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.