Cost effectiveness analysis of pharmacokinetically-guided 5-fluorouracil in folfox chemotherapy for metastatic colorectal cancer

Dosing chemotherapy based on pharmacokinetics (PK) instead of body surface area (BSA) has been shown to decrease interindividual variability in drug exposure. PK-guided 5-fluorouracil (5-FU) instead of BSA-guided 5- FU for patients with metastatic colorectal cancer (mCRC) leads to decreased toxicity and increased overall survival (OS). In this article, we use Markov modeling to show that this is a cost-effective strategy, costing $23,000 per quality-adjusted life-year (QALY) gained. Background: Dosing chemotherapy based on BSA results in marked interindividual variability in drug exposure. A randomized trial showed increased OS and decreased toxicity with PK-guided compared with BSA-based 5-FU dosing in patients with mCRC. The objective of this study was to compare the cost effectiveness of PK-based 5- FU dosing with BSA-based 5-FU dosing in patients with mCRC receiving FOLFOX (5-FU, leucovorin, and oxaliplatin). Materials and Methods: We developed a Markov model to evaluate the cost effectiveness of PK FOLFOX compared with BSA FOLFOX. Progression risks and cause-specific mortality were extrapolated from the fitted survival models. Costs for administration and management of adverse events were estimated based on 2013 Medicare reimbursement rates and average sale prices. Results: PK FOLFOX provided 2.03 QALYs at a cost of $50,205 compared with BSA FOLFOX, which provided 1.46 QALYs at a cost of $37,173. The incremental cost-effectiveness ratio (ICER) was $22,695 per QALY. The ICER remained < $50,000 per QALY in all univariate and multivariate sensitivity analyses. Conclusion: At a $50,000 per QALY threshold, PK FOLFOX is cost effective for mCRC. Because of the cost effectiveness profile and OS advantage with PK FOLFOX, it should be evaluated further in comparative effectiveness studies.