Understanding Unmet Need and Recent Advances in CLE at AAD 2026

For clinicians managing cutaneous lupus erythematosus (CLE), the challenge has never been recognizing the disease — it has been treating it. Rash, pruritus, and photosensitivity are familiar presentations, but so is the frustrating clinical reality that follows: progressive skin damage, irreversible scarring, alopecia, and dyspigmentation that standard-of-care options too often fail to prevent.¹ Antimalarials, corticosteroids, and off-label immunosuppressants remain the primary tools — agents associated with incomplete responses, cumulative toxicity, and significant residual disease burden in a population that is disproportionately young, female, and diverse.

Litifilimab (BIIB059) is an investigational humanized IgG1 monoclonal antibody targeting blood dendritic cell antigen 2 (BDCA2), a receptor predominantly expressed on plasmacytoid dendritic cells (pDCs). By binding BDCA2, litifilimab inhibits pDC-mediated production of type I interferon and other pro-inflammatory mediators implicated in lupus pathogenesis. At the 2026 American Academy of Dermatology (AAD) Annual Meeting, Biogen presented Phase 2 data from Part A of the AMETHYST Phase 2/3 study — the second positive Phase 2 trial of litifilimab in CLE, following earlier results from the LILAC study. In AMETHYST Part A, litifilimab met its primary endpoint, demonstrating a statistically significant 11.8% higher rate of clear or almost clear skin versus placebo at Week 16 (14.7% vs 2.9%; 95% CI: 1.39, 22.27; P < .05). Clinically meaningful separation from placebo emerged as early as Week 4, and at Week 24, 40.8% of litifilimab-treated participants achieved a CLASI-50 response compared with 21% receiving placebo. Notably, the trial enrolled a globally representative population — 74% women and 33% non-white participants — reflecting the demographic heterogeneity clinicians encounter in practice. The safety profile was consistent with prior studies, and litifilimab has received FDA Breakthrough Therapy Designation for CLE.²

In this video series, two experts with deep clinical and research expertise in CLE — Joseph Merola, MD, MMSc, and Victoria Werth, MD — discuss the current treatment landscape, the unmet needs that persist for patients who fail or cannot tolerate existing options, and the clinical implications of the litifilimab data presented at AAD 2026.

References

1. Drenkard C, Barbour KE, Greenlund KJ, Lim SS. The burden of living with cutaneous lupus erythematosus. Front Med (Lausanne). 2022;9:897987. doi:10.3389/fmed.2022.897987
2. Biogen Inc. Biogen announces second positive Phase 2 litifilimab trial in cutaneous lupus erythematosus at 2026 American Academy of Dermatology Annual Meeting, showing a significant reduction in skin disease activity. Published March 28, 2026. https://investors.biogen.com/news-releases/news-release-details/biogen-announces-second-positive-phase-2-litifilimab-trial