Kiniksa Pharmaceuticals : J.P. Morgan Presentation on Corporate Priorities and Expected 2021 Milestones

Every Second Counts!™	J.P. Morgan Healthcare Conference

January 11, 2021

Forward Looking Statements

This presentation (together with any other statements or information that we may make in connection herewith) contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 with respect to Kiniksa Pharmaceuticals, Ltd. (and its consolidated subsidiaries, collectively, unless context otherwise requires, "Kiniksa," "we," "us" or "our"). In some cases, you can identify forward looking statements by terms such as "may," "will," "should," "expect," "plan," "anticipate," "could," "intend," "goal," "design," "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 presentation that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation, statements regarding: our corporate priorities and strategy; product development and prospects; potential value drivers; prospects for 2021; potential indications; potential market opportunities and competitive position; on going, planned and potential clinical trials and other studies; timing and potential impact of clinical data; mechanisms and potential of our product candidates; regulatory and other submissions, applications and approvals; commercial strategy, pre-commercialization activities and commercial launch timing; expected run rate for our cash, cash equivalents and short-term investments; expected funding of our operating plan; and capital allocation.

These statements involve known and unknown risks, uncertainties, and other important factors that may cause our actual results, performance or achievements to be materially different from those expressed or implied by the forward-looking statements, including without limitation: potential delays or difficulties with our clinical trials or startup thereof; potential inability to demonstrate safety or efficacy or otherwise producing negative, inconclusive or uncompetitive results; potential for changes in final data from preliminary or interim data; potential inability to replicate in later clinical trials positive results from earlier trials and studies; impact of additional data from us or other companies; potential undesirable side effects caused by our product candidates; our reliance on third parties for manufacturing and conducting clinical trials, research and other studies; potential changes in our strategy, corporate priorities, operating plan and funding requirements; drug substance and/or drug product shortages; substantial new or existing competition; potential for applicable regulatory authorities to not accept our regulatory filings or to delay or deny approval of any of our product candidates or to require additional trials to support any such approval; complications in coordinating requirements, regulations and guidelines of regulatory authorities across jurisdictions for our clinical trials; potential impact of the COVID-19 pandemic, and measures taken in response to the pandemic, on our business and operations as well as the business and operations of our manufacturers, CROs upon whom we rely to conduct our clinical trials, and other third parties with whom we conduct business or otherwise engage, including the FDA and other regulatory authorities; and our ability to attract and retain qualified personnel. These and the other important factors are discussed under the caption "Risk Factors" in our Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on November 5, 2020 and other filings subsequently filed with the SEC. These forward-looking statements reflect various assumptions of Kiniksa's management that may or may not prove to be correct. No forward-looking statement is a guarantee of future results, performance, or achievements, and one should avoid placing undue reliance on such statements. Except as otherwise indicated, this presentation speaks as of the date of this presentation. We undertake no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

This presentation also contains estimates, projections, and/or other information regarding our industry, our business and the markets for certain of our product candidates, including data regarding the estimated size of those markets, and the incidence and prevalence of certain medical conditions. Unless otherwise expressly stated, we obtained this industry, business, market and other data from reports, research surveys, clinical trials, studies and similar data prepared by market research firms and other third parties, from industry, medical and general publications, and from government data and similar sources. Information that is based on estimates, forecasts, projections, market research, or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information.

2

Building Patient-Centric Leadership in Immune-Modulating Therapies

Leveraging internal & external expertise to drive growth

4 Product Candidates; First	Targeting Debilitating Diseases
PDUFA Date in 1Q 20211	with Unmet Medical Need

Pipeline-in-a-Molecule

Validated Mechanisms orPotential Across the Portfolio Strong Biologic Rationale

3	1) Rilonacept PDUFA goal date for recurrent pericarditis is March 21, 2021; PDUFA = Prescription Drug User Fee Act

Worldwide Commercial Rights to Four Immune-Modulating Product Candidates

Program & Target

Preclinical

Phase 1

Phase 2

Phase 3

Regulatory2

Commercial Rights

Rilonacept1

PDUFA: 03/21/21;

Worldwide

Orphan Drug Designation &

Recurrent Pericarditis

IL-1α & IL-1β

Breakthrough Therapy

(Excluding MENA)

Designation

Orphan Drug

Giant Cell Arteritis

Worldwide

Designation

Mavrilimumab

GM-CSFRα

Worldwide

COVID-19 Pneumonia & Hyperinflammation

Vixarelimab

Breakthrough Therapy

Worldwide

Prurigo Nodularis

OSMRβ

Designation

KPL-404

Worldwide

Severe Autoimmun

e Diseases

CD40

	1) Rilonacept (ARCALYST®) is approved and marketed for cryopyrin-associated periodic syndrome (CAPS) and maintenance of remission of Deficiency of Interleukin-1 Receptor Antagonist (DIRA) in the United States by Regeneron Pharmaceuticals, Inc.; 2)
4	The FDA granted Breakthrough Therapy designation to rilonacept for recurrent pericarditis in 2019 and Orphan Drug designation to rilonacept for pericarditis in 2020; The FDA granted Orphan Drug designation to mavrilimumab for giant cell arteritis in
2020; The FDA granted Breakthrough Therapy designation to vixarelimab for the treatment of pruritus associated with prurigo nodularis in 2020; IL-1α = interleukin-1α ; IL-1β = interleukin-1β;GM-CSFRα = granulocyte macrophage colony stimulating
factor receptor alpha; OSMRβ = oncostatin M receptor beta; PDUFA = Prescription Drug User Fee Act ; MENA = Middle East North Africa