MoonLake Immunotherapeutics Faces Securities Class Action Suit Over Phase 3 Trial Results

Strategic Insights -

A securities class action lawsuit, Bridgewood v. MoonLake Immunotherapeutics, et al., has been filed against MoonLake (NASDAQ: MLTX) after the company announced disappointing Phase 3 trial results for its treatment candidate sonelokimab (SLK). Investors saw their shares plummet $55.75, or about 90%, on September 29, 2025. Hagens Berman, a national shareholders rights firm, is investigating claims that MoonLake misled investors about SLK's trial design and efficacy data.

Key Takeaways:

  • The lawsuit alleges that MoonLake made false and misleading statements about SLK's structural advantages and efficacy in treating hidradenitis suppurativa (HS).
  • The company claimed that SLK's Nanobody structure would confer superior clinical benefits over traditional monoclonal antibodies, but the complaint alleges that this was not supported by evidence.
  • Investors learned the truth on September 28, 2025, when MoonLake revealed that only one of its two SLK Phase 3 trials achieved statistical significance, and even those results demonstrated lower efficacy than a competitor's FDA-approved product (BIMZELX).
  • The price of MoonLake shares cratered $55.75 (-90%) on September 29, 2025, following the announcement of the disappointing trial results.
  • Hagens Berman is investigating claims that MoonLake misled investors and is encouraging those who suffered significant losses to contact the firm.
  • The firm is also urging persons with knowledge that may assist in the investigation to come forward.

Statistics:

  • The price of MoonLake shares plummeted $55.75, or about 90%, on September 29, 2025.
  • The lawsuit covers the period from March 10, 2024, to September 29, 2025.
  • Ninety percent of investors lost money in MoonLake stock after the disappointing phase 3 trial results.
  • The SEC Whistleblower program offers rewards of up to 30 percent of any successful recovery made by the SEC.

Sources:

  • "Securities Class Action Lawsuit Filed Against MoonLake Immunotherapeutics."
  • Hagens Berman website.
  • SEC Whistleblower program information.