medwireNews: Guselkumab improves axial symptoms relative to placebo in people with axial psoriatic arthritis (PsA) and radiographic evidence of sacroiliitis, shows a post-hoc analysis of the DISCOVER-1 and DISCOVER-2 studies.
As previously reported by medwireNews, the primary analysis of the two phase 3 studies showed that guselkumab 100 mg every 4 weeks or every 8 weeks significantly improved the overall signs and symptoms of PsA relative to placebo.
The current analysis used the BASDA modified (m)BASDAI (excluding peripheral joint pain), and ASDAS indices to assess the impact of guselkumab on axial symptoms in 312 (mean age 45 years, 61% men) of the original 1120 DISCOVER-1 and DISCOVER-2 participants.
All 312 individuals had axial disease documented by previous imaging or pelvic radiography at screening consistent with sacroiliitis. At baseline, the mean BASDAI, mBASDAI, and ASDAS scores were 6.5, 6.5, and 3.9 points, respectively.
At week 24, the least squares mean reductions in BASDAI from baseline were significantly greater in the participants who received guselkumab every 4 weeks (n=103) and every 8 weeks (n=91) than in those who received placebo (n=118), at 2.7, 2.7 and 1.3 points, respectively.
The corresponding reductions for mBASDAI were 2.6, 2.7, and 1.4 points, while for ASDAS, the least squares mean reductions at week 24 were 1.4 points in both guselkumab groups versus 0.7 points in the placebo group, which was also a significant difference.
In addition, significantly higher proportions of participants who received guselkumab every 4 weeks and every 8 weeks achieved a 50% or greater improvement in BASDAI compared with placebo, at 38% and 40% versus 19%, respectively.
Philip Mease (University of Washington, Seattle, USA) and co-investigators note that the separation between the guselkumab groups and the placebo group was apparent from week 8 for both BASDAI and ASDAS scores, and was maintained at week 52.
They also report that the improvements with guselkumab were independent of HLA-B27 status, which “has previously been thought to be associated with axial involvement and more severe disease” in people with PsA.
The authors conclude in The Lancet Rheumatology that “guselkumab might be an effective therapy for patients with psoriatic arthritis who have axial symptoms, and that response to guselkumab therapy can be achieved for both HLA-B27-positive and HLA-B27-negative patients.”
They add that a prospective, randomized, controlled trial of guselkumab with additional imaging evaluations and assessment tools specific to axial PsA is now underway in patients with PsA with axial involvement.
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