Kiniksa Pharmaceuticals International, plc

Previous wording

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our unaudited consolidated financial statements and related notes included elsewhere in this Quarterly Report, and our audited consolidated financial statements and related notes for the year ended December 31, 2024 included in our Annual Report on Form 10-K (our “Annual Report”). Some of the information contained in this discussion and analysis or set forth elsewhere in this Quarterly Report, including information with respect to our plans and strategy for our business, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in the risks identified in Part II-Item 1A “Risk Factors” section of this Quarterly Report and our other filings with the Securities and Exchange Commission (the “SEC”) our actual results could differ materially from the results, performance or achievements expressed in or implied by these forward-looking statements.

Current wording

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our unaudited condensed consolidated financial statements and related notes included elsewhere in this Quarterly Report, and our audited consolidated financial statements and related notes for the year ended December 31, 2025 included in the Annual Report. Some of the information contained in this discussion and analysis or set forth elsewhere in this Quarterly Report, including information with respect to our plans and strategy for our business, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in the risks identified in Part I, Item 1A of the Annual Report, as updated by any information appearing in Part II, Item 1A of any of our subsequent Quarterly Reports on Form 10-Q, and our other filings with the Securities and Exchange Commission (the “SEC”) our actual results could differ materially from the results, performance or achievements expressed in or implied by these forward-looking statements.

Previous wording

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 thetreatment 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 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.

Current wording

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 thetreatment 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 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. Since then we have worked to qualify Samsung Biologics Co., Ltd. (“Samsung”) as our replacement contract development and manufacturing organization (“CDMO”) and, in April 2026, the FDA accepted the supplemental biologics license application related to such technology transfer and assigned a Prescription Drug User Fee Act target action date of June 19, 2026. 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.

Previous wording

KPL-387 is an investigational, fully human immunoglobulin G2 monoclonal antibody that binds human interleukin-1 receptor 1 (“IL-1R1”), inhibiting IL-1α- and IL-1β-mediated signaling. KPL-387 is an independently developed asset that we believe has the potential to help grow the market and to further advance recurrent pericarditis treatment options for patients by potentially enabling dosing with a single monthly subcutaneous self-injection in a liquid formulation. In June 2024, we initiated a Phase 1 clinical trial of KPL-387 in normal healthy volunteers. 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. 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 the 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.

Current wording

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 April 2026, we announced our expectation to initiate a pivotal Phase 3 clinical trial of KPL-387 in recurrent pericarditis by the end of 2026. In October 2025, the FDA granted Orphan Drug Designation to KPL-387 for the treatment of pericarditis.

Previous wording

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 IND-enabling activities with respect to this asset.

Current wording

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, and expect to initiate a Phase 1 first-in-human clinical trial by the end of 2026.

Previous wording

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.

Current wording

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”). In February 2025, we announced our plans to discontinue development of abiprubart in Sjogren's Disease and to explore strategic alternatives for the asset.

Previous wording

We have been generating product revenue from sales of ARCALYST since April 2021. ARCALYST is sold through a third party logistics provider that distributes primarily through a select network of specialty pharmacies (collectively, “customers”), which deliver the medication to patients by mail. ARCALYST is currently approved for sale only in the United States, and, therefore, we expect to derive substantially all of our product revenue from the United States for the foreseeable future.

Current wording

We have been generating product revenue from sales of ARCALYST since April 2021. ARCALYST is sold through a third-party logistics provider that distributes primarily through a select network of specialty pharmacies (collectively, “customers”), which deliver the medication to patients by mail. ARCALYST is currently only approved for sale in the United States, and, therefore, we expect to derive substantially all of our product revenue from the United States for the foreseeable future.

Previous wording

best estimate based on available information and will be adjusted to reflect known changes in the factors that impact such allowances. Adjustments for variable consideration are determined based on the contractual terms with customers, historical trends, communications with customers and the levels of inventory remaining in the distribution channel, as well as expectations about the market for the product and anticipated introduction of competitive products.

Current wording

Our net revenues represent total revenues adjusted for discounts and allowances, including estimated cash discounts, chargebacks, rebates, returns, copay assistance, and specialty pharmacy and distributor fees. These adjustments represent variable consideration under ASC 606 and are estimated using the expected value method and are recorded when revenue is recognized on the sale of the product. These adjustments are established by management as its best estimate based on available information and will be adjusted to reflect known changes in the factors that impact such allowances. Adjustments for variable consideration are determined based on the contractual terms with customers, historical trends, communications with customers and the levels of inventory remaining in the distribution channel, as well as expectations about the market for the product and anticipated introduction of competitive products.

Previous wording

Under the Huadong Collaboration Agreements, we received a total upfront cash payment of $22.0 million, which included $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. In addition, we will be eligible to receive additional contingent sales-based milestones payments related to ARCALYST. 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. We recognized the $10.0 million related to the mavrilimumab license during the year ended December 31, 2022 and do not expect to recognize any additional license and collaboration revenue following the termination of the mavrilimumab Huadong Collaboration Agreement. We have recognized $0.2 million of revenue of the $32.0 million transaction price under the ARCALYST license agreement as of September 30, 2025, and will recognize the remaining revenue as materials are shipped.

Current wording

Under the Huadong Collaboration Agreement, we received a total upfront cash payment of $12.0 million for the Huadong Territory license of ARCALYST. In the fourth quarter of 2024, following the achievement of a regulatory milestone under the 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. In addition, we will be eligible to receive additional contingent sales-based milestones payments related to ARCALYST. Huadong will also be obligated to pay us tiered percentage royalties on ARCALYST ranging from the low-to-mid teens on annual net sales 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

Previous wording

We are party to a license agreement (the “Genentech License Agreement”) with Genentech, effective September 2022, pursuant to which we granted Genentech exclusive worldwide rights to develop and commercialize vixarelimab and related antibodies (each, a “Genentech Licensed Product”).

Current wording

In the third quarter of 2022, we entered into a license agreement (the “Genentech License Agreement”) with Genentech, pursuant to which we granted Genentech exclusive worldwide rights to develop and commercialize vixarelimab and related antibodies (each, a “Genentech Licensed Product”).

Previous wording

Under the Genentech License Agreement, we received an upfront payment of $80.0 million for the license. Additionally, in 2023, we received a total of $35.0 million in additional payments from Genentech related to delivery of certain drug material to Genentech and Genentech’s achievement of a development milestone. In the fourth quarter of 2023, following the achievement of a development milestone related to a second indication under the Genentech License Agreement, Genentech became obligated to make an additional cash payment of $10.0 million, which was received in the first quarter of 2024. In the second quarter of 2024, we received $5.0 million following the achievement of a development milestone related to a third indication under the Genentech License Agreement. We will be eligible to receive up to a total of approximately $600.0 million in contingent payments, including specified development, regulatory and sales-based milestones, of which approximately $570.0 million remains as of September 30, 2025. 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

Current wording

Under the Genentech License Agreement, we will be eligible to receive up to a total of approximately $600.0 million in contingent payments, including specified development, regulatory and sales-based milestones, of which approximately $570.0 million remains as of March 31, 2026. 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.

Previous wording

Cost of goods sold includes production and distribution costs of ARCALYST, amortization of the $20.0 million payment we made to Regeneron in the first quarter of 2021 upon achievement of a regulatory milestone and other miscellaneous product costs associated with ARCALYST. Cost of goods sold also includes labor and overhead costs associated with the production of ARCALYST associated with supply chain, quality, and regulatory activities, and the technology transfer of the manufacturing process for the ARCALYST drug substance.

Current wording

Cost of goods sold includes production and distribution costs of ARCALYST, amortization of the $20.0 million payment we made to Regeneron in the first quarter of 2021 upon achievement of a regulatory milestone and other miscellaneous product costs associated with ARCALYST. Cost of goods sold also includes labor and overhead costs associated with the production of ARCALYST associated with supply chain, quality, and regulatory activities, and the technology transfer of the manufacturing process for ARCALYST.

Previous wording

Collaboration expenses consist of Regeneron’s share of the profit related to ARCALYST sales under the Regeneron Agreement and the cost of products sold under collaboration agreements. 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. With respect to the technology transfer of ARCALYST drug substance manufacturing from Regeneron to Samsung, to the extent permitted by the Regeneron Agreement, the fully-burdened costs of each of us and Regeneron incurred in performing such technology transfer shall 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.

Current wording

Collaboration expenses consist of Regeneron’s share of the profit related to ARCALYST sales under the Regeneron Agreement and the cost of products sold under collaboration agreements. 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. With respect to the technology transfer of ARCALYST drug substance manufacturing initiated by Regeneron in March 2023, to the extent permitted by the Regeneron Agreement, the fully-burdened costs of each of us and Regeneron incurred in performing such technology transfer shall 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.

Previous wording

●expenses incurred under agreements with CROs that are primarily engaged in the oversight and conduct of our clinical trials and CDMOs that are primarily engaged to provide preclinical and clinical drug substance and product for our research and development programs for our product candidates;

Current wording

●expenses incurred under agreements with contract research organizations (“CROs”) that are primarily engaged in the oversight and conduct of our clinical trials and CDMOs that are primarily engaged to provide preclinical and clinical drug substance and product for our research and development programs for our product candidates;

Previous wording

At this time, we cannot reasonably estimate or know the nature, timing and costs of the efforts that will be necessary to complete the clinical development of our current or future product candidates or when, if ever, we will realize revenue from the sale of our current or future product candidates. This uncertainty is due to the numerous risks and uncertainties, including those described in Part II, Item 1A. “Risk Factors” in this Quarterly Report.

Current wording

At this time, we cannot reasonably estimate or know the nature, timing and costs of the efforts that will be necessary to complete the clinical development of our current or future product candidates or when, if ever, we will realize revenue from the sale of our current or future product candidates.

Previous wording

Selling, general and administrative expenses consist primarily of salaries and benefits, including share based compensation expense for personnel in selling, marketing, medical, executive, business development, finance, human resources, legal and support personnel functions. Selling, general and administrative expenses also include external commercialization, marketing, and professional fees for legal, patent, and accounting services.

Current wording

Selling, general and administrative expenses consist primarily of salaries and benefits, including share based compensation expense for personnel in selling, marketing, medical, executive, business development, finance, human

Previous wording

Other income consists of interest income recognized from investments in money market funds, United States Treasury notes and other miscellaneous income offset by expenses related to investments.

Current wording

Other income, net consists of interest income recognized from investments in money market funds, United States Treasury Securities and other miscellaneous income offset by expenses related to investments.

Previous wording

company’s income, resulting in an effective zero percent tax rate. As a result, we have not recorded any income tax benefits from our losses incurred in Bermuda during the reporting periods in which we were incorporated there, and no net operating loss carryforwards are currently available to us for those losses. Following the Redomiciliation, our income is subject to the enacted UK statutory corporate tax rate and net operating losses incurred have an indefinite carryforward. Our wholly owned United States subsidiaries, Kiniksa Pharmaceuticals, Inc. (“Kiniksa US”), and Primatope Therapeutics, Inc. are subject to federal and state income taxes in the United States. Our wholly owned subsidiary Kiniksa Pharmaceuticals (UK), Ltd. (“Kiniksa UK”), its Swiss branch office, and Kiniksa UK’s wholly owned subsidiaries, Kiniksa Pharmaceuticals (Germany) GmbH, Kiniksa Pharmaceuticals (France) SARL, and Kiniksa Pharmaceuticals, GmbH (“Kiniksa Switzerland”) are subject to taxation in their respective countries.

Current wording

Our income is subject to the enacted United Kingdom statutory corporate tax rate. Our wholly owned United States subsidiaries, including Kiniksa Pharmaceuticals, Inc. (“Kiniksa US”), are subject to federal and state income taxes in the United States. Our wholly owned subsidiary Kiniksa Pharmaceuticals (UK), Ltd. (“Kiniksa UK”), its Swiss branch office, and Kiniksa UK’s wholly owned subsidiaries, including Kiniksa Pharmaceuticals, GmbH (“Kiniksa Switzerland”) are subject to taxation in their respective countries.

Previous wording

On July 4, 2025, new U.S tax legislation was signed into law (known as the "One Big Beautiful Bill Act" or "OBBBA") which makes permanent many of the tax provisions enacted in 2017 as part of the Tax Cuts and Jobs Act that were set to expire at the end of 2025. In addition, the OBBBA makes changes to certain U.S. corporate tax provisions, but many are generally not effective until 2026. While we continue to assess the impact of the tax provisions of the OBBBA on our consolidated financial statements, we currently believe that the tax provisions of the legislation are not expected to have a material impact on our operations.

Current wording

On July 4, 2025, new U.S tax legislation was signed into law (known as the "One Big Beautiful Bill Act" or "OBBBA") which makes permanent many of the tax provisions enacted in 2017 as part of the Tax Cuts and Jobs Act that were set to expire at the end of 2025. The tax provisions of the legislation did not have a material impact on our operations.

Previous wording

We recognized net revenue from the sale of ARCALYST of $180.9 million for the three months ended September 30, 2025, compared to $112.2 million for the three months ended September 30, 2024, an increase of $68.6 million. The increase in product revenue was driven primarily by an increase in patient enrollment.

Current wording

We recognized net revenue from the sale of ARCALYST of $214.3 million for the three months ended March 31, 2026, compared to $137.8 million for the three months ended March 31, 2025, an increase of $76.5 million. The increase in product revenue was driven primarily by an increase in patient enrollment.

Previous wording

We recognized cost of goods sold of $56.7 million for the nine months ended September 30, 2025, compared to $43.0 million for the nine months ended September 30, 2024, an increase of $13.7 million. The increase in cost of goods sold relates primarily to the increase in sales of ARCALYST offset by a decrease in technology transfer costs. Cost of goods sold related to the technology transfer of the manufacturing process of ARCALYST drug substance were $8.3

Current wording

We recognized cost of goods sold of $20.8 million for the three months ended March 31, 2026, compared to $17.9 million for the three months ended March 31,2025, an increase of $2.9 million. The increase in cost of goods sold relates primarily to the increase in sales of ARCALYST offset by favorable production variances.

Previous wording

Collaboration expenses were $63.3 million for the three months ended September 30, 2025, compared to $29.3 million for the three months ended September 30, 2024, an increase of $34.0 million. Collaboration expenses increased due to increased revenue from sales of ARCALYST.

Current wording

Collaboration expenses were $75.6 million for the three months ended March 31, 2026, compared to $43.8 million for the three months ended March 31, 2025, an increase of $31.8 million. The increase of $31.8 million relates primarily to increased revenue from sales of ARCALYST.

Previous wording

Direct costs for our KPL-387 program were $11.4 million during the three months ended September 30, 2025, compared to $6.8 million during the three months ended September 30, 2024. The increase in expenses incurred primarily related to the start-up of our Phase 2/3 clinical trial in recurrent pericarditis during the three months ended September 30, 2025, as compared to the performance of our Phase 1 clinical trial in healthy volunteers during the three months ended September 30, 2024.

Current wording

Direct costs for our KPL-387 program were $16.2 million during the three months ended March 31, 2026, compared to $5.2 million during the three months ended March 31, 2025. The increase in expenses incurred primarily related to the enrollment and continuation of our Phase 2/3 clinical trial in recurrent pericarditis during the three months ended March 31, 2026, as compared to the Phase 1 clinical trial in normal healthy volunteers during the three months ended March 31, 2025.

Previous wording

Direct costs for our KPL-1161 program were $1.8 million for the three months ended September 30, 2025, compared to $0.3 million during the three months ended September 30, 2024. For the three months ended September 30, 2025 and 2024, expenses incurred primarily related to pre-clinical development.

Current wording

Direct costs for our KPL-1161 program were $1.0 million for the three months ended March 31, 2026, compared to $0.1 million during the three months ended March 31, 2025. For the three months ended March 31, 2026 and 2025, expenses incurred primarily related to pre-clinical development.

Previous wording

The direct costs for our abiprubart program were $0.7 million during the three months ended September 30, 2025, compared to $8.5 million during the three months ended September 30, 2024, a decrease of $7.8 million. The decrease in expenses incurred primarily related to the close-out of our Phase 2b clinical trial in Sjögren’s Disease during the three months ended September 30, 2025, as compared to the manufacturing of clinical material, continuation of cohort four of our Phase 2 clinical trial in rheumatoid arthritis (“RA”) and start-up costs of our Phase 2b clinical trial in Sjögren’s Disease during the three months ended September 30, 2024.

Current wording

The direct costs for our abiprubart program were $0.1 million during the three months ended March 31, 2026, compared to $4.4 million during the three months ended March 31, 2025, a decrease of $4.3 million. For the three months ended March 31, 2025, expenses incurred primarily related to the close-out of our Phase 2b clinical trial in Sjögren’s Diseaseand $2.5 million of termination expenses associated with cancelled manufacturing agreements.

Previous wording

Unallocated research and development expenses were $10.0 million and $10.1 million for the three months ended September 30, 2025 and September 30, 2024, respectively. Personnel-related costs for the three months ended September 30, 2025 and 2024 included share-based compensation of $1.7 million and $1.6 million, respectively.

Current wording

Unallocated research and development expenses were $10.0 million and $9.3 million for the three months ended March 31, 2026 and March 31, 2025, respectively. Personnel-related costs for the three months ended March 31, 2026 and 2025 included share-based compensation of $1.6 million and $1.2 million, respectively.

Previous wording

Selling, general and administrative expenses were $49.1 million for the three months ended September 30, 2025, compared to $46.4 million for the three months ended September 30, 2024. The increase of $2.7 million was primarily due to an increase of $7.9 million in personnel-related costs largely attributable to an increase in headcount offset by a decrease in sales and marketing expenses of $4.0 million largely attributable to the timing of free goods designation. Personnel-related costs for the three months ended September 30, 2025 and 2024 included share-based compensation of $7.9 million and $5.8 million, respectively.

Current wording

Selling, general and administrative expenses were $61.2 million for the three months ended March 31, 2026, compared to $43.5 million for the three months ended March 31, 2025. The increase of $17.6 million was primarily due to an increase of $10.8 million in personnel-related costs largely attributable to an increase in headcount and an increase in sales and marketing expenses of $5.2 million largely attributable to increased promotional activities and the timing of free goods designation. Personnel-related costs for the three months ended March 31, 2026 and 2025 included share-based compensation of $7.9 million and $5.8 million, respectively.

Previous wording

For the three months ended September 30, 2025, we recorded an income tax provision of $8.7 million relating primarily to income earned in Switzerland, the United States, and the UK, net of benefits related to share-based compensation, United States federal and state research and development credits (“R&D Credits”), and the Foreign Derived Intangible Income (“FDII”) deduction. For the three months ended September 30, 2024, we recorded an income tax provision of $5.5 million relating primarily to income earned in the UK, Switzerland and the United States, net of the FDII deduction and R&D Credits.

Current wording

We recorded an income tax provision of $10.1 million and $7.0 million for the three months ended March 31, 2026 and March 31, 2025, respectively. The provision for income taxes was driven primarily by income earned in Switzerland, UK and the United States as well as uncertain tax positions offset in part by tax benefits related to share-based compensation, United States federal and state research and development credits (“R&D Credits”) and Foreign Derived Intangible Income (“FDII”) deduction.

Previous wording

As of September 30, 2025, our principal source of liquidity was cash, cash equivalents and short-term investments, which totaled $352.1 million. Net income (loss) was $44.8 million and ($34.3) million for the nine months ended September 30, 2025 and 2024, respectively. We expect our cash balance and our expected cash inflows from operations to allow us to meet our current operating plan.

Current wording

As of March 31, 2026, our principal source of liquidity was cash, cash equivalents and short-term investments, which totaled $468.1 million. Net income was $22.6 million and $8.5 million for the three months ended March 31, 2026 and 2025, respectively. We expect our cash balance and our expected cash inflows from operations to allow us to meet our current operating plan.

Previous wording

Under various agreements with third parties, we have agreed to make milestone payments, pay royalties, pay annual maintenance fees and to meet due diligence requirements, each based upon specified events. Pursuant to the Regeneron Agreement, we have entered into a supply agreement with Regeneron to purchase both clinical and commercial product. We have committed to minimum payments to Regeneron of $56.1 million, all of which are due within one year. We have entered into lease agreements for office and laboratory space, and vehicles, with total future lease payments of $11.7 million, of which $4.1 million are due within one year. In connection with our ongoing technology transfer of ARCALYST drug substance manufacturing, we have entered into a Master Services Agreement and a Product Specific Agreement with Samsung. Our commitments under such agreements, which include the purchase of raw materials and related service fees, will obligate us to minimum payments of $136.9 million, $18.4 million of which are due within one year. As of September 30, 2025, we have capitalized $17.5 million of production cost into inventory as semi-finished goods related to drug substance manufactured at Samsung. We have additionally entered into agreements with several CDMOs to provide us with preclinical and clinical trial materials for our non-ARCALYST assets, which obligate us to minimum payments of $12.0 million all of which are due within one year. We have long-term incentive plans for our employees that may result in cash award payments of $22.6 million, based upon the achievement of certain regulatory milestones, none of which are expected to be achieved in the next year.

Current wording

Under various agreements with third parties, we have agreed to make milestone payments, pay royalties, pay annual maintenance fees and to meet due diligence requirements, each based upon specified events. Pursuant to the Regeneron Agreement, we have entered into a supply agreement with Regeneron to purchase both clinical and commercial product. We have entered into lease agreements for office and laboratory space, and vehicles, with total future lease payments of $9.9 million, $3.6 million of which are due within one year. In connection with our ongoing technology transfer of ARCALYST drug substance manufacturing, we have entered into a Master Services Agreement and a Product Specific Agreement with Samsung. Our commitments under such agreements, which includes the purchase of raw materials and related service fees, obligates us to minimum payments of $147.1 million, $59.8 million of which are due within one year. As of March 31, 2026, we have capitalized $21.1 million of production cost into inventory as semi-finished goods related to drug substance manufactured at Samsung. We have additionally entered into agreements with several CDMOs to provide us with preclinical and clinical trial materials for our non-ARCALYST assets, which obligate us to minimum payments of $10.2 million all of which are due within one year. We have long-term incentive plans for our employees that may result in cash award payments of $23.1 million, based upon the achievement of certain regulatory milestones, none of which are expected to be achieved in the next year.

Previous wording

Under various agreements with third parties, we are entitled to receive upfront payments, milestone payments, and royalties, each based upon specified milestones. In 2024, we received $15.0 million in development milestone payments from Genentech related to a second and third indication under the Genentech License Agreement. In 2025, we received a $20.0 million milestone payment related to Huadong’s achievement of a regulatory milestone under the ARCALYST Huadong Collaboration Agreement.

Current wording

Under various agreements with third parties, we are entitled to receive upfront payments, milestone payments, and royalties, each based upon specified milestones. In 2025, we received a $20.0 million milestone payment related to Huadong’s achievement of a regulatory milestone under the Huadong Collaboration Agreement, $10.0 million of which was paid to Regeneron in 2025 as part of the Regeneron Agreement.

Previous wording

Net cash provided by operations was $84.1 million and $6.9 million for the nine months ended September 30, 2025 and 2024, respectively. The increase in cash provided by operating activities is primarily due to an increase in net contribution from higher ARCALYST sales and an increase in cash received from licensing agreements of $5.0 million.

Current wording

Net cash provided by operations was $50.2 million and $22.3 million for the three months ended March 31, 2026 and 2025, respectively. The increase in cash provided by operating activities is primarily due to an increase in net contribution from higher ARCALYST sales offset by a decrease in net cash received from licensing agreements of $20.0 million.

Previous wording

Net cash used in investing activities was $118.2 million and $27.6 million for the nine months ended September 30, 2025 and 2024, respectively. The increase in net cash used in investing activities was driven by managing our cash and short-term investment portfolio mix.

Current wording

Net cash used in investing activities was $31.9 million and $51.5 million for the three months ended March 31, 2026 and 2025, respectively. The increase in net cash used in investing activities was driven by managing our cash and short-term investment portfolio mix as we deployed higher levels of cash into Treasury Securities with longer-terms.

Previous wording

During the nine months ended September 30, 2025 and 2024, net cash provided by financing activities was $25.4 million and $10.1 million, respectively, consisting of proceeds from the exercise of share options offset by payments in connection with ordinary shares tendered for employee tax obligations.

Current wording

During the three months ended March 31, 2026 and 2025, net cash provided by financing activities was $6.1 million and $2.8 million, respectively, consisting of proceeds from the exercise of share options offset by payments in connection with ordinary shares tendered for employee tax obligations.

Previous wording

We expect to incur significant expenses in connection with our ongoing and planned activities as we continue to commercialize ARCALYST and advance our current and future product candidates through preclinical and clinical development, seek regulatory approval and commercialize one or more of our current or future product candidates, if approved. We may also incur expenses in connection with collaboration, licensing or other strategic transactions. Further, we may incur expenses related to milestone, royalty and other payments payable to third parties with whom we have entered into license, acquisition and other similar agreements to acquire the rights to our product candidates. We expect to incur expenses as we:

Current wording

We expect to incur significant expenses in connection with our ongoing and planned activities as we continue to commercialize ARCALYST and advance our current and future product candidates through preclinical and clinical development, seek regulatory approval and commercialize one or more of our current or future product candidates, if approved. We may also incur expenses in connection with collaboration, licensing or other strategic transactions. Further, we may incur expenses related to milestone, royalty and other payments payable to third parties with whom we have entered into license, acquisition and other similar agreements to acquire the rights to our product candidates* *

Previous wording

Because of the numerous risks and uncertainties associated with research, development and commercialization of biologic products, we are unable to estimate the exact amount of our working capital requirements. Our future funding requirements may be impacted by a number of factors, including those described in Part II, Item 1A. “Risk Factors” in this Quarterly Report.

Current wording

Because of the numerous risks and uncertainties associated with research, development and commercialization of biologic products, we are unable to estimate the exact amount of our working capital requirements. Our future funding requirements may be impacted by a number of factors, including those described in Part I, Item 1A of the Annual Report, as updated by any information appearing in Part II, Item 1A of any of our subsequent Quarterly Reports on Form 10-Q.

Previous wording

Our consolidated financial statements are prepared in accordance with generally accepted accounting principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenue, costs and expenses, and the disclosure of contingent assets and liabilities in our financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily

Current wording

Our condensed consolidated financial statements are prepared in accordance with generally accepted accounting principles in the United States. The preparation of our condensed consolidated financial statements and related disclosures requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenue, costs and expenses, and the disclosure of contingent assets and liabilities in our financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.