Kiniksa Pharmaceuticals International : 2025 Annual Report
KNSA
Published on 05/08/2026 at 01:33 pm EDT
Vanessa Jill João
Living with Recurrent Pericarditis
2025
A N N U A L R E P O R T
Dear Fellow Shareholders,
In 2025, Kiniksa continued to deliver meaningful progress across our commercial and clinical portfolio, helping patients suffering from debilitating diseases with significant unmet need.
Continued ARCALYST commercial growth and disciplined capital allocation position Kiniksa for near- and long-term success. We are building the foundation for future growth through strategic investments in the commercialization of ARCALYST as well as the advancement of our pipeline of interleukin-1 alpha (IL-1α) and interleukin-1 beta (IL-1β) inhibition assets.
ARCALYST
ARCALYST, an IL-1α & IL-1β cytokine trap, is the only U.S. Food and Drug Administration (FDA)-approved therapy for the treatment of recurrent pericarditis and reduction in risk of recurrence. In the five years since launch, ARCALYST has redefined the treatment paradigm for this disease, establishing IL-1 pathway inhibition as the preferred second-line approach, ahead of corticosteroids. In August 2025, the
American College of Cardiology formally recognized this evolution with the publication of its Concise Clinical Guidance, recommending IL-1 pathway inhibition after the use of NSAIDs and colchicine for patients suffering from recurrent pericarditis.
Expanding adoption of IL-1α & IL-1β inhibition with ARCALYST was the primary driver of our robust commercial performance throughout 2025. Over the course of the year, we saw meaningful increases in the breadth and depth of prescribing, treatment duration, and penetration across the recurrent pericarditis population. More than 4,150 healthcare providers have prescribed ARCALYST since launch, with approximately 29% writing more than one prescription. Importantly, the majority of new prescriptions are coming from existing prescribers, speaking to the effectiveness of our educational efforts and the growing appreciation
physicians have for ARCALYST as a safe and effective treatment that can
be used continuously throughout the duration of this chronic disease. Average total duration of therapy continues to grow and is approaching 3 years, in line with the median duration of disease. As a result, approximately 18% of the annual target population of 14,000 patients with multiple recurrences were actively on ARCALYST treatment as of the end of 2025. Furthermore, growing physician familiarity prescribing ARCALYST is contributing to broader use in patients on their first recurrence, who account for around 20% of ARCALYST prescriptions. The upside potential within the additional 26,000 patients each year who experience their first recurrence is large, particularly among those suffering from additional risk factors associated with longer disease duration.
ARCALYST sales grew 62% year-over-year to $677.6 million in 2025, and we believe substantial opportunity remains.
Our strong and profitable commercial collaboration positions us to enable the next phase of growth for ARCALYST. We continue to make disciplined investments to maximize our opportunity in recurrent pericarditis by efficiently reaching additional patients and physicians. Alongside our field force, we are advancing digital marketing initiatives to promote patient self-advocacy and AI-driven targeting to position our field personnel for timely engagement with physicians. We are also evaluating opportunities to further expand the impact of Pericardial Disease Centers (PDCs), where ARCALYST adoption continues to outpace that of other sites. As of the end of 2025, there were 18 PDCs across the U.S. specializing in recurrent pericarditis.
Additionally, we are committed to ongoing innovation with ARCALYST and continue to support a collaborative Phase 2 study in cardiac sarcoidosis conducted by Mayo Clinic and The Johns Hopkins University.
KPL-387
KPL-387, our independently developed monoclonal antibody that binds human interleukin-1 receptor 1 (IL-1R1) to inhibit the signaling activity of the cytokines IL-1α & IL-1β, represents a meaningful opportunity to build on our leadership in recurrent pericarditis.
As the market leader, we are leveraging our existing clinical expertise to explore additional efficacious treatment options for patients. With this program, we are advancing a validated mechanism that could address key patient needs and expand penetration into the addressable market. We believe KPL-387 could enable once-monthly dosing with a single subcutaneous self-injection in a liquid formulation, offering convenient administration using an autoinjector. In 2025, we initiated the registrational Phase 2/3 development program of KPL-387 in recurrent pericarditis, with Phase 2 data expected in the second half of 2026.
We are also conducting a supplemental Phase 2 Transition to KPL-387 Monotherapy Dosing & Administration Study to provide healthcare professionals with additional information at the time of launch to support initiating KPL-387.
Market research indicates there may be strong demand among the vast majority of surveyed patients and healthcare professionals for a highly efficacious IL-1α & IL-1β inhibitor with the target profile of KPL-387. Approximately 75% of surveyed recurrent pericarditis patients would prefer a treatment with such a target profile over currently available
or other investigational therapies. Additionally, among ARCALYST-naïve patients, approximately 75% stated an increased willingness to take an injectable therapy if presented in an autoinjector. On the physician side, approximately 92% indicated a high likelihood of prescribing the KPL-387 target profile for new patients, in the context of available commercial and investigational therapies. Both patient and physician preferences highlight the potential for KPL-387 to address key needs for those with recurrent pericarditis.
In October 2025, the FDA granted Orphan Drug Designation to KPL-387 for the treatment of pericarditis, including recurrent pericarditis. We are working diligently to bring this potential treatment option to patients and are aiming to be on the market in the 2028/2029 timeframe.
KPL-1161
KPL-1161 is an Fc-modified monoclonal antibody IL-1α & IL-1β antagonist developed independently by Kiniksa that binds IL-1R1, with a target profile of once-quarterly subcutaneous dosing. We believe this profile may support treatment across a range of cardiovascular and IL-1 mediated diseases. KPL-1161 is currently in preclinical development, and we expect to initiate a Phase 1 first-in-human trial by the end of 2026.
Financial Position
Through consistent execution and prudent capital allocation, Kiniksa has maintained a robust balance sheet with positive annual cash flow. Our financial strength provides capacity to continue investing responsibly in value creation by maximizing the opportunity with ARCALYST, advancing our clinical pipeline, and pursuing business development initiatives, which remain fundamental to our strategy. Alongside our existing assets, we continue to evaluate opportunities to expand our portfolio with programs that have strong biologic rationale and validated mechanisms.
Supported by the relentless devotion of Kiniksa's employees, we are well-positioned to drive future success, generate long-term value, and help many more patients in need. Thank you for your ongoing support.
Every Second Counts!
Sincerely,
Sanj K. Patel
CEO and Chairman of the Board
Washington, D.C. 20549
(Mark One)
For the fiscal year ended December 31, 2025 OR
For the transition period from to Commission File Number: 001-38492
(Exact name of registrant as specified in its charter)
England and Wales 98-1795578
(State or other jurisdiction of incorporation or organization)
Kiniksa Pharmaceuticals International, plc 105 Piccadilly, Second Floor
London, W1J 7NJ England, United Kingdom (781) 431-9100
(I.R.S. Employer Identification Number)
(Address, zip code and telephone number, including area code of principal executive offices)
Kiniksa Pharmaceuticals Corp.
100 Hayden Avenue
Lexington, MA, 02421
(781) 431-9100
(Address, zip code and telephone number, including area code of agent for service)
N/A
(Former name, former address and former fiscal year, if changed since last report)
Securities registered pursuant to Section 12(b) of the Act:
Title of each class
Trading Symbol(s)
Name of each exchange on which registered
Class A Ordinary Shares
KNSA
The Nasdaq Stock Market LLC (Nasdaq Global Select Market)
Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No ☐
Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐ No ☒
Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐
Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer", "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange Act.
Large Accelerated Filer ☒ Accelerated Filer ☐ Non-accelerated Filer ☐ Smaller Reporting Company ☐ Emerging Growth Company ☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐
Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☒
If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐
Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant's executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐
Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒
As of the last business day of the Registrant's most recently completed second fiscal quarter, June 30, 2025, the aggregate market value of the voting and non-voting common equity held by non-affiliates of the Registrant, based on the closing price of the ordinary shares on The Nasdaq Global Select Market was approximately $1,114.0 million.
As of February 20, 2026, there were 76,535,377 ordinary shares outstanding in aggregate, comprised of:
45,900,637 Class A ordinary shares, nominal value $0.000273235 per share 1,795,158 Class B ordinary shares, nominal value $0.000273235 per share 12,781,964 Class A1 ordinary shares, nominal value $0.000273235 per share 16,057,618 Class B1 ordinary shares, nominal value $0.000273235 per share
DOCUMENTS INCORPORATED BY REFERENCE
Portions of the registrant's definitive proxy statement for its 2026 Annual Meeting of Shareholders, which the registrant intends to file with the Securities and Exchange Commission pursuant to Regulation 14A within 120 days after the end of the registrant's fiscal year ended December 31, 2025, are incorporated by reference into Part III of this Annual Report on Form 10-K.
PART I
Page
Item 1. Business ................................................................................ 7
Item 1A. Risk Factors ............................................................................ 43
Item 1B. Unresolved Staff Comments ............................................................... 93
Item 1C. Cybersecurity ........................................................................... 93
Item 2. Properties ............................................................................... 94
Item 3. Legal Proceedings ........................................................................ 94
Item 4. Mine Safety Disclosures ................................................................... 94
Item 5. Market for Registrant's Common Equity, Related Stockholder Matters and Issuer Purchases of
Equity Securities ................................................................................ 95
Item 6. Reserved................................................................................. 96
Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations ............. 97
Item 7A. Quantitative and Qualitative Disclosures About Market Risk 109
Item 8. Financial Statements and Supplementary Data 110
Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure 110
Item 9A. Controls and Procedures 110
Item 9B. Other Information 111
Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 111
Item 10. Directors, Executive Officers and Corporate Governance 112
Item 11. Executive Compensation 112
Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters 112
Item 13. Certain Relationships and Related Transactions, and Director Independence 112
Item 14. Principal Accounting Fees and Services 112
Item 15. Exhibits and Financial Statement Schedules 113
Item 16. Form 10-K Summary 119
This Annual Report on Form 10-K (this "Annual Report") contains forward-looking statements. All statements other than statements of historical facts contained in this Annual Report should be considered forward-looking statements, including statements regarding: our beliefs that KPL-387 will expand the recurrent pericarditis market and provide additional treatment options for patients; our beliefs about dosing and administration for our product candidates, including that KPL-387 has the potential for monthly subcutaneous self-administration in a liquid formulation and that KPL-1161 has the potential for quarterly subcutaneous dosing; our expectation to have data from the Phase 2 portion of our trial of KPL-387 in recurrent pericarditis in the second half of 2026 and that we plan to use the totality of the data to determine further development strategy; our plan to initiate a Phase 1 first-in-human clinical trial of KPL-1161 by the end of 2026; our plan to explore strategic alternatives for abiprubart; our belief that advancing KPL-387 through the clinic and into the market will further our mission of meeting patients' needs; the results we expect to receive from our commercialization efforts; the incidence and prevalence for our target patient populations; our belief that each of our product candidates holds the potential to offer differentiated therapy to patients; planned indications for our products and product candidates; our expectations regarding the value we expect to receive/pay under our current license and collaboration agreements; the plans and strategy of our competitors; our expectations around the intellectual property protection we hope to receive for our products and product candidates; the intellectual property strategy we expect to employ to protect our portfolio; our plans to apply for patent term extensions; our predictions regarding future regulations and legislation; our planned commercial strategy; our plans to rely on third-parties, such as specialty pharmacies, contract research organizations ("CROs") and contract development and manufacturing organizations ("CDMOs"); our relationships with payers; future supply for our products and product candidates; the timing and likelihood of success of our ongoing technology transfer of ARCALYST drug substance manufacturing; the expected impact of the United States' tariffs on our operations, including that we do not expect that tariffs in their current state to have a material impact on our overall business, financial condition or results of operations; plans to conduct operations through one or more of our foreign subsidiaries; the ways in which we expect to incur expenses, including through any future clinical or commercialization efforts; our expectation that our cash balance and our expected cash inflows form operations will allow us to meet our current operating plan and that our existing cash, cash equivalents and short-term investments will enable us to fund our operating expenses and capital expenditure requirements for at least the next 12 months; statements regarding our expected near-term expenditures and revenue; and other similar statements.
These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.
In some cases, you can identify forward-looking statements by terms such as "may," "will," "should," "expect," "plan," "anticipate," "could," "intend," "goal," "design," "target," "project," "contemplate," "believe," "estimate," "predict," "potential" or "continue" or the negative of these terms or other similar expressions, although not all
forward-looking statements contain these identifying words. The forward-looking statements in this Annual Report are only predictions. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our business, financial condition and results of operations. These forward-looking statements speak only as of the date of this Annual Report and are subject to a number of risks, uncertainties and assumptions described under the sections in this Annual Report entitled "Summary Risk Factors", "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" and elsewhere in this Annual Report.
Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond our control, you should not place undue reliance on our forward-looking statements. Except as required by applicable law, we do not assume and specifically disclaim any obligation to update any forward-looking statements, whether as a result of any new information, future events, changed circumstances or otherwise.
Our business is subject to numerous risks and uncertainties, including those described in Part I, Item 1A. "Risk Factors" in this Annual Report. You should carefully consider these risks and uncertainties when investing in our Class A ordinary shares. The principal risks and uncertainties affecting our business include the following:
we may not be able to continue to commercialize ARCALYST or be successful in commercializing any future products, potentially impacting our ability to generate revenue;
we rely on a select network of third party specialty pharmacies to market and sell ARCALYST that may not meet our or our patients' needs;
successful commercialization of our products and product candidates, if approved, will depend in part on the extent to which third party payors, including governmental authorities and private health insurers, provide funding, establish and maintain favorable coverage and pricing policies and set adequate reimbursement levels;
it may be difficult for us to realize the benefit of increasing the price of certain of our commercialized products;
current and future healthcare legislation or executive or administrative action may have a material adverse effect on our business and results of operations;
our business and operations are subject to extensive healthcare regulation and enforcement by various government entities, and our failure to adhere to these regulatory requirements could have a detrimental impact on our business;
if we are unable to advance our product candidates in clinical development, obtain regulatory approval and pursue commercialization, or experience significant delays in doing so, our business may be significantly harmed;
the incidence and prevalence for target patient populations of our products and product candidates have not been established with precision; if the market opportunities for our products and product candidates are smaller than we estimate, or any approval that we obtain is based on a narrower definition of our targeted patient population, our revenue and ability to achieve profitability may be materially adversely affected;
clinical development of our product candidates is a lengthy and expensive process with uncertain timelines, costs and outcomes;
we may encounter substantial delays in our preclinical studies and/or clinical trials or we may fail to demonstrate safety and efficacy to the satisfaction of applicable regulatory authorities;
we may find it difficult to enroll participants in our clinical trials in a timely manner;
interim, preliminary and "topline" data from our clinical trials that we announce or publish from time to time may change as more participant data become available and final data may differ from such interim, preliminary and "topline" data;
we contract with third parties, including CDMOs to manufacture our commercial supply of ARCALYST and clinical supply of our product candidates and for certain research and development; this reliance on third parties increases the risk that we may not have sufficient quantities of ARCALYST or our product candidates or such quantities at an acceptable cost, which could delay, prevent or impair our research and development or commercialization efforts;
we are conducting a technology transfer of the manufacturing process for ARCALYST drug substance from Regeneron Pharmaceuticals, Inc. ("Regeneron") to Samsung Biologics Co., Ltd. ("Samsung"), and the analytical testing methods of ARCALYST drug substance and drug product to new contract testing labs ("CTLs"), which will be subject to significant risks and uncertainties;
we rely, and expect to continue to rely, on third parties, including independent investigators and CROs to activate sites, conduct and otherwise support our research activities, preclinical studies, clinical trials and other trials for our product candidates; if these third parties do not successfully carry out their contractual duties, comply with regulatory requirements or meet expected deadlines, we may not be able to obtain regulatory approval or commercialize our product candidates, and our business could be substantially harmed;
if we are unable to adequately protect our proprietary technology or obtain and maintain patent protection for our technology and patents, if the scope of the patent protection obtained is not sufficiently broad or if the terms of our patents are insufficient to protect 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 products may be materially impaired;
licensing of intellectual property is of critical importance to our business and involves complex legal, business and scientific issues. If we breach any of the agreements related to our product or product candidates, we could lose the ability to continue the development and commercialization of the related product or product candidate;
we face significant competition, which may result in others discovering, developing or commercializing drugs before or more successfully than us;
we may not successfully execute our growth strategy to identify, discover, develop, in-license or acquire additional product candidates or technologies, our strategy may not deliver anticipated results or we may refine or otherwise alter our growth strategy;
we may seek to acquire businesses or undertake business combinations, collaborations or other strategic transactions that may not be successful or on favorable terms, if at all, and we may not realize the intended benefits of such transactions;
we have entered into and may seek to enter into collaboration, licensing or other strategic transactions or arrangements to further develop, commercialize or otherwise attempt to realize value from one or more of our products and product candidates; such arrangements or transactions may not be successful or on favorable terms, which could adversely affect our ability to develop, commercialize or attempt to realize value from our products and product candidates;
we may be adversely affected by continuing geopolitical tensions, including the introduction of tariffs or reciprocal tariffs that may be imposed by the United States and its global trading partners that could collectively cause economic uncertainty and increased costs to product development and manufacturing;
the concentration of ownership of the voting power of our ordinary shares, including our Class B ordinary shares, and conversion rights of the holders of our Class A1 and Class B1 ordinary shares, which are held entirely by entities affiliated with certain of our directors, may prevent new investors from influencing significant corporate decisions and may have an adverse effect on the price of our Class A ordinary shares; and
the rights afforded to our shareholders are governed by English law; not all rights available to shareholders under United States law will be available to holders of our ordinary shares.
Unless otherwise indicated, certain industry data and market data included in this Annual Report were obtained from independent third party surveys, market research, publicly available information, reports of governmental agencies and industry publications and surveys. All of the market data used in this Annual Report involve a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. We believe that the information from these industry publications and surveys included in this Annual Report is reliable.
ARCALYST® is a registered trademark of Regeneron. Solely for convenience, trademarks, service marks and trade names referred to in this Annual Report may be listed without identifying symbols.
We are a biopharmaceutical company developing and commercializing novel therapies for diseases with unmet need, with a focus on cardiovascular indications. Our portfolio of assets is based on strong biologic rationale or validated mechanisms and offers the potential for differentiation.
ARCALYST is an interleukin-1α ("IL-1α") and interleukin-1β ("IL-1β") cytokine trap. In 2017, we licensed ARCALYST from Regeneron, which discovered and initially developed the drug. Our exclusive license to ARCALYST from Regeneron includes worldwide rights, excluding the Middle East and North Africa, for all applications other than those in oncology and local administration to the eye or ear.
We received 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. Recurrent pericarditis is a painful inflammatory cardiovascular disease with an estimated United States prevalent population of approximately 40,000 patients seeking and receiving medical treatment. ARCALYST is also approved in the United States for the treatment of Cryopyrin-Associated Periodic Syndromes ("CAPS"), including Familial Cold Autoinflammatory Syndrome ("FCAS") and Muckle-Wells Syndrome in adults and children 12 years and older, and the maintenance of remission in Deficiency of Interleukin-1 Receptor Antagonist ("DIRA") in adults and children weighing 10 kg or more.
ARCALYST is commercially available across the United States through a select network of specialty pharmacies. We are responsible for sales and distribution of ARCALYST in all approved indications in the United States and evenly split profits on sales as well as third party proceeds with Regeneron. In 2022, we granted Hangzhou Zhongmei Huadong Pharmaceutical Co., Ltd. ("Huadong") exclusive rights to develop and commercialize ARCALYST in the Huadong Territory (as defined below). 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 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. We hold an exclusive worldwide license to abiprubart from Beth Israel Deaconess Medical Center, Inc. ("BIDMC").
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 to explore strategic alternatives for the asset.
SPECIALTY CARDIOVASCULAR
OTHER (NON-CARDIOVASCULAR)
The following table summarizes our current products, product candidates and out-licensing arrangements:
Program
Indication
Preclinical
Phase 1
Phase 2
Phase 3
Commercial
ARCALYST® (rilonacept)1-3
IL-1α & IL-1β Trap
Recurrent Pericarditis
Cardiac Sarcoidosis
Collaborative Study Agreement with Mayo Clinic & The Johns Hopkins University
KPL-3874
IL-1 Antagonist mAb
Recurrent Pericarditis
KPL-1161
Fc-Modified IL-1 Antagonist mAb
Undisclosed
Abiprubart
Anti-CD40 mAb
Exploring Strategic Alternatives
Program
Licensee
Exclusive Licensed Territory
OUT-LICENSING AGREEMENTS
ARCALYST (rilonacept)
IL-1α & IL-1β Trap
Huadong Medicine
Asia Pacific Region, Excluding Japan
Vixarelimab
Anti-OSMRβ mAb
Roche and Genentech
Worldwide
Approved in the United States; ARCALYST is also approved in the United States for CAPS and DIRA.
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 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.
Kiniksa has worldwide rights, excluding the Middle East and North Africa; Kiniksa granted Huadong exclusive rights in the Asia Pacific Region, excluding Japan.
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.
The core of our strategy is the identification, development and commercialization of therapeutic medicines for patients suffering from debilitating cardiovascular diseases with significant unmet medical need. We put patients first and live by our motto: Every Second Counts™.
Critical components of our business strategy include the following:
Overview
ARCALYST is an IL-1α and IL-1β cytokine trap. ARCALYST is currently approved in the United States for the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and children 12 years and older, the treatment of CAPS, including FCAS and Muckle-Wells Syndrome in adults and children 12 years and older, and the maintenance of remission in DIRA in adults and children weighing 10 kg or more. ARCALYST was sold by Regeneron in the United States for the treatment of CAPS from 2008 and the maintenance of remission in DIRA from 2020 until we assumed responsibility for sales in such indications in March 2021.
Recurrent pericarditis is the primary indication for which we are commercializing ARCALYST. It is a severe, debilitating and chronic autoinflammatory cardiovascular disease with an estimated United States prevalent population of approximately 40,000 patients seeking and receiving medical treatment. 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.
In 2022, we granted Huadong exclusive rights to develop and commercialize ARCALYST in the Huadong Territory. 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.
Mechanism of Action
ARCALYST is an inhibitor of IL-1α and IL-1β cytokines. Cytokines are small proteins that play important roles in intercellular signaling, and IL-1α and IL-1β have been demonstrated to play a key role in inflammatory diseases. IL-1α and IL-1β provoke potent, proinflammatory events by engaging the IL-1α and IL-1β receptor. Following tissue insult, the release of IL-1α acts as the primary initiating signal to coordinate the mobilization of immune cells to the damaged area, while IL-1β is secreted mostly by macrophages and is a prototypical cytokine of the canonical NLRP-3 inflammasome. IL-1α and IL-1β signaling results in a dramatic increase in the production of cytokines that orchestrate the proliferation and recruitment of phagocytes to the site of damage, resulting in inflammation. Moreover, IL-1α and
IL-1β signaling also affects other immune system cells, such as T-cells and B-cells.
IL-1β's role in the inflammation process has been extensively studied, while, in comparison, much is still unknown about the independent function of IL-1α in disease pathology. Despite driving similar immunological outcomes, IL-1α and IL-1β differ substantially in their expression and regulation, and non-redundant roles for IL-1α or IL-1β have been demonstrated in multiple inflammatory diseases. There are disease states in which IL-1β inhibition alone does not appear to be sufficient for disease remission in the absence of IL-1α inhibition. Published studies suggest certain autoinflammatory diseases may, in fact, be pathologically driven primarily by IL-1α.
We believe that inhibiting both IL-1α and IL-1β signaling is important for treating recurrent pericarditis. In a published case study, a participant with a refractory form of recurrent pericarditis, who was well controlled on anakinra, was switched from anakinra to canakinumab, which inhibits only IL-1β, for tolerability reasons. The participant's disease returned despite further dose escalation of canakinumab. When the participant was switched back to anakinra, which inhibits ILα and ILβ, the disease promptly went back into remission. 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 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. We are currently engaged in a collaborative study agreement to explore ARCALYST as a treatment for cardiac sarcoidosis and are exploring strategic opportunities for further development. In particular, we believe ARCALYST may be advantageous in acute indications that may benefit from a weekly subcutaneous therapy with a proven method of action.
Background and Market Opportunity for Recurrent Pericarditis
Pericarditis is the most common disorder involving the pericardium, the two-layered sac that surrounds the heart. Pericarditis is an inflammation of this sac and is typically characterized by significant chest pain, shortness of breath, coughing and fatigue and is often misconstrued by patients as a heart attack. In addition, typical signs of pericarditis include pericardial friction rub, electrocardiogram changes or pericardial effusion, which is a buildup of fluid around the heart. Pericarditis is described as recurrent if, following an initial occurrence of pericarditis, it recurs after a symptom-free period of about four to six weeks. Pericarditis is considered chronic if symptoms of any one episode last longer than three months, typically causing significant pain and frustration. If pericarditis is left untreated, patients can develop thickening and scarring of the pericardium, potentially requiring invasive surgical stripping. Pericardial effusion, if large enough, can compress the heart extrinsically, requiring emergent drainage.
In March 2021, we received FDA approval to market ARCALYST for the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and children 12 years of age and older. Claims analysis, cross validated with published estimates, support a prevalent population of patients with recurrent pericarditis seeking and receiving medical treatment to be approximately 40,000 patients in the United States per year. Our commercialization efforts are focused initially on the approximately 14,000 patients in the United States who suffer from persistent underlying disease, multiple recurrences and an inadequate response to conventional therapy. Outside of our core target patient population, there are approximately 26,000 additional patients who are experiencing their first recurrence of the disease. 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.
Current Treatment Landscape for Recurrent Pericarditis
ARCALYST, a weekly, subcutaneously injected, recombinant fusion protein that blocks IL-1α and IL-1β signaling, is the first and only FDA-approved therapy for recurrent pericarditis. A patient's initial acute episode of pericarditis is typically treated with NSAIDs or colchicine. Prior to ARCALYST's approval, episodes of recurrent pericarditis would usually have been treated in a similar manner or by adding long-term systemic corticosteroids. Both colchicine and corticosteroids often have adverse effects when used at high doses or for extended periods of time.
Colchicine's adverse effects include gastrointestinal distress and neutropenia. 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 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:
Collaborative study agreement with Mayo Clinic and The Johns Hopkins University
PROBE-design study to evaluate efficacy and safety of rilonacept over 24 weeks of treatment in participants with cardiac sarcoidosis1
D1/Week 0 Week 12 Week 24 Week 28
Diagnosis of
Cardiac Sarcoidosis
on Standard Therapy
Persistent
Inflammation on PET Scan
Rilonacept + non-biologic standard therapy
1:1 Safety
(n=60) F/U
Non-Biologic Standard Therapy alone
PET
Scan
PET
Scan
Modified with permission from Mayo Clinic
Primary Efficacy Endpoint
Change from baseline in number of segments with FDG uptake on cardiac FDG-PET scan at Week 24
Key Secondary Endpoints
Change from baseline in number of segments with FDG uptake at Week 12
Change from baseline in SUVMax at Week 12
Change from baseline in SUVMax at Week 24
Change from baseline in SPRS on FDG-PET scan at Week 24
1.) Mayo Clinic is the IND-holder (IND: 172350); Clinicaltrials.gov NCT06660732.
PROBE = prospective, randomized, open label, blinded endpoint; CS = cardiac sarcoidosis; SC = subcutaneous; FDG = flurodeoxyglucose; PET = positron emission tomography; SUVMax = maximum standardized uptake value; SPRS = summed perfusion rest score; qwk = every week; F/U = follow-up.
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, 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. 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 FDA-approved treatment for this debilitating disease.
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 manage individual flares episodically. 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 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.
Fifth, we have built a robust patient support program to optimize patient experiences with ARCALYST and Kiniksa. Our Kiniksa OneConnect™ program offers 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.
Overview
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
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
KPL-387 binds IL-1R1, inhibiting the signaling of IL-1α and IL-1β cytokines. 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.
Our Solution
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
Preclinical Development
In vitro studies with KPL-387 demonstrated its ability to potently inhibit IL-6 production from peripheral blood mononuclear cells when stimulated with either Il-1α or IL-1β. 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.
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 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 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:
Phase 2: Dose-focusing study
DOSE-FOCUSING : TREATMENT PERIOD (WEEKS 0-24)
KPL-387 300mg SC q2wk
KPL-387 300mg SC q4wk
R
1:1:1:1
KPL-387 100mg SC q2wk
KPL-387 100mg SC q4wk
Screening
LONG-TERM EXTENSION (UP TO 24 MONTHS)2
NSAIDs and/or colchicine1
Population:
Up to ~80 patients diagnosed with RP presenting at screening with a qualifying pericarditis episode despite treatment with conventional oral therapies.
Phase 2 Primary Efficacy Endpoint
Time to Treatment Response3
Phase 2 Key Secondary Endpoints
Time to Pain Response
Time to CRP normalization (CRP ≤ 0.5 mg/dL).
1) KPL-387 will be administered in addition to conventional oral pericarditis medications (NSAIDs and/or colchicine) from baseline to Week 1 and then weaned off pericarditis medications to achieve KPL-387 monotherapy by Week 2. Participants previously treated with glucocorticoids must have discontinued their use at least 72 hours prior to first study drug administration; 2) Up to 24 months or the time KPL-387 is approved for commercial use in that region to treat recurrent pericarditis; 3) Treatment Response is defined as Pain Response (NRS score ≤ 2 on the 11-point daily pericarditis pain NRS) and at least one CRP level ≤ 0.5 mg/dL within 7 days before or after the Pain Response.
NSAID = non-steroidal anti-inflammatory drug; RP = recurrent pericarditis; CRP = C-reactive protein; NRS = numerical rating scale (for chest pain); R = randomization; SC = subcutaneous
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 pericarditis therapies to KPL-387 monotherapy. 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:
Supplemental Phase 2 study evaluating efficacy and safety of various dosing regimens used to transition patients to KPL-387 monotherapy from standard therapies
Phase 2 Transition to KPL-387 Monotherapy Dosing & Administration
(Weeks 0-16)
Long-Term Extension
(Up to 24 months3)
LONG-TERM EXTENSION
Open-Label KPL-387 SC3
Open-Label KPL-387 SC
Prior Therapies
NSAIDs and/or colchicine glucocorticoids2
anakinra rilonacept
Population
Up to ~80 participants with well-controlled RP1 receiving standard therapies: NSAIDs and/or colchicine, glucocorticoids2, and/or IL-1α and IL-1β inhibition (anakinra or rilonacept)
Study Objective
To evaluate the efficacy/safety of dosing regimens used to transition patients with well-controlled RP to KPL-387 monotherapy from stable prior treatment with standard therapies
1) No recurrence within 3 months prior to baseline; CRP < 0.5 mg/dL within 14 days of Baseline and NRS ≤ 3 at Baseline; no clinical worsening or suspicion of impending recurrence; 2) Glucocorticoids or IL-1 pathway inhibitors may be used alone or in combination with NSAIDs and/or colchicine; 3) Up to 24 months or the time KPL-387 is approved for commercial use in that region to treat recurrent pericarditis.
NSAID = non-steroidal anti-inflammatory drug; RP = recurrent pericarditis; SC = subcutaneous
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 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. 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. 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.
We conduct internal discovery activities directed toward wholly owned molecules for the treatment of debilitating disease targets where we believe there to be a strong mechanistic rationale and potential for clear differentiation from existing approved agents or those in development.
We do not currently own or operate any late-stage manufacturing facilities. Although we have built a development and manufacturing facility to produce drug substance to support certain research, preclinical and other clinical development for our product candidates, we rely, and expect to continue to rely, on third parties for the manufacture of our late-stage product candidates and certain of our early-stage product candidates for the majority of our clinical development efforts, as well as for the commercial manufacture of ARCALYST and our future products.
Regeneron currently manufactures and supplies all of our requirements of ARCALYST for development and commercial activities pursuant to the Supply Agreement (as defined below). 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. 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. As part of this process, we are working with Samsung, who will serve as the new manufacturer of ARCALYST drug substance and CTLs who will serve as the new analytical testing labs of ARCALYST drug substance and drug product. See, Risk Factors - Risks Related to Manufacturing and Our Reliance on Third
Parties - We are conducting a technology transfer with respect to the manufacturing process of ARCALYST drug substance from Regeneron to Samsung and the analytical testing methods of ARCALYST drug substance and drug product to new CTLs. 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 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 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. We also may elect to pursue additional CDMOs for manufacturing supplies of drug substance and finished drug product in the future.
Our reliance on third parties to manufacture certain of our products and product candidates exposes us to risks, and any technology transfer of the manufacturing process for our products or product candidates may be subject to a number of risks and uncertainties, see "Risk Factors - Risks Related to Manufacturing and Our Reliance on Third Parties."
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. For more information, see "Business-Our Products-ARCALYST -Commercial Strategy for ARCALYST."
The biotechnology and pharmaceutical industries are characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. We face potential competition from many different sources, including pharmaceutical and biotechnology companies, academic institutions and governmental agencies and public and private research institutions. 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.
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:
ARCALYST
spondylarthritis); AVTX-009 (by Avalo Therapeutics in hidradenitis suppurativa); 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.
KPL-387
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.
For recurrent pericarditis, there are a number of drugs in development that explore alternative dosing methods and frequencies to the once-weekly subcutaneous dosing method of ARCALYST, the only currently FDA-approved treatment. Both CardiolRx and VTX2735, in Phase 3 and 2 development by Cardiol Therapeutics and Ventyx Biosciences, respectively, are being investigated for oral administration. 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 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.
Abiprubart
There are various programs in clinical development antagonizing the CD40 / CD154 costimulatory pathway; 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 Relapsing Multiple Sclerosis, Non-relapsing Secondary Progressive Multiple Sclerosis, Systemic Lupus Erythematosus, Type 1 Diabetes and Focal segmental glomerulosclerosis. Biogen, Inc. and UCB S.A. are developing dapirolizumab pegol (anti-CD40L) for the treatment of moderately to severely active Systemic Lupus Erythematosus.
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. H. 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).
In August 2022, we entered into a license agreement (the "Genentech License Agreement") with Genentech, Inc. and F. Hoffmann-La Roche Ltd. (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").
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 to Biogen, Inc. (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.
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 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 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. In the fourth quarter of 2024, following the achievement of a regulatory milestone under the ARCALYST Huadong Collaboration Agreement, Huadong became obligated to make an additional cash payment of $20.0 million, which was received in the first quarter of 2025. We remain eligible to receive up to approximately $50.0 million in sales-based milestone payments for ARCALYST. Due to its termination, we do not expect to receive any future payments under the mavrilimumab Huadong Collaboration Agreement. 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 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. We and Huadong participate in a joint steering committee, which coordinates and oversees the exploitation of ARCALYST in the Huadong Territory.
We will supply certain materials to support development and commercialization activities for ARCALYST. Absent early termination, the ARCALYST Huadong Collaboration Agreement will continue on a country-by-
country or region-by-region basis until there are no more royalty payments owed to us in such country or region. Huadong has the right to terminate the ARCALYST Huadong Collaboration Agreement at its discretion upon 12 months' notice and either party may terminate the ARCALYST Huadong Collaboration 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, we may terminate the ARCALYST Huadong Collaboration Agreement if Huadong or its affiliates or sublicensees challenges the scope, validity or enforceability of our patent rights being licensed to Huadong. If Huadong and its affiliates do not conduct any material development or commercialization activities for ARCALYST in the People's Republic of China for a continuous period of longer than six months, then, subject to certain exceptions, we may terminate the ARCALYST Huadong Collaboration Agreement with 60 days' prior written notice. In addition, Huadong's rights under the ARCALYST Huadong Collaboration Agreement in certain regions within the Huadong Territory may be subject to termination upon failure by Huadong to perform certain clinical, development or commercialization activities, as applicable, in such regions.
In-Licensing Agreements
License Agreement with Regeneron
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. In March 2021, when the FDA granted approval of ARCALYST for the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and children 12 years and older, we assumed the sales and distribution of ARCALYST for CAPS and DIRA in the United States.
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. 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 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.
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. We may terminate the agreement for convenience at any time with one year's written notice. We may also terminate with three months' written notice if we reasonably determine that ARCALYST is unsafe in the indications we are pursuing. 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.
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. 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.
Beth Israel Deaconess Medical Center License Agreement
In 2019, we acquired all of the outstanding securities of Primatope Therapeutics, Inc. ("Primatope"), the company that owned or controlled the intellectual property related to abiprubart. In connection with our acquisition of Primatope, we acquired the rights to an exclusive license to certain intellectual property rights controlled by BIDMC to make, use, develop and commercialize abiprubart under the BIDMC license agreement (the "BIDMC Agreement").
Under the BIDMC Agreement, we are solely responsible for all development, regulatory and commercial activities and costs. We are also responsible for costs related to filing, prosecuting and maintaining the licensed patent rights. Under the BIDMC Agreement, we are obligated to pay an insignificant annual maintenance fee as well as future clinical and regulatory milestone payments of up to an aggregate of $1.2 million to BIDMC. We are also obligated to pay a low single-digit royalty on annual net sales of products licensed under the agreement, if approved.
Our success depends in part on our ability to obtain and maintain proprietary protection for our drug candidates, manufacturing and process discoveries and other know-how, to operate without infringing the proprietary rights of others and to prevent others from infringing our proprietary rights. We plan to protect our proprietary position using a variety of methods, which include pursuing United States and foreign patent applications related to our proprietary technology, inventions and improvements, which can include compositions of matter, drug product formulations, methods of use and methods of manufacture. We also rely on trade secrets, know-how, continuing technological innovation and potential in-licensing opportunities to develop and maintain our proprietary position.
ARCALYST
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. 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. 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. See "Business-In-Licensing Agreements - License Agreement with Regeneron" above for additional information on our rights under the Regeneron Agreement.
KPL-387
We own pending patent applications relating to KPL-387, which cover formulations and methods of manufacturing KPL-387. 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 (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" below for additional information on regulatory exclusivities.
KPL-1161
We own a pending patent application relating to KPL-1161, which covers composition of matter. If issued, patents covering the composition of matter will have statutory expiration dates in 2046, not including any patent term extensions or adjustments.
Abiprubart
We own, via our acquisition of Primatope, granted patents and pending patent applications in the United States and numerous other jurisdictions relating to abiprubart. We also have an exclusive license with BIDMC to granted patents and pending patent applications in the United States and numerous other jurisdictions relating to abiprubart.
These patents and patent applications cover abiprubart as a composition of matter and its use. As of December 31, 2025, the patent rights acquired from Primatope include four patents granted in the United States and 32 patents granted in other jurisdictions, including Australia, Brazil and selected countries in Europe and Asia. In addition, the patent rights acquired from Primatope include patent applications pending in the United States, Australia, Europe, Canada and selected countries in Asia. The issued composition of matter patents acquired from Primatope have statutory expiration dates in 2036, not including any patent term extensions or adjustments. As of December 31, 2025, the patent rights licensed from BIDMC include two patents granted in the United States and 58 patents granted in other jurisdictions, including Australia, Canada and selected countries in Europe and Asia. In addition, the patent rights licensed from BIDMC include patent applications pending in the United States, Europe and Canada. The issued composition of matter patents licensed from BIDMC have statutory expiration dates in 2032, not including any patent term extensions or adjustments. Patent term extension could extend the expiration date of one patent in the United States and patents in certain other jurisdictions, each in accordance with applicable law.
Other Intellectual Property
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."
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. There can be no assurance that any of our pending patent applications will issue or that we will benefit from any patent term extension or favorable adjustment to the term of any of our patents.
Government authorities in the United States at the federal, state and local level and in other countries and jurisdictions, including the European Union, extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, labeling, packaging, storage, record-keeping, promotion, advertising, distribution, post-approval monitoring and reporting, marketing and export and import of drug products. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulations requires the expenditure of substantial time and financial resources. Generally, before a new drug can be marketed, considerable data demonstrating its quality, safety and efficacy must be obtained, organized into a format specific for each regulatory authority, submitted for review and approved by the regulatory authority.
United States Government Regulation of Biological Products
In the United States, the FDA regulates biologics under the Federal Food, Drug, and Cosmetic Act (the "FDCA") and the Public Health Service Act (the "PHSA") and their implementing regulations. Biologics are also subject to other federal, state and local statutes and regulations.
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 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;
Approval by an independent institutional review board (an "IRB") overseeing each clinical trial site, in each case before a trial may be initiated;
Performance of adequate and well-controlled human clinical trials in accordance with Good Clinical Practices ("GCPs") and other clinical trial related regulations to evaluate the safety and efficacy of the product candidate for each proposed indication;
Submission to FDA of a BLA for marketing approval after completion of the required pivotal clinical trials;
Satisfactory completion of any FDA pre-approval inspections of the manufacturing facility or facilities where the product will be produced to assess compliance with cGMPs; and
FDA review and approval of the BLA.
Preclinical Studies
Before testing any biological product candidate, including our product candidates, in humans, the product candidate must undergo rigorous preclinical testing. The preclinical development stage generally involves laboratory evaluations of the chemistry, formulation and stability of the product candidate, as well as animal trials to evaluate toxicity. The conduct of the preclinical tests must comply with federal regulations and requirements, including GLP regulations. 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.
Clinical Trials
Clinical trials involve the administration of the investigational product to normal healthy volunteers or participants under the supervision of qualified investigators. Clinical trials must be conducted in accordance with GCPs, which include the requirement that all research subjects provide their informed consent for their participation in any clinical trial. Clinical trials also must be conducted under protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, participant selection and inclusion/exclusion criteria and the parameters to be used to monitor subject safety and assess efficacy. 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. 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 (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. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB's requirements or if the drug has been associated with unexpected serious harm to participants. There also are requirements governing the reporting of ongoing clinical trials and completed clinical trial results to public registries.
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 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.
Phase 2 clinical trials involve studies in participants with the target disease or condition to determine the optimal dose and dosing schedule. At the same time, safety and further pharmacokinetic and pharmacodynamic information is collected, possible adverse effects and safety risks are identified and a preliminary evaluation of efficacy is conducted.
Phase 3 clinical trials generally involve a larger number of participants at multiple, geographically dispersed clinical trial sites and are designed to provide the data necessary to demonstrate the effectiveness of the product candidate for its intended use, its safety in use and to establish the overall benefit/risk relationship of the product candidate and provide an adequate basis for product labeling and approval.
Post-approval trials, sometimes referred to as Phase 4 clinical trials, may be conducted after initial marketing approval. These trials are used to gain additional experience from the treatment of participants in the intended therapeutic indication, particularly for long-term safety follow up. In certain instances, the FDA may mandate the performance of Phase 4 clinical trials as a condition of approval of a BLA.
BLA Review and Approval
Assuming successful completion of the required clinical testing, the results of the preclinical studies and clinical trials, together with detailed information relating to the product's CMC and proposed labeling, among other things, are submitted to the FDA as part of a BLA requesting marketing approval for a product for one or more indications. To support marketing approval, the data submitted from company sponsored clinical trials or potentially other alternative sources must be sufficient in quality and quantity to establish the safety, purity and potency (or efficacy) of the investigational product to the satisfaction of the FDA. In relevant cases, the BLA must include data relevant to safety, efficacy and dosing for pediatric populations. FDA approval of a BLA must be obtained before a biologic may be marketed in the United States.
In most cases, the submission of a BLA is subject to a substantial application user fee. Within 60 days following submission of the application, the FDA reviews all BLAs submitted to ensure that they are sufficiently complete for substantive review before it accepts them for filing. The FDA may require the sponsor to provide additional information before accepting the BLA for filing. 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. 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 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.
The BLA approval process is lengthy and difficult, and the FDA may refuse to approve a BLA if the applicable regulatory criteria are not satisfied or may require additional clinical or other data and information. After the FDA evaluates a BLA, it will issue an approval letter or a Complete Response Letter ("CRL"). An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A CRL indicates the deficiencies in the submission and may require substantial additional testing or information for the FDA to reconsider the BLA. If and when the deficiencies have been addressed to the FDA's satisfaction, the FDA will issue an approval letter.
FDA approval authorizes commercial marketing of a drug or biologic product with specific prescribing information and for specific indications. As a condition of approval, the FDA may require, among other things, post-approval trials or testing and surveillance programs to monitor the product after commercialization or
implementation of a risk evaluation and mitigation strategy ("REMS") to ensure the benefits of the product outweigh the potential risks. The FDA may prevent or limit further marketing of a product based on the results of post-marketing trials or surveillance programs, or new safety findings after market introduction. After approval, certain changes to the approved product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further testing requirements and FDA review and approval.
Orphan Drug Designation
Under the Orphan Drug Act, the FDA may grant orphan designation to a drug or biologic product intended to treat a rare disease or condition, which is generally a disease or condition that affects fewer than 200,000 individuals in the United States or more than 200,000 individuals in the United States and for which there is no reasonable expectation that the cost of developing and making the product available in the United States for this type of disease or condition will be recovered from sales of the product. After the FDA grants Orphan Drug designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan Drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.
Orphan Drug designation entitles a party to financial incentives such as opportunities for grant funding towards clinical trial costs, tax advantages and user-fee waivers. In addition, if a product that has orphan designation subsequently receives the first FDA approval for the disease or condition for which it has such designation, the product is entitled to Orphan Drug exclusivity, which means that the FDA may not approve any other applications to market the same drug for the same indication for seven years from the date of such approval, except in limited circumstances, such as a showing of clinical superiority to the product with orphan exclusivity.
A designated Orphan Drug may not receive Orphan Drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. In addition, exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition.
Expedited Review and Approval
The FDA is authorized to designate certain product candidates for expedited development and review if they are intended to address an unmet medical need in the treatment of a serious or life-threatening disease or condition. These programs include Fast Track designation, Breakthrough Therapy designation, accelerated approval and priority review.
To be eligible for a Fast Track designation, the FDA must determine, based on the request of a sponsor, that a product is intended to treat a serious or life-threatening disease or condition and demonstrates the potential to address an unmet medical need for such disease or condition. Fast Track designation provides opportunities for more frequent interactions with the FDA review team to expedite development and review of the product. The FDA may also review sections of the BLA for a Fast Track product on a rolling basis before the complete application is submitted, if the sponsor and the FDA agree on a schedule for the submission of the application sections, and the sponsor pays any required user fees upon submission of the first section of the BLA.
A product candidate intended to treat a serious or life-threatening disease or condition may also be eligible for Breakthrough Therapy designation. A product candidate can receive Breakthrough Therapy designation if preliminary clinical evidence indicates that the product candidate, alone or in combination with one or more other drugs or biologics, may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The designation includes all of the Fast Track program features, as well as more intensive FDA interaction and guidance beginning as early as Phase 1 and an organizational commitment to expedite the development and review of the product candidate, including involvement of senior managers.
A product candidate intended to treat serious or life-threatening diseases or conditions may be eligible for accelerated approval upon a determination that the product candidate has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity or prevalence of the condition and the availability or lack of alternative treatments. As a condition of approval, the FDA generally requires that a sponsor of a product receiving accelerated approval perform adequate and well-controlled confirmatory clinical trials to verify the predicted clinical benefit. A product that receives accelerated approval may be subject to expedited withdrawal procedures if the sponsor fails conduct the required confirmatory trials in a timely manner or if such trials fail to verify the predicted clinical benefit. In addition, the FDA currently requires as a condition for accelerated approval pre-approval of promotional materials, which could adversely impact the timing of the commercial launch of the product.
The FDA may designate a product candidate for priority review if the product candidate is designed to treat a serious condition, and if approved, would provide a significant improvement in safety or effectiveness compared to marketed products. The FDA will attempt to direct additional resources to the evaluation of an application for a biologic designated for priority review in an effort to facilitate the review. The FDA endeavors to review original BLAs with priority review designations within six months of the filing date as compared to ten months under its standard review goals.
Even if a product qualifies for one or more of these programs, the FDA may later decide that the product no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened. Furthermore, Fast Track designation, Breakthrough Therapy designation, accelerated approval and priority review do not change the standards for approval and may not ultimately expedite the development or approval process.
Post-approval Requirements
Once a BLA is approved, a product will be subject to certain post-approval requirements. 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 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.
In addition, FDA regulations require that products be manufactured in specific approved facilities and in accordance with cGMPs. 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 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. Accordingly, we and our CDMOs must continue to expend time, money and effort in the areas of production and quality-control to maintain compliance with cGMPs.
Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or failure to comply with regulatory requirements, may result in, among other things:
restrictions on the marketing or manufacturing of the product, complete withdrawal of the product from the market or product recalls;
fines, warning letters or other enforcement-related letters or clinical holds on post-approval clinical trials;
refusal of the FDA to approve pending BLAs or supplements to approved BLAs, or suspension or revocation of product approvals;
product seizure or detention, or refusal to permit the import or export of products;
injunctions or the imposition of civil or criminal penalties; and
consent decrees, corporate integrity agreements, debarment or exclusion from federal healthcare programs; or mandated modification of promotional materials and labeling and the issuance of corrective information.
Biosimilars and Exclusivity
An abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product was created by the Biologics Price Competition and Innovation Act of 2009 (the "BPCIA") as part of the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act (the "ACA").
Under the BPCIA, a manufacturer may submit an application for a biological product that is "biosimilar to" or "interchangeable with" a previously approved "reference product." Biosimilarity requires that the biological product be highly similar to the reference product and that there be no clinically meaningful differences in safety, purity and potency. This must be demonstrated through analytical studies, animal studies and a clinical trial or trials. In order to meet the higher hurdle of interchangeability, a sponsor must demonstrate that the biosimilar product can be expected to produce the same clinical result as the reference product, and for a product that is administered more than once, that the risk of switching between the reference product and biosimilar product is not greater than the risk of maintaining the patient on the reference product.
Under the BPCIA, a reference biological product is granted 12 years of data exclusivity from the time of first licensure of the product, and the FDA will not accept an application for a biosimilar or interchangeable product based on the reference biological product until four years after the date of first licensure of the reference product.
Foreign Government Regulation
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 time required to obtain approval in other countries and jurisdictions might differ from and be longer than that required to obtain FDA approval. Regulatory approval in one country or jurisdiction does not ensure regulatory approval in another, but a failure or delay in obtaining regulatory approval in one country or jurisdiction may negatively impact the regulatory process in others.
Regulatory Framework in the European Union
Clinical Trials
Clinical trials of medicinal products in the European Union ("EU") are governed by the Clinical Trials Regulation (EU) No 536/2014 (the "CTR"), which became applicable on January 31, 2022, and repealed the Clinical Trials Directive. 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 ("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 to streamline the regulatory review. 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. 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 regulated by the CTR.
Medicines used in clinical trials must be manufactured in accordance with cGMP. Other national and EU-wide regulatory requirements may also apply.
Marketing Authorization
In the EU, medicinal products can only be placed on the market after obtaining a marketing authorization (an "MA"). 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 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
Disclaimer
Kiniksa Pharmaceuticals International plc published this content on May 08, 2026, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on May 08, 2026 at 17:32 UTC.