4 January 2018 / CONFIDENTIAL

JPMorgan Presentation

Relentless. Passionate. Focused.™

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4 January 2018 / CONFIDENTIAL 2

This presentation (together with any other statements or information that we may furnish to you) includes or may include certain statements, estimates and forward-looking projections with respect to Kiniksa or our anticipated future performance or events. Forward-looking statements frequently are used in discussing potential product applications, potential acquisitions or collaborations, product development activities, clinical studies, regulatory submissions and approvals, and similar operating matters.

Many factors may cause actual results to differ from forward-looking statements, including inaccurate assumptions and a broad variety of risks and uncertainties, some of which are known and others of which are not. They reflect various assumptions of our management that may or may not prove to be correct. In addition, this presentation does not purport to be all-inclusive or contain all information that you may desire in considering an investment in Kiniksa. No forward-looking statement is a guarantee of future results or events, and one should avoid placing undue reliance on such statements. Except as otherwise indicated, this presentation speaks as of the date indicated above. Kiniksaundertakes no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

THIS PRESENTATION DOES NOT CONSTITUTE AN OFFER TO SELL TO, OR A SOLICITATION OF AN OFFER TO BUY FROM, ANYONE IN ANY STATE OR IN ANY OTHER JURISDICTION IN WHICH SUCH AN OFFER OR SOLICITATION IS NOT AUTHORIZED.

Forward Looking Statements

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KINIKSA

A company with a sequential pipeline, FIRMLY rooted in strong biologic

rationale, validated mechanisms, and designed to deliver near, mid and

long-term value

4 January 2018 / CONFIDENTIAL

Kiniksa Senior Team

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Sanj K. PatelChairman & Chief Executive Officer

Steve MahoneyPresident & Chief Operating Officer

John PaoliniChief Medical Officer

Brendan ClassonHead of Research

Christine MaurerSVP Program Management

Carsten BoessChief Business Officer

Chris HeberligChief Financial Officer

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Global Vision

Focus on Rare/Specialty Diseases

Rapid Development

Meaningful Impact

Our StrategyAcquire, Discover & Rapidly Develop: Life-changing therapies for devastating diseases

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Rapid Progress

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Program Status / Activity

KPL-716

JPMorgan Conference 2017

• Pre-IND Program

Program Status / Activity

KPL-914

To date

• Phase 3 start planned for 2018

KPL-301 • Phase 2 start planned for 2018

KPL-716 • Phase 2 start planned for 2018

KPL-045 • Currently in IND-enabling studies

KPL-404 • Currently in IND-enabling studies

Corporate • $80M Series A Financing Corporate • $40M Series B Financing

Research • Initiated discovery on noveln targets

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Kiniksa Pipeline

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Program & Mechanism Preclin

KPL-914

Early Clinical

MidClinical Pivotal Indications / Status / Milestones RightsBLA MktIndication

OrphanInflammatory

Inflamm. Cardio

• *Commercially approved product

• Nominal revenue post-BLA transfer to Kiniksa• Transfers to Kiniksa

upon sBLA approval

• Starting lead-in study

• Anticipate P3 start in 2018• World Wide (ex.

Middle East)

Inflamm.Derm.

• Phase 1b study currently enrolling patients as proof-of-mechanism

• Planning P2b start in rare inflammatory in ‘18KPL-716 • World Wide

Autoimmune • Currently conducting IND-enabling studiesKPL-045 • World Wide

Autoimmune • Currently conducting IND-enabling studiesKPL-404 • World Wide

Autoimmune• Hundreds of patient years worth of data

• Kiniksa to conduct programs in smaller autoimmune diseases (P2 start in 2018)

KPL-301 • World Wide

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KPL-914

Kiniksa portfolio: Potential to treat broad spectrum of autoimmune & autoinflammatory diseases with high unmet need

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Innate Modulator

Adaptive Modulator

Autoinflammatory(e.g., rare monogenetic fever diseases, IBD, etc)

Autoimmune(e.g., myasthenia gravis, ITP, pemphigus vulgaris)

KPL-301

KPL-716

KPL-045

KPL-404Indications

Immunity

KPL-914• Receptor cytokine trap and modulator of innate immunity

KPL-301• Monoclonal antibody inhibitor of a key growth factor for

monocytes and granulocytes (e.g., neutrophils, eosinophils and basophils)

KPL-716• Monoclonal antibody inhibitor two inflammatory cytokines

involved in Th2 response / cell mediated immunity, pruritus, fibrosis and barrier dysfunction

KPL-045• Monoclonal antibody inhibitor of a T-cell co-stimulatory

receptor inhibitor involved in activated T-memory function

KPL-404• Monoclonal antibody inhibitor of a central control node of T-

cell dependent, B-cell mediated humoral adaptive immunity

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KPL-301

Phase 2-ready

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KPL-914 Phase 3-ready

KPL-716

Phase 1b

KPL-045

Pre-Clin

KPL-404

Pre-Clin

Receptor cytokine trap and modulator of innate immunity

• Approved and marketed biologic product

• Targeting rare inflammatory cardiovascular disease/high unmet need

• Strong scientific rationale/validated mechanism

• Clear rationale for differentiation across additional indications

• Starting lead-in study/preparing to initiate Phase 3 Pivotal in 2018

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KPL-914 KPL-716 KPL-045 KPL-404

Monoclonal antibody inhibiting signaling of key growth factor for monocytes and granulocytes

• Demonstrated safety and efficacy in large autoimmune disease thru P2b

• Focusing now on rare, debilitating diseases with less competition and higher unmet need

• Copious GMP drug supply to enable quick start of Phase 2 studies

• Pipeline-in-a-molecule potential

KPL-301 Phase 2-ready

4 January 2018 / CONFIDENTIAL

KPL-301

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KPL-914 KPL-045 KPL-404

Monoclonal antibody inhibitor of two inflammatory cytokines involved in Th2 response / cell mediated immunity, pruritus, fibrosis and barrier dysfunction

• Highly differentiated mechanism (simultaneously interrupts 2 key pathways)

• Currently dosing Phase 1b study in patients

• Plan to start Phase 2 studies in 2018

• Pipeline-in-a-molecule potential

KPL-716 Phase 1b

4 January 2018 / CONFIDENTIAL

KPL-301

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KPL-914 KPL-716 KPL-404

Monoclonal antibody inhibitor of a critical T-cell co-stimulatory receptor inhibitor involved in activated T-memory function

• Target implicated in autoimmune diseases by existing approved therapy

• Comprehensive non-clinical package

• Proof of mechanism in several validated pre-clinical models

• Pipeline-in-a-molecule potential

• Currently conducting IND-enabling studies

KPL-045 Pre-Clin

4 January 2018 / CONFIDENTIAL

KPL-301

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KPL-914 KPL-716 KPL-045

Monoclonal antibody inhibitor of a central control node of T-cell dependent, B-cell mediated humoral adaptive immunity

• Established Proof of Concept in previous studies

• Potentially a best-in-class molecule

• Targeting a variety of rare and specialty autoimmune diseases

• Pipeline-in-a-molecule potential

• Currently conducting IND-enabling studies

KPL-404 Pre-Clin

4 January 2018 / CONFIDENTIAL

Kiniksa 2018 Plans Multiple programs in the clinic

Pivotal study in a rare, debilitating disease

Multiple discovery-stage programs

Additional molecules in IND-enabling studies

4 January 2018 / CONFIDENTIAL

Passion for Patients

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Every Second Counts Every Second Counts!