Exploratory Efficacy Evaluation of Apremilast for the Treatment of Japanese Patients with Palmoplantar Pustulosis: 32-Week Results from a Phase 2, Randomized, Placebo-Controlled Study

Introduction Palmoplantar pustulosis (PPP) is a pruritic, painful, chronic dermatitis that greatly impacts functioning and quality of life and can be difficult to treat. Approved treatment options for PPP are limited, and many patients do not fully respond to current treatments. Methods This was a randomized, double-blind, placebo-controlled, phase 2 study in Japanese patients with moderate to severe PPP and inadequate response to topical treatment. Patients were randomized 1:1 to receive apremilast 30 mg twice daily or placebo for 16 weeks followed by an extension phase where all patients received apremilast through week 32. PPP Area and Severity Index (PPPASI), modified PPPASI (which evaluates pustules and vesicles separately), and Palmoplantar Severity Index (PPSI) total scores and subscores (erythema, pustules/vesicles, and desquamation/scales) were evaluated over 32 weeks of apremilast treatment. Achievement of ≥ 50% improvement in PPPASI (PPPASI-50) was evaluated at week 16 among baseline demographic and clinical characteristic subgroups. Results At week 16, improvements in total score and subscores for PPPASI, modified PPASI, and PPSI, as well as rates of PPPASI-50 were at least moderately greater with apremilast than placebo. Mean PPPASI total score decreased by − 68.3% from baseline to week 32 with continued apremilast treatment. At week 32, mean change from baseline in PPPASI/modified PPPASI subscores ranged from − 58.5% to − 77.0% with apremilast. At week 32, PPSI total score for physician and patient assessments decreased by − 51.3% and − 40.0%, respectively, with continued apremilast treatment. PPPASI-50 response at week 16 was greater with apremilast versus placebo in most demographic and baseline characteristic subgroups. Conclusions Improvements in all PPPASI and PPSI total scores and subscores observed with apremilast over 16 weeks were maintained through 32 weeks in patients with moderate to severe PPP and inadequate response to topical treatment. Rates of PPPASI-50 response at week 16 were mostly consistent across patient subgroups. ClinicalTrials.gov NCT04057937.