As part of the National Institute for Health and Care Excellence's (NICE) Single Technology Appraisal (STA) process, ruxolitinib was assessed to determine the clinical and cost effectiveness of its use in the treatment of disease-related splenomegaly or symptoms in adults with myelofibrosis. Ruxolitinib had previously been assessed as part of the STA process and was not recommended in NICE guidance issued in June 2013 (TA289). A review of TA289 was commissioned following the availability of new longer-term survival data; a price discount patient access scheme (PAS) was also introduced. The Centre for Reviews and Dissemination (CRD) and Centre for Health Economics (CHE) Technology Appraisal Group at the University of York was commissioned to act as the independent Evidence Review Group (ERG). This article provides a summary of the manufacturer or sponsor of the technology's (referred to as the company) submission, the ERG review and the resulting NICE guidance issued in March 2016. The main clinical effectiveness data were derived from two good-quality multicentre randomised controlled trials (RCTs): COMFORT-II compared ruxolitinib with best available therapy (BAT) and COMFORT-I compared ruxolitinib with placebo. Both RCTs demonstrated a statistically significant reduction in splenomegaly and its associated symptoms in intermediate-2 and high-risk myelofibrosis patients. Overall survival was statistically significantly improved with ruxolitinib compared with BAT at 3.5 years of follow-up in the COMFORT-II trial (hazard ratio 0.58, 95 % CI 0.36-0.93). Grade 3-4 adverse events were more frequent in the ruxolitinib group than in the BAT group; 42 % compared with 25 %. Evidence relating to patients with lower-risk disease or low platelet counts (50-100 × 109/L) was less robust. The company's economic model was well-presented and had an appropriate model structure. The base-case incremental cost-effectiveness ratio (ICER) was estimated to be around £45,000 per quality-adjusted life-year (QALY) gained (including the PAS discount). Extensive sensitivity and scenario analyses were presented, demonstrating that the estimated ICER was robust to a range of input values and assumptions made in the model. Alternative scenarios presented by the ERG showed only modest increases in the estimated ICER, primarily as a result of including an element of drug wastage within the model. Alternative scenarios resulted in estimated ICERs ranging from around £45,000 to £49,000 per QALY gained (including the PAS discount). At the first appraisal meeting, the NICE Appraisal Committee concluded that ruxolitinib was clinically effective and was a cost effective use of National Health Service (NHS) resources for patients with high-risk myelofibrosis who meet NICE's end-of-life criteria. Following the consultation, the company offered a revised PAS, resulting in a revised base-case ICER of £31,229 per QALY gained. The company also presented new evidence on the cost effectiveness of ruxolitinib in intermediate-2 and high-risk subgroups and a revised version of the model. The NICE Appraisal Committee considered the new evidence and recommended ruxolitinib for the treatment of patients with intermediate-2-risk disease as well as patients with high-risk disease, based on International Prognostic Scoring System (IPSS) prognostic factors.