Background The safety and efficacy of apremilast (APR), including improvements in physical disability, were compared with placebo in the PALACE 1 study of patients who had active psoriatic arthritis despite prior conventional disease-modifying antirheumatic drugs (DMARDs) and/or biologics. Physical function is a substantial burden in patients with psoriatic arthritis, and the Health Assessment Questionnaire-Disability Index (HAQ-DI) is commonly used in clinical trials to assess this impairment.1
Objectives Assess the long-term (104-week) impact of APR therapy on physical function in patients enrolled in the PALACE 1 study.
Methods Patients were randomized (1:1:1) to receive placebo, APR 20 mg BID (APR20), or APR 30 mg BID (APR30) stratified by baseline DMARD use (yes/no). Patients whose swollen and tender joint counts had not improved by ≥20% at Week 16 were considered non-responders and were required to be re-randomized (1:1) to APR20 or APR30 if they were initially randomized to placebo, or continued on their initial APR dose. At Week 24, all patients remaining on placebo were re-randomized to APR20 or APR30. Treatment efficacy analysis at Week 16 was performed based on the intent-to-treat population, and analyses at Week 52 and Week 104 were based on data as observed. Physical function, a prespecified secondary end point, was measured in patients using the Health Assessment Questionnaire-Disability Index (HAQ-DI) scores. Proportion of patients achieving minimal clinically important differences (MCID) in the HAQ-DI score (improvements of ≥0.13 or ≥0.30 from baseline) were collected.
Results At Week 16, the change from baseline in physical function was significantly improved with APR30 vs. placebo, as measured by the HAQ-DI score (Table). Improvements in physical function were maintained at Weeks 52 and 104. At Week 52, 59.8% (APR30) and 60.0% (APR20) of patients achieved HAQ-DI MCID ≥0.13 and 44.7% (APR30) and 45.8% (APR20) achieved MCID ≥0.30. At Week 104, 62.4% (APR30) and 57.7% (APR20) achieved HAQ-DI MCID ≥0.13 and 54.5% (APR30) and 51.5% (APR20) achieved MCID ≥0.30.
Conclusions Patients treated with APR30 reported clinically meaningful improvements in physical function compared with those treated with placebo, as measured by the HAQ-DI scores at Week 16. Improvements in physical function were maintained long term at Weeks 52 and 104
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Disclosure of Interest F. Zhang Employee of: Celgene Corporation, Z. Clancy Employee of: Celgene Corporation, S. Li Employee of: Celgene Corporation, A. Kavanaugh Grant/research support from: Abbott, Amgen, Astra-Zeneca, Bristol-Myers Squibb, Celgene Corporation, Centocor-Janssen, Pfizer Inc, Roche, and UCB, Consultant for: Abbott, Amgen, Astra-Zeneca, Bristol-Myers Squibb, Celgene Corporation, Centocor-Janssen, Pfizer Inc, Roche, and UCB, A. Adebajo: None declared, J. Wollenhaupt Grant/research support from: Abbott, Bristol-Myers Squibb, MSD, Pfizer Inc, and UCB, Consultant for: Abbott, Bristol-Myers Squibb, MSD, Pfizer Inc, and UCB