FDA Meeting Reduces Regulatory Overhang for MoonLake's Sonelokimab BLA

What happened

MoonLake Immunotherapeutics recently held a Type B meeting with the FDA for sonelokimab in hidradenitis suppurativa (HS), following mixed Phase 3 results in 2025 where one trial missed its primary endpoint due to a high placebo rate. The FDA agreed that existing Phase 2 MIRA and Phase 3 VELA data are sufficient for a Biologics License Application (BLA) submission without requiring additional clinical trials. This allows MoonLake to target a BLA submission in the second half of 2026, removing a key regulatory uncertainty that had pressured the stock. The development de-risks the near-term regulatory path and accelerates timelines, potentially restoring investor confidence. However, this positive step must be viewed critically against ongoing clinical, financial, and competitive challenges.

Implication

First, this regulatory clarity eliminates the need for additional HS trials, saving time and resources while addressing a major uncertainty from the mixed Phase 3 data. Second, it suggests potential FDA acceptance of pooled or treatment-policy analyses, which could support a smoother BLA review process. However, investors should remain cautious as the BLA approval is not guaranteed, and label restrictions or safety concerns could still emerge. Third, liquidity remains a critical issue with low cash reserves as of mid-2025, requiring close watch on financing events to avoid dilution. Fourth, competitive pressures in HS from approved IL-17 inhibitors like bimekizumab and secukinumab persist, limiting upside without superior efficacy. Finally, key swing factors such as 52-week HS outcomes in 2026 and PsA Phase 3 readouts will determine long-term value, necessitating a balanced risk assessment.

Thesis delta

The previous thesis was HOLD/NEUTRAL due to high regulatory risk after mixed HS Phase 3 results, with a focus on FDA feedback as a key swing factor. The FDA's agreement to accept existing data for BLA submission significantly reduces this regulatory overhang, shifting the risk/reward profile towards a more favorable near-term outlook. However, the stance should remain cautious until liquidity is secured and upcoming clinical readouts confirm efficacy and safety, as competition and execution risks persist.