MoonLake's psoriatic arthritis drug meets key goals in late-stage trial (updated)

MoonLake Immunotherapeutics

10/08/2026 13:58

Adds shares in paragraph 2, analyst comments in bullets 6 and 7
By Padmanabhan Ananthan
Aug 10 (Reuters) - MoonLake Immunotherapeutics MLTX.O said on Monday its experimental drug met all main goals in a late-stage trial involving adults with an inflammatory disease who had not previously received biologic medicines.
However, shares of the Switzerland-based company fell more than 8% in premarket trading amid investor concerns about how the drug stacks up against UCB's UCB.BR Bimzelx, an FDA approved biologic for the condition.
Psoriatic arthritis is a type of arthritis that can affect people who have psoriasis, a skin condition that causes itchy, scaly patches on the skin.
In the study, 42.1% of patients with psoriatic arthritis receiving a 60 mg dose of sonelokimab after an initial induction dose achieved a significant improvement in symptoms by week 16, MoonLake said.
66.5% of patients achieved at least a 20% improvement in psoriatic arthritis symptoms, while 41.2% reached minimal disease activity. Among patients with skin-related symptoms, 61% saw a major improvement in psoriasis, the company added. 
Patients also reported better physical function and quality of life, with no new safety concerns identified, MoonLake said.
MoonLake did not disclose how sonelokimab performed against placebo, saying treatment-group comparisons would remain blinded until the late-stage program was completed.
Clear Street analyst Kaveri Pohlman told Reuters MoonLake's data for sonelokimab was strong and largely matched results seen with UCB's Bimzelx.
The stock's decline likely reflected investor expectations for a clearer advantage over Bimzelx, Pohlman said, while the absence of a placebo arm also made it difficult to assess the magnitude of benefit relative to placebo. 
The late-stage study will continue through 52 weeks, with full results expected in the first half of 2027.
Sonelokimab, MoonLake's lead drug candidate, is also being evaluated for the treatment of hidradenitis suppurativa, a chronic skin disease characterized by painful, boil-like lumps that form beneath the skin.

(Reporting by Padmanabhan Ananthan in Bengaluru; Editing by Jonathan Ananda)
((Padmanabhan.Ananthan@thomsonreuters.com;))