A class action lawsuit has been filed against Moonlake Immunotherapeutics on behalf of investors who suffered losses between March 10, 2024, and September 29, 2025. The complaint alleges that the company issued false statements or concealed key information regarding its sole drug candidate, SLK. Specifically, it is claimed that Moonlake did not disclose that SLK and BIMZELX share the same molecular targets, that SLK's unique Nanobody structure would not provide a superior clinical benefit over the traditional monoclonal antibody structure of BIMZELX, and that the expected increased tissue penetration of SLK would not result in improved clinical efficacy. The lawsuit asserts that these factors undermined the company's positive statements about SLK's purported advantages. The legal action seeks to recover losses for affected shareholders.