As part of its Single Technology Appraisal Process, the National Institute for Health and Care Excellence (NICE) invited the manufacturer of degarelix (Ferring Pharmaceuticals) to submit evidence for the clinical and cost effectiveness of degarelix for the treatment of advanced hormone-dependent prostate cancer. The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). The ERG produced a critical review of the evidence contained within the company’s submission to NICE. The evidence, which included a randomised controlled trial (RCT) of degarelix versus leuprorelin, found that degarelix was non-inferior to leuprorelin for reduction of testosterone levels and that degarelix achieved a more rapid suppression of prostate-specific antigen levels and subsequently decreased incidences of testosterone flare associated with luteinising hormone releasing-hormone (LHRH) agonists. However, protection against testosterone flare for the comparators in the clinical trials was not employed in line with UK clinical practice. Further claims surrounding overall survival, cardiovascular adverse events and clinical equivalence of the comparator drugs from six RCTs of degarelix should be regarded with caution because of flaws and inconsistencies in the pooling of trial data to draw conclusions. The cost-effectiveness evidence included a de novo economic model. Based on the ERG’s preferred base case, the deterministic incremental cost-effectiveness analysis (ICER) for degarelix versus 3-monthly triptorelin was £14,798 per quality-adjusted life-year (QALY) gained. Additional scenario analyses undertaken by the ERG resulted in ICERs for degarelix versus 3-monthly triptorelin ranging from £17,067 to £35,589 per QALY gained. Subgroup analyses undertaken using the Appraisal Committee’s preferred assumptions suggested that degarelix was not cost effective for the subgroup with metastatic disease but could be cost effective for the subgroup with spinal metastases. The company submitted further evidence to NICE following an initial negative Appraisal Committee decision. Further analyses from the Decision Support Unit found that that, whilst some evidence indicated that degarelix could be cost effective for a small subgroup of people with spinal cord compression (SCC), data on the potential size of this subgroup and the rate of SCC were insufficient to estimate an ICER based on the evidence submitted by the company and a separately commissioned systematic review. NICE recommended degarelix as an option for treating advanced hormone-dependent prostate cancer in people with spinal metastases, only if the commissioner can achieve at least the same discounted drug cost as that available to the UK NHS in June 2016.