A recent post hoc analysis of the Phase 2 LILAC study, published in the Journal of the European Academy of Dermatology and Venereology, has demonstrated that litifilimab improves multiple measures of skin disease activity in patients with cutaneous lupus erythematosus (CLE). Compared with placebo, treatment with litifilimab was associated with higher response rates across several Cutaneous Lupus Erythematosus Disease Area and Severity Index-Activity (CLASI-A) thresholds, greater proportions of patients achieving clear or almost clear skin, and improvements in physician-assessed skin condition.
CLE is an autoimmune disease characterized by inflammatory skin lesions that can cause persistent erythema, scaling, scarring, dyspigmentation, and considerable impairment in quality of life. Despite its substantial disease burden, targeted treatment options remain limited, highlighting the need for therapies that address the underlying immunological mechanisms.
Litifilimab is a humanized monoclonal antibody that targets blood dendritic cell antigen 2 (BDCA2), a receptor expressed on plasmacytoid dendritic cells. Binding to BDCA2 triggers receptor internalization and suppresses the production of type I and III interferons, along with other inflammatory cytokines and chemokines implicated in CLE pathogenesis. Part B of the randomised, double-blind, placebo-controlled Phase 2 LILAC study previously demonstrated a dose-response relationship for the percentage change in CLASI-A score from baseline to week 16. The subsequent post hoc analyses examined additional skin-specific outcomes to provide a broader assessment of treatment response.
The study included adults with histologically confirmed CLE and a baseline CLASI-A score of at least 8, with or without systemic manifestations. Participants received subcutaneous litifilimab at doses of 50 mg, 150 mg, or 450 mg, or placebo, every four weeks through week 16. Efficacy assessments included CLASI-20, CLASI-50, CLASI-70, and CLASI-90 responses, representing improvements of at least 20%, 50%, 70%, and 90%, respectively, from baseline. Additional outcomes included a reduction of at least seven points in CLASI-A score, achievement of clear (CLASI-A 0–1) or almost clear (CLASI-A 0–3) skin status, and changes assessed using the Physician’s Global Assessment (PGA) of CLE and Physician’s Global Impression (PGI) of change in CLE.
At week 16, a greater proportion of participants receiving litifilimab achieved CLASI-20/50/70/90 responses compared with those receiving placebo, with response rates ranging from 3.8% to 72.1% across the evaluated thresholds and treatment groups, compared with 0% to 43.8% in the placebo group. Statistically significant differences in CLASI-20 and CLASI-50 responses were observed as early as Week 4, suggesting an early improvement in skin disease activity.
A clinically meaningful reduction of at least seven points in CLASI-A score was also observed more frequently among litifilimab-treated participants between weeks 4 and 16, with response rates ranging from 13.8% to 43.9%, compared with 10.5% to 21.1% in the placebo group. By Week 16, greater proportions of participants receiving litifilimab had achieved clear or almost clear skin status. Improvements in CLASI-A scores were also numerically greater across the evaluated subgroups.
Physician-reported assessments provided further support for the observed improvements. According to PGA evaluations, more litifilimab-treated participants shifted from moderate or severe disease to almost clear skin status. Similarly, a greater proportion were rated as much improved on the PGI of change in CLE, indicating that reductions in disease activity were accompanied by clinically observable improvements in skin condition.
These findings provide additional evidence of the potential efficacy of litifilimab in reducing cutaneous disease activity across multiple response thresholds. They also reinforce the value of CLASI-A as an outcome measure for assessing treatment response in CLE. However, because these findings were derived from post hoc analyses, they should be interpreted as supportive evidence rather than independent confirmation of efficacy. The results highlight the therapeutic potential of targeting BDCA2-mediated inflammatory signaling in CLE, a condition with substantial unmet treatment needs. Further investigation is ongoing through a Phase 2/3 clinical study and its associated long-term extension to evaluate the efficacy and longer-term outcomes of litifilimab in this patient population.
Reference
Werth VP, Merola JF, Furie R, Kalunian K, van Vollenhoven RF, Romero-Diaz J, Li Q, Yang W, Barbey C. Litifilimab efficacy on skin outcomes in cutaneous lupus erythematosus in the Phase 2 LILAC study. J Eur Acad Dermatol Venereol. 2026 Sep;40(9):1481-1489.
