Written By: Pharmacally Medical News Desk
Galapagos reported topline results from two Phase 3-enabling studies of its selective TYK2 inhibitor, GLPG3667, showing a mixed outcome in autoimmune disease programs. In the GALARISSO (NCT05695950) dermatomyositis trial, once-daily oral GLPG3667 at 150 mg achieved the primary endpoint with a statistically significant improvement in Total Improvement Score at week 24 versus placebo and showed meaningful gains on several secondary disease activity measures. Safety and tolerability were consistent with prior studies
In contrast, the GALACELA (NCT05856448) systemic lupus erythematosus (SLE) study did not meet its primary endpoint of SLE Responder Index-4 response at week 32. The drug delivered numerical improvements over placebo on several secondary outcomes, including skin-related measures, but failed to reach statistical significance in the main analysis. Final week 48 data from the ongoing SLE study is expected in the second quarter of 2026 and will be critical for further assessment.
Commenting on the mixed outcome from both trials, Galapagos CEO Henry Gosebruch said the dermatomyositis data reinforce the anti-inflammatory potential of GLPG3667 and align with earlier studies, while the safety profile to date looks encouraging. He added that the company is weighing next steps across the program, including renewed partnering talks for dermatomyositis and a broader look at other serious autoimmune diseases, even as it assesses the mixed picture from the lupus study.
Galapagos plans to review strategic options to advance GLPG3667 in dermatomyositis and potentially other indications, including seeking partners to support further development.
References
Galapagos Announces Topline Results from Two Phase 3-Enabling Studies with Selective TYK2 Inhibitor GLPG3667 in Dermatomyositis and Systemic Lupus Erythematosus, 18 December 2025, https://www.glpg.com/press-releases/galapagos-announces-topline-results-from-two-phase-3-enabling-studies-with-selective-tyk2-inhibitor-glpg3667-in-dermatomyositis-and-systemic-lupus-erythematosus/
A Study Evaluating the Effects of GLPG3667 Administered as Oral Treatment in Adult Participants with Active Systemic Lupus Erythematosus (GALACELA), ClinicalTrials.gov ID NCT05856448, https://www.clinicaltrials.gov/study/NCT05856448
A Study Evaluating the Effects of GLPG3667 Given as Oral Treatment for up to 24 Weeks in Adults with Dermatomyositis (GALARISSO), ClinicalTrials.gov ID NCT05695950, https://clinicaltrials.gov/study/NCT05695950