Kiniksa Pharmaceuticals International : Corporate Presentation – April 2026

Published: 2026-04-28 08:47:10 ET KNSA

Published on 04/28/2026 at 08:47 am EDT

Corporate Presentation

APRIL 2026

Building on our successful foundation by prioritizing development of novel therapies for cardiovascular indications

Established leadership in recurrent

pericarditis market

Continued growth potential with

only ~18% penetration into multiple recurrence population1

Expected 2026 ARCALYST revenue

of $930 to $945M

Advancing Clinical

Portfolio

Conducting KPL-387 Phase 2/3 trial in

recurrent pericarditis

KPL-387 Phase 2 data expected in 2H

2026; Phase 3 pivotal trial expected to initiate by the end of 2026

KPL-1161 Phase 1 first-in-human trial

to initiate by the end of 2026

Maintaining Strong

Financial Position

Q1 2026 cash reserves of ~$468M

Current operating plan expected to

remain cash flow positive on an

annual basis

Financial strength provides capacity

to continue investing in additional

value creation

1) As of Q4 2025.

Developing novel therapies for diseases with unmet need, prioritizing cardiovascular indications

SPECIALTY CARDIOVASCULAR

ARCALYST® (rilonacept)1-3

IL-1α & IL-1β Trap

KPL-3874

IL-1 Antagonist mAb

KPL-1161

Fc-Modified IL-1 Antagonist mAb

OTHER (NON-CARDIOVASCULAR)

Abiprubart

Anti-CD40 mAb

Exploring Strategic Alternatives

Undisclosed

Recurrent Pericarditis

Collaborative Study Agreement with Mayo Clinic & The Johns Hopkins University

Cardiac Sarcoidosis

Recurrent Pericarditis

Commercial

Phase 3

Phase 2

Phase 1

Preclinical

Indication

Program

Licensee

Exclusive Licensed Territory

OUT-LICENSING AGREEMENTS

ARCALYST (rilonacept)

IL-1α & IL-1β Trap

Huadong Medicine

Asia Pacific Region, Excluding Japan

Vixarelimab

Anti-OSMRβ mAb

Roche and Genentech

Worldwide

1) Approved in the U.S.; ARCALYST is also approved in the U.S. for cryopyrin-associated periodic syndromes (CAPS) and deficiency of the interleukin-1 receptor antagonist (DIRA); 2) The FDA granted Breakthrough Therapy designation to ARCALYST for recurrent pericarditis in 2019; the FDA granted Orphan Drug exclusivity to ARCALYST in March 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; 3) Kiniksa has worldwide rights, excluding the Middle East and North Africa; Kiniksa granted Huadong Medicine exclusive rights in the Asia Pacific Region, excluding Japan; 4) The FDA granted Orphan Drug Designation to KPL-387 for the treatment of pericarditis in 2025.

IL-1α = interleukin-1α; IL-1β = interleukin-1β; IL-1 = interleukin-1; mAb = monoclonal antibody; OSMRβ = oncostatin M receptor beta

ARCALYST ®

IL-1α AND IL-1β CYTOKINE TRAP

DISEASE AREA: Recurrent pericarditis1; painful and debilitating autoinflammatory cardiovascular disease

COMPETITION2: First and only FDA-approved therapy for recurrent pericarditis

REGULATORY: U.S. Orphan Drug exclusivity for treatment of and reduction in risk of recurrence of recurrent pericarditis; European Commission Orphan Drug designation in idiopathic pericarditis

STATUS: FDA-Approved

ECONOMICS: 50/50 split on profit and third-party proceeds

RIGHTS: Kiniksa has worldwide rights3 (excluding MENA) for all indications outside those in oncology and local administration to the eye or ear

1) ARCALYST is also approved and marketed for Cryopyrin-Associated Periodic Syndromes (CAPS) and maintenance of remission of Deficiency of Interleukin-1 Receptor Antagonist (DIRA) in the United States; 2) Drugs@FDA: ARCALYST Prescribing Information, Ilaris Prescribing Information, Kineret Prescribing Information; Kaiser et al. Rheumatol Int (2012) 32:295-299; Theodoropoulou et al. Pediatric Rheumatology 2015, 13(Suppl 1):P155; Fleischmann et al, 2017 ACR/ARHP Abstract 1196; Kosloski et al, J of Clin Pharm 2016, 56 (12) 1582-1590; Cohen et al. Arthritis Research & Therapy 2011, 13:R125; Cardiel et al. Arthritis Research & Therapy 2010, 12:R192; Hong et al. Lancet Oncol 2014, 15: 656-666; 3) Kiniksa granted Huadong Medicine exclusive rights in the Asia Pacific Region, excluding Japan.

IL-1α = interleukin-1α ; IL-1β = interleukin-1β; MENA = Middle East North Africa

Of the 14,000 annual patients with multiple recurrences, there is a high turnover of ~50% of patients each year, meaning ongoing opportunities to ensure diagnosis and targeted treatment

Approximately 14,000 recurrent pericarditis patients in the U.S. suffer from persistent underlying disease, with multiple recurrences and inadequate response to conventional therapy1

Multiple

Recurrences

~14,000

Recurrent

Pericarditis

~40,000

Pericarditis

~160,000

~160,000: Epidemiological analysis using large national surveillance databases to calculate the pooled annualized prevalence of pericarditis (Basis for Orphan Drug Designation)2

~40,000: Up to 30% experience at least one recurrence; some recur over multiple years3,4

~14,000: Nearly 50% annual turnover with ~7,000 patients

entering into the pool each year5

All figures annual period prevalence

1) Cremer et al. American Journal of Cardiology. 2016;2311-2328; 2) Data on file, Kiniksa Pharmaceuticals; 3) Imazio et al. Circulation. 2005;112:2012-2016; 4) Adler et al. Circulation. 1998;97:2183-2185; 5) Klein A, Cremer P,

Kontzias A, et al. US database study of clinical burden and unmet need in recurrent pericarditis. J Am Heart Assoc. 2021; 10:e018950. doi:10.1161/JAHA. 120.018950. 6

In addition to inflammatory cytokines such as IL-6, promotion and progression of the inflammatory process in pericarditis is due to IL-1α and IL-1β

CRP, C-reactive protein; DAMPs, damage-associated molecular patterns; IL, interleukin; PAMPs, pathogen-associated molecular patterns; WBC, white blood cell.

The Autoinflammatory Cycle of Recurrent Pericarditis: Tissue damage caused by IL-1α and IL-1β in the pericardium stimulates additional IL-1α and IL-1β, thereby creating a cycle of perpetual pericardial inflammation

In the three years following approval, ARCALYST increasingly replaced corticosteroids after NSAIDs and colchicine

RESONANCE RWE: Expert Centers in U.S.

ACC Concise Clinical Guidance: First U.S. Formal Guidance

‡

†

Second-Line use in patients with Recurrent Pericarditis failing NSAIDs/Aspirin/Colchicine1

IL-1 pathway inhibition is now the ACC-recommended second-line treatment after initial therapy

Updated Treatment Algorithm

Initial therapy

NSAIDs or aspirin plus colchicine

Second-line

IL-1 pathway inhibition (e.g., ARCALYST)

Consider corticosteroid

No Response (autoinflammatory phenotype)*

Consider radical pericardiectomy (at high-volume surgical center)

Refractory Cases

ARCALYST has increasingly replaced corticosteroids in second-line use

Adapted from Wang TKM, et al. J Am Coll Cardiol. 2025

*Autoinflammatory phenotype is defined as patients having fever and/or elevation of CRP and/or CMR imaging evidence of pericardial inflammation.

‡Of 64 patients starting ARCALYST after aspirin/NSAIDs/colchicine, 8 patients utilized steroids as a short-term bridge prior to starting ARCALYST (n=1 in 2021, n=2 in 2022, n=1 in 2023); 8 patients (n=2 in 2021, n=4 in 2023) utilized anakinra as a short-term bridge prior to starting ARCALYST; . €Of those who transitioned from aspirin/NSAIDs/colchicine to second-line ARCALYST, 5% subsequently used corticosteroids for >30 days and <5% subsequently used corticosteroids for <30 days; *1 year prior to ARCALYST approval; † Partial year after ARCALYST commercial availability April 1, 2021 - Dec 31, 2021; £Data were censored at last check-in visit.

1) Cremer, P, Luis, S, Garshick, M. et al. IL-1 Pathway Inhibition in Recurrent Pericarditis Management: Real-World Adoption of Corticosteroid Sparing in RESONANCE. JACC Adv. 2025 Sep, 4 (9). https://doi.org/10.1016/j.jacadv.2025.102050. RWE = Real World Evidence; ACC = American College of Cardiology

Increasing Penetration into

ARCALYST Label Covers Recurrent Pericarditis

(Annual Epidemiology of Approximately 40,000)

1st Recurrence

~26,000

Multiple Recurrence

Population

18%

13%

Percentage

A sizable portion could be appropriate for biologic treatment

Additional Opportunity

~20% of patients on ARCALYST were prescribed when they were on their 1st recurrence1

2022 2023 2024 2025

End of Year

>2nd Recurrence

~14,000

Initial Target Population

~80% of patients on ARCALYST were prescribed when they had 2+ recurrences1

While the initial target population focused

on patients with multiple recurrences...

…growing adoption of IL-1α & IL-1β inhibition has expanded

focus to additional patients earlier in the disease course

Sources: Klein A, Cremer P, Kontzias A, Furqan M, Tubman R, Roy M, Magestro M. Annals of Epidemiology. 2019;36:71; Lin D, Majeski C, DerSarkissian M, Magestro M, Cavanaugh C, Laliberte F, Lejune D, Mahendran M, Duh M, Klein A, Cremer P, Kontzias A, Furqan M, Tubman R, Roy M, Mage. (Nov, 2019). Real-World Clinical Characteristics and Recurrence Burden of Patients Diagnosed with Recurrent Pericarditis in the United States. Poster session presented at the American Heart Association, Philadelphia, PA.

1) HCP market research 2026; Kiniksa data on file.

$214.3M

Q1 2026 Net Revenue

Representing 56% YoY Growth

~3 Years1

Average Total Duration of Therapy Growing and Approaching Median Disease Duration

⅓ of Multiple Recurrence Patients Continue

Suffering at 5 Years and ¼ at 8 Years

>4,5501

Total Prescribers

~1,320 Repeat Prescribers

~18%2

Penetration into Multiple Recurrence Population

Increasing Utilization in 1st Recurrence Population

Strong Payer Approval and Patient Compliance

1) Data since launch through 3/31/2026; 2) as of Q4 2025.

Support creation of an efficient network of care with Pericardial Disease Centers (PDCs)

Leverage AI and machine learning to efficiently target potential prescribers

Advance direct-to-patient digital marketing

Drive physician awareness of the 2025 ACC Concise Clinical Guidance

ACC = American College of Cardiology

Acceleration in new-to-brand and restart patients offset higher patient stops over time

Illustrative Patient Flow

New Starts

Patient Restarts

ARCALYST Patient Flow

New to Brand Patients

Strong steady growth: >4,550 unique prescribers; ~29% of which are repeat prescribers

Patient Stops

Patient Restarts

Increases over time as base of active ARCALYST patients grows with Initial Starts and Restarts

Increases over time as patient stops increase; currently ~45% after ~8 weeks

Active Patients

Increases over time driven by New-to-Brand and Restart growth; as of Q4 2025, ~18% of 14K multiple recurrence patient population

Launch (2021)

Time

Patients with multiple recurrences often continue suffering from flares for a median of 3 years1

Average Total Duration of Therapy

Growing and Approaching Median Disease Duration1

Natural History of Patients with Multiple Recurrences

⅓ of Patients with Multiple Recurrences Suffer at 5 Years and ¼

Continue to Experience Flares at 8 Years1

Lin D, Laliberté F, Majeski C, et al. Disease and economic burden associated with recurrent pericarditis in a privately insured United States population. Adv Ther. 2021;38(10):5127-5143. doi:10.1007/s12325-021-

01868-7; 2) As of Q1 2026. 13

Total and Repeat Prescribers of ARCALYST for

Recurrent Pericarditis Patients

The Growing Repeat Prescriber Base is Delivering ~50%

of All New Patient Prescriptions

>4,550

Patients

~1,150

~1,400

~70

~230

~480

~820

~1,320

>3,150

Patients

≥4 Patients

~600

>400

~1,000

>1,000

~2,000

Q1 2022 Q1 2023 Q1 2024 Q1 2025 Q1 2026

Strong, steady growth in both new and repeat prescribers, supporting long-term growth-potential

Both physicians and patients are gaining positive experiences with ARCALYST as the first and only approved therapy for recurrent pericarditis

Cardiologist market research shows a steady increase in their level of comfort with

Q1 2022 Q1 2023 Q1 2024 Q1 2025 Q1 2026

prescribing biologics

~50% of all new prescriptions in Q1 2026 came from repeat prescribers

Pricing Access Distribution

ARCALYST list price of $25,158 per month

Based on first and only FDA-approved therapy for recurrent pericarditis, in-line with specialty biologics with Breakthrough Therapy and Orphan Drug designation

Helping to ensure patient affordability and access to treatment is one of our core principles and to this end, we offer a suite of programs to support affordability to eligible patients who are prescribed ARCALYST; eligible patients are able to get ARCALYST for a copay of as low as $0

Kiniksa's goal is to maintain rapid and broad access to ARCALYST for patients with Recurrent Pericarditis, CAPS, and DIRA

Payer mix for ARCALYST is largely commercial (>60%)

Payer engagement has increased awareness of recurrent pericarditis and the differentiated value of ARCALYST

The Kiniksa OneConnect program is a personalized treatment support program for patients prescribed ARCALYST

ARCALYST is distributed through a closed network of designated specialty pharmacies and the Veterans Affairs

The distribution network for ARCALYST was developed to provide a high and consistent level of patient support with broad access. Network pharmacies provide customized services to support patients

CAPS = Cryopyrin-Associated Periodic Syndromes ; DIRA = Deficiency of IL-1 Receptor Antagonist

Revenue guidance raised to $930-$945M from $900-$920M

Expected Net

Product Sales

Positioning ARCALYST as 2nd line Standard of Care

$677.6M

$417.0M

Deepening penetration into 2+ recurrence population

$38.5M1

$122.5M

$233.2M

Driving adoption among larger 1st recurrence population

2021 2022 2023 2024 2025 2026

1) 2021 = 9 months of availability (Q2-Q4).

ARCALYST Net Sales (CAPS + DIRA + Recurrent Pericarditis)2

Minus 100% of Profit Split Eligible Cost of Goods Sold3

Minus 100% of ARCALYST Field Force Expenses

Minus ARCALYST Marketing & Commercial Expenses (Subject to Specified Limits)

Minus 100% of ARCALYST Regulatory & Certain Other Expenses

ARCALYST Collaboration Operating Profit

Minus 50% of ARCALYST Collaboration Operating Profit and 50% of ARCALYST Licensing Proceeds

Collaboration Expenses

(Booked as a separate line item within OpEx)

Minus R&D Expenses for Additional Indications or Other Studies Required for Approval for ARCALYST

Minus ARCALYST Marketing & Commercial Expenses that Exceeded Specified Limits (if any)

Kiniksa Operating Income from ARCALYST

Kiniksa is responsible for sales and distribution of ARCALYST in all approved indications in the United States.

Kiniksa's license to ARCALYST includes worldwide rights*, excluding MENA, for all applications other than those in oncology and local administration to the eye or ear.

Kiniksa covers 100% of development expenses related to approval of additional indications.

Kiniksa evenly splits profits on ARCALYST

sales and licensing proceeds with Regeneron.

*Kiniksa exclusively licensed rights for the development and commercialization of ARCALYST in APAC (ex-Japan) to Huadong Medicine

1) Subject to description contained in definitive agreement; 2) Global net sales for CAPS, DIRA and recurrent pericarditis recognized as revenue on Kiniksa's income statement; 3) Profit Split-Eligible Cost of Goods Sold = total cost of goods sold - amortization of Regeneron milestone payment.

CAPS = Cryopyrin-Associated Periodic Syndromes; DIRA = Deficiency of the Interleukin-1 Receptor Antagonist; MENA =Middle East and North Africa; APAC = Asia Pacific Region

KPL-387

MONOCLONAL ANTIBODY IL-1 RECEPTOR ANTAGONIST INHIBITING IL-1α AND IL-1β SIGNALING

DISEASE AREA: Recurrent pericarditis; painful and debilitating autoinflammatory cardiovascular disease

SCIENTIFIC RATIONALE: Inhibition of IL-1α and IL-1β signaling well-established for the treatment for recurrent pericarditis1-3

REGULATORY: U.S. Orphan Drug Designation for the treatment of pericarditis

STATUS: Phase 2 portion of pivotal Phase 2/3 clinical trial enrolling and dosing; dose-focusing (Phase 2) data expected in 2H 2026

ECONOMICS: Independently developed and wholly-owned

RIGHTS: All indications worldwide

1) Klein AL, Imazio M, Cremer P, et al. Phase 3 trial of interleukin-1 trap rilonacept in recurrent pericarditis. N Engl J Med. 2021;384(1):31-41; ARCALYST (rilonacept) prescribing information 2021; 2) Arnold, D. D., Yalamanoglu,

A., & Boyman, O. (2022). Systematic review of safety and efficacy of IL-1-targeted biologics in treating immune-mediated disorders. Frontiers in immunology, 13, 888392; 3) Dinarello CA, Simon A, van der Meer JWM. Treating inflammation by blocking interleukin-1 in a broad spectrum of diseases. Nat rev drug Discov, 2012;11(8);633-652. 18

KPL-387

Fully human IgG2 monoclonal antibody

Binds to IL-1R1, inhibiting both IL-1α & IL-1β cytokine-mediated signaling

IL-1α and IL-1β inhibition is well-established

and well-tolerated

Monthly dosing potential with single subcutaneous self-injection in liquid formulation

Created in BioRender. Lawton, M. (2025) https://BioRender.com/hvx08bv

IL-1R1 = interleukin-1 receptor 1; IL-1R3 = interleukin-1 receptor 3; IL-1α = interleukin-1 alpha; IL-1β = interleukin-1 beta; IgG2 = immunoglobulin G2; MYD88 = myeloid differentiation primary response 88; IKK = IkappaB

kinase; NF-KB = nuclear factor-kappa B; MKK = mitogen-activated protein kinase kinase; JNK = jun N-terminal kinase; p38 = p38 mitogen-activated protein kinase; IL-6 = interleukin 6; TNFα = tumor necrosis factor-alpha 19

The vast majority of surveyed HCPs report that an efficacious IL-1α & IL-1β inhibitor with the target profile of KPL-387 would be best positioned to address unmet needs of patients living with recurrent pericarditis and is likely to expand the market

Key Needs Filled

Less frequent dosing

Streamlined preparation

Patient-friendly administration

~75%

~70%

Patient Preferences

Of all RP patients prefer the KPL-387 target profile over available commercial and investigational therapies

Of all RP patients would be willing to stay on a monthly autoinjector for longer, with fewer missed doses, compared to a weekly subcutaneous dosing presentation

~92%

HCP Preferences

Report high likelihood of prescribing KPL-387 for new patients, in the context of available commercial and investigational therapies

Current ARCALYST patients demonstrate high compliance and adherence, but HCPs receptive to switching upon patient request

~75%

Of ARCALYST-naïve patients would be more willing to take an injectable therapy if presented in an autoinjector

HCPs indicate a sizable increase in proportion of patients likely to use an IL-1α & β inhibitor if KPL-387 comes to market

"It [would be] easy to use because there is no need to mix and wait for it to work. The autoinjector [would] make it simple. It [would] also be more convenient to take it once a month." - ARCALYST patient

"The dosing regimen of once monthly versus once weekly is a

game changer for patients." - Physician

Source: Kiniksa data on file.

Disclaimer

Kiniksa Pharmaceuticals International plc published this content on April 28, 2026, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on April 28, 2026 at 12:46 UTC.