MoonLake reports positive Phase 3 IZAR-1 results for sonelokimab in psoriatic arthritis

Aug 10, 2026

MoonLake Immunotherapeutics announced positive Week 16 results from its Phase 3 IZAR-1 trial of sonelokimab for psoriatic arthritis, meeting all primary and secondary endpoints. However, the company's stock fell over 8% in premarket trading. Investors expressed concern over how the drug's efficacy stacks up against UCB's approved biologic Bimzelx, alongside anxiety surrounding recent heavy insider selling by MoonLake executives.

IZAR-1 Phase 3 trial results

▪In the IZAR-1 trial, a 60 mg dose of sonelokimab with induction resulted in 42.1% of patients achieving an ACR50 response at Week 16.
▪In the IZAR-1 trial, 66.5% of patients achieved an ACR20 response, 41.2% reached minimal disease activity, and 61% of patients with skin involvement achieved a PASI90 response at Week 16.
▪The Phase 3 IZAR-1 trial remains blinded for comparative analyses versus placebo and will continue through Week 52, with full results expected in the first half of 2027.
▪MoonLake Immunotherapeutics announced that its Phase 3 IZAR-1 trial of sonelokimab in biologic-naïve adults with active psoriatic arthritis met all primary and secondary clinical endpoints at Week 16.

Sonelokimab competitive positioning

▪Clear Street analyst Kaveri Pohlman stated that MoonLake Immunotherapeutics' trial data for sonelokimab was strong and largely matched results seen with UCB's FDA-approved biologic Bimzelx.
▪Clear Street analyst Kaveri Pohlman noted that the absence of a placebo arm in the initial IZAR-1 disclosure made it difficult to assess the magnitude of sonelokimab's benefit relative to placebo.

Stock price decline

▪MoonLake Immunotherapeutics' shares fell more than 8% in premarket trading on August 10, 2026, amid investor concerns regarding how sonelokimab compares to UCB's Bimzelx.
▪MoonLake Immunotherapeutics' stock price gapped down on August 10, 2026, opening at $17.24 after previously closing at $18.26.

Cash runway through mid-2028

▪MoonLake Immunotherapeutics expects its existing capital to fund operating expenses and capital requirements into mid-2028, with up to $400 million available under its Hercules Capital debt facility.
▪MoonLake Immunotherapeutics ended the second quarter of 2026 with $537 million in cash, cash equivalents, and short-term marketable debt securities.

Insider selling activity

▪MoonLake Immunotherapeutics insider Kristian Reich sold 50,000 shares of company stock on June 17, 2026, at an average price of $19.43 under a pre-arranged Rule 10b5-1 trading plan.
▪MoonLake Immunotherapeutics CEO Da Silva Jorge Santos sold 68,289 shares of company stock on July 10, 2026, at an average price of $20.02 under a pre-arranged Rule 10b5-1 trading plan.
▪MoonLake Immunotherapeutics insiders made 20 reported stock sales and zero purchases over the six months preceding August 10, 2026, including transactions by the CEO, CSO, and CFO.