Efficacy of guselkumab on axial involvement in patients with active psoriatic arthritis and sacroiliitis: a post-hoc analysis of the phase 3 DISCOVER-1 and DISCOVER-2 studies

Background Guselkumab was efficacious in reducing signs and symptoms of psoriatic arthritis the phase 3 DISCOVER-1 DISCOVER-2 studies. We aimed to evaluate efficacy guselkumab post-hoc analyses patients with imaging-confirmed sacroiliitis consistent axial involvement. Methods In DISCOVER-1, 381 active (defined as ?3 swollen joints, tender C-reactive protein [CRP] ?0·3 mg/dL) DISCOVER-2, 739 ?5 CRP ?0·6 were randomly allocated receive 100 mg every 4 weeks, 8 weeks (week 0, week 4, then weeks), or placebo. These pooled, included disease documented by previous imaging pelvic radiography at screening (confirmed investigator). Efficacy assessments least squares mean changes, 95% CIs, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score, modified BASDAI (mBASDAI; excluding peripheral joint pain), spinal pain, Score (ASDAS), proportions achieving a 50% improvement score (BASDAI50) ASDAS responses inactive (score <1·3), major (change ?2·0), clinically important ?1·1). Findings Of 1120 two DISCOVER studies, 312 (28%) this analysis, whom 118 placebo group, 103 91 group. 191 (61%) male, 121 (39%) female, age 45·1 (SD 11·2). HLA-B27 status assessed 190 patients; 57 (30%) HLA-B27-positive 133 (70%) HLA-B27-negative. At 24, changes from baseline ?2·7 (95% CI ?3·2 ?2·2) both groups versus ?1·3 (?1·8 ?0·9) group; similar results observed for mBASDAI pain. Least scores 24 ?1·4 ?1·7 ?1·2) ?0·7 (?0·9 ?0·5) 36 (38%) group 34 (40%) those achieved BASDAI50 21 (19%) greater guselkumab-treated Across outcomes, separation 8. Improvements seen independent status. improvements maintained 52 groups. Interpretation Patients who treated had (as early 8) than did placebo-treated participants, sustained 52. Funding Janssen Research & Development LLC.