MoonLake Immunotherapeutics (MLTX) Stock Plunges ~90%, Sparks Class‑Action Lawsuit

MoonLake Immunotherapeutics (NASDAQ: MLTX) saw its stock collapse nearly 90% in a single day after the release of disappointing Phase 3 data for its only drug candidate, sonelokimab (SLK). On November 28, 2025, law firm Hagens Berman Sobol Shapiro LLP filed a securities‑fraud class action suit, claiming the company misled investors about SLK’s prospects. MoonLake had promoted SLK — a “Nanobody” targeting inflammatory cytokines IL‑17A and IL‑17F — as having a potential edge over existing monoclonal antibody therapies, such as BIMZELX, arguing its smaller size and novel structure would deliver stronger clinical benefit. But when results from the pivotal VELA Phase 3 trials arrived, one of the two trials (VELA‑2) failed to hit its primary endpoint, and the efficacy from the other was still well below that of BIMZELX — dashing hopes for SLK. Investors reacted swiftly: MLTX shares dropped from US$61.99 to US$6.24 — a fall of US$55.75 per share, or almost 90% — between September 26 and 29, 2025. The class‑action complaint alleges the company made materially false or misleading statements, inflating the stock value by overstating SLK’s competitive edge. Hagens Berman’s investigation covers the period from March 10, 2024 to September 29, 2025. Investors who suffered losses during this time are being urged to submit claims before the lead‑plaintiff deadline on December 15, 2025. #MoonLake #MLTX #Sonelokimab #BiotechCrash #SlimScan #GrowthStocks #CANSLIM