Biogen Inc. (Nasdaq: BIIB) reported 52-week Phase II data from the ongoing AMETHYST Phase II/III study showing that 27.2% of participants treated with litifilimab achieved clear or almost clear skin at Week 52, up from 19.0% at Week 24, in cutaneous lupus erythematosus (CLE).
Biogen states that there are no approved targeted therapies for cutaneous lupus erythematosus (CLE) and that the last drug was approved in the 1950s, and it describes the 52-week dataset as the longest reported for litifilimab in this indication, with the blinded Phase III results expected in the first half of 2027.
By Week 52, 27.2% of participants who received litifilimab from the start achieved clear or almost clear skin on the Cutaneous Lupus Activity Investigators' Global Assessment Revised erythema score, up from 19.0% at Week 24. On the Cutaneous Lupus Erythematosus Disease Area and Severity Index Activity-70 (CLASI-70) measure, 28.8% reached a 70% or greater reduction in disease activity at Week 52, versus 21.7% at Week 24. Among participants who crossed over from placebo at Week 24, 33.7% achieved clear or almost clear skin by Week 52, with onset reported as early as four weeks.
The Phase II portion enrolled 93 adults with active subacute or chronic cutaneous lupus erythematosus (CLE) who were refractory or intolerant to antimalarial therapy, and Biogen noted that secondary endpoints at Week 24 were not adjusted for multiplicity.
Biogen said litifilimab was generally well tolerated over 52 weeks, with no new safety signals identified. Serious adverse events occurred in 3.4% (3/88) of participants during the extended treatment period, while nasopharyngitis, influenza, and arthralgia were the most common adverse events, each occurring in at least 5% of participants.