Phase 3, Randomized Study of Apremilast in Japanese Participants With Palmoplantar Pustulosis (PPP)

* Key Inclusion Criteria * Japanese participants ≥ 18 years of age upon entry into initial screening * Palmoplantar pustulosis diagnosis with or without pustulotic arthro-osteitis (PAO) for no less than 24 weeks * PPPASI total score of ≥12 at screening and at baseline * Moderate or severe pustules/vesicles on palms or soles (PPPASI severity score ≥2) at screening and at baseline * Inadequate response (defined as repeated relapsing-remitting in the same location for a 24-week period) to topical treatments prior to or at screening * Key Exclusion Criteria * Changes in disease severity during screening (PPPASI total score change ≥ 5 improvement, from screening to baseline) * Periodontitis requiring treatment * Chronic or recurrent tonsillitis or sinusitis requiring any continuous treatment * Has a diagnosis of plaque-type psoriasis at baseline * Has the presence of pustular psoriasis on any part of the body other than the palms and soles * Has evidence of skin conditions of hand and feet at baseline that would interfere with evaluations of the effect of Investigational Product * Has unstable cardiovascular disease, defined as a recent clinical deterioration or a cardiac hospitalization within 12 weeks prior to screening * Malignancy or history of malignancy * Participant has received any procedures for focal infection within 24 weeks of baseline * Female participants who are breastfeeding or who plan to breastfeed while on study * Female partici…