MoonLake Announces Positive Topline Results from the Phase 3 IZAR-1 Trial of Sonelokimab in Psoriatic Arthritis Demonstrating Significant Improvements Across all Clinical Endpoints, and Reports Second Quarter 2026 Financial Results

* Phase 3 IZAR-1 trial in bio-naïve patients met all clinical endpoints at Week 16 for 60 mg sonelokimab * The primary endpoint of ACR50 was met with a high response of 42.1% for sonelokimab’s 60 mg with induction, and significant responses were observed across key secondary endpoints, including ACR20 (66.5%), MDA (41.2%) and PASI90 (61%), supporting the broad multidomain efficacy profile of sonelokimab in psoriatic arthritis * Meaningful and statistically significant improvements were seen across patient-reported outcomes and physical function measures, including HAQ-DI and SF-36 PCS * Blinded safety analysis suggests a profile consistent with previous studies and no new safety signals were identified, reinforcing sonelokimab's potential to become a leading treatment option for patients living with psoriatic arthritis, and enabling MoonLake’s entry into another multi-billion dollar indication * The IZAR-1 trial remains blinded and will continue until Week 52 with MoonLake expecting the full readout in H1 2027 whereas the IZAR-2 trial (a trial in TNF-refractory patients) is expected to complete enrollment in Q3 2026 * MoonLake ended the second quarter with $537.0 million in cash, cash equivalents and short-term marketable debt securities and expects to have a cash runway to mid-2028; additionally, up to $400 million in non-dilutive funds remain available through its debt facility with Hercules Capital ZUG, Switzerland, August 10, 2026 – MoonLake Immunotherapeutics (NASDAQ: MLTX) ("MoonLake" or the "Company"), a clinical-stage biotechnology company focused on creating next-level therapies for inflammatory diseases, today announced positive topline results from the Phase 3 IZAR-1 trial evaluating sonelokimab in biologic-naïve adults with active psoriatic arthritis (PsA) and reported second quarter 2026 financial results.