Treatment of early oligoarticular psoriatic arthritis with apremilast: primary outcomes at week 16 from the FOREMOST randomised controlled trial.

Objectives: Oligoarticular psoriatic arthritis (PsA) is frequent but rarely studied. The objective was to assess the efficacy of apremilast in early oligoarticular PsA.

Methods: FOREMOST (NCT03747939) was a phase 4 multicentre, randomised, double-blind, placebo-controlled trial. Patients had early (symptom duration ≤5 years) oligoarticular PsA (>1 but ≤4 swollen and >1 but ≤4 tender joints; 2-8 total active joints). Patients were randomised 2:1 to apremilast 30 mg two times per day or placebo for 24 weeks, with an early escape at week 16. The primary endpoint was the proportion of patients at week 16 who achieved minimal disease activity (MDA)-Joints (modification of MDA mandating ≤1 swollen joint and ≤1 tender joint) based on sentinel joints (those affected at baseline) with a combination of non-responder imputation and multiple imputations. Exploratory analysis assessed all joints.

Results: Of 308 patients randomised (apremilast: n=203; placebo: n=105), mean (SD) PsA duration was 9.9 (10.2) months, mean (SD) age was 50.9 (12.5) years and 39.9% of patients were using a conventional synthetic disease-modifying antirheumatic drug. MDA-Joints (sentinel joints (primary endpoint) and all joints) were achieved by significantly more patients with apremilast (33.9% and 21.3%) vs placebo (16.0% and 7.9%) at week 16 (p=0.0008 and nominal p=0.0028, respectively). Greater improvements in patient-reported outcomes, clinical disease activity and skin involvement were also seen with apremilast versus placebo.

Conclusions: FOREMOST is the first randomised controlled trial designed for early oligoarticular PsA and showed apremilast improves clinical and patient-reported outcomes. This trial may inform the optimal management of PsA in these patients.

Trial registration number: NCT03747939.