A multicentre open-label study of apremilast in palmoplantar pustulosis (APLANTUS)

BACKGROUND: Palmoplantar pustulosis (PPP) is a chronic skin disease with painful erythematous scaly or crusty lesions and pustules on the palms and soles. Apremilast is a phosphodiesterase 4 inhibitor that has proven effective in the therapy of psoriasis, psoriatic arthritis and in oral ulcers associated with Behcet's disease.

OBJECTIVE: To explore the efficacy of apremilast in PPP.

METHODS: APLANTUS was a phase 2 single-arm multicentre study of apremilast in 21 subjects with moderate-to-severe PPP. Primary endpoint was the per cent change of the Palmoplantar Pustulosis Psoriasis Area and Severity Index (PPPASI) at week 20 compared to baseline.

RESULTS: 20 weeks of oral treatment with apremilast in patients with moderate-to-severe PPP resulted in a significant decrease of the PPPASI with a median reduction of 57.1% (p < 0.001), and 61.9% of patients achieved at least a 50% improvement of the PPPASI relative to baseline. The total number of pustules per patient decreased significantly relative to baseline with 76.2% of patients achieving at least a 50% reduction in total pustules count at week 20. Improvement of PPP was also apparent in a significant decrease of the dermatologic life quality index (DLQI). The median DLQI score dropped from 8.5 at baseline to 2.0 at week 20 (p = 0.030). Apremilast was generally well tolerated, and no serious adverse events occurred.

CONCLUSIONS: Patients with PPP treated with apremilast showed benefit both in objective and subjective disease parameters. Apremilast should be investigated further in this difficult-to-treat skin condition. EudraCT number: 2016-005122-11.