Background/Purpose: In the randomized, placebo-controlled Phase 2 LILAC study of litifilimab (NCT02847598), Part B (participants with active CLE with/without SLE) met its primary endpoint of percentage change from baseline in CLASI-A score at Week 16, with a greater proportion of participants achieving a CLASI-50 response (decrease of ≥50% from baseline in CLASI-A score) with litifilimab than placebo at Week 16.¹ The CLASI-A measures disease activity in CLE based on clinical components and anatomical locations. Activity is measured by erythema, scale/hypertrophy, non-scarring alopecia, recent hair loss (preceding 30 days), and mucous membrane lesions.² We conducted post-hoc analyses to further understand how the individual CLASI-A subcomponents contributed to the change from baseline to Week 16. The PGA–Skin, a physician-reported measure of skin disease activity, was also analyzed.

Methods: Study design and baseline participant characteristics for Part B have been reported.¹ For the CLASI-A subcomponents analysis, erythema and scale/hypertrophy are presented in 4 categories based on the baseline score quartiles. Alopecia, recent hair loss, and mucous membrane lesions scores are presented as recorded. Overall skin condition, measured by PGA–Skin, was rated as mild, moderate, or severe. For participants who were considered as treatment failures, the worse of baseline or last visit before treatment failure carried forward was used to impute values for all the post-treatment failure visits. Data after the participants’ treatment discontinuation were censored.

Results: The erythema, scale/hypertrophy, and alopecia subcomponents showed greater improvement in the litifilimab groups relative to placebo at all post-baseline visits (Figure 1). At baseline, the proportions of participants with significant activity were: 72.7–84.0% for erythema (score ≥5.5), 73.1–85.4% for scale/hypertrophy (score ≥2), 60.4–76.9% for alopecia (score ≥1), 45.5–61.5% for recent hair loss, and 12.1–29.2% for mucous membrane lesions (Table 1). At Week 16, greater improvements with litifilimab versus placebo were observed consistently across the erythema, scale/hypertrophy, and alopecia subcomponents (Table 1). A minority of participants  had mucous membrane lesions at baseline, so no conclusion could be drawn for this subcomponent. In the PGA–Skin analysis at Week 16, 28.0% and 45.8–60.0% of participants in the placebo and litifilimab groups, respectively, were rated with mild disease (Figure 2).

Conclusion: Results from these post-hoc analyses indicated that the CLASI-A subcomponents of erythema, scale/hypertrophy, alopecia, and recent hair loss contributed to the observed overall CLASI-A score improvements at Week 16. In most subcomponents, greater score improvements were observed in the litifilimab-treated participants compared with placebo. Together with the higher proportion of participants with mild overall skin condition in the litifilimab groups at Week 16, these results support the continued development of litifilimab in CLE.

¹Werth VP, et al. N Engl J Med 2022;387:321–331

²Albrecht J, et al. J Invest Dermatol 2005;125:889–894

We thank the LILAC investigators and participants for their valuable contributions.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/effect-of-litifilimab-on-cutaneous-lupus-erythematosus-disease-area-and-severity-index-activity-clasi-a-subcomponents-and-physician-global-assessment-skin-pga-skin-in-patie/