Febuxostat for the treatment of hyperuricaemia in people with gout: a single technology appraisal

Abstract

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of febuxostat for the management of hyperuricaemia in patients with gout based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The submission's evidence came from two randomised controlled trials comparing the efficacy and safety of febuxostat with allopurinol. The trials were of reasonable methodological quality and measured a clinically relevant range of outcomes. A pooled clinical efficacy analysis showed that a daily dose of 80 mg or 120 mg of febuxostat was significantly more effective than fixed-dose allopurinol (300/100 mg/day) at lowering serum uric acid (sUA) levels to therapeutic targets (< 6 mg/dl); however, a large percentage of febuxostat patients did not achieve the primary end point and the fixed-dose allopurinol regimen may have introduced bias. There were no differences between treatments in more clinically important outcomes such as gout flares and tophi resolution after 52 weeks of treatment. No subgroup analyses were conducted for patients with renal impairment, non-responders to allopurinol or patients with severe disease. Supplementary data from a 2-year open-label extension study were also provided, but were difficult to interpret and poorly reported. The incidence of adverse events was similar between treatments, although more febuxostat recipients discontinued treatment prematurely. A decision tree model was developed to determine the cost-effectiveness of febuxostat. The scope was limited to the comparison of continual febuxostat treatment with continual allopurinol treatment. Switching between treatments or withdrawing treatment in patients whose sUA levels had not decreased was not permitted. The model predicted a cost-effectiveness of 16,324 pounds [95% confidence interval (CI) 6281 pounds to 239,928 pounds] per quality-adjusted life-year (QALY) gained for febuxostat compared with allopurinol after 2 years of treatment. The incremental cost per QALY was below 20,000 pounds in 63% of the simulations undertaken. Changes in the time horizon did not materially affect the results. The ERG believes that the modelling structure employed was not appropriate to estimate the cost-effectiveness of febuxostat within a treatment algorithm. In addition, there were concerns about the methodology used for collecting data on key model inputs. Given these reservations the cost-effectiveness of febuxostat could not be determined. The guidance issued by NICE in August 2008 as a result of the STA states that febuxostat is recommended as an option for the management of chronic hyperuricaemia in gout only for people who are intolerant of allopurinol or for whom allopurinol is contraindicated.