Galapagos GALARISSO DM study meets primary endpoint, GALACELA SLE study misses

Galapagos (GLPG) announced the topline results from two Phase 3-enabling studies evaluating the efficacy and safety of GLPG3667, a selective TYK2 inhibitor, in patients with dermatomyositis and active systemic lupus erythematosus. The GALARISSO DM study met its primary endpoint, showing that GLPG3667, administered once daily at 150 mg in addition to standard-of-care therapy, achieved a statistically significant clinical benefit in the Total Improvement Score at Week 24, compared to placebo. The pre-specified threshold of statistical significance was set at 10%. GLPG3667 also showed meaningful clinical improvements compared to placebo on several secondary endpoints of disease activity, including TIS20, TIS40, TIS60 and m-CDASI-A2. GLPG3667 demonstrated a favorable safety and tolerability profile throughout the 24-week treatment period. In the GALACELA SLE study, GLPG3667, administered once daily at 75 mg and 150 mg in addition to standard-of-care therapy, the primary endpoint analysis of dose-response on SLE responder index -4 at Week 32 did not meet statistical significance. However, GLPG3667 showed numerical improvements over placebo on several secondary endpoints, particularly on skin-related outcomes. The safety profile was consistent with previous studies with GLPG3667. The GALACELA study is currently ongoing, and the final Week 48 data, expected in the second quarter of 2026, will be essential to assess the totality of the evidence and determine potential next steps for the SLE program. The company aims to present data at an upcoming medical conference. Gilead (GILD) agreed to temporarily waive certain rights under the 10-year global option, license and collaboration agreement between Galapagos and Gilead, enabling Galapagos to pursue external partnership opportunities for GLPG3667.