Biogen Announces Positive Phase 2 Results for Litifilimab in Cutaneous Lupus Erythematosus from AMETHYST Study

on

Biogen reported positive Phase 2 results from the AMETHYST study for litifilimab, an anti-BDCA2 monoclonal antibody, in treating cutaneous lupus erythematosus (CLE), presented at the 2026 American Academy of Dermatology Annual Meeting.12

The study met its primary endpoint at Week 16:
14.7% of litifilimab participants achieved clear or almost clear skin (CLA-IGA-R score 0-1) vs. 2.9% on placebo (11.8% difference, p<0.05).12

Secondary improvements included CLASI-50 response:
19.3% at Week 4 and 40.8% at Week 24 for litifilimab vs. 5.5% and 21% for placebo; 16.3% achieved minimal disease activity (CLASI 0-3) vs. 0% on placebo.12

Litifilimab has FDA Breakthrough Therapy Designation based on AMETHYST and prior LILAC Phase 2 study; no targeted therapies are approved for CLE.12

Safety:
Adverse events in 74.6% litifilimab vs. 64.7% placebo (mostly mild/moderate); serious AEs 6.8% vs. 2.9%. Phase 3 ongoing.12

Sources:

1. https://www.investing.com/news/company-news/biogen-reports-positive-phase-2-results-for-lupus-skin-drug-93CH-4586535

2. https://www.globenewswire.com/news-release/2026/03/28/3264201/0/en/Biogen-Announces-Second-Positive-Phase-2-Litifilimab-Trial-in-Cutaneous-Lupus-Erythematosus-at-2026-American-Academy-of-Dermatology-Annual-Meeting-Showing-a-Significant-Reduction-i.html