Biogen Reports Positive Phase 2 Results for Litifilimab for Treatment of Cutaneous Lupus Erythematosus

Biogen announced positive results from the Phase 2 part of the AMETHYST Phase 2/3 study (part A) of investigational therapy, litifilimab (also known as BIIB059), at the 2026 American Academy of Dermatology Annual Meeting. The mid-phase results reinforce the drug’s potential as a first-in-class treatment of cutaneous lupus erythematosus (CLE, a chronic autoimmune skin disease). CLE can cause permanent scarring and disproportionately affects women and diverse populations. Current treatment options remain limited, and there’s a significant unmet need for innovative therapies.

In this two-part, double-blind, placebo-controlled study, litifilimab met its primary endpoint, showing a statistically significant reduction (14.7%) in skin disease activity at week 16 compared to placebo (2.9%). More trial participants living with CLE and treated with the drug achieved clear or almost clear skin, with noticeable benefits as early as week 4 sustained through week 24. These findings are built on previous, positive Phase 2 LILAC results. Litifilimab is the only investigational program with consistent, positive efficacy results in multiple CLE studies.

The study also demonstrated that litifilimab was generally well tolerated, with a safety profile consistent with prior studies. Phase 3 data on litifilimab in systemic lupus erythematosus is expected later this year. The Lupus Foundation of America (LFA) has supported litifilimab trials through LFA POINT, a web-based training site designed to coordinate the training and testing for clinical instruments in the assessment of people with lupus. Continue to follow the LFA for updates on lupus drug developments. Learn more about lupus and the skin.

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