MoonLake ($MLTX) Failed Drug Trial, Misleading Efficacy Claims, and 89% Stock Collapse Case

S.D. New York

Court

1:25-cv-08500

Case number

03/10/2024

Class period Start

09/29/2025

Class period End

12/15/2025

Lead Plaintiff motion deadline

$MLTX investors filed a claim against MoonLake Immunotherapeutics for overstating the superiority of its Nanobody® drug sonelokimab (SLK), misleading investors about its potential to outperform competitors, and failing to disclose that Phase 3 trials were unlikely to show clinical benefits over existing treatments.
After announcing weak results from its pivotal Phase 3 trial, $MLTX collapsed 89.9% on September 29, 2025.
$MLTX investors can join this case to be notified about potential recovery.
Case Details:

Between March 2024 and September 2025, MoonLake Immunotherapeutics promoted its Nanobody® drug, sonelokimab (SLK), as a breakthrough treatment for hidradenitis suppurativa. Executives claimed SLK offered superior clinical benefits over approved drugs like BIMZELX, citing better tissue penetration, stronger binding, and higher response rates. The company framed upcoming Phase 3 trial results as a major catalyst and reassured investors about its potential.

The complaint alleges MoonLake lacked data to support these claims and knew that SLK and BIMZELX targeted the same inflammatory pathways. Internally, MoonLake had no credible evidence that SLK would outperform competitors or placebo, yet continued to project strong results and downplayed risks tied to trial design and efficacy assumptions.

On September 28, 2025, MoonLake announced disappointing Phase 3 trial results. One trial barely met its endpoint with only a modest effect; the second failed outright. Analysts called the outcome a worst-case scenario. The next day, $MLTX fell 89.9%, wiping out most of the company’s market value.

Based on these events, $MLTX investors filed a claim against MoonLake, alleging the company:
It overstated the clinical benefits of its Nanobody® drug sonelokimab.
It misrepresented the competitive landscape and failed to disclose risks tied to trial design.
It issued false or misleading statements lacking a reasonable basis.
Investors argue MoonLake misled the market by exaggerating SLK’s capabilities, causing massive losses when the Phase 3 results revealed it could not outperform approved treatments.

Case Type

US Securities Class Action

Case Status

Lead Plaintiff Appointment

Alleged Offence

Misleading Statements,

Financial Misrepresentation

Suspected Party

Management

Security Type

Stocks

Trade Direction

Long

Shock Event Date

09/29/2025

Filing date

10/15/2025

Lead Plaintiff Deadline

12/15/2025

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