Incremental cost-effectiveness of the pre- and post-bevacizumab eras of metastatic colorectal cancer therapy in British Columbia, Canada

Abstract

Objectives: Bevacizumab, with 5-Fluorouracil-based therapy, has been shown to prolong survival among patients with metastatic colorectal cancer (mCRC), at a relatively high cost. We evaluated the cost-effectiveness of therapy for mCRC in the eras prior to, and following, the introduction of bevacizumab on a population basis.

Methods: All patients with newly-diagnosed mCRC in 2003/2004 (the pre-bevacizumab era) and 2006 (the post-bevacizumab era) referred to the British Columbia Cancer Agency were included. A cost-utility/cost-effectiveness analysis was conducted using 'real-world' data and a Markov approach. Costs were estimated from provincial pharmacy and radiation databases, as well as national inpatient, day-surgery and ambulatory care data sources. Cost per quality adjusted life year gained (QALY) and life year gained (LYG) ratios were calculated, and one-way and probabilistic sensitivity analyses were conducted to test the robustness of the model.

Results: Median overall survival improved from 15.6 to 19.5 months (p = 0.03). For patients in the post-bevacizumab era there was a gain of an average of 0.06 QALYs or 0.325 LYG at a cost increase of $3791 per patient, resulting in a incremental cost-effectiveness ratio of $62,469/QALY or $15,617/LYG. This improved to $43,058/QALY or $10,764/LYG when the analysis was restricted to patients potentially eligible for bevacizumab. Results were generally robust to changes in model parameters, but were sensitive to the costs of chemotherapy and to differential utilities used in the Markov model.

Conclusions: The introduction of bevacizumab was associated with increased costs, but cost-effectiveness estimates were in-line with those reported for other cancer therapies.