Kiniksa Pharmaceuticals Reports Fourth Quarter and Full Year 2024 Financial Results and Recent Portfolio Execution - ARCALYST (rilonacept) Q4 2024 and full year 2024 net product revenue of $122.5 million and $417.0 milli

Kiniksa Pharmaceuticals

Reports Fourth Quarter and Full Year 2024 Financial Results and Recent Portfolio Execution

ARCALYST (rilonacept) Q4 2024 and full year 2024 net product revenue of $122.5 million and $417.0 million, respectively

2025 net product revenue expected to be $560 - $580 million -

KPL-387 Phase 2/3 clinical trial in recurrent pericarditis expected to initiate in mid-2025; Phase 2 data expected in 2H 2026 -

Abiprubart development in Sj gren's Disease to be discontinued -

operating plan expected to remain cash flow positive on an annual basis -

Conference call and webcast scheduled for 8:30 am ET today -

February 25, 2025 - Kiniksa Pharmaceuticals International, plc (Nasdaq: KNSA) (Kiniksa), a biopharmaceutical company

developing and commercializing novel therapies for diseases with unmet need, with a focus on cardiovascular indications, today reported

fourth quarter and full year 2024 financial results and recent portfolio execution.

"Strong commercial execution in 2024 resulted in 79% year-over-year

ARCALYST sales growth to $417.0 million. We believe substantial opportunity remains for ARCALYST, and expect 2025 sales of between $560

and $580 million," said Sanj K. Patel, Chairman and Chief Executive Officer of Kiniksa. "Today, we are excited to announce

the development program for KPL-387, which we believe could expand the treatment options for recurrent pericarditis patients by enabling

a single monthly subcutaneous injection in a liquid formulation. We have interacted with the FDA and plan to initiate a Phase 2/3 clinical

trial of KPL-387 in recurrent pericarditis in mid-2025. In line with our prioritization of cardiovascular indications, we plan to discontinue

the development of abiprubart in Sj gren's Disease. On behalf of our entire organization, I would like to thank the patients,

caregivers, and investigators who contributed to our study."

ARCALYST (IL-1 and IL-1 cytokine trap)

KPL-387 (monoclonal antibody IL-1 receptor antagonist)

KPL-1161 (Fc-modified monoclonal antibody IL-1 receptor antagonist)

Conference Call Information

Kiniksa is a biopharmaceutical company dedicated to improving the

lives of patients suffering from debilitating diseases by discovering, acquiring, developing, and commercializing novel therapies for

diseases with unmet need, with a focus on cardiovascular indications. Kiniksa's portfolio of assets is based on strong biologic

rationale or validated mechanisms and offers the potential for differentiation. For more information, please visit www.kiniksa.com.

ARCALYST is a weekly, subcutaneously injected recombinant dimeric

fusion protein that blocks interleukin-1 alpha (IL-1 ) and interleukin-1 beta (IL-1 ) signaling. ARCALYST was discovered by

Regeneron Pharmaceuticals, Inc. (Regeneron) and is approved by the U.S. Food and Drug Administration (FDA) for the treatment of recurrent

pericarditis (RP) and reduction in risk of recurrence in adults and children 12 years and older. ARCALYST is also approved by the FDA

for the treatment of Cryopyrin-Associated Periodic Syndromes (CAPS), including Familial Cold Autoinflammatory Syndrome (FCAS) and Muckle-Wells

Syndrome (MWS) in adults and children 12 years and older, and the maintenance of remission of Deficiency of Interleukin-1 Receptor Antagonist

(DIRA) in adults and pediatric patients weighing 10 kg or more. The FDA granted Orphan Drug Exclusivity to ARCALYST upon its approval

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

pericarditis in 2021.

IMPORTANT SAFETY INFORMATION ABOUT ARCALYST

For more information about ARCALYST, talk to your doctor

and see the Product Information.

KPL-387 is an independently developed, investigational, fully human

IgG2 monoclonal antibody that binds IL-1R1, inhibiting the signaling of the cytokines IL-1 and IL-1 . Kiniksa believes KPL-387

could expand the treatment options for recurrent pericarditis patients by enabling dosing with a single monthly SC injection in a liquid

KPL-1161 is an independently developed, investigational, Fc-modified

IgG2 monoclonal antibody that binds IL-1R1, inhibiting the signaling of the cytokines IL-1 and IL-1 , with a target profile

of quarterly SC dosing. Kiniksa is currently engaging in IND-enabling development activities for KPL-1161.

Abiprubart is an investigational humanized monoclonal antibody that

binds to CD40 and is designed to inhibit the CD40-CD154 (CD40 ligand) interaction, a key T-cell co-stimulatory signal critical for B-cell

maturation and immunoglobulin class switching and Type 1 immune responses. Kiniksa believes disrupting the CD40-CD154 co-stimulatory

interaction is an attractive approach to addressing multiple autoimmune disease pathologies.

Forward-Looking Statements

This press release contains forward-looking statements. In some cases,

you can identify forward looking statements by terms such as "may," "will," "should," "expect,"

"plan," "anticipate," "could," "intend," "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.

All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking

statements, including without limitation, statements regarding: our belief that substantial opportunity remains for ARCALYST and our

expectation that ARCALYST 2025 net product revenue will be between $560 million and $580 million; our plan to initiate a Phase 2/3 clinical

trial of KPL-387 in recurrent pericarditis in mid-2025, with Phase 2 data expected in the second half of 2026; our plan to discontinue

abiprubart development in Sj gren's Disease and explore strategic alternatives for the asset; our expectation that our current

operating plan will remain cash flow positive on an annual basis; our plan to focus development on diseases with unmet need, prioritizing

cardiovascular indications; our belief that KPL-387 could expand the treatment options for recurrent pericarditis patients by enabling

a single monthly SC injection in a liquid formulation; our target profile of monthly and quarterly dosing for KPL-387 and KPL-1161, respectively;

our beliefs about the mechanisms of our assets and potential impact of their approach; and our belief that our portfolio of assets offers

the potential for differentiation.

These forward-looking statements are based on management's current

expectations. These statements are neither promises nor guarantees, but 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, including without limitation, the following: delays or difficulty

in enrollment of patients in, and activation or continuation of sites for, our clinical trials; delays or difficulty in completing our

clinical trials as originally designed; potential for changes between final data and any preliminary, interim, top-line or other data

from clinical trials; our inability to replicate results from our earlier clinical trials or studies; impact of additional data from

us or other companies, including the potential for our data to produce negative, inconclusive or commercially uncompetitive results;

potential undesirable side effects caused by our products and product candidates; our inability to demonstrate safety and efficacy to

the satisfaction of applicable regulatory authorities; potential for applicable regulatory authorities to not accept our filings, delay

or deny approval of any of our product candidates or require additional data or trials to support approval; our reliance on third parties

as the sole source of supply of the drug substance and drug product used in our products and product candidates; raw material, important

ancillary product and drug substance and/or drug product shortages; our reliance on third parties to conduct research, clinical trials,

and/or certain regulatory activities for our product candidates; complications in coordinating requirements, regulations and guidelines

of regulatory authorities across jurisdictions for our clinical trials; business development activities and their impact on our financial

performance and strategy; changes in our operating plan, business development strategy or funding requirements; and existing or new competition.

These and other important factors discussed in our filings with the

U.S. Securities and Exchange Commission, including under the caption "Risk Factors" contained therein, could cause actual

results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking

statements represent management's estimates as of the date of this press release. Except as required by law, we disclaim any intention

or obligation to update or revise any forward-looking statements. These forward-looking statements should not be relied upon as representing

our views as of any date subsequent to the date of this press release.

ARCALYST is a registered trademark of Regeneron

Pharmaceuticals, Inc.

Every Second Counts!

Kiniksa Investor Contact

Jonathan Kirshenbaum

Kiniksa Media Contact

KINIKSA PHARMACEUTICALS

SELECTED CONSOLIDATED