Abstract

Objectives

To assess the value for money of alternative chemotherapy strategies for managing advanced colorectal cancer using irinotecan or oxaliplatin, either in sequence or in combination with fluorouracil.

Methods

A cost-effectiveness model was developed using data from the UK fluorouracil, oxaliplatin, and CPT11 (irinotecan) – use and sequencing (FOCUS) trial. The analysis adopted the perspective of the UK National Health Service. Input parameters were derived using a system of risk equations (for probabilities), count data regression models (for resource use), and generalized linear models (for utilities). Parameter estimates were obtained using Markov chain Monte Carlo methods, propagating the simulation values through the state-transition model to characterize appropriately the joint distributions of expected cost, survival and quality-adjusted life years for each treatment strategy. An acceptability frontier was used to represent the probability that the optimal option is cost-effective at different values of the cost-effectiveness threshold.

Results

The base-case analysis used drug unit costs provided by a typical English hospital. First-line doublet therapy combination therapy fluorouracil (5FU) plus irinotecan was the most cost-effective strategy at standard thresholds, with an incremental cost-effectiveness ratio (ICER) of £14,877 (pound sterling) compared with first-line 5FU until treatment failure followed by single agent irinotecan. Other strategies were all subject to extended dominance. A sensitivity analysis using published drug (list) prices found the most cost-effective strategy would be first-line fluorouracil until failure followed by 5FU plus irinotecan (ICER: £19,753).

Conclusions

The combination of 5FU and irinotecan (whether used first or second line) appears to be more cost-effective than the single agent sequential therapies used in the FOCUS trial, or 5FU plus oxaliplatin.