Objective: To evaluate the clinical and biological activity of apremilast in patients with severe plaque-type psoriasis.
Research design and methods: Apremilast, a phosphodiesterase-4 inhibitor, inhibits in vitro activity of multiple inflammatory factors implicated in the pathogenesis of psoriasis. Patients received 20 mg apremilast orally for 29 days. Immunohistological analysis was conducted on lesional-skin biopsies for psoriasis-associated inflammatory markers. Lipopolysaccharide-stimulated tumor necrosis factor-alpha levels were evaluated in blood. Psoriasis Area and Severity Index (PASI), static Physician's Global Assessment, and Body Surface Area were used to monitor disease severity.
Results: There were 19 patients enrolled in this study, of whom 17 completed the study. Epidermal thickness was reduced by a mean of 20.5% from baseline to day 29. Among the responders, T cells were reduced by 28.8% and 42.6% in the dermis and epidermis, respectively. Similarly, CD11c cells were reduced by 18.5% and 40.2% in the dermis and epidermis, respectively. Fourteen of the 19 (73.7%) patients demonstrated an improvement in their PASI scores.
Limitations: This was a small, single-arm, open-label pilot study; therefore there was neither a placebo nor a comparison group.
Conclusion: Apremilast demonstrated biological activity and improved psoriasis clinical efficacy scores in patients with severe plaque-type psoriasis. The majority of adverse events were mild in nature. Two adverse events (fatigue and dizziness) were judged by the investigator to be moderate and related to apremilast. In addition, there were no clinically-relevant abnormal laboratory test results in subjects treated with apremilast for 29 days.
Trial registration: ClinicalTrials.gov NCT00604682.