Johnson & Johnson said TREMFYA (guselkumab) met the primary and major secondary endpoints in the Phase 4 STAR study of biologic-naïve adults with active psoriatic arthritis and axial involvement. At Week 24, TREMFYA improved BASDAI, a patient-reported disease activity score covering spinal pain, stiffness, fatigue, joint symptoms and tenderness, compared with placebo. It also significantly reduced axial symptoms measured by ASDAS-CRP and MRI-confirmed inflammation in the sacroiliac joints. STAR is described as the first dedicated randomized, double-blind, placebo-controlled study to prospectively evaluate an IL-23 inhibitor in patients whose axial involvement was confirmed by MRI. The study enrolled 411 participants worldwide and included 24 weeks of placebo-controlled treatment followed by 24 weeks of active treatment. The safety profile was consistent with TREMFYA's established profile in PsA, with no new safety signals. Detailed efficacy, safety and MRI results are due at an upcoming scientific congress. Johnson & Johnson said the findings expand evidence for TREMFYA in axial PsA, an area with limited prospective research and no universally accepted classification criteria. The company recently received U.S. Food and Drug Administration approval for a label expansion covering inhibition of progression of structural joint damage in adults with active PsA.