MoonLake's Sonelokimab Meets All Phase 3 Endpoints in Psoriatic Arthritis
On August 10, 2026, MoonLake Immunotherapeutics announced positive topline results from its global Phase 3 IZAR-1 trial evaluating the novel Nanobody® sonelokimab (an IL-17A and IL-17F inhibitor) in biologic-naïve adults with active psoriatic arthritis (PsA). The trial successfully met its primary endpoint and all key secondary endpoints at Week 16.
For the primary endpoint, 42.1% of patients treated with the sonelokimab 60 mg with induction regimen achieved an American College of Rheumatology 50 (ACR50) response at Week 16. The trial also demonstrated robust multi-domain efficacy across musculoskeletal and dermatological symptoms:
- 66.5% of patients achieved an ACR20 response.
- 41.2% of patients achieved Minimal Disease Activity (MDA).
- 61.0% of patients with concomitant skin involvement achieved a Psoriasis Area and Severity Index 90 (PASI90) response.
The blinded safety analysis was consistent with previous clinical studies, showing no new safety signals. The trial remains blinded and will continue through Week 52 to evaluate long-term durability, with a full readout expected in the first half of 2027.
Dr. Jorge Santos da Silva, CEO of MoonLake, noted:
"The positive topline results from IZAR-1 represent an important milestone for MoonLake and, more importantly, for patients living with psoriatic arthritis. We are particularly encouraged by the strong efficacy observed across multiple clinically relevant endpoints simultaneously, which has been our focus."
Prof. Kristian Reich, Chief Scientific Officer of MoonLake, added:
"Psoriatic arthritis is a complex and heterogeneous disease, requiring therapies that can effectively address multiple manifestations simultaneously. The breadth of response observed in IZAR-1 across clinical, functional and patient-reported outcomes is highly encouraging."
These results set the path for sonelokimab to compete in another multi-billion dollar indication following its lead program in hidradenitis suppurativa (HS), for which a Biologics License Application (BLA) is planned for late September 2026.