Apremilast in Palmo-Plantar Psoriasis

This study will compare the safety and efficacy of Apremilast 30mg to placebo in subjects with moderate to severe plaque psoriasis involving palms and/or soles. Apremilast will be administered orally twice daily for 16 to 32 weeks, and will be compared against placebo (dummy drug with no active ingredient). This study will enroll approximately 100 adult subjects with moderate to severe plaque psoriasis involving palms and/or soles in approximately 20 centers in US and Canada. To be eligible, subjects must have moderate to severe plaque psoriasis involving palms or soles, with lesions covering at least 10% of the surface of palms and soles at the baseline visit. Study treatments will be assigned randomly (like flipping a coin) at a 1:1 ratio, meaning that there will be a 1 in 2 chance of either receiving Apremilast or placebo during the first 16 weeks. Subjects will not know which of the two treatments they receive. The study doctor, the study staff will not know which treatment they receive either. All subjects will receive Apremilast from Week 16 to Week 32. Subjects will be asked to complete questionnaires about their hand and feet pain, their quality of life, their general health and the impact of psoriasis on their work. Medical photographs of palms and soles will be taken for subjects at selected study sites only. At Baseline and Week 16 visits, for willing subjects at certain study sites, skin biopsies can be taken. The biopsies will be analyzed for the presence of antibodies, antigens or certain cellular messengers that can be quantified. It is also possible to study the skin cellular structure and organization. A total of 3 biopsies will be taken: At Baseline visit, one biopsy from psoriasis on palms or soles and one biopsy from normal skin of palms or soles will be collected. At Week 16 visit, only one biopsy from psoriasis on palms or soles will be collected.