MoonLake Immunotherapeutics' (MLTX) Reported Phase 3 Trial Data for Sole Drug Candidate, 90% Stock Crash Triggers Investor Suit -- Hagens Berman

MLTX Investors with Losses Encouraged to Contact Hagens Berman

SAN FRANCISCO, Nov. 25, 2025 /PRNewswire/ -- MoonLake Immunotherapeutics (NASDAQ: MLTX), a clinical-stage biotechnology company, has been hit with a securities fraud class action lawsuit after its share price plummeted nearly 90% in a single day. The sharp decline was triggered by the release of disappointing Phase 3 trial results for its lead and only drug candidate, sonelokimab (SLK).

Global plaintiffs' rights firm Hagens Berman is actively investigating the alleged claims. The firm urges investors in MoonLake who suffered significant losses to submit your losses now.

Class Period: Mar. 10, 2024 – Sep. 29, 2025
Lead Plaintiff Deadline: Dec. 15, 2025
Visit: www.hbsslaw.com/investor-fraud/mltx
Contact the Firm Now: [email protected]
                                       844-916-0895

MoonLake Immunotherapeutics (MLTX) Securities Class Action:

The complaint, filed in the U.S. District Court for the Southern District of New York, alleges that MoonLake and certain executives made materially false and misleading statements to investors about SLK's clinical prospects, specifically exaggerating its benefits over competitors.

The controversy centers on MoonLake's investigational therapeutic, SLK, which is designed to treat moderate to severe hidradenitis suppurativa (HS), a chronic inflammatory skin disease.

For months leading up to the data release, the company allegedly touted the drug's distinctive "Nanobody" structure as a major competitive advantage, suggesting it would translate into superior efficacy compared to conventional monoclonal antibody treatments, like a competing FDA-approved drug, BIMZELX. The claims focused on the Nanobody's smaller size and supposed ability to offer "higher clinical responses for patients."

However, the reality check allegedly came on Sep. 28, 2025. MoonLake reported its Week 16 results from the highly anticipated VELA Phase 3 trials. VELA-2, one of the two trials, failed to meet its primary endpoint. More critically, analysts and investors quickly noted that the efficacy results, even from the trial that did succeed statistically, were substantially lower than those previously achieved by the competitor drug, BIMZELX.

On the news, the price of MoonLake stock cratered, falling by $55.75 per share, or nearly 90%, from $61.99 to $6.24 in the following trading day. Analysts described the outcome as a "disastrous result" and a "near worst-case scenario."

The securities suit alleges that MoonLake failed to disclose crucial information, namely that:

• SLK and its competitor, BIMZELX, share the same molecular targets (the inflammatory cytokines IL-17A and IL-17F).
• SLK's distinct Nanobody structure would not, in fact, confer a superior clinical benefit over the competitor's traditional monoclonal antibody.
• Plaintiffs argue that the company's continuous touting of SLK's molecular advantages as a pathway to "gold standard" efficacy was misleading, artificially inflating the stock price during the class period (from March 10, 2024, to September 29, 2025).

Hagens Berman's Investigation

National shareholders rights firm Hagens Berman has launched its own investigation into the claims that MoonLake misled investors about the trial design and efficacy data. Reed Kathrein, the Hagens Berman partner leading the investigation, stated, "We're focused on investors' losses and whether MoonLake may have intentionally misled investors about the SLK's purported advantages over BIMZELX while claiming that SLK could become a 'gold standard.'"

If you invested in MoonLake and have substantial losses, or have knowledge that may assist the firm's investigation, submit your losses now »

If you'd like more information and answers to frequently asked questions about the MoonLake case and our investigation, read more »

Whistleblowers: Persons with non-public information regarding MoonLake should consider their options to help in the investigation or take advantage of the SEC Whistleblower program. Under the new program, whistleblowers who provide original information may receive rewards totaling up to 30 percent of any successful recovery made by the SEC. For more information, call Reed Kathrein at 844-916-0895 or email [email protected].

About Hagens Berman
Hagens Berman is a global plaintiffs' rights complex litigation firm focusing on corporate accountability. The firm is home to a robust practice and represents investors as well as whistleblowers, workers, consumers and others in cases achieving real results for those harmed by corporate negligence and other wrongdoings. Hagens Berman's team has secured more than $2.9 billion in this area of law. More about the firm and its successes can be found at hbsslaw.com. Follow the firm for updates and news at @ClassActionLaw.

SOURCE Hagens Berman Sobol Shapiro LLP