The Clinical and Cost Effectiveness of Aflibercept in Combination with Irinotecan and Fluorouracil-Based Therapy (FOLFIRI) for the Treatment of Metastatic Colorectal Cancer Which has Progressed Following Prior Oxaliplatin-Based Chemotherapy: a Critique of the Evidence

Abstract

The National Institute for Health and Care Excellence (NICE) invited the manufacturer of aflibercept (Sanofi) to submit clinical and cost-effectiveness evidence for aflibercept in combination with irinotecan and fluorouracil-based therapy [irinotecan/5-fluorouracil/folinic acid (FOLFIRI)] for the treatment of metastatic colorectal cancer which has progressed following prior oxaliplatin-based chemotherapy, as part of the Institute’s Single Technology Appraisal process. The Centre for Reviews and Dissemination and Centre for Health Economics at the University of York were commissioned to act as the independent Evidence Review Group (ERG). This article provides a description of the company submission, the ERG review and the resulting NICE guidance TA307 issued in March 2014. The ERG critically reviewed the evidence presented in the manufacturer’s submission and identified areas requiring clarification, for which the manufacturer provided additional evidence. The clinical effectiveness data were derived from one good-quality double-blind randomised controlled trial (RCT), the VELOUR trial, which compared aflibercept plus FOLFIRI with placebo plus FOLFIRI. This RCT found a small but statistically significant increase in overall survival (OS); the difference in median OS was 1.44 months (13.5 months in the aflibercept group and 12.06 months in the placebo group). There was also a statistically significant increase in progression-free survival (PFS) with aflibercept; the difference in median PFS was 2.23 months (6.9 months in the aflibercept group and 4.67 months in the placebo group). However, grade 3–4 adverse events were more frequent in the aflibercept group than the placebo group: 83.5 % compared with 62.5 %. Treatment-emergent adverse events led to permanent discontinuation of treatment in 26.8 % of patients in the aflibercept group and 12.1% of patients in the placebo group. The manufacturer’s submission included an estimation of mean OS benefit based on extrapolation of the data, which was considerably longer than the median OS benefit reported (4.7 vs. 1.44 months). The ERG considered this to be an over estimate. The base-case incremental cost-effectiveness ratio (ICER) for the overall population was reported by the manufacturer to be £36,294 per quality-adjusted life-year (QALY). After correcting the model programming and updating the model to include the ERG’s preferred parameter estimates, the ICER from the ERG’s alternative base case was £54,368 per QALY. The extrapolation of the OS curves was the key cost-effectiveness driver and a major source of uncertainty in the model. Additional scenarios related to the extrapolation of OS undertaken by the ERG resulted in ICERs between £62,894 and £92,089 per QALY. After consideration of the manufacturer’s submission and the ERG’s critique, and submissions from other stakeholders, the NICE Appraisal Committee concluded that aflibercept in combination with irinotecan and fluorouracil-based therapy could not be considered a cost effective use of National Health Service resources for treating metastatic colorectal cancer that is resistant to or has progressed after an oxaliplatin-containing regimen. Aflibercept in combination with irinotecan and fluorouracil-based therapy is not recommended for the treatment of metastatic colorectal cancer that is resistant to or has progressed after an oxaliplatin-containing regimen in NICE guidance TA307.