Kiniksa Pharmaceuticals Reports First Quarter 2024 Financial Results and Recent Portfolio Execution - ARCALYST (rilonacept) Q1 2024 net product revenue of $78.9 million, representing 85% year-over-year growth - - ARCALYS

Kiniksa Pharmaceuticals

Reports First Quarter 2024 Financial Results and Recent Portfolio Execution

(rilonacept) Q1 2024 net product revenue of $78.9 million, representing 85% year-over-year growth -

2024 expected net product revenue increased to $370 - $390 million -

Phase 2b trial in Sj gren's Disease planned to initiate in 2H 2024 -

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

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

BERMUDA - April 23, 2024 - Kiniksa

Pharmaceuticals, Ltd. (Nasdaq: KNSA) (Kiniksa), a commercial-stage biopharmaceutical company with a pipeline of immune-modulating

assets designed to target a spectrum of cardiovascular and autoimmune diseases, today reported first quarter 2024 financial results and

recent portfolio execution.

"One of the drivers of strong

ARCALYST growth is an expanding utilization of ARCALYST as a steroid-sparing therapy for patients suffering from recurrent pericarditis.

In addition, with continued frequent prescriber engagement and high physician and patient satisfaction, we now expect 2024 ARCALYST net

sales to increase from our previous guidance of between $360 and $380 million to $370 and $390 million," said Sanj K. Patel, Chairman

and Chief Executive Officer of Kiniksa. "Additionally, we believe abiprubart has the potential to provide meaningful benefit through

convenient subcutaneous dosing, and we plan to initiate a Phase 2b trial in Sj gren's Disease in the second half of 2024.

This continued commercial execution and pipeline advancement is included in our current operating plan, which we expect to remain cash

flow positive on an annual basis."

ARCALYST (IL-1 and IL-1

Abiprubart (anti-CD40 monoclonal

antibody inhibitor of CD40-CD154 interaction)

Mavrilimumab (monoclonal antibody

inhibitor targeting GM-CSFR )

Kiniksa is a commercial-stage 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, abiprubart, 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 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.

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.

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 potential partnership opportunities for mavrilimumab.

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 expectation that ARCALYST 2024 net product revenue

will be between $370 million and $390 million; our plan to initiate a Phase 2b clinical trial of abiprubart in Sj gren's Disease

in the second half of 2024; our expectation to remain cash flow positive on an annual basis within our current operating plan; future

clinical trial design, including the design of our planned Phase 2b trial of abiprubart in Sj gren's Disease; our beliefs

about the mechanisms of our product candidates and potential impact of their approach, including that using abiprubart to disrupt the

CD40-CD154 co-stimulatory 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: risks arising from the planned redomiciliation of our principal holding company from Bermuda to the United Kingdom; 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 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; 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.

Every Second Counts!

Kiniksa Investor and Media Contact

KINIKSA PHARMACEUTICALS, LTD.

CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except share and per share amounts)

KINIKSA PHARMACEUTICALS, LTD.

SELECTED CONSOLIDATED BALANCE SHEET DATA