As part of the National Institute for Health and Care Excellence's (NICE) single technology appraisal (STA) process, apremilast was assessed to determine the clinical and cost effectiveness of its use in the treatment of moderate to severe plaque psoriasis in two patient populations, differentiated by the severity of the patient's Psoriasis Area Severity Index (PASI) score. The Centre for Reviews and Dissemination (CRD) and the Centre for Health Economics (CHE) Technology Appraisal Group at the University of York was commissioned to act as the evidence review group (ERG). This article provides a summary of the company's submission, the ERG report and NICE's subsequent guidance. In the company's initial submission, a sequence of treatments including apremilast was found to be both more effective and cheaper than a comparator sequence without it in both populations considered. However, this result was found to be highly sensitive to a series of assumptions made by the company, primarily reflecting the costs of best supportive care once no further treatments are available, and the source of utility estimates. A re-estimation of the cost effectiveness of apremilast by the ERG suggested that the apremilast sequence in the two populations was more effective, but due to high additional costs was not indicative of a cost-effective use of NHS resources. As such, in the final appraisal decision NICE concluded that apremilast was not cost effective in either population.