Application and modifications of minimal disease activity measures for patients with psoriatic arthritis treated with adalimumab: subanalyses of ADEPT

Abstract

Objective: This posthoc analysis evaluated the percentage of patients with psoriatic arthritis (PsA) who achieved minimal disease activity (MDA) and compared the results with a modified MDA substituting the physician global assessment (PGA) for the Psoriasis Activity and Severity Index (PASI) using data from the ADalimumab Effectiveness in Psoriatic Arthritis Trial (ADEPT; NCT00646386).

Methods: Patients with active PsA were randomized to receive adalimumab 40 mg or placebo every other week for 24 weeks. MDA was defined as achieving ≥ 5 of the following criteria: tender joint count ≤ 1; swollen joint count ≤ 1; PASI ≤ 1 or body surface area ≤ 3%; patient pain score ≤ 15 [1-100 mm visual analog scale (VAS)]; patient global assessment (PGA) of disease activity ≤ 20 (1-100 mm VAS); Health Assessment Questionnaire ≤ 0.5; and tender entheseal points ≤ 1 (only heels assessed). For modification of the MDA, PASI ≤ 1 was substituted with PGA "Clear" as MDAPGA1 and PGA "Clear" or "Almost clear" as MDAPGA2.

Results: Sixty-seven patients were treated with adalimumab and 69 with placebo. At Week 24, MDA, MDAPGA1, and MDAPGA2 were achieved by 39%, 37%, and 39%, respectively, of patients treated with adalimumab versus 7%, 5%, and 8% of patients on placebo (p < 0.001). Kappa coefficients indicated good agreement between PASI and PGA at Week 24.

Conclusion: ADEPT results indicated that significantly more patients treated with adalimumab achieved MDA by Week 24 compared with placebo. Modification of the MDA by replacing PASI ≤ 1 with PGA assessments did not alter the results, which may improve feasibility of practical use of the index.

Keywords: ADALIMUMAB; PSORIATIC ARTHRITIS; SEVERITY OF ILLNESS INDEX.