Kiniksa Pharmaceuticals Reports Second Quarter 2023 Financial Results and Recent Portfolio Execution - ARCALYST (rilonacept) Q2 2023 net product revenue of $54.5 million - - ARCALYST 2023 net product revenue guidance inc

Kiniksa Pharmaceuticals

Reports Second Quarter 2023 Financial Results and Recent Portfolio Execution

(rilonacept) Q2 2023 net product revenue of $54.5 million -

2023 net product revenue guidance increased to $220 - $230 million, representing ~84% year-over-year growth at the midpoint -

Phase 2 rheumatoid arthritis data expected in 1H 2024 -

reserves now expected to fund operations into at least 2027 -

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

- July 25, 2023 - Kiniksa Pharmaceuticals, Ltd. (Nasdaq: KNSA) (Kiniksa), a biopharmaceutical company

with a pipeline of immune-modulating assets designed to target a spectrum of cardiovascular and autoimmune diseases, today reported second

quarter 2023 financial results and recent portfolio execution.

"Kiniksa continues to make significant progress in bringing ARCALYST,

the first and only FDA-approved therapy for recurrent pericarditis, to patients in need. As a result of increased call frequency and expanded

reach with target prescribers, we are seeing increased prescriber adoption and patient enrollments. We are still in the early stages of

building the recurrent pericarditis market and remain encouraged by the high level of patient satisfaction, payer approval rates, and

duration of therapy. These key metrics provide conviction in raising our 2023 ARCALYST sales guidance to between $220 million and $230

million," said Sanj K. Patel, Chairman and Chief Executive Officer of Kiniksa. "Within our pipeline, we continue to enroll

patients in the KPL-404 Phase 2 trial in rheumatoid arthritis and expect data in the first half of 2024. Additionally, we have a strong

financial position and our cash reserves, combined with our continued ARCALYST commercial execution and financial discipline, now provide

cash runway into at least 2027."

Portfolio and Collaboration Execution

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

KPL-404 (monoclonal antibody inhibitor of CD40-CD154 interaction)

Mavrilimumab (monoclonal antibody inhibitor targeting GM-CSFR )

Vixarelimab (monoclonal antibody inhibitor of signaling through

Conference Call Information

Kiniksa is a biopharmaceutical company focused on discovering, acquiring,

developing, and commercializing therapeutic medicines for patients suffering from debilitating diseases with significant unmet medical

need. Kiniksa's immune-modulating assets, ARCALYST, KPL-404, and mavrilimumab, are based on strong biologic rationale or validated

mechanisms, target a spectrum of underserved cardiovascular and autoimmune conditions, and offer 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 recurrent pericarditis, cryopyrin-associated periodic syndromes (CAPS), including Familial Cold Autoinflammatory Syndrome and

Muckle-Wells Syndrome, and deficiency of IL-1 receptor antagonist (DIRA). The FDA granted Breakthrough Therapy designation to ARCALYST

for the treatment of recurrent pericarditis in 2019 and Orphan Drug designation to ARCALYST for the treatment of pericarditis in 2020.

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

IMPORTANT SAFETY INFORMATION

For more information

about ARCALYST, talk to your doctor and see the Product Information.

KPL-404 is an investigational

humanized monoclonal antibody that is designed to inhibit 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 interaction

is an attractive approach to address multiple autoimmune disease pathologies.

Mavrilimumab is an investigational

fully human monoclonal antibody that blocks activity of GM-CSF by specifically binding to the alpha subunit of the GM-CSF receptor (GM-CSFR ).

Phase 2 clinical trials of mavrilimumab in rheumatoid arthritis and giant cell arteritis achieved their primary and secondary endpoints

with statistical significance. Kiniksa is evaluating the development of mavrilimumab in rare cardiovascular diseases where the GM-CSF

mechanism has been implicated.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning

of the Private Securities Litigation Reform Act of 1995. 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 expectation that ARCALYST

full-year 2023 net product revenue will be between $220 million and $230 million; our expectation that we will report data from our Phase

2 clinical trial of KPL-404 in rheumatoid arthritis in the first half of 2024; our expectation about our cash reserves funding our current

operating plan into at least 2027; our beliefs about the mechanisms of action of our product candidates and potential impact of their

approach, including that using KPL-404 to disrupt the CD40-CD154 interaction is an attractive approach to address multiple autoimmune

disease pathologies; and our belief that all of our product candidates offer 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; inability to successfully execute on our commercial

strategy for ARCALYST; 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; our reliance on Regeneron as the current sole manufacturer of ARCALYST; risks arising from our ongoing technology

transfer of ARCALYST drug substance manufacturing; 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; 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. All

other trademarks are the property of their respective owners.

Every Second Counts!

Kiniksa Investor and Media Contact

KINIKSA PHARMACEUTICALS, LTD.

SELECTED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS)

KINIKSA PHARMACEUTICALS, LTD.

SELECTED CONSOLIDATED BALANCE SHEET DATA