Galapagos Announces Topline Results from Two Phase 3-Enabling Studies with Selective TYK2 Inhibitor GLPG3667 in Dermatomyositis and Systemic Lupus Erythematosus

Core Insights - Galapagos NV announced positive topline results from two Phase 3-enabling studies for GLPG3667, a selective TYK2 inhibitor, showing significant clinical benefits in dermatomyositis but not in systemic lupus erythematosus [1][3][4] Dermatomyositis Study (GALARISSO) - The GALARISSO study met its primary endpoint, demonstrating a statistically significant clinical benefit with a Total Improvement Score (TIS) of 14.26 at Week 24 (p=0.0848) compared to placebo [2][4] - GLPG3667 also showed meaningful improvements on secondary endpoints, including TIS20, TIS40, TIS60, and m-CDASI-A, with a favorable safety profile throughout the 24-week treatment period [2][4] Systemic Lupus Erythematosus Study (GALACELA) - In the GALACELA study, GLPG3667 did not achieve statistical significance for the primary endpoint (SLE responder index SRI-4) at Week 32, despite showing numerical improvements on several secondary endpoints, particularly skin-related outcomes [3][4] - The ongoing GALACELA study is expected to provide final Week 48 data in the second quarter of 2026, which will be crucial for assessing the overall evidence and determining next steps for the SLE program [3][4] Strategic Development - The company plans to evaluate all strategic alternatives, including resuming its partnering process to accelerate GLPG3667's development in dermatomyositis and exploring opportunities in other severe autoimmune diseases [1][4][5] - Gilead has temporarily waived certain rights under their collaboration agreement, allowing Galapagos to pursue external partnership opportunities for GLPG3667 [5] Background on Diseases - Dermatomyositis (DM) is a rare autoimmune disorder characterized by severe muscle weakness and skin manifestations, with a high unmet need for effective treatments [9] - Systemic lupus erythematosus (SLE) is a chronic autoimmune disease affecting multiple organ systems, with current treatments often associated with partial efficacy and significant toxicities [10]