To assess the importance of trial characteristics as contextual factors when evaluating the treatment effect of targeted therapies for patients with psoriatic disease.
We identified randomized controlled trials (RCTs) evaluating targeted therapies approved for psoriatic arthritis (PsA) and psoriasis (8 biologics and apremilast). The effect of targeted therapies was analyzed in the 2 psoriatic conditions combined by using drug retention as a common outcome, and separately by using the American College of Rheumatology 20% improvement criteria (ACR20) for PsA and the Psoriasis Area Severity Index 75% improvement score (PASI75) for psoriasis. We explored potential effect modification of trial characteristics in stratified and meta-regression analyses. Odds ratios (ORs) were calculated and compared among the trial eligibility criteria via the ratio of ORs.
Forty-eight PsA and psoriasis trials (51 comparisons; 17,737 patients) were eligible. Overall retention was OR 2.16 (95% confidence interval [95% CI] 1.70-2.75) with higher odds for PsA trials compared with psoriasis trials (ratio of ORs 2.55 [95% CI 1.64-3.97]). The eligibility criteria "targeted therapy history," "minimum required disease duration," "required negative rheumatoid factor," and "required Classification Criteria for Psoriatic Arthritis criteria" were of importance for achieving ACR20 in PsA. The eligibility criterion "minimum required disease duration" was of importance for achieving PASI75 in psoriasis. A total of 7 PsA trials had rescue before time-point-of-retention reporting (adaptive trials).
From this exploratory meta-epidemiologic study, we now have evidence from RCTs to support the notion that patients with PsA are more likely to adhere to targeted therapies compared to patients with psoriasis. Furthermore, we identified a few contextual factors of importance in regard to achieving ACR20 in PsA trials and PASI75 in psoriasis trials.