February 2025, we announced our plan to initiate a Phase 2/3 clinical trial of KPL-387 in recurrent pericarditis in mid-2025.

We expect data from the Phase 2 portion of the trial in the second half of 2026.

KPL-387 is an independently developed asset that we believe

may expand the recurrent pericarditis market and provide an additional treatment option for patients, with the potential to add the convenience of monthly subcutaneous self-administration with a liquid formulation.

In October 2025, the FDA granted Orphan Drug Designation to KPL-387 for the treatment of pericarditis.

We are currently conducting the Phase 2 dose-focusing portion of the Phase 2/3 clinical trial of KPL-387 in recurrent pericarditis, with data expected in the second half of 2026.

We plan to use the totality of the data to determine further development strategy.

In addition, we are conducting a supplemental Phase 2 transition to KPL-387 monotherapy dosing and administration study to evaluate the efficacy and safety of dosing regimens used to transition patients from standard therapies to KPL-387 monotherapy.

Mechanism of Action

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We believe there are diseases of the cardiovascular system where tissue inflammation may be driven by IL-1α and/or IL-1β, and we intend to consider development of KPL-387 in these indications and in others where we believe IL-1α and/or IL-1β plays a key role in disease pathophysiology.

We are developing KPL-387 for the treatment of recurrent pericarditis.

We believe its formulation offers the potential opportunity for convenient delivery in a prefilled syringe or autoinjector once a month.

We are developing KPL-387 for the treatment of recurrent pericarditis, where we believe IL-1 inhibition therapies offer significant advantages over other treatment modalities.

Further, we believe an IL-1 inhibitor with the potential to combine convenient monthly dosing and a patient friendly, convenient autoinjector could meet patient needs and provide an additional treatment option for recurrent pericarditis patients.

Preclinical Development and Clinical Trials

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In vivo pharmacokinetic studies of KPL-387 in non-human primates demonstrated good pharmacokinetic properties.

We believe that these pharmacokinetic data, combined

with the potent inhibition of IL-1 signaling that we observed in vitro , suggest that this therapeutic effect could be achieved with monthly subcutaneous administration in future clinical studies.

We believe that these pharmacokinetic data, combined with the potent inhibition of IL-1 signaling that we observed in vitro , suggest that this therapeutic effect could be achieved with monthly subcutaneous administration in future clinical studies.

Phase 1 Clinical Trial

In June 2024, we initiated a Phase 1 clinical trial of KPL-387 in healthy volunteers.

Topline data from the trial have shown that a single subcutaneous dose of KPL-387 maintained levels in circulation sufficient to support our belief that KPL-387 could offer the potential for monthly subcutaneous dosing in recurrent pericarditis, a chronic disease that can last for years.

We aim to further explore this hypothesis during Phase 2 development.

Topline data from the trial have shown that a single subcutaneous dose of KPL-387 maintained levels in circulation sufficient to support our belief that the drug could offer the potential for monthly subcutaneous administration in recurrent pericarditis, a chronic disease that can last for years.

We aim to explore this hypothesis further during Phase 2 development.

Phase 2 Clinical Trial

In February 2025, we announced our plan to initiate a Phase 2/3 clinical trial of KPL-387 in recurrent pericarditis in mid-2025.

We expect data from the Phase 2 portion of the trial in the second half of 2026.

In July 2025, we initiated our Phase 2/3 clinical trial of KPL-387 in recurrent pericarditis, beginning with the Phase 2 dose-focusing portion of the study.

The trial is designed to enroll up to approximately 80 patients with recurrent pericarditis who present at screening with a qualifying pericarditis episode despite treatment with conventional oral therapies.

The primary efficacy endpoint is time to treatment response and time to CRP normalization (CRP ≤ 0.5mg/dL).

We expect data from this trial in the second half of 2026 and plan to use the totality of the data to determine further development strategy.

The following graphic shows the trial design in more detail:

The trial is designed to enroll up to 80 participants with well-controlled recurrent pericarditis receiving standard therapies (NSAIDS and/or colchicine, glucocorticoids and/or IL-1α and IL-1β inhibition).

The following graphic shows the trial design in more detail:

KPL-1161 is an independently developed, pre-clinical, Fc-modified immunoglobulin G2 monoclonal antibody that binds IL-1R1, inhibiting IL-1α- and IL-1β-mediated signaling.

KPL-1161 is a modified version of KPL-387 designed to have an increased drug half-life that we believe could support quarterly subcutaneous dosing.

We are currently conducting pre-clinical development of this asset.

We are currently conducting pre-clinical development of this asset and plan to initiate a Phase 1 first-in-human clinical trial of KPL-1161 by the end of 2026.

Abiprubart is an investigational monoclonal antibody inhibitor of CD40-CD154 costimulatory interaction.

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In February 2025, we announced our plans to discontinue development of abiprubart in the indication and explore strategic alternatives for the asset.

We previously conducted a proof-of-concept Phase 2 clinical trial of abiprubart in RA.

We previously conducted a proof-of-concept Phase 2 clinical trial of abiprubart in RA and a Phase 2b clinical trial of abiprubart in Sjögren’s Disease.

We believe that disrupting the CD40-CD154 co-stimulatory interaction is an attractive approach to addressing multiple autoimmune disease pathologies.

We also believe that abiprubart’s ability to be administered in a high-concentration subcutaneous formulation that enables monthly dosing potentially distinguishes it from other competitors.

In July 2024, we commenced a Phase 2b clinical trial of abiprubart in Sjögren’s Disease.

In February 2025, as part of our strategic reprioritization of our portfolio and certain capital allocation considerations, we announced our plans to discontinue our Phase 2b clinical trial of abiprubart in Sjögren’s Disease.

We expect to immediately end clinical trial enrollment and initiate winddown activities.

Mavrilimumab is a fully-human monoclonal antibody that is designed to antagonize GM-CSF signaling by binding to the alpha subunit of the GM-CSF receptor.

In February 2025, we delivered a notice of termination to MedImmune, notifying them of our intent to terminate for convenience the MedImmune Agreement (as defined below) effective May 22, 2025.

In 2022, we granted Huadong exclusive rights to develop and commercialize mavrilimumab in the Asia Pacific region, excluding Japan.

In February 2025, we provided written notice to Huadong that Huadong has not conducted material development activity with respect to mavrilimumab in the People’s Republic of China for a continuous period in excess of six months as required under the mavrilimumab Huadong Collaboration Agreement.

Unless Huadong conducts material development activity within 60 days of the notice, the mavrilimumab Huadong Collaboration Agreement will terminate in April 2025.

Discovery Activities

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The Supply Agreement terminates upon the sooner of the termination of the Regeneron Agreement and the date of the completion of the transfer of technology related to the manufacture of ARCALYST drug substance.

Regeneron, in turn, relies upon a third party CDMO to conduct fill/finish operations for ARCALYST.

We are currently conducting a transfer of technology related to the manufacturing process of ARCALYST drug substance and the analytical testing methods of ARCALYST drug substance and drug product.

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Such technology transfer will be subject to significant risks and uncertainties.

” Fill-finish, labeling, packaging and shipping services are conducted by additional third-party contractors.

We also have engaged CDMOs to produce our clinical product candidates.

We intend to use such CDMOs for development and scale-up work for any future clinical trials and eventual commercialization of such product candidates, if approved.

We require our CDMOs to conduct manufacturing activities in compliance with current good manufacturing practice or similar foreign requirements (“cGMP”).

We require our CDMOs to conduct manufacturing activities in compliance with current good manufacturing practice or comparable foreign requirements (“cGMP”).

We have assembled a team of experienced employees and consultants to provide the necessary technical, quality and regulatory oversight of our CDMOs.

We currently perform most process development internally but are reliant on CDMOs for late-stage clinical manufacturing, process qualification and validation and commercial supply.

We currently perform most process development internally but are reliant on CDMOs for late-stage clinical product manufacturing, process qualification, validation and commercial supply.

We anticipate that the CDMOs currently manufacturing our product candidates will have the capacity to support both future clinical supply and commercial-scale production, but we do not have any formal agreements at this time with any of such CDMOs to cover commercial production.

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Commercial Operations

Our commercial team combines dozens of years of pharmaceutical commercial leadership experience with a passion for helping patients with significant unmet medical need.

Our commercial team combines years of pharmaceutical commercial leadership experience with a passion for helping patients with significant unmet medical need.

Since March 2021, we have marketed ARCALYST, our only commercial product, in the United States for recurrent pericarditis and have established our own specialty salesforce to expand our commercialization efforts nationwide.

Our salesforce is complemented by our medical affairs, payor and patient services teams.

In 2024, we launched a number of initiatives intended to increase disease awareness of recurrent pericarditis, including sponsoring the American Heart Association’s Addressing Recurrent Pericarditis initiative and launching our Life DisRPted campaign.

For more information, see “ Business—Our Products—ARCALYST – Commercial Strategy for ARCALYST .”

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Our products and any product candidates that we successfully develop and commercialize may compete with existing products and new products that may become available in the future.

We believe the key competitive factors affecting the success of ARCALYST and any product candidates that we successfully develop and commercialize, are their efficacy, safety, convenience, price, the effectiveness of companion diagnostics in guiding the use of related products, market acceptance by prescribers and patients, the level of biosimilar competition and the availability of reimbursement from government and other third party payors.

Our commercial opportunities 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 (including method of delivery and administration by the patient) or are less expensive than our products.

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

In addition, if a competitor obtains regulatory approval for an orphan drug before us, and we are developing a product candidate for the same orphan indication, subject to applicable jurisdictional laws, Orphan Drug exclusivity may no longer be available for our product candidate, if approved, unless we can show a significant benefit over the already approved orphan drug.

Moreover, where we and a competitor are developing the same or similar drug for the same orphan indication, and the competitor is first to obtain regulatory approval and is granted orphan exclusivity, subject to applicable jurisdictional laws, we may be denied regulatory approval of our product candidate for such orphan indication for the duration of the competitor’s Orphan Drug exclusivity period.

This may allow a competitor to gain a market advantage ahead of any potential commercialization of one of our product candidates, if approved.

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 biosimilar products.

See “ Risk Factors—Risks Related to Competition, Executing our Strategy and Managing Growth—We face substantial competition, which may result in others discovering, developing or commercializing drugs before or more successfully than we do.

We are aware of the following products currently marketed or in clinical development for the treatment of the diseases that we are targeting or may plan to target:

Competition poses a number of risks to our company, with a number of competitive factors affecting our ability to market and commercialize our products and product candidates.

For more information, see “ Risk Factors—Risks Related to Competition, Executing our Strategy and Managing Growth—We face substantial competition, which may result in others discovering, developing or commercializing drugs before or more successfully than we do.

We are aware of the following drugs currently marketed or in clinical development for the treatment of the diseases that we are targeting or may plan to target:

Recurrent Pericarditis :

We are not aware of any FDA-approved therapies for recurrent pericarditis, but we are aware of three competitors developing treatments for this indication.

CardiolRx is an oral cannabidiol being developed by Cardiol Therapeutics in a Phase 2/3 setting, targeting patients who are discontinuing treatment with an IL-1 blocker.

R-Pharm International is developing goflikicept, which inhibits IL-1α/IL-1β-induced signaling.

This drug is approved and marketed in Russia but its Phase 2/3 United States trial has been suspended as of November 2024.

Ventyx Biosciences is developing VTX2735, which is designed to inhibit the NLRP3 inflammasome, an intracellular sensor of a broad range of danger signals, that leads to the release of IL-1β and IL-18.

In addition to their development program in CAPS, Ventyx Biosciences has announced their intention to initiate a Phase 2 trial of VTX2735 in recurrent pericarditis in January 2025.

We are not aware of any other FDA-approved therapies for recurrent pericarditis, but we are aware of several competitors developing treatments for this indication.

CardiolRx is an oral cannabidiol being developed by Cardiol Therapeutics in a Phase 3 clinical trial, targeting patients who are discontinuing treatment with an IL-1 blocker.

R-Pharm International is developing goflikicept, which is a cytokine trap that inhibits IL-1α/IL-1β-induced signaling.

This drug is approved and marketed in Russia but with no currently active trial in the United States.

Ventyx Biosciences is developing VTX2735, which is designed to inhibit the NLRP3 inflammasome, an intracellular sensor of a broad range of danger signals, that leads to the production and release of IL-1β and IL-18.

In addition to their development program in CAPS, Ventyx Biosciences is conducting a Phase 2 trial of VTX2735 in recurrent pericarditis, which began in January 2025.

In January 2026, Ventyx Biosciences announced that it had entered into a definitive agreement to be acquired by Eli Lilly and Company (this acquisition is expected to close in the first half of 2026).

Monte Rosa Therapeutics is developing MRT-8102 (a molecular glue degrader targeting NEK-7) and has announced plans to expand their ongoing Phase 1 proof-of-concept studies in individuals at high risk for cardiovascular disease and are planning to initiate a Phase 2 study in patients with atherosclerotic cardiovascular disease.

They have indicated that they continue to evaluate additional indications including recurrent pericarditis.

Dual IL-1α and IL-1β Inhibition :

Other drugs, while not approved for the treatment of recurrent pericarditis, also inhibit IL-1α/IL-1β-induced signaling.

Anakinra (KINERET), marketed by Swedish Orphan Biovitrum AB, is currently approved for use in RA, CAPS and DIRA.

Lutikizumab is being developed by Abbvie for the treatment of hidradenitis suppurativa and goflikicept is currently in development for recurrent pericarditis.

Anakinra (KINERET), marketed by Swedish Orphan Biovitrum AB, is currently approved for use in RA, CAPS and DIRA, and lutikizumab (a bispecific antibody targeting IL-1α andIL-1β) is being developed by Abbvie for the treatment of hidradenitis suppurativa, ulcerative colitis, atopic dermatitis, psoriatic arthritis, rheumatoid arthritis, and Crohn’s Disease.

IL-1β Inhibition Alone :

There are also drugs that inhibit IL-1β-induced signaling but do not inhibit IL-1α-induced signaling.

Syndrome (HIDS), Mevalonate Kinase Deficiency (MKD), Familial Mediterranean Fever (FMF), Adult Onsent Still’s Disease (AOSD), Systemic Juvenile Idiopathic Arthritis (SJIA) and gout flares.

Canakinumab (ILARIS), marketed by Novartis Pharmaceuticals Corporation, is currently approved for use in CAPS, Tumor Necrosis Factor Receptor Associated Periodic Syndrome (TRAPS), Hyperimmunoglobulin D Syndrome (HIDS), Mevalonate Kinase Deficiency (MKD), Familial Mediterranean Fever (FMF), Adult Onset Still’s Disease (AOSD), Systemic Juvenile Idiopathic Arthritis (SJIA) and gout flares.

Other Competitors .

We are also aware of several other molecules that do not directly compete with our approved indications for ARCALYST but nonetheless target IL-1α and/or IL-1β directly or indirectly.

Clinical stage development programs targeting IL-1α and/or IL-1β directly or indirectly via the NLRP3 inflammasome include:

lutikizumab (by Abbvie for the treatment of hidradenitis suppurativa, ulcerative colitis, atopic dermatitis and Crohn’s Disease);

Development programs targeting IL-1α and/or IL-1β directly or indirectly via the NLRP3 inflammasome include:

ZYIL-1 (by Zydus Lifesciences in amyotrophic lateral sclerosis);

HT-6184 (by Halia in myelodysplastic syndromes, inflammatory pain);

MRT-8102 (by Monte Rosa Therapeutics, no development indications announced);

OLT1177 (by Olatec Therapeutics in osteoarthritis of the knee and acute gout flares);

DFV-890 (by Novartis in FCAS);

MAS-825 (by Novartis for the treatment of hidradenitis suppurativa and Still’s disease);

Selnoflast (by Roche, no indications announced);

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SSGJ-613 (by Sunshine Guojian Pharmaceuticals in acute gout);

Natrunix (by XBIOTECH Inc in rheumatoid arthritis, axial spondylarthritis);

Natrunix (by XBIOTECH Inc in rheumatoid arthritis, axial

spondylarthritis);

AVTX-009 (by Avalo Therapeutics in hidradenitis suppurativa);

CAN-10 (by Cantargia in healthy subjects and plaque psoriasis) and VENT-02 (by Ventus Therapeutics, no indications announced).

CAN-10 (by Cantargia in healthy subjects and plaque psoriasis);

PCRX-202 (by Pacira Biosciences, osteoarthritis of the knee), SAR445399 (by Sanofi in hidradenitis suppurativa);

LAD191/ALM27134 (by Almirall in hidradenitis suppurativa) and VENT-02 (by Ventus Therapeutics, no indications announced).

There are also therapies that modulate IL-1α-induced signaling in preclinical and clinical development for diseases other than recurrent pericarditis from Johnson & Johnson and XBIOTECH USA, INC.

In addition, Invea Therapeutics is developing INVA8003, a small-molecule inhibitor targeting apoptosis-associated speck-like protein containing a caspase activation and recruitment domain, with a stated intent to prioritize an indication for which injectable IL-1α and/or IL-1β therapies are already approved.

Since we currently expect to develop KPL-387 for the treatment of recurrent pericarditis, we believe that it will compete with the same assets as those described under “ Business—Competition—ARCALYST ”, which includes a number of drugs that target IL-1α and/or IL-1β.

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Goflikicept, currently marketed solely in Russia, though with prior clinical studies conducted in the United States, is dosed subcutaneously every two weeks following an initial loading dose.

We expect that additional therapies offering even more convenient dosing, including those listed in the sections above, may enter the market, including therapies that offer quarterly dosing.

We expect that additional therapies offering even more convenient dosing and administration, including those listed in the sections above, may enter the market, including therapies that offer quarterly dosing.

For KPL-387 to succeed on a commercial basis, if approved, we expect that it will need to compete against such drugs by offering a more convenient dosing regimen and/or an improved risk-benefit profile than other available options.

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however, we believe the high concentration liquid formulation of abiprubart may enable chronic subcutaneous dosing at a higher dose level than other similar drugs, which could be a key differentiator.

Amgen is developing Dazodalibep (anti-CD40L) for the treatment of Sjogren’s Syndrome with Moderate to Severe Systemic Disease Activity.

Sanofi S.A./ImmuNext Inc.

are developing frexalimab (anti-CD40L) for the treatment of Multiple Sclerosis, Systemic Lupus Erythematosus, Type 1 Diabetes and Focal segmental glomerulosclerosis;

are developing frexalimab (anti-CD40L) for the treatment of Relapsing Multiple Sclerosis, Non-relapsing Secondary Progressive Multiple Sclerosis, Systemic Lupus Erythematosus, Type 1 Diabetes and Focal segmental glomerulosclerosis.

are developing dapirolizumab pegol (anti-CD40L) for the treatment of moderately to severely active Systemic Lupus Erythematosus.

and Eledon Pharmaceuticals, Inc.

is developing AT-1501 (anti-CD40L) for use by patients undergoing kidney transplantation.

Such drugs are being developed for intravenous administration only.

Other programs present the potential for subcutaneous administration.

Innovent Bio is developing IBI-355 (anti-CD40L, no indication announced) and H.

Lundbeck A/S is developing Lu AG22515 (bi-specific, anti-CD40L & Albumin (scFv)2-Fab, no indication announced).

Eledon Pharmaceuticals, Inc.

is developing tegoprubart (anti-CD40L) for use by patients undergoing kidney transplantation.

AbbVie is developing Ravagalimab (anti-CD40) for the treatment of moderately to severely active Rheumatoid Arthritis.

Lundbeck A/S is developing Lu AG22515 (bi-specific, anti-CD40L & Albumin (scFv)2-Fab) for the treatment of moderate to severe thyroid eye disease.

Tonix Pharmaceuticals, Inc is developing TNX-1500 (anti-CD40L) for use in kidney transplant recipients.

Innovent Bio is developing IBI-355 (anti-CD40L, no indication announced).

License and Acquisition Agreements

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(collectively, “Genentech”), pursuant to which we granted Genentech exclusive worldwide rights to develop, manufacture and commercialize vixarelimab and related antibodies (each, a “Genentech Licensed Product”).

The Genentech License Agreement became effective in September 2022 following termination of the statutory waiting period under the Hart-Scott Rodino Act.

Under the Genentech License Agreement, we received an upfront payment of $80.0 million for the license.

In total, we have recognized $50.0 million in additional payments from Genentech related to delivery of certain drug material to Genentech and Genentech’s achievement of development milestones under the Genentech License Agreement.

We remain eligible to receive up to approximately $570.0 million in additional contingent payments, including specified development, regulatory and sales-based milestones, before fulfilling our upstream financial obligations.

(as further described in Note 13 to our consolidated financial statements included elsewhere in this Annual Report).

We will also be eligible to receive tiered percentage royalties on a Genentech Licensed Product-by-Genentech Licensed Product basis ranging from low double digits to mid-teens on annual net sales of each Genentech Licensed Product, subject to certain customary reductions, with an aggregate minimum floor, before fulfilling our upstream financial obligations.

Royalties will be payable on a Genentech Licensed Product-by-Genentech Licensed Product and country-by-country basis until the latest to occur of the expiration of certain patents that cover a Genentech Licensed Product, the expiration of regulatory exclusivity for such Genentech Licensed Product or the tenth anniversary of first commercial sale of such Genentech Licensed Product in such country.

Pursuant and subject to the terms of the Genentech License Agreement, Genentech has the exclusive worldwide right to conduct development and commercialization activities for Genentech Licensed Products at its sole cost.

In 2024, we fulfilled our responsibility under the Genentech License Agreement to complete the Phase 2b clinical trial assessing the efficacy, safety and tolerability of vixarelimab in reducing pruritis in prurigo nodularis.

Absent early termination, the Genentech License Agreement will continue until there are no more royalty or other payment obligations owed to us.

Genentech has the right to terminate the Genentech License Agreement at its discretion with prior written notice and either party may terminate the Genentech License Agreement in the event of an uncured material breach of the other party or in the case of insolvency of the other party.

In addition, the Genentech License Agreement will terminate upon termination of the Biogen Agreement (as defined below).

In addition, the Genentech License Agreement will terminate upon termination of our upstream license agreement related to vixarelimab.

Huadong Collaboration Agreements

In February 2022 we entered into two collaboration and license agreements (each, a “Huadong Collaboration Agreement” and together, the “Huadong Collaboration Agreements”) with Huadong, pursuant to which we granted Huadong exclusive rights to develop and commercialize ARCALYST and develop, manufacture and commercialize mavrilimumab (each, a “Huadong Licensed Product” and together, the “Huadong Licensed Products”) in the following countries:

People’s Republic of China, Hong Kong SAR, Macao SAR, Taiwan Region, South Korea, Indonesia, Singapore, The Philippines, Thailand, Australia, Bangladesh, Bhutan, Brunei, Burma, Cambodia, India, Laos, Malaysia, Maldives, Mongolia, Nepal, New Zealand, Sri Lanka, and Vietnam (collectively, the “Huadong Territory”).

We otherwise retained our current rights to the Huadong Licensed Products outside the Huadong Territory.

Unless Huadong conducts material development activity within 60 days of the notice, the mavrilimumab Huadong Collaboration Agreement will terminate on April 25, 2025.

In February 2022 we entered into two collaboration and license agreements (each, a “Huadong Collaboration Agreement” and together, the “Huadong Collaboration Agreements”) with Huadong, pursuant to which we granted Huadong exclusive rights to develop and commercialize ARCALYST and develop, manufacture and commercialize mavrilimumab in each case in a territory currently consisting of the following countries:

People’s Republic of China, Hong Kong SAR, Macao SAR, Taiwan Region, Indonesia, The Philippines, Thailand, Bangladesh, Bhutan, Brunei, Burma, Cambodia, India, Laos, Malaysia, Maldives, Mongolia, Nepal, New Zealand, Sri Lanka and Vietnam (collectively, the “Huadong Territory”).

We otherwise retained our rights to ARCALYST and mavrilimumab outside the Huadong Territory.

In April 2025, we and Huadong entered into a mutual termination agreement pursuant to which we agreed to terminate the mavrilimumab Huadong Collaboration Agreement and release all claims related thereto.

The ARCALYST Huadong Collaboration Agreement remains in effect.

Under the Huadong Collaboration Agreements, we received a total upfront cash payment of $22.0 million, which includes $12.0 million for the Huadong Territory license of ARCALYST and $10.0 million for the Huadong Territory license of mavrilimumab.

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Huadong will also be obligated to pay us tiered percentage royalties ranging from the low to mid-teens on annual net sales of ARCALYST in the Huadong Territory, subject to certain reductions tied to ARCALYST manufacturing costs and certain other customary reductions, with an aggregate minimum floor.

Royalties will be payable for ARCALYST on a country-by-country or region-by-region basis until the later of (i) 12 years after the first commercial sale of ARCALYST in such country or region in the Huadong Territory, (ii) the date of expiration of the last valid patent claim of our patent rights or any joint collaboration patent rights that covers ARCALYST in such country or region in the Huadong Territory, and (iii) the expiration of the last regulatory exclusivity for ARCALYST in such country or region in the Huadong Territory.

Royalties will be payable on a country-by-country or region-by-region basis until the later of (i) 12 years after the first commercial sale of ARCALYST in such country or region in the Huadong Territory, (ii) the date of expiration of the last valid patent claim of our patent rights or any joint collaboration patent rights that covers ARCALYST in such country or region in the Huadong Territory and (iii) the expiration of the last regulatory exclusivity for ARCALYST in such country or region in the Huadong Territory.

Pursuant and subject to the terms of the Huadong Collaboration Agreements, Huadong has the exclusive right to conduct Huadong Territory-specific development activities for ARCALYST in the Huadong Territory, the first right to support global development of ARCALYST by serving as the sponsor of the global clinical trials conducted in the Huadong Territory and the exclusive right to commercialize ARCALYST in the Huadong Territory.

Huadong will be responsible for all costs of development activities and commercialization in the Huadong Territory.

Huadong will be

responsible for all costs of development activities and commercialization in the Huadong Territory.

We and Huadong participate in a joint steering committee, which coordinates and oversees the exploitation of ARCALYST in the Huadong Territory.

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License Agreement with Regeneron

In September 2017, we entered into a license agreement with Regeneron (the “Regeneron Agreement”).

Pursuant to the Regeneron Agreement, we have an exclusive license under certain intellectual property rights controlled by Regeneron to develop and commercialize ARCALYST worldwide, excluding the Middle East and North Africa, for all indications other than those in oncology and local administration to the eye or ear.

In September 2017, we entered into a license agreement with Regeneron (the “Regeneron Agreement”)”), pursuant to which we were granted an exclusive license under certain intellectual property rights controlled by Regeneron to develop and commercialize ARCALYST worldwide, excluding the Middle East and North Africa, for all indications other than those in oncology and local administration to the eye or ear.

Upon receiving positive data in RHAPSODY, our pivotal Phase 3 clinical trial of ARCALYST, Regeneron transferred the biologics license application (“BLA”) for ARCALYST to us.

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Under the Regeneron Agreement, we paid $32.5 million in connection with upfront fees and the achievement of regulatory milestones.

We evenly split profits on sales of ARCALYST with Regeneron , where profits are determined

after deducting from net sales of ARCALYST certain costs related to the manufacturing and commercialization of ARCALYST.

We evenly split profits on sales of ARCALYST with Regeneron , where profits are determined after deducting from net sales of ARCALYST certain costs related to the manufacturing and commercialization of ARCALYST.

Such costs include but are not limited to (i) our cost of goods sold for product used, sold or otherwise distributed for patient use by us;

(ii) customary commercialization expenses, including the cost of our field force and (iii) our cost to market, advertise and otherwise promote ARCALYST, with such costs identified in subsection (iii) subject to specified limits.

To the extent permitted in accordance with the Regeneron Agreement, the fully-burdened costs of each of us and Regeneron incurred in performing (or having performed) the technology transfer of the manufacturing process for ARCALYST drug substance will also be deducted from net sales of ARCALYST to determine profit.

To the extent permitted in accordance with the Regeneron Agreement, the fully-burdened costs incurred by each of us and Regeneron in performing (or having performed) the technology transfer of the manufacturing process for ARCALYST drug substance will also be deducted from net sales of ARCALYST to determine profit.

We also evenly split with Regeneron any proceeds received by us from any licensees, sublicensees and distributors in consideration for the sale, license or other disposition of rights with respect to ARCALYST, including upfront payments, milestone payments and royalties.

Regeneron has a right of first negotiation over our engagement of any third party to support our promotional activities in excess of a specified level and over the assignment or sale of our rights to any product containing ARCALYST to a third party.

In addition, we will need Regeneron’s prior written consent for the sublicense of certain rights to a third party, provided that such consent shall not be unreasonably withheld, conditioned or delayed with respect to the sublicensing of rights outside of the United States.

Furthermore, under certain circumstances, we will need Regeneron’s prior consent to assign our rights under the Regeneron Agreement.

The Regeneron Agreement will expire on the date on which we, our affiliates or sublicensees are no longer developing or commercializing any product containing ARCALYST.

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Regeneron may terminate the agreement if there is a consecutive twelve-month period during which we do not conduct any material development or commercialization activities or we do not grant a sublicense to a third party to do so, or if we challenge Regeneron’s patent rights in any country in our territory.

Either party may terminate the agreement in the event of a material breach by the other party that remains uncured for 90 days (or 30 days for payment-related breaches), or by either party due to the insolvency or bankruptcy of the other party.

Either party may terminate the agreement in the event of a material breach

by the other party that remains uncured for 90 days (or 30 days for payment-related breaches), or by either party due to the insolvency or bankruptcy of the other party.

We have also entered into a commercial supply agreement with Regeneron (the “Supply Agreement”), under which Regeneron agreed to manufacture product for our clinical and commercial use.

License Agreement with MedImmune

In December 2017, we entered into a license agreement with MedImmune (subsequently acquired by AstraZeneca PLC) (the “MedImmune Agreement”), pursuant to which MedImmune granted us an exclusive, sublicensable, worldwide license to certain intellectual property rights to make, use, develop and commercialize mavrilimumab and any other product containing an antibody to the GM-CSF receptor alpha that is covered by certain MedImmune patent rights for all indications.

We also acquired non-exclusive licenses to other MedImmune technology for use in exploiting licensed products.

We also acquired reference rights to relevant manufacturing and regulatory documents, and MedImmune’s existing supply of mavrilimumab drug substance and product.

We were obligated to use commercially reasonable efforts to develop and commercialize the licensed products.

In February 2025, we delivered a notice of termination to MedImmune, notifying them of our intent to terminate for convenience the MedImmune Agreement effective May 22, 2025.

Following such termination effective date, the rights and licenses granted to us by MedImmune pursuant to the MedImmune Agreement will terminate.

Under the MedImmune Agreement, we paid a total of $23.0 million in connection with upfront fees, a pass-through payment and milestone payment related to the achievement of specified clinical milestones.

Biogen Asset Purchase Agreement

In September 2016, we entered into an asset purchase agreement (the “Biogen Agreement”) with Biogen MA Inc.

(“Biogen”) to acquire all of Biogen’s right, title and interest in and to certain assets used in or relating to vixarelimab and other antibodies covered by certain patent rights, including patents and other intellectual property rights, clinical data, certain contracts, know-how and clinical drug supply (the “Acquired Biogen Assets”).

In addition, Biogen granted us a non-exclusive, sublicensable, worldwide license to certain background patent rights related to the vixarelimab program.

Under the Biogen Agreement, we are obligated to use commercially reasonable efforts to develop and commercialize the Acquired Biogen Assets.

Under the Biogen Agreement, we paid a total of $26.3 million in connection with upfront fees, a technology transfer payment and certain specified milestone payments.

We are obligated to make additional milestone payments for each antibody product that includes the Acquired Biogen Assets (each, a “Biogen Antibody Product” and, together, “Biogen Antibody Products”), of up to $315.0 million in the aggregate upon the achievement of specified milestones.

These milestone payments relate to multiple indications for a Biogen Antibody Product and are comprised of up to $165.0 million in the aggregate upon achievement of specified clinical and regulatory milestone events and $150.0 million in the aggregate upon the achievement of specified annual net sales milestones.

Commencing on the first commercial sale of a Biogen Antibody Product, we are obligated to pay tiered royalties on escalating tiers of annual net sales of licensed products starting in the high single-digit percentages and ending below the teens.

We must pay such royalties on a Biogen Antibody Product-by-Biogen Antibody Product and country-by-country basis until the latest to occur of the expiration of patents that cover a Biogen Antibody Product, the expiration of regulatory exclusivity or the tenth anniversary of first commercial sale of such product in such country.

We have also agreed to pay certain obligations under third party contracts retained by Biogen that relate to vixarelimab.

Under the Biogen Agreement, Biogen has a time-limited right of first negotiation to purchase the assets we acquired from Biogen or obtain a license to exploit Biogen Antibody Products, in each case, in the event we decide to sell the Acquired Biogen Assets, including through the sale of our company, or out-license the rights to the Biogen Antibody Products.

Biogen waived such right in connection with the Genentech License Agreement.

The Biogen Agreement will terminate upon the expiration of all payment obligations in all countries related to the last Biogen Antibody Product subject to the Biogen Agreement.

The Biogen Agreement may be terminated by us with 90 days’ prior notice, by either party in the event of a material breach by the other party that remains uncured for 90 days (or 30 days for payment-related breaches) or by both parties upon mutual consent.

In the event of a termination, the Acquired Biogen Assets, including certain licenses and rights related thereto, will revert to Biogen, and, upon written request by Biogen, we are required to grant to Biogen an exclusive, worldwide, sub-licensable license to certain of our intellectual property related to the Acquired Biogen Assets, including know-how and patent rights.

In July 2017, we and Biogen entered into Amendment No.

1 to the Biogen Agreement, which clarified the scope of the antibodies subject to the Biogen Agreement.

In August 2022, we entered into Amendment No.

2 to the Biogen Agreement (the “Second Biogen Amendment”).

Pursuant to the terms of the Second Biogen Amendment, commencing on the effective date of the Genentech License Agreement, certain defined terms in the Biogen Agreement were amended, including “Net Sales”, “Indication”, “Product”, “Combination Product” and “Valid Claim”.

In addition, the tiered royalty rates to be paid by us to Biogen increased by an amount equal to less than one percent.

Upon the termination or expiration of the Genentech License Agreement, the amendments to the terms of the Biogen Agreement, as set forth in the Second Biogen Amendment, will terminate and all terms of the Biogen Agreement will revert to the version of such terms in effect as of immediately prior to the effective date of the Genentech License Agreement.

Beth Israel Deaconess Medical Center License Agreement

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We have a field-specific exclusive license under the Regeneron Agreement to granted patents and pending applications in the United States and numerous other jurisdictions relating to ARCALYST.

As of December 31, 2024, the patent rights in-licensed under the Regeneron Agreement relating to our program include three granted patents in the United States and a patent granted in Japan.

In addition, the patent rights in-licensed under the Regeneron Agreement relating to our program include patent applications that are pending in the United States, Canada, Europe and selected countries in Asia.

A United States patent covering ARCALYST as a composition of matter expired in 2020, and relevant composition of matter patents issued outside of the United States expired in 2023.

Four patents covering methods of using ARCALYST in the treatment of recurrent pericarditis have issued in the United States and have a statutory term that expires in 2038, not including any patent term adjustment.

Five patents covering methods of using ARCALYST in the treatment of recurrent pericarditis have issued in the United States and have a statutory term that expires in 2038, not including any patent term adjustment.

In March 2021, the FDA granted approval for ARCALYST for the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and children 12 years of age and older, which granted us seven years of marketing exclusivity in the United States.

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If issued, such patents will have statutory expiration dates in 2045, not including any patent term extensions or adjustments.

As of December 31, 2025, one patent covering KPL-387 formulations has issued in the United States, expiring in 2045, not including any patent term extensions.

We also own a pending patent application covering methods of using KPL-387 in the treatment of recurrent pericarditis.

If issued, patents covering methods of using KPL-387 in treating recurrent pericarditis will have statutory expiration dates in 2046, not including any patent term extensions or adjustments.

If we are successful in obtaining regulatory approval of KPL-387 for the treatment of recurrent pericarditis, we also expect to rely on data exclusivity and orphan exclusivity to protect our market position.

If we are successful in obtaining regulatory approval of KPL-387 for the treatment of recurrent pericarditis, we also expect to rely on data exclusivity and orphan exclusivity (if we satisfy the criteria for orphan drug exclusivity at the time of approval and thereafter) to protect our market position.

For example, in the United States, a new biologic product receives 12 years of data exclusivity upon receiving regulatory approval.

In the EU, a new product generally receives eight years of data exclusivity and an additional two years of market exclusivity upon regulatory approval.

See “ Business – Government Regulation - Biosimilars and Exclusivity;

Government Regulation - Orphan Drug Designation;

Government Regulations - Regulatory Framework in the European Union - Data and Marketing Exclusivity;

and Government Regulations - Regulatory Framework in the European Union – Orphan Medicinal Products ” below for additional information on regulatory exclusivities.

In the EU, a new

product generally receives eight years of data exclusivity and an additional two years of market exclusivity upon regulatory approval.

See “ Business – Government Regulation ” below for additional information on regulatory exclusivities.

We own a pending patent application relating to KPL-1161, which covers composition of matter.

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Other Intellectual Property

In addition to the above, we maintain certain other intellectual property, including patents, trademarks and know-how, related to our pre-clinical development and broader Kiniksa brand.

In addition to the above, we maintain certain other intellectual property, including patents, trademarks and know-how, related to our other assets, pre-clinical development and broader Kiniksa brand.

There can be no assurances that patents will issue from any of our pending patent applications or that any of our existing patents may be extended.

See “ Risk Factors—Risks Related to Intellectual Property— If we are unable to adequately protect our proprietary technology or obtain and maintain patent protection for our technology and products, if the scope of the patent protection obtained is not sufficiently broad, or if the terms of our patents are insufficient to protect our product candidates for an adequate amount of time, our competitors could develop and commercialize technology and products similar or identical to ours, and our ability to successfully commercialize our technology and products may be materially impaired .”

See “ Risk Factors—Risks Related to Intellectual Property.”

In the future, if and when our drug candidates receive approval by the FDA or comparable regulatory authorities in other jurisdictions (as applicable, “regulatory authorities”), provided the legal requirements are met, we expect to apply for patent term extensions on issued patents covering those drugs, depending upon the length of the clinical trials for each drug and other factors.

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The process required by the FDA before a biologic may be marketed in the United States generally involves the following:

● Completion of extensive preclinical tests, animal studies, and toxicology, pharmacology and formulation studies in accordance with applicable regulations, including Good Laboratory Practice (“GLP”) regulations;

● Completion of extensive preclinical tests;

animal studies;

and toxicology, pharmacology and formulation studies in accordance with applicable regulations, including the FDA’s good laboratory practice (“GLP”) regulations, or similar foreign standards ;

● Submission to FDA of an investigational new drug application (an “IND”) which must become effective before human clinical trials may begin;

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The conduct of the preclinical tests must comply with federal regulations and requirements, including GLP regulations.

The sponsor must submit the results of the preclinical studies as part of an IND, along with other information, including information about chemistry, manufacturing and controls (“CMC”).

Before conducting a clinical trial in the United States, the sponsor must provide the results of the preclinical studies as part of an IND submitted to the FDA, along with other information, including information about chemistry, manufacturing and controls (“CMC”).

An IND is a request for authorization from the FDA to administer an investigational product to humans and must become effective before human clinical trials may begin.

An IND automatically becomes effective 30 days after receipt by the FDA, unless before that time the FDA places the clinical trial on hold and the IND sponsor must resolve any outstanding issues before clinical trials can proceed.

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Each protocol, and any subsequent amendments to the protocol, must be submitted to the FDA as part of the IND.

Furthermore, an IRB representing each institution at which the clinical trial will be conducted must review and approve the plan for any clinical trial, including, among other things, the protocol and informed consent information to be provided to clinical trial subjects or their legal representatives, to ensure that the

risks to individuals participating in the clinical trials are minimized and are reasonable in relation to anticipated benefits.

Furthermore, an IRB representing each institution at which the clinical trial

will be conducted must review and approve the plan for any clinical trial, including, among other things, the protocol and informed consent information to be provided to clinical trial subjects or their legal representatives, to ensure that the risks to individuals participating in the clinical trials are minimized and are reasonable in relation to anticipated benefits.

The IRB also must monitor the clinical trial until completed.

Some clinical trials also include oversight by an independent group of qualified experts organized by the clinical study sponsor, commonly known as a Data Safety Monitoring Board, which may recommend continuation of a trial as planned, changes in the trial or cessation of the trial at designated check points based on access to certain data from the trial.

Some clinical trials also include oversight by an independent group of qualified experts organized by the clinical study sponsor, commonly known as a Data Safety Monitoring Board (a “DSMB”) or Data Monitoring Committee (a “DMC”), which may recommend continuation of a trial as planned, changes in the trial or cessation of the trial at designated check points based on access to certain data from the trial.

The FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the participants are being exposed to an unacceptable health risk.

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Human clinical trials are typically conducted in three sequential phases, which may overlap or be combined.

● Phase 1 clinical trials generally involve a small number of healthy participants.

● Phase 1 clinical trials generally involve a small number of participants, who are usually healthy participants (Phase 1a), although Phase 1 clinical trials can, in certain circumstances, involve patients with the target disease or condition (Phase 1b).

The primary purpose of these clinical trials is to assess the metabolism, pharmacologic action, tolerability and safety of the drug.

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Once the BLA submission is accepted for filing, the FDA begins an in-depth substantive review.

The FDA reviews a BLA to determine, among other things, whether the product is safe, pure and potent and the facility in which it is manufactured, processed, packed or held meets standards designed to assure the product’s continued safety, purity and potency.

product’s continued safety, purity and potency.

Most BLAs are reviewed within ten months from the filing date or six months from the 60-day filing date for BLAs with priority review, subject in each case to extensions by the FDA.

Before approving a BLA, the FDA will typically conduct a pre-approval inspection of the manufacturing facilities for the new product to determine whether the manufacturing processes and facilities comply with cGMPs and

are adequate to ensure consistent product production within required specifications.

The FDA also may inspect the sponsor and one or more clinical trial sites to assure compliance with GCP requirements and the integrity of the clinical data submitted to the FDA.

Additionally, the FDA may refer applications for novel biologic candidates, which present challenges in interpretation of the safety or efficacy data, to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved.

The FDA also may inspect the sponsor and one or more clinical trial sites to assure compliance with GCP requirements and integrity of the clinical data submitted to the FDA.

Additionally, the FDA may refer applications for novel biologic candidates, which present challenges in interpretation of the safety or efficacy data, to an Advisory Committee, typically a panel that includes clinicians and other experts appointed by the FDA Commissioner or a designee, for review, evaluation and a recommendation as to whether the application should be approved.

The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations when making decisions on approval.

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For instance, the FDA closely regulates the post-approval marketing and promotion of drugs and biologics, including standards and regulations for direct-to-consumer advertising, off-label promotion, industry-sponsored scientific and educational activities and promotional activities involving the internet and social media.

Drugs and biologics may be marketed only for the approved indications and in accordance with the provisions of the approved labeling.

Drugs and biologics may only be marketed for the approved indications and in accordance with the provisions of the approved labeling.

Adverse event reporting and submission of periodic reports are required following FDA approval of a BLA.

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We rely, and expect to continue to rely, on third party CDMOs for the production of clinical and commercial quantities of our products in accordance with cGMP regulations.

We, and our CDMOs are required to

We, and our CDMOs are required to register our establishments with the FDA and certain state agencies.

Registration with the FDA subjects us and our CDMOs to periodic unannounced inspections by the FDA, during which the agency inspects manufacturing facilities to assess compliance with cGMPs.

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In addition to regulations in the United States, we are subject to a variety of regulations in other jurisdictions governing, among other things, clinical trials, marketing authorization, post-marketing requirements and any commercial sales and distribution of products approved in such jurisdictions.

The product approval process ultimately varies between countries and jurisdictions and can involve additional product testing and additional administrative review periods.

The product approval process ultimately varies between

countries and jurisdictions and can involve additional product testing and additional administrative review periods.

The time required to obtain approval in other countries and jurisdictions might differ from and be longer than that required to obtain FDA approval.

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The CTR is directly applicable in all EU member states without the need for member states to further implement it into national law.

The CTR notably harmonizes the assessment and supervision processes for clinical trials throughout the EU via a Clinical Trials Information System, which contains a centralized EU portal and database.

The CTR notably harmonizes the assessment and supervision processes for clinical trials throughout the EU via a Clinical Trials Information System (“CTIS”), which contains a centralized EU portal and database.

If the sponsor of the clinical trial is not established within the EU, it must appoint an EU entity to act as its legal representative.

The sponsor must take out a clinical trial insurance policy, and in most EU member states, the sponsor is liable to provide ‘no fault’ compensation to any study subject injured in the clinical trial.

While the Clinical Trials Directive required a separate clinical trial application (a “CTA”) to be submitted in each member state, to both the competent national health authority and an independent ethics committee, much like the FDA and IRB respectively, the CTR introduces a centralized process and only requires the submission of a single application to all member states concerned.

The CTR allows sponsors to make a single submission to both the competent authority and an ethics committee in each member state, leading to a single decision per member state.

The CTA must include information concerning the trial protocol and the manufacture and quality of the medicinal product under investigation.

The assessment procedure of the CTA has been harmonized as well, including a joint assessment by all member states concerned, and a separate assessment by each member state with respect to specific requirements related to its own territory, including ethics rules.

The assessment procedure of the CTA has been harmonized.

For each clinical trial submitted in CTIS, one reporting member state will lead the assessment process for those elements of the clinical trial application that are common throughout the EU, and member states concerned by the application may raise objections to the reporting member state’s assessment.

Each member state is responsible for assessing the elements specific to its own territory, including ethics rules.

Once the CTA is approved, clinical study development may proceed.

Documents and data from the CTA are made publicly available through CTIS at time of decision about the clinical trial, subject to the redaction of personal data and confidential information.

Since January 2025, all clinical trials (including those which are ongoing but approved under the previous legal framework) are subject to the provisions of the CTR.

Since January 2025, all clinical trials (including those which are ongoing but approved under the previous legal framework) are regulated by the CTR.

Medicines used in clinical trials must be manufactured in accordance with cGMP.

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To obtain a MA of a product candidate in the EU, we must submit a MA application (an “MAA”).

The process for doing this depends, among other things, on the nature of the medicinal product.

There are two types of MAs:

The process for doing this depends, among other things, on the nature and therapeutic category of the medicinal product.

There are two types of MAs that can be granted by the relevant competent authorities:

● “Centralized MAs” are issued by the European Commission through the centralized procedure, based on the opinion of the Committee for Medicinal Products for Human Use (the “CHMP”) of the EMA, and are valid throughout the EU.

The centralized procedure is compulsory for certain types of medicines, such as (i) medicines derived from biotechnological processes, (ii) products designated as orphan medicinal products, (iii) advanced-therapy medicines (such as gene-therapy, somatic cell-therapy or tissue-engineered products) and (iv) products with a new active substance indicated for the treatment of specified diseases, such as HIV/AIDS, cancer, diabetes, neurodegenerative diseases or autoimmune and other immune dysfunctions and viral diseases.

The centralized procedure is optional for products containing a new active substance not yet authorized in the EU, or for products that represent a significant therapeutic, scientific or technical innovation, or whose authorization would be in the interest of public health in the EU.

Under the centralized procedure the maximum timeframe for the evaluation of an MAA by the EMA is 210 days, excluding clock stops, when additional written or oral information is to be provided by the applicant in response to questions asked by the CHMP.

● “National MAs” are issued by the competent authorities of the EU member states, only cover their respective territory, and are available for investigational medicinal products that fall outside the mandatory scope of the centralized procedure.

Where a product has already been authorized for marketing in an EU

member state, this national MA can be recognized in another member state through the Mutual Recognition Procedure.

If the product has not received a national MA in any member state at the time of application, it can be approved simultaneously in various member states through the decentralized procedure.

The centralized procedure is optional for products containing a new active

substance not yet authorized in the EU, or for products that represent a significant therapeutic, scientific or technical innovation or whose authorization would be in the interest of public health in the EU.

Under the centralized procedure the maximum timeframe for the evaluation of an MAA by the EMA is 210 days, excluding any procedural clock stops.

Clock-stops are periods during which the evaluation is paused to allow the applicant sufficient time to provide additional information in response to questions asked by the CHMP.

● “National MAs” are granted by the competent authorities of the EU member states, only cover their respective territory and are available for medicinal products that fall outside the mandatory scope of the centralized procedure.

Where a product has already been authorized for marketing in an EU member state, this national MA can be recognized in one or more additional member states through the Mutual Recognition Procedure.

If the product has not received a national MA in any member state at the time of application, it can be approved simultaneously in two or more member states through the decentralized procedure.

Under the decentralized procedure an identical dossier is submitted to the competent authorities of each of the member states in which the MA is sought, one of which is selected by the applicant as the reference member state.

Under the above-described procedures, in order to grant the MA, the competent authorities of the EU make an assessment of the risk-benefit balance of the product on the basis of scientific criteria concerning its quality, safety and efficacy.

Consistent with EU pharmaceutical law requirements, in order to grant the MA, the competent authorities of the EU assess the risk-benefit balance of the product against the scientific criteria relating to its quality, safety and efficacy.

MAs have an initial duration of five years.

After these five years, the authorization may be renewed on the basis of a reevaluation of the risk-benefit balance.

After this period, the authorization may be renewed and its validity extended, subject to a satisfactory reevaluation of the risk-benefit balance of the product.

In the EU, a “conditional” MA may be granted in cases where all the required safety and efficacy data are not yet available.

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and (iv) the benefit of the immediate availability to patients of the medicinal product is greater than the risk inherent in the fact that additional data are still required.

The conditional MA is subject to conditions to be fulfilled for generating the missing data or ensuring increased safety measures.

It is valid for one year and must be renewed annually until all related conditions have been fulfilled.

Once any pending studies are provided, the conditional MA can be converted into a traditional MA.

However, if the conditions are not fulfilled within the timeframe set by the EMA and approved by the European Commission, the MA will cease to be renewed.

A conditional MA is subject to specific obligations such as generating comprehensive evidence to confirm the benefit-risk balance of the product.

It is valid for one year and must be renewed annually until all conditions are fulfilled.

Once outstanding data are provided and satisfactorily assessed, the conditional MA can be converted into a standard (traditional) MA.

However, if the conditions are not fulfilled within the timeframe set by the EMA and approved by the European Commission, the MA will cease to be renewed or may be revoked.

Data and Marketing Exclusivity

The EU also provides opportunities for market exclusivity.

New products authorized for marketing (i.e., reference products) generally receive eight years of data exclusivity and an additional two years of market exclusivity upon receiving an MA.

During the data exclusivity period in the EU, biosimilar applicants may not rely on the pre-clinical and clinical trial data contained in the dossier of the reference product when applying for a biosimilar MA.

During the market exclusivity period in the EU, a biosimilar MAA can be submitted and approved, and data previously covered by data exclusivity may be referenced, but no biosimilar product can be commercialized until the expiration of such period (for a total of ten years of data and market exclusivity).

The overall ten-year market exclusivity period can be extended to a maximum of eleven years if, during the first eight years of those ten years, the MA holder obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are held to bring a significant clinical benefit in comparison with existing therapies.

There is a special regime for biosimilars, or biological medicinal products that are similar to a reference medicinal product but that do not meet the definition of a generic medicinal product, for example, because of differences in raw materials or manufacturing processes.

For such products, the results of appropriate preclinical or clinical trials must be provided, and guidelines from the EMA detail the type of quantity of supplementary data to be provided for different types of biological product.

There are no such guidelines for complex biological products, such as gene or cell therapy medicinal products, and so it is unlikely that biosimilars of those products will currently be approved in the EU.

However, guidance from the EMA states that they will be considered in the future in light of the scientific knowledge and regulatory experience gained at the time.

The EU also provides opportunities for marketing exclusivity.

Newly authorized products that qualify as reference medicinal products – based on a complete, stand-alone dossier consisting of pharmaceutical, non-clinical and clinical trial data – receive eight years of data exclusivity, followed by additional two years of marketing exclusivity upon receiving an MA.

During the data exclusivity period in the EU, biosimilar applicants are not permitted to rely on the pre-clinical and clinical trial data contained in the dossier of the reference product when applying for a biosimilar MA.

Once the eight-year data exclusivity has expired, a biosimilar MAA can be submitted and approved.

However, no biosimilar product can be commercialized until the full ten-year exclusivity period has expired.

The overall ten-year data and marketing exclusivity period can be extended to a maximum of eleven years if, during the first eight years of those ten years, the MA holder obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are held to bring a significant clinical benefit in comparison with existing therapies.

Approval of a biosimilar differs from the conventional regulatory process for approving generic products because biosimilars do not meet the definition of a generic medicinal product.

This is primarily due to differences in raw materials or manufacturing processes or the complex nature of biological products.

Approval of a biosimilar require submission of appropriate preclinical or clinical trial results.

The EMA and its advisory committees have developed detailed guidelines specifying the type of supplementary data that should be provided for different classes of biological products.

These guidelines outline the evidence necessary to demonstrate that the biosimilar is comparable to the

reference product in terms of quality, safety, and efficacy.

Currently, there exist no specific guidelines for complex biological products, such as gene or cell therapy medicinal products.

The EMA has indicated that guidance for such complex biological products may be developed in the future, taking into account advancements in scientific knowledge and regulatory experience as they are gained.

Orphan Medicinal Products

The criteria for designating an “orphan medicinal product” in the EU, are similar in principle to those in the United States.

The criteria for designating an “orphan medicinal product” in the EU, are broadly similar to those in the United States with the additional requirement in the EU to demonstrate significant benefit during the designation procedure.

Under Article 3 of Regulation (EC) 141/2000, a medicinal product may be designated as orphan if (1) it is intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition;

(2) either (a) such condition affects no more than five in 10,000 persons in the EU when the application is made, or (b) the product, without the benefits derived from orphan status, would not generate sufficient return in the EU to justify investment;

and (3) there exists no satisfactory method of diagnosis, prevention or treatment of such condition authorized for marketing in the EU, or if such a method exists, the product will be of significant benefit to those affected

by the condition.

Orphan medicinal products are eligible for financial incentives such as reduction of fees or fee waivers and are, upon grant of a MA, entitled to ten years of market exclusivity for the approved therapeutic indication.

During this ten-year orphan market exclusivity period, the competent authorities cannot accept another MAA, grant an MA or accept an application to extend a MA for a similar product for the same indication.

Orphan Drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.

Orphan Drug designation does not confer any advantage in, or shorten the duration of, the regulatory review and approval process.

The ten-year market exclusivity in the EU may be reduced to six years if, at the end of the fifth year, it is established that the product no longer meets the criteria for orphan designation, for example, if the product is sufficiently profitable not to justify maintenance of market exclusivity.

Additionally, a MA may be granted to a similar product for the same indication at any time if (i) the second applicant can establish that its product, although similar, is safer, more effective or otherwise clinically superior;

(ii) the applicant consents to a second orphan medicinal product application;

or (iii) the applicant cannot supply enough orphan medicinal product.

(ii) the marketing authorization holder for the first approved product consents to a second orphan medicinal product application;

or (iii) the marketing authorization holder cannot supply sufficient quantities of the approved orphan medicinal product.

Pediatrics Development

In the EU, MAAs for new medicinal products generally must either include the results of studies conducted in the pediatric population or contain a PDCO-approved plan to address the needs of the pediatric population in an appropriate and timely way, in compliance with a pediatric investigation plan (a “PIP”) agreed with the EMA’s Pediatric Committee (the “PDCO”).

The PIP sets out the timing and measures proposed to generate data to support a pediatric indication of the drug for which MA is being sought.

The PDCO can grant a deferral of the obligation to implement some or all of the measures of the PIP until there are sufficient data to demonstrate the efficacy and safety of the product in adults.

Further, the obligation to provide pediatric clinical trial data can be waived by the PDCO when this data is not needed or appropriate because the product is likely to be ineffective or unsafe in children, the disease or condition for which the product is intended occurs only in adult populations, or when the product does not represent a significant therapeutic benefit over existing treatments for pediatric patients.

Once the MA is obtained in all EU member states and study results are included in the product information, even when negative, the product is eligible for six months’ supplementary extension of the basic patent protection under a supplementary protection certificate (if any is in effect at the time of approval) or, in the case of orphan medicinal products, a two-year extension of the ten-year orphan market exclusivity is granted.

No extension to any supplementary protection certificate can be granted on the basis of pediatric studies for orphan indications.

In the EU, MAAs for new medicinal products must be accompanied by the results of studies contained in a pediatric investigation plan (a “PIP”) agreed with the EMA’s Pediatric Committee (the “PDCO”), unless a deferral or a waiver applies.

The PIP sets out the timing and measures proposed to generate the necessary data determining the conditions in which a medicinal product may be authorized to treat the pediatric population.

The PDCO can grant a deferral of the obligation, allowing the requirement to carry out some or all of the measures of the PIP to be postponed until sufficient data are available to demonstrate the efficacy and safety of the product in adults.

Further, the obligation to provide pediatric clinical trial data can be waived by the PDCO when such data are necessary or appropriate because the product is likely to be ineffective or unsafe in children, the disease or condition for which the product is intended occurs only in adult populations, or when the product does not represent a significant therapeutic benefit over existing treatments for pediatric patients.

Once the MA is obtained in all EU member states and study results are included in the product information, regardless of whether those results would lead to approval of a pediatric indication, the product is eligible for six months’ supplementary extension of the basic patent protection under a supplementary protection certificate (if one is in effect at the time of approval) or, in the case of orphan medicinal products, a two-year extension of the ten-year orphan market exclusivity may be granted under the same conditions.

An extension of a supplementary protection certificate cannot be granted for orphan medicinal products, and only one of these incentives may be awarded.

PRIME Designation

In the EU, innovative products that target conditions with an unmet medical need may be eligible for a number of expedited development and review programs, such as the Priority Medicine (“PRIME”) scheme, which provides incentives similar to the Breakthrough Therapy designation in the United States.

PRIME is a voluntary operational framework based on increased interaction and early dialogue between the EMA and companies developing promising medicines, to optimize their product development plans and speed up their evaluation to help them reach patients earlier.

In the EU, innovative products that address conditions with an unmet medical need – either because no treatment option exists or because they can offer a major therapeutic advantage over existing treatments– may be eligible for early and proactive support.

Such products can benefit from a range of expedited development and review programs, including the Priority Medicines (“PRIME”) scheme, which shares a common objective with the US Breakthrough Therapy designation to optimize and accelerate the development and regulatory assessment of promising therapies.

The benefits of a PRIME designation include the appointment of a rapporteur before submission of an MAA, early dialogue and scientific advice at key development milestones and the potential to qualify products for accelerated review earlier in the application process.

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The holder of an MA for a medicinal product must also comply with pharmacovigilance legislation and its related regulations and guidelines, which entail many requirements for conducting pharmacovigilance, or the assessment and monitoring of the safety of medicinal products.

The holder of a MA must establish and maintain a pharmacovigilance system and appoint an individual qualified person for pharmacovigilance (a “QPPV”) who is responsible for the establishment and maintenance of that system and oversees the safety profiles of medicinal products

and any emerging safety concerns.

Key obligations include expedited reporting of suspected serious adverse reactions and submission of periodic safety update reports (“PSURs”).

All new MAAs must include a risk management plan (“RMP”), describing the risk management system that the company will put in place and documenting measures to prevent or minimize the risks associated with the product.

The RMP must be updated any time new information on the medicinal product becomes available which has a significant impact on the content of the RMP.

The holder of a MA must establish and maintain a pharmacovigilance system and appoint a qualified person for pharmacovigilance (a “QPPV”) who is responsible for the establishment and maintenance of that system.

MA holders required to record all suspected adverse reactions within and outside the EU and report all serious suspected adverse reactions expeditiously.

In addition, MA holders are required to submit periodic safety update reports (“PSURs”) or periodic benefit-risk evaluation reports to evaluate the benefit-risk balance of a medicinal product at defined time points after its authorization.

All new MAAs must include a risk management plan (“RMP”), describing the risk management system consisting of a set of pharmacovigilance activities and interventions designed to identify, characterize, prevent or minimize the risks relating to a medicinal product, including the assessment of those activities and interventions.

The RMP must be updated whenever new information becomes available that significantly impacts its content.

The regulatory authorities may also impose specific obligations as a condition of the MA.

Such risk-minimization measures or post-authorization obligations may include additional safety monitoring, more frequent submission of PSURs, or the conduct of additional clinical trials or post-authorization safety studies.

In addition, the advertising and promotion of medicinal products is also subject to laws concerning promotion of medicinal products, interactions with physicians, misleading and comparative advertising and unfair commercial practices.

These risk-minimization measures or post-authorization requirements may include additional safety monitoring, more frequent submission of PSURs or the conduct of additional clinical trials or post-authorization safety studies.

Advertising and promotion of medicinal products are subject to strict legal requirements, including those governing interactions with healthcare professionals, misleading and comparative advertising and unfair commercial practices.

All advertising and promotional activities for the product must be consistent with the approved summary of product characteristics, and therefore all off-label promotion is prohibited.

Direct-to-consumer advertising of prescription medicines is also prohibited in the EU.

Although general requirements for advertising and promotion of medicinal products are established under EU directives, the details are governed by regulations and various trade associations’ codes of conduct in each member state and can differ from one country to another.

Failure to comply with EU and national laws that apply to the conduct of clinical trials, manufacturing approval, MA of medicinal products and marketing of such products, both before and after grant of the MA, manufacturing of medicinal products, statutory health insurance, bribery and anti-corruption or with other applicable regulatory requirements may result in administrative, civil or criminal penalties.

Direct-to-consumer advertising of prescription medicines is prohibited in the EU.

Although general requirements for advertising and promotion of medicinal products are established under EU directives, the specific rules are set out in national regulations and the codes of conduct of various trade associations within each member state for the rules to be enforced.

As a result, the detailed requirements and enforcement practices can vary from country to country.

Failure to comply with EU and national laws that apply to the conduct of clinical trials, manufacturing approval, MA of medicinal products and marketing of such products, both before and after grant of the MA, manufacturing of medicinal products, bribery and anti-corruption or with other applicable regulatory requirements may result in administrative, civil or criminal penalties.

These penalties could include delays or refusal to authorize the conduct of clinical trials or to grant an MA, product withdrawals and recalls, product seizures, suspension, withdrawal or variation of the MA, total or partial suspension of production, distribution, manufacturing or clinical trials, operating restrictions, injunctions, suspension of licenses, fines and criminal penalties.

Regulatory Framework in the United Kingdom

Since the end of the Brexit transition period on January 1, 2021, Great Britain (England, Scotland and Wales) has not been directly subject to EU laws, however under the terms of the Ireland/Northern Ireland Protocol, EU laws generally apply to Northern Ireland.

Since the end of the Brexit transition period on January 1, 2021, Great Britain (England, Scotland and Wales) has not been directly subject to EU laws.

However, under the terms of the Ireland/Northern Ireland Protocol, EU laws applied to Northern Ireland.

In February 2023, the EU and UK reached an agreement, known as the Windsor Framework, on the future of trade with Northern Ireland, which amends certain aspects of the Northern Ireland protocol.

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The EU laws that have been transposed into United Kingdom (the “UK”) law through secondary legislation remain applicable in Great Britain.

However, under the Retained EU Law (Revocation and Reform) Act 2023, which received royal assent on June 29, 2023, any retained EU law not expressly preserved and “assimilated” into domestic law or extended by ministerial regulations (to no later than June 23, 2026) was automatically expired and revoked by December 31, 2023.

However, under the Retained EU Law (Revocation and Reform) Act 2023, which

received royal assent on June 29, 2023, any retained EU law not expressly preserved and “assimilated” into domestic law or extended by ministerial regulations (to no later than June 23, 2026) was automatically expired and revoked by December 31, 2023.

New legislation such as the EU CTR or in relation to orphan medicines is, therefore, not applicable to Great Britain.

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As of January 1, 2021, the Medicines and Healthcare products Regulatory Agency (the “MHRA”) is the UK’s standalone medicines and medical devices regulator.

The MHRA has introduced changes to national licensing procedures, including procedures to prioritize access to new medicines that will benefit patients, including a 150-day assessment and a rolling review procedure.

All existing EU MAs for centrally authorized products were automatically converted or grandfathered into UK MAs, effective in GB (only), free of charge on January 1, 2021, unless the MA holder chose to opt-out.

In order to use the centralized procedure to obtain a MA that will be valid throughout the EEA, companies must be established in the EEA.

Therefore, after Brexit, companies established in the UK can no longer use the EU centralized procedure and instead an EEA entity must hold any centralized MAs.

In order to obtain a UK MA to commercialize products in the UK, an applicant must be established in the UK and must follow one of the UK national authorization procedures or one of the remaining post-Brexit international cooperation procedures.

The MHRA may use the MHRA’s decentralized or mutual recognition procedures which enable MAs approved in EU member states (or Iceland, Liechtenstein or Norway) to be granted in GB (the so-called “MRDC Reliance Procedure”).

Until December 31, 2023, the MHRA was able to rely on a decision taken by the European Commission on the approval of a new (centralized procedure) MA when determining an application for a GB authorization (the so called “EC Decision Reliance Procedure”).

Since January 1, 2024, the EC Decision Reliance Procedure has been replaced by the new International Recognition procedure (“IRP”).

The IRP expands the trusted regulatory partners to which the MHRA relies upon to include Australia, Canada, Switzerland, Singapore, Japan, the United States and the EU.

The MHRA will retain the authority to reject IRP applications if the evidence provided is considered insufficiently robust.

To be used or sold in the UK, a drug must have a valid MA granted through the national application process.

National applications are governed by the Human Medicines Regulations (SI 2012/1916).

Applications are made electronically through the MHRA Submissions Portal.

The MHRA operates fixed submission and assessment timetables for innovative medicines applications to facilitate consultation with its statutory advisory committee, the Commission on Human Medicines (“CHM”).

The MHRA assessment procedure for a MA application involves an initial evaluation, including orphan designation if applicable, and consultation with expert advisory groups as needed.

By Day 90, applicants receive a consolidated request for information (“RFI”), which pauses the review clock until a complete response is submitted electronically.

Responses are assessed by Day 150, with further RFIs issued for minor issues or a CHM letter for major objections.

Each subsequent RFI requires a complete response within three months, and the clock is restarted upon submission.

Applicants may make written or oral representations to the CHM if major objections remain.

Final compliance checks are conducted once all issues are resolved, and the MHRA issues a grant or refusal letter specifying any conditions and the MA expiry date.

The entire assessment process is designed to be completed within 210 calendar days, excluding any procedural clock-stops for additional information or representations.

The innovative medicines timetable allows for a positive decision within 150 clock-on days if all issues are resolved following one round of questions.

Where there are outstanding issues at Day 150, we will come to a final decision as soon as possible and within 210 clock-on days.

The innovative medicines timetable allows for a positive decision within 150 clock-on days if all issues are resolved following one round of questions.

Where there are outstanding issues at Day 150, we will come to a final decision as soon as possible and within 210 clock-on days.

In addition, the MHRA 150-day accelerated review is a specialized, fast-track national MA procedure designed for innovative medicines, new active substances, and biosimilars, aiming for a decision in 150 "clock-on" days rather than the standard 210.

It requires high-quality applications, typically involving one round of questions and a 60-day cool-down period for responses.

On August 30, 2023, the MHRA published detailed guidance on its recently announced new International Recognition Procedure (“IRP”) for MAAs.

The IRP applies from January 1, 2024, and replaces existing EU decision reliance procedure.

to apply for authorizations from seven international regulators (e.g.

Health Canada, Swiss Medic, FDA, EMA, among others).

The IRP allows the MHRA to take into account the assessment and decision-making of the ‘Reference Regulators” to perform a targeted assessment of IRP applications but retain the authority to reject applications if the evidence provided is considered insufficiently robust.

There exist two recognition timetables for new IRP MAAs:

IRP Route A (60 days) and IRP Route B (110 days), both starting from validation.

Eligibility is determined via an applicant-completed form six weeks before submission.

Recognition A applies to applications with Reference Regulator approval within the past two years, with no clock stop, but may revert to Recognition B if major objections arise.

IRP Route B covers Reference Regulator approvals within the past ten years (or exceptionally older) and applies if specific criteria, such as conditional approvals, manufacturing changes, or UK-specific requirements, are met.

IRP Route B allows for consultation with the CHM and aligns with CHM dates for new active substances.

Applications not eligible for either timetable may be submitted as full national applications if MHRA requirements are met.

IRP can be used for post-authorization measures including line extensions, variations, and renewal application.

There will be no pre-MA orphan designation.

Instead, the MHRA will review applications for orphan designation in parallel to the corresponding MA application.

The criteria are essentially the same, but have been tailored for the market, i.e., the prevalence of the condition in GB, rather than the EU, must not be more than five in 10,000.

The criteria are essentially the same as the EU rules, but have been tailored for the market, i.e., the prevalence of the condition in GB, rather than the EU, must not be more than

five in 10,000.

Should an orphan designation be granted, the period or market exclusivity will be set from the date of first approval of the product in GB.

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Other Healthcare Laws

In the U.S., activities of pharmaceutical manufacturers are subject to numerous other federal, state, and local laws designed to, for example, prevent “fraud and abuse” in the delivery of and payment for healthcare;

In the United States, activities of pharmaceutical manufacturers are subject to numerous other federal, state and local laws designed to, for example, prevent “fraud and abuse” in the delivery of and payment for healthcare;

promote transparency in interactions with others in the healthcare industry;

require reporting of drug prices and payment of rebates or offering of discounts to certain government programs and public and private payors;

protect consumers;

and regulate government payment for drugs.

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In the United States and markets in other countries, patients rely on third party payors to reimburse healthcare costs.

Third party payors include government authorities, managed care plans, private health insurers and other organizations.

In the United States, the process for determining whether a third party payor will provide coverage and the related coverage criteria for a biological product typically is separate from, but related to, the process for setting the price of such product or for establishing the level of reimbursement that the payor will pay for the product once coverage is approved.

Third party payors include government authorities or health care programs, managed care plans, private health insurers and other organizations.

In the United States, the process for determining whether a third party payor will provide coverage and the related coverage criteria for a biological product typically is separate from the process for setting the price of such product or for establishing the level of reimbursement that the payor will pay for the product once coverage is approved.

Third party payors may limit coverage or take other action to control utilization of covered products, including restricting coverage to specific products on an approved list, also known as a formulary, which might not include all of the FDA-approved products for a particular indication, or place products at certain formulary levels that result in lower reimbursement levels, which results in higher cost-sharing financial obligation imposed on patients.

Additionally, coverage, coverage criteria and reimbursement for products can differ significantly from payor to payor.

One third party payor’s decision to cover a particular medical product does not ensure that other payors will also provide coverage for the medical product or will provide coverage at an adequate reimbursement rate.

One third party payor’s decision to cover a particular biologic does not ensure that other payors will also provide coverage for the biologic or will provide coverage at an adequate reimbursement rate.

As a result, the coverage determination process usually requires manufacturers to provide scientific, clinical and health economic support for the use of their products to each payor separately, which is a time-consuming process.

Third party payors are increasingly challenging the prices charged for medical products and services, examining the medical necessity and reviewing the cost-benefit of pharmaceutical products, in addition to questioning safety and efficacy.

Third party payors are increasingly challenging the prices charged for medical products and services, examining the medical necessity and reviewing the cost-benefit of biopharmaceutical products, in addition to questioning safety and efficacy.

If third party payors do not consider a product to offer a favorable cost-benefit compared to other available therapies, they may not cover that product after FDA approval or, if they do, the level of payment may not be sufficient to allow a manufacturer to sell its product at a profit.

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Some jurisdictions operate positive and negative list systems under which products may only be marketed once a reimbursement price has been agreed to by the government.

Member states may approve a specific price or level of reimbursement for the

pharmaceutical product, or alternatively adopt a system of direct or indirect controls on the profitability of the company responsible for placing the pharmaceutical product on the market, including volume-based arrangements, caps and reference pricing mechanisms.

Member states may approve a specific price or level of reimbursement for the pharmaceutical product, or alternatively adopt a system of direct or indirect controls on the profitability of the company responsible for placing the pharmaceutical product on the market, including volume-based arrangements, caps and reference pricing mechanisms.

To obtain reimbursement or pricing approval, some of these countries may require the completion of clinical trials that compare the cost effectiveness of a particular product to currently available therapies.

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Under the MDRP, participating manufacturers are required to pay a rebate for each unit of product reimbursed under the state Medicaid programs.

The amount of the rebate for each product is set by law and depends in part on the prices at which our products are sold to certain other purchasers and may be subject to an additional discount if certain pricing increases more than inflation.

The amount of the rebate for each product is set by law and depends in part on the prices at which our products are sold to certain other purchasers and may be subject to an additional

discount if certain pricing increases more than inflation.

State Medicaid programs and Medicaid managed care plans can seek additional “supplemental” rebates from manufacturers.

Medicare is a federal program that is administered by the federal government that covers individuals age 65 and over, disabled individuals and individuals with certain conditions.

Medicare is a federal program that is administered by the federal government that covers individuals age 65 and over, disabled individuals and certain other eligible individuals.

Medicare Part B generally covers drugs that are usually administered by physicians or other clinicians.

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Medicare Part D provides coverage for self-administered drugs (i.e., drugs that do not need to be injected or otherwise administered by a physician).

Medicare Part D is administered by private prescription drug plans approved by the U.S.

government and each drug plan establishes its own Medicare Part D formulary for prescription drug coverage and pricing, which the drug plan may modify from time-to-time.

The prescription drug plans negotiate pricing with manufacturers and may condition formulary placement on the availability of manufacturer discounts.

Manufacturers with marketed brand name drugs are required to provide discounts on brand name prescription drugs utilized by Medicare Part D beneficiaries, with discount requirements changing over time.

Medicare Part D is administered by private prescription drug plans approved by the United States government.

Each drug plan establishes its own government-approved Medicare Part D formulary for prescription drug coverage and pricing, which the drug plan may modify from time-to-time.

The prescription drug plans negotiate rebates with manufacturers and may condition formulary placement on the availability of manufacturer discounts.

Manufacturers with marketed brand name drugs and biologics are required to provide discounts on such drugs and biologics utilized by Medicare Part D beneficiaries, under a manufacturer discount program.

Additionally, as the result of recent changes under the Inflation Reduction Act of 2022 (“IRA”), drug utilization under Medicare Part B and Part D may be subject to an additional Medicare discount if the pricing increases more than inflation.

● Federal Purchasers .

Drug products are subject to discounted pricing when purchased by federal agencies via the Federal Supply Schedule (“FSS”).

FSS participation is required for a drug to be covered and reimbursed by certain federal agencies and for coverage under Medicaid, Medicare Part B and the Public Health Service (“PHS”) 340B drug pricing program.

FSS pricing is negotiated periodically with the Department of Veterans Affairs.

FSS pricing is intended not to exceed the price that a manufacturer charges its most-favored non-federal customer for its product.

In addition, prices for drugs purchased by the Veterans Administration, Department of Defense (including drugs purchased by military personnel and dependents through the TRICARE retail pharmacy program), Coast Guard and PHS are subject to a cap on pricing (known as the “federal ceiling price”) and may be subject to an additional discount if pricing increases more than the rate of inflation.

FSS participation is required for a drug to be covered and reimbursed by certain federal agencies and for coverage of any manufacturer drug products under the MDRP and Medicare Part B.

FSS pricing is subject to statutory reporting requirements and also is negotiated periodically with the Department of Veterans Affairs, including by reference to a manufacturer’s comparable non-federal customer pricing.

By statute, prices for drugs purchased by the Veterans Administration, Department of Defense (including drugs purchased by military personnel and dependents through the TRICARE retail pharmacy program), Coast Guard and the Public Health Service (“PHS”) are subject to a cap on pricing (known as the “federal ceiling price”) and may be subject to an additional discount if pricing increases more than the rate of inflation.

● PHS 340B Drug Pricing Program .

To maintain coverage of drugs under the MDRP and Medicare Part B, manufacturers are required to extend discounts to certain purchases under the PHS 340B drug pricing program.

Purchasers eligible for discounts include hospitals that serve a disproportionate share of financially needy patients, community health clinics and other entities that receive health services grants from the PHS.

Additionally, a number of states have either implemented or are considering implementation of drug price transparency legislation.

To obtain coverage of drugs under the MDRP and Medicare Part B, manufacturers are required to extend discounts to certain purchasers under the PHS 340B drug pricing program.

Purchasers eligible for 340B discounts include hospitals that serve a disproportionate share of financially needy patients, community health clinics and other entities that receive certain health services grants from the PHS.

Additionally, several states have either implemented or are considering implementing drug price transparency legislation.

Requirements under such laws include advance notice of planned price increases, reporting price increase amounts and factors considered in taking such increases, wholesale acquisition cost information disclosure to prescribers, purchasers and state agencies, and new product notice and reporting.

Such legislation could limit the price or payment for certain drugs, and a number of states may impose civil monetary penalties or pursue other enforcement mechanisms against manufacturers who fail to comply with drug price transparency requirements.

A number of states may impose civil monetary penalties or pursue other enforcement mechanisms against manufacturers who fail to comply with drug price transparency requirements.

Certain other state legislation focuses on limiting the price or payment for certain drugs.

Healthcare Reform and Potential Changes to Healthcare Laws

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Recent examples include federal legislation that eliminated a statutory cap on Medicaid drug rebate program rebates effective January 1, 2024.

As another example, the Inflation Reduction Act (the “IRA”) of 2022 includes a number of changes intended to address rising prescription drug prices in Medicare Parts B and D, with varying implementation dates.

These changes include caps on Medicare Part D out-of-pocket costs, Medicare Part B and Part D drug price inflation rebates, a new Medicare Part D manufacturer discount drug program (replacing the prior Medicare Part D coverage gap discount program) and a drug price negotiation program for certain high spend Medicare Part B and D drugs (with the first list of drugs announced in 2023).

The IRA is anticipated to have a significant impact on the pharmaceutical industry.

As another example, subsequent to the enactment of the IRA, in 2022, the Biden Administration announced its commitment to expanding certain IRA reforms.

There have been significant and wide-ranging reforms to federal policy and the federal government under the new Trump Administration.

Drug pricing and payment reform was a focus of the prior Trump Administration and that focus is likely to continue under the new Trump Administration.

Other potential healthcare reform efforts under the Trump Administration may affect access to healthcare coverage or the funding of health care benefits.

There is significant uncertainty regarding the nature or impact of any such reform as may be implemented by the Trump Administration through executive action or by Congress.

As another example, the IRA of 2022 includes a number of changes intended to address rising prescription drug prices in Medicare Parts B and D, with varying implementation dates.

high spend Medicare Part B and D drugs (with the first set of negotiated Medicare maximum fair prices going into effect in 2026).

The IRA has had a significant impact on the pharmaceutical industry and that impact is anticipated to continue.

Beyond the IRA, changes to Medicaid effective in 2024 eliminated the Medicaid rebate cap and changes to certain Medicare price reporting requirements for drugs beginning in 2026 will likely increase the administrative and compliance burden for manufacturers.

In addition, recent legislation expanded the orphan drug exclusion in the IRA Medicare drug price negotiation program.

Under the current presidential administration, there has been significant reform activity focused on drug pricing and reimbursement.

For example, an Executive Order was issued in April 2025 with multiple directives aimed at lowering drug prices, including refining the Medicare drug price negotiation program established by the IRA, accelerating competition for high-cost prescription drugs by accelerating approval of generics and biosimilars and facilitating the process for re-classifying prescription drugs as over-the-counter drugs, and increasing drug importation.

In May 2025, another Executive Order was issued that directed government agencies and officials to identify most-favored nation pricing targets for prescription drugs (and looked to pharmaceutical manufacturers to make significant progress towards delivering target prices to patients), prevent foreign countries from disproportionately shifting the cost of global pharmaceutical research and development to the U.S., and facilitate direct-to-consumer purchasing programs for pharmaceutical manufacturers to sell their products to patients at the most-favored-nation price.

In the wake of the Executive Orders and related executive initiatives, a number of pharmaceutical manufacturers have announced direct-to-consumer offerings with discounted prices and/or reached agreement with the federal government regarding pricing for drugs, including prices for Medicaid drugs and newly launched products.

As part of the initiative, the federal government has also launched a website providing pharmaceutical direct-to-consumer channels.

Federal agencies are developing new drug pricing pilot programs, such as a Medicaid model which would authorize the federal government to negotiate Medicaid supplemental rebates with participating manufacturers on behalf of state Medicaid programs, in exchange for standardized coverage criteria for participating manufacturer drugs, and proposed Medicare Part B and Part D pilot models that, if finalized as proposed, would replace existing inflation-based Medicare rebates with rebates determined on the basis of international prices, for drugs and patients subject to the model.

Other healthcare reform efforts or actions may affect access to healthcare coverage or the funding of health care benefits, although the full impact of such efforts or actions cannot be predicted.

For example, the Congressional Budget Office has estimated that Medicaid provisions in the 2025 budget reconciliation legislation, including restrictions in eligibility and funding for Medicaid, as well as changes to the healthcare marketplace such as the elimination of certain subsidies, will increase the number of uninsured patients.

Additionally, there has been increasing legislative and enforcement interest in the United States with respect to specialty drug pricing practices.

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Healthcare reform efforts have been and may continue to be subject to scrutiny, legal challenge and subsequent amendment, creating further uncertainty.

In addition, other broader legislative changes have been adopted that could have an adverse effect upon, and could prevent, our products’ commercial success.

For example, the Budget Control Act of 2011, as amended, resulted in the imposition of reductions in Medicare (but not Medicaid) payments to providers in 2013 and remains in effect through 2032 unless additional Congressional action is taken.

Other government actions could have an adverse effect upon, and could prevent, our products’ commercial success.

For example, the current presidential administration’s announced tariff on branded or patented drugs may increase the cost of drug products that are imported from abroad or manufactured using products or materials imported from abroad.

The timeline for implementation of this tariff has not yet been finalized.

As another example, the Budget Control Act of 2011, as amended, resulted in the imposition of reductions in Medicare (but not Medicaid) payments to

providers in 2013 and remains in effect through 2032 unless additional Congressional action is taken.

Any significant spending reductions affecting Medicare, Medicaid or other publicly funded or subsidized health programs that may be implemented and/or any significant taxes or fees that may be imposed on us could have an adverse impact on our results of operations.

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The HTA intends to boost cooperation among EU member states in assessing health technologies, including new medicinal products, and providing the basis for cooperation at the EU level for joint clinical assessments in these areas.

The HTA permits EU member states to use common HTA tools, methodologies, and procedures across the EU,

working together in four main areas, including joint clinical assessment of the innovative health technologies with the most potential impact for patients, joint scientific consultations whereby developers can seek advice from HTA authorities, identification of emerging health technologies to identify promising technologies early, and continuing voluntary cooperation in other areas.

The HTA permits EU member states to use common HTA tools, methodologies and procedures across the EU, working together in four main areas, including joint clinical assessment of the innovative health technologies with the most potential impact for patients, joint scientific consultations whereby developers can seek advice from HTA authorities, identification of emerging health technologies to identify promising technologies early and continuing voluntary cooperation in other areas.

Individual EU member states will continue to be responsible for assessing non-clinical (e.g., economic, social, ethical) aspects of health technology and making decisions on pricing and reimbursement.

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and (vi) streamlining regulatory procedures, reducing approval timeline by over 50 days for centrally authorized products.

In April 2024, the European Parliament adopted its position at first reading of the two EU legislative proposals.

Certain of the legislative changes proposed by the Commission were revised by the European Parliament.

For example, the Parliament wanted to introduce a minimum regulatory data protection period of seven and a half years in addition to two years of market protection.

Companies would be eligible for additional periods of data protection if their product addresses an unmet medical need, if comparative clinical trials are conducted and if a significant share of the research and development takes place in the EU and at least partly in collaboration with EU research entities.

Timelines for these proposed changes to legislation are currently unknown as the legislative proposals must be approved by the European Parliament and the European Council.

It is unlikely that new legislation will be adopted before 2026.

On December 11, 2025, the European Council (consisting of the EU member states) and the European Parliament reached an agreement on the final shape of the new rules.

The agreed text now awaits formal adoption by both the Parliament and Council, after which it will be published in the Official Journal of the EU.

The new Directive and Regulation will then enter into force following a transition period of 18 to 36 months, ultimately modernizing EU pharmaceutical law to better support innovation, access, and supply.

The agreed framework provides among other things that new medicines benefit from eight years of data protection and one year of market protection, with possible extensions for addressing unmet medical needs or additional indications, up to a maximum of 11 years.

Developers of new antibiotics may receive transferable vouchers for extra market protection, and orphan medicines can receive up to 11 years of combined protection, along with early regulatory guidance.

In addition, the European Commission proposed in December 2025 the Biotech Act which seeks to strengthen the competitiveness of the biotechnology sector and facilitate the development and timely market entry of biotechnology innovations, while ensuring high standards for the protection of human health.

Other Regulations

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● the United States Foreign Corrupt Practices Act (the “FCPA”), the U.K.

or authorizing the payment of anything of value to any foreign government official, government staff member, political party or political candidate for the purpose of obtaining or retaining business or to otherwise obtain favorable treatment or influence a person working in an official capacity abroad.

Bribery Act 2010 (the “Bribery Act”) and similar anti-bribery or anti-corruption laws, regulations or rules in other countries in which we operate, which prohibit companies and their representatives from paying, offering to pay, promising to pay or authorizing the payment of anything of value to any foreign government official, government staff member, political party or political candidate for the purpose of obtaining or retaining business or to otherwise obtain favorable treatment or influence a person working in an official capacity abroad.

The Bribery Act may also create liability where we fail to prevent a person associated with us from committing a bribery offense.

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● analogous United States state laws and regulations, such as state anti-kickback and false claims laws that may apply to sales or marketing arrangements and claims involving healthcare items or services reimbursed by nongovernmental third party payors, including private insurers;

and state laws that require pharmaceutical companies to adopt certain compliance standards;

and state laws that require

pharmaceutical companies to adopt certain compliance standards;

restrict interactions with healthcare professionals;

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We believe that the success and growth of our business depends in large part on our continued ability to attract, retain and motivate qualified personnel at all levels of our company.

To do that, we employ a number of measures, including competitive compensation and benefits, fostering a culture that values diversity and inclusion, maintaining an ethical workplace and focusing on employee safety and wellness.

These measures help form our human capital management framework and are advanced through the following actions, programs and initiatives:

Competitive Pay and Benefits.

We provide our employees with competitive fixed salaries, cash bonus opportunities designed to incentivize achievement of our goals and individual objectives, equity awards and opportunities for equity ownership through our employee share purchase plan and a robust benefit package designed to promote well-being across different aspects of our employees’ lives, including comprehensive health insurance, dental and vision plans, life and other employment related insurance, retirement planning through a 401(k) plan with partial company match, and paid time off.

Diversity, Equity and Inclusion.

We value diversity and inclusion at all levels of our company.

We believe that our business benefits from the different perspectives that a diverse workforce brings, and we pride ourselves on having an inclusive culture.

Our diversity statement formally expresses our commitment to diversity, equity and inclusion (“DEI”) goals.

This initiative is part of our broader effort to establish a systematic approach towards DEI.

Our Code of Business Conduct and Ethics outlines our aim of cultivating a diverse and inclusive work environment.

We mandate that our employees train annually on non-discrimination, antiracism, and promoting a diverse and inclusive workplace.

As an additional demonstration of our focus on DEI, we signed the MassBio’s CEO Pledge for a More Equitable and Inclusive Life Sciences Industry to recognize racial inequity in our industry and to work towards a more equitable and inclusive life sciences industry.

We provide our employees with competitive base salaries, cash bonus opportunities designed to incentivize achievement of our corporate goals, equity awards and opportunities for equity ownership through our employee share purchase plan and a robust benefit package designed to promote well-being across different aspects of our employees’ lives, including comprehensive health insurance, dental and vision plans, life and other employment related insurance, retirement planning through a 401(k) plan with partial company match and paid time off.

Ethics in the Workplace.

We aim to run a compliant and ethical business, which we believe attracts and maintains the highest caliber of executives and employees.

Each employee of our company is required to confirm in writing that they understand and will comply with our policies, including but not limited to our Code of Business Conduct and Ethics, our insider trading and compliance policy, our policies against bribery and corruption and our policies regarding interactions with healthcare professionals.

Employees are required to participate in periodic and as-needed trainings in order to refresh their understanding of our policies and provide additional instruction for new issues as and when they arise.

Overall, we believe that our commitment to compliance, quality and ethics throughout our business makes us a stronger and more competitive organization.

We believe this attracts and retains the highest caliber of executives and employees who deliver for our patients and execute on our corporate strategy.

Each employee of our company is required to confirm in writing that they understand and will comply with our policies, including but not limited to our Code of Business Conduct and Ethics, anti-harassment policy, our insider trading and compliance policy, our policies against bribery and corruption and our policies regarding interactions with healthcare professionals.

Further, we believe our company benefits from a broad range of experiences and viewpoints that enable innovative approaches to our business and operations.

We foster a culture where employees put compliance first and speak up on important ethical issues.

Employees are required to participate in periodic and as-needed trainings to refresh their understanding of our policies and to provide additional training for new issues as and when they arise.

For the clinical and manufacturing activities that we perform and oversee, we adhere to operating within the accepted GLP, GCP, cGMP and other similar regulatory guidelines.

Overall, we believe that our commitment to quality and ethics throughout our business makes us a stronger, compliant and competitive organization.

Health and Safety.

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Our Corporate Information

We were initially incorporated under the laws of Bermuda in July 2015 and, in April 2024, subsequently announced the completion of the change of place of incorporation of our principal holding company from Bermuda to the United Kingdom (the “Redomiciliation”), pursuant to a scheme of arrangement approved by both the Bermuda Supreme Court and our shareholders, which caused the shareholders of our former parent company, Kiniksa Pharmaceuticals, Ltd., to become the shareholders of our current parent company, Kiniksa Pharmaceuticals International, plc.

Our registered office is located at 23 Old Bond Street, London, W1S 4PZ, England, United Kingdom.

The telephone number for our registered office is +1 (781) 431-9100.

We were initially incorporated under the laws of Bermuda in July 2015 and, in June 2024, subsequently announced the completion of the change of place of incorporation of our principal holding company from Bermuda to the United Kingdom (the “Redomiciliation”), pursuant to a scheme of arrangement approved by both the Bermuda Supreme Court and our shareholders, which caused the shareholders of our former parent company, Kiniksa Pharmaceuticals, Ltd., to become the shareholders of our current parent company, Kiniksa Pharmaceuticals International, plc.

Our registered office is located at 105 Piccadilly, Second Floor, London, W1J 7NJ, England, United Kingdom.

Our executive offices are located at 100 Hayden Avenue, Lexington, Massachusetts, 02421.

The telephone number for our offices is +1 (781) 431-9100.

Our website address is www.kiniksa.com.

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and from and after the Redomiciliation, to Kiniksa Pharmaceuticals International, plc.

In addition, references to “ordinary shares” prior to the Redomiciliation are to Kiniksa Pharmaceuticals, Ltd.’s common shares and from and after the Redomiciliation are to Kiniksa Pharmaceuticals International, plc’s ordinary shares.

In addition, references to “ordinary shares” prior to the Redomiciliation

are to Kiniksa Pharmaceuticals, Ltd.’s common shares and from and after the Redomiciliation are to Kiniksa Pharmaceuticals International, plc’s ordinary shares.

Where You Can Find More Information

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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