OBJECTIVES: In the UK, prostate cancer is the most commonly-occurring cancer in males; it has an incidence rate of 103 per 100,000. First-line therapy for patients with advanced prostate cancer is commonly a luteinising hormone-releasing hormone (LHRH) agonist.   Degarelix is a testosterone-ablating therapy that acts as gonadotrophin-releasing hormone (GnRH) antagonist. It induces a decrease in both testosterone and prostate-specific antigen (PSA) levels, without the initial testosterone surge which can be associated with LHRH agonist therapies such as leuprorelin, goserelin and triptorelin. A previous model assessing the cost-effectiveness of degarelix was published by Lu et al (2011). However, only limited data were available at the time and here we present a model based on longer term data. METHODS: A cost-utility model using a cohort state transition structure was developed to assess the cost effectiveness of degarelix. The 5-year data informing the model was derived from the Phase III clinical trials (CS21 and CS21a). Advisory boards conducted with UK clinicians informed the model structure. Patients transferred through disease states according to their PSA progression – identified by clinicians as a key indicator of progression to second-line treatment. Adverse events for which there were statistically significant differences were also included in the model. A scenario analysis was undertaken where PSA progression was assumed to be equal for degarelix and leuprorelin, although data indicate a lower risk with degarelix. RESULTS: Degarelix showed a reduction in costs (£5,152) and increase in QALYs (0.24) when compared to leuprorelin in the base case. In the scenario analysis, treatment with degarelix was also dominant. CONCLUSIONS: Updated modelling undertaken with the most recent data indicates that treatment with degarelix is dominant – this remains the case when it is conservatively assumed, that PSA progression is not important, contrary to what was informed by clinicians, and seen in the trial data.