A Study Evaluating the Efficacy and Tolerability of Oral Apremilast for the Treatment of Nail Psoriasis

Psoriasis vulgaris is a common inflammatory condition of the skin that results in scaly red itchy plaques. In addition to affecting the skin, psoriasis can also cause disease in the finger and toe nails. Nail psoriasis is a chronic disease and can present with the following clinical findings: splinter hemorrhage, leukonychia, red spots in the lunula, nail pitting, nail plate crumbling, hyperkeratosis, and/or nail plate separation from the nail bed. The most characteristic nail findings associated with nail psoriasis are nail pitting, onycholysis with a rim of erythema, and oil spots. Special interest will be paid to identifying these particular nail findings in patients, however all potential nail psoriasis symptoms will be assessed in patients in this study. Due to the highly visible nature of disease in the fingernails, nail psoriasis often results in a substantial deleterious effect on a patient's quality of life. Patients also can have significant pain and disability due to nail psoriasis. Psoriasis patients who have nail involvement are known to have more severe psoriasis disease and diminished quality of life when compared to psoriasis patients without nail disease. Patients with nail psoriasis often also have psoriatic arthritis, and untreated psoriatic arthritis is known to lead to joint destruction with potentially severe morbidity. Nail psoriasis has a reported incidence of 80 to 90% (Jiaravuthiasan, et al). Because nail psoriasis causes a substantial disease burden for patients, it is critical that safe and effective treatments are found for this specific type of psoriasis. Unfortunately, nail psoriasis is often difficult to treat. Apremilast is an orally available small molecule inhibitor of phosphodiesterase 4 (PDE4) that is FDA approved for the treatment of psoriasis and psoriatic arthritis. PDE4 is one of the main phosphodiesterases expressed in immune cells, and its inhibition by apremilast is thought to increase cyclic adenosine monophosphate and thereby decrease the inflammatory response. Specifically, apremilast is believed to down regulate pro-inflammatory cytokines including TNF-α, (Tumor necrosis Factor) IL-23 (Interleukin), IL-17, and others. Apremilast has shown promising results for treating psoriatic arthritis and nail disease; however more data is needed regarding its effect on nail psoriasis (Kavanaugh, et al). We hypothesize that apremilast will prove to be highly effective in treating nail psoriasis. We propose to conduct an open label clinical trial to investigate the efficacy and tolerability of apremilast in treating nail psoriasis, where we will follow the package insert guidelines for treating patients with apremilast.