Kiniksa Pharmaceuticals, Ltd. (KNSA) Earnings

Management highlights

### Commercial Execution for Arclist - Grew penetration of the multiple recurrence patient population to 21% by the end of Q2 2026, up from ~18% at the end of 2025, leaving substantial untapped growth opportunity - Added ~450 new first-time prescribers in Q2 2026, bringing the total prescriber base to over 5,000, out of a total addressable pool of more than 25,000 eligible U.S. healthcare providers that manage recurrent pericarditis - The number of repeat prescribers (who have written 2+ Arclist prescriptions) increased by ~150 quarter-over-quarter, bringing the share of repeat prescribers to 29% of the total prescriber base - Key growth-driving initiatives: 1. Invested in AI and machine learning to provide sales teams predictive insights on who to target, when to visit, and what messaging to deliver, increasing field team efficiency 2. Launched a direct-to-consumer (DTC) marketing campaign called Hearts Home in April 2026 to educate patients and drive them to discuss Arclist with their providers; early engagement results are encouraging 3. Disseminated the 2025 ACC Concise Clinical Guidance, which recommends Arclist earlier in the treatment course (after NSAIDs/colchicine and before corticosteroids), driving expanded utilization as providers adjust treatment paradigms ### Clinical Pipeline Development - KPL387, an investigational treatment for recurrent pericarditis, completed the Phase 2 dose-focusing portion of its integrated Phase 2-3 trial. Data confirmed the 300mg once-monthly subcutaneous dose delivers rapid, durable efficacy (median time to treatment response of 4 days, median CRP normalization in 8 days) with a favorable safety profile consistent with IL-1 pathway inhibition - The pivotal Phase 3 trial of KPL387 (named PASTORAL) has already initiated and is actively enrolling patients; it uses the same registrational endpoint (reduction in pericarditis recurrence risk) as the successful Arclist Phase 3 Rapsody trial, with a potential commercial launch targeted for 2028-2029 - KPL1161, an FC-modified IL-1 alpha and beta inhibitor designed for causal dosing, remains on track to initiate Phase 1 testing by the end of 2026 ### Financial Position - Ended Q2 2026 with $525.9 million in cash, generating $58 million in net cash during the quarter, leaving the company with a robust balance sheet to fund pipeline execution - Operating income for Q2 2026 was $27.2 million, and net income was $25.4 million, both increasing year-over-year despite higher investment in R&D and commercialization

Guidance

- Management raised full year 2026 revenue guidance upward from the prior range of $930 to $945 million to a new range of $980 to $995 million, reflecting stronger than expected Q2 2026 commercial growth for Arclist - Gross-to-net discount ratio is expected to remain at current lower levels through the rest of 2026, with the majority of the impact from adjusted copay support programs already realized in the first half of the year, following normal historical seasonal patterns - Management reaffirmed the target launch window for KPL387 of 2028 to 2029 - No changes were made to long-term operating or investment guidance, as the company plans to continue disciplined execution of its commercial and clinical strategy

Segment performance

Connexa has one core commercial product segment: Arclist, the company's approved treatment for recurrent pericarditis. In Q2 2026, Arclist generated net revenue of $243.6 million, representing 55% year-over-year growth versus Q2 2025, and $29 million sequential growth over Q1 2026. This is the largest quarterly net revenue increase for Arclist since its launch over five years ago. Arclist collaboration profit grew 68% year-over-year to $176.1 million, outpacing revenue growth. Arclist contributes 100% of the company's current commercial revenue. All other programs are in clinical development and do not generate revenue.

Risks & headwinds

Forward-looking statements regarding clinical trial results, revenue growth, and product launch timelines are subject to inherent risks and uncertainties that could cause actual outcomes to differ materially from current expectations, as detailed in the company's SEC filings. Key unquantified risks include: potential failure of the KPL387 Phase 3 trial to meet its primary endpoint, slower than expected penetration of the recurrent pericarditis market, unexpected safety signals in clinical programs, and changes to clinical practice or reimbursement that could impact Arclist adoption. The company does not undertake any obligation to update forward-looking statements unless required by law.

Analyst Q&A

• Q: This was the strongest quarter of Arclist sales growth since launch; what drove this growth, and can this level be sustained going forward? /

  A: The strong Q2 growth is the result of cumulative, ongoing execution across the entire commercial strategy. The quarter added over 450 new prescribers and 150 new repeat prescribers, the highest number of new prescribers since launch. Key contributors include improved targeting from AI/ML, early traction from the new DTC campaign, and growing adoption of the ACC guidance that recommends earlier Arclist use. With only 21% penetration of the multiple recurrence patient population, there remains significant long-term growth opportunity. The company will continue executing to capture this opportunity.

• Q: With Phase 2 KPL387 data complete, are any adjustments to the Phase 3 trial to differentiate KPL387's profile? What is the commercial opportunity for a monthly IL-1 regimen? /

  A: The 300mg monthly dose selected for Phase 3 already has a differentiated profile: it delivers rapid onset of action and durable efficacy across the full monthly dosing interval, with a liquid formulation. Market research shows 75% of patients prefer the KPL387 monthly profile over existing and other investigational therapies, and 92% of providers report high likelihood to prescribe it for new patients. An additional IL-1 therapy is also expected to expand the overall overall IL-1 inhibition patient pool. The Phase 3 uses the same proven, well-accepted randomized withdrawal design as Arclist's successful registrational trial.

• Q: Do you plan to add sales force headcount given current momentum, or will you continue relying on AI and guideline dissemination? What is the purpose of the KPL387 transition study for patients switching from Arclist? /

  A: The company continuously evaluates Salesforce structure and targeting to maximize reach of providers, and will continue to leverage a mix of AI, machine learning, digital marketing, and existing resources to penetrate the underpenetrated market. The KPL389 transition study is a Phase 2 trial that tests different dosing regimens for switching patients from existing therapies (including NSAIDs, colchicine, corticosteroids, and other IL-1 inhibitors) to KPL387. The data will support label dosing and administration guidance to enable smooth switching for clinicians and patients.

• Q: What share of new Arclist prescriptions are for first recurrence patients, and is this group driving recent growth? /

  A: Approximately 20% of new Q2 2026 Arclist prescriptions are for first recurrence patients, with the remaining 80% for patients with 2+ recurrences. First recurrence is a larger patient population (~26,000 patients out of a total 40,000 eligible U.S. patients) and prescription share in this group has grown over time, reflecting growing provider confidence in Arclist use earlier in the disease course and greater awareness of its broad approved label, representing ongoing long-term opportunity.