medwireNews: Results of a placebo-controlled phase III trial suggest that abatacept treatment has beneficial effects on musculoskeletal symptoms among patients with psoriatic arthritis (PsA), but the impact on skin lesions is less evident.
The ASTRAEA (Active Psoriatic Arthritis Randomized Trial) researchers found that a significantly higher proportion of 213 patients treated with the selective T-cell costimulation modulator achieved at least a 20% improvement in ACR criteria (ACR20) at week 24 compared with 211 placebo-treated patients, at 39.4% versus 22.3%.
And a numerically higher proportion of patients receiving abatacept experienced a reduction of 0.35 or more in the Health Assessment Questionnaire–Disability Index score (31.0 vs 23.7%), but this difference did not reach statistical significance.
These data “suggest that selective inhibition of the CD28-dependent costimulatory pathway critical for T-cell activation may offer a novel treatment option in PsA,” Philip Mease (Swedish Medical Center and University of Washington, Seattle, USA) and colleagues write in the Annals of the Rheumatic Diseases.
However, they note that the psoriatic skin response was “more modest” than the musculoskeletal response. There was “a small numerical increase” in the proportion of patients who experienced at least a 50% improvement in the Psoriasis Area and Severity Index (PASI) score at 24 weeks among those treated with abatacept versus placebo, at 26.7% versus 19.6%, and a corresponding 16.4% and 10.1% experienced at least a 75% improvement in the PASI score.
“It is […] possible that a higher dose of abatacept may be required for optimal efficacy in skin versus musculoskeletal symptoms, similar to previous findings with the [tumor necrosis factor inhibitor] etanercept,” suggest Mease and colleagues.
The rates of adverse events (AEs) and serious AEs at 24 weeks were comparable in the abatacept and placebo groups (54.5 vs 53.1% and 2.8 vs 4.3%, respectively), and the most common AEs in both groups were infections (26.8 vs 29.9%). One serious infection was considered related to abatacept, and treatment was discontinued in this patient.
Together, these findings “demonstrate that abatacept had an overall beneficial effect on musculoskeletal symptoms and was well tolerated in a relatively refractory population of patients with PsA,” conclude the authors, noting that approximately 60% of study participants had received prior treatment with a tumor necrosis factor inhibitor.
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