Kiniksa Pharmaceuticals Reports Third Quarter 2023 Financial Results and Recent Portfolio Execution - ARCALYST (rilonacept) Q3 2023 net product revenue of $64.8 million, representing ~94% year-over-year growth - - KPL-40

Kiniksa Pharmaceuticals

Reports Third Quarter 2023 Financial Results and Recent Portfolio Execution

(rilonacept) Q3 2023 net product revenue of $64.8 million, representing ~94% year-over-year growth -

Phase 2 rheumatoid arthritis data from Cohorts 1-3 now expected in Q1 2024 -

reserves of $201 million expected to fund operations into at least 2027 -

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

BERMUDA - October 31, 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 third quarter 2023 financial results and recent portfolio

"We continue to advance all aspects

of our business, including strong revenue growth with ARCALYST and clinical trial execution with KPL-404, and we have cash runway into

at least 2027," said Sanj K. Patel, Chairman and Chief Executive Officer of Kiniksa. "On the commercial side, we are building

the recurrent pericarditis market and are focused on helping as many patients as possible. We are currently tracking to the high end

of our previously issued guidance of $220 million to $230 million in product revenue. Within our clinical development portfolio, we have

completed enrollment in the third cohort of the Phase 2 trial of KPL-404 in rheumatoid arthritis. We now expect data from Cohorts 1-3

in the first quarter of 2024."

ARCALYST (IL-1 and IL-1

KPL-404 (monoclonal antibody inhibitor

of CD40-CD154 interaction)

Mavrilimumab (monoclonal antibody

inhibitor targeting GM-CSFR )

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.

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 exclusivity

to ARCALYST in 2021 for 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.

SAFETY INFORMATION ABOUT ARCALYST

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

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.

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 we will report data from cohorts 1-3 of our Phase 2 clinical trial of KPL-404 in rheumatoid

arthritis in the first quarter of 2024 and data from cohort 4 of such trial in the second quarter of 2024; our expectation that our full-year

net product revenue will be at the high end of our $220 million to $230 million guidance range; 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

PHARMACEUTICALS, LTD.

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS)

PHARMACEUTICALS, LTD.

CONSOLIDATED BALANCE SHEET DATA