Long-term experience with apremilast in patients with psoriatic arthritis: 5-year results from a PALACE 1–3 pooled analysis

BACKGROUND: The efficacy and safety of apremilast were assessed in patients with psoriatic arthritis (PsA) in three phase III clinical trials with similar designs (PALACE 1, 2, and 3). METHODS: Following a 24-week, randomized (1:1:1 to apremilast 30 mg twice daily, 20 mg twice daily, or placebo), double-blind phase and a 28-week blinded active treatment phase, patients could receive apremilast in open-label extension studies for an additional 4 years. Eligible adult patients had active PsA for ≥ 6 months and three or more swollen joints and three or more tender joints despite prior treatment with disease-modifying anti-rheumatic drugs. RESULTS: A total of 1493 randomized patients received one or more doses of study medication (placebo: n = 496; apremilast 30 mg twice daily: n = 497; apremilast 20 mg twice daily: n = 500). In patients continuing apremilast treatment, response was sustained without new safety issues. At week 260, 67.2% of remaining patients achieved an ACR20 response, and 44.4% and 27.4% achieved ACR50 and ACR70 responses, respectively. Among patients with baseline enthesitis and dactylitis, 62.4% achieved a Maastricht Ankylosing Spondylitis Enthesitis Score of 0 and 80.9% achieved a dactylitis count of 0, respectively. In patients who had ≥ 3% baseline psoriasis body surface area involvement, 43.6% achieved ≥ 75% reduction from the baseline Psoriasis Area and Severity Index scores. The most commonly reported adverse events (AEs) were diarrhea, nausea, headache, upper respiratory tract infection, and nasopharyngitis, with most diarrhea and nausea AEs occurring within the first 2 weeks of treatment and usually resolving within 4 weeks. Reported rates of depression during the study were low (≤ 1.8%). The majority of patients maintained their weight within 5% of baseline during the study. No new safety concerns or increases in the incidence or severity of AEs were observed over the long term. CONCLUSIONS: Apremilast maintained clinical benefit and a favorable safety profile for up to 5 years among patients with PsA. TRIAL REGISTRATION: ClinicalTrials.gov NCT01172938, NCT01212757, NCT01212770 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13075-019-1901-3) contains supplementary material, which is available to authorized users.