Cost-effectiveness analysis of sunitinib in patients with metastatic and/or unresectable gastrointestinal stroma tumours (GIST) after progression or intolerance with imatinib.

INTRODUCTION Sunitinib is a multiselective oral inhibitor of several tyrosine-kinase receptors that has demonstrated its efficacy in patients with metastatic and/or unresectable gastrointestinal stroma tumours (GIST) who were resistant to or intolerant to previous treatment with imatinib. The purpose of this study is to assess the cost-effectiveness of sunitinib vs. best supportive care (BSC) in GIST as a second- line treatment, from the perspective of the Spanish National Health System. MATERIALS AND METHODS A Markov model was used to assess the cost effectiveness of sunitinib (50 mg/day, 4 weeks "on" and 2 weeks "off") vs. BSC in GIST as a second-line treatment. Transition probabilities between the three health states considered in the model (progression-free survival (PFS), progression and death) were obtained from a clinical trial [Demetri et al. (2006) Lancet 368:1329-1338]. Health resource data (drugs, medical visits, laboratory and radiology tests, palliative care and adverse events) were obtained from an expert panel. Deterministic and probabilistic sensitivity analyses were conducted. RESULTS Projected PFS years, life years (LY) and quality of life adjusted years (QALYs) were higher for sunitinib compared with BSC: 0.50 vs. 0.24, 1.59 vs. 0.88 and 1.00 vs. 0.55. Mean costs per patient were 23,259 euros with sunitinib and 1,622 euros with BSC. The incremental cost-effectiveness ratios (ICERs) obtained were: 4,090 euros/month PFS, 30,242 euros/LY and 49,090 euros/QALY gained. The most influential variables for the results were the efficacy and unit cost of sunitinib. CONCLUSIONS According to the efficiency thresholds for oncology patients in developed countries, sunitinib is considered cost-effective vs. BSC with acceptable costs per LY and QALY gained.