Cost estimates and economic implications of expanded RAS testing in metastatic colorectal cancer

Abstract

Background: In colorectal cancer (CRC), evidence shows that expanding RAS testing to analyze more mutations may better predict benefit from anti-EGFR therapy. The economic implications of expanding RAS testing for metastatic CRC were analyzed.

Materials and methods: Estimates of standard KRAS exon 2 testing were based on the Centers for Medicare and Medicaid Services (CMS) 2014 Diagnostic Laboratory Fee Schedule, and expanded RAS testing was estimated using a sensitivity analysis done with various potential cost scenarios (1, 2, 10, and 30 times the cost of the standard KRAS test). The cost estimates for cetuximab and panitumumab were based on the CMS payment allowance limits for Medicare Part B.

Results: A total of 28,692 patients with metastatic CRC were estimated to be eligible annually for RAS testing. For cetuximab, the societal cost of standard KRAS testing plus the drug versus expanded testing plus the drug would be $1.16 billion versus $816 million if the cost of the tests were the same. If the cost of the expanded RAS test were 30 times the cost of the standard test, then the societal cost of standard KRAS testing plus the drug versus expanded testing plus the drug would be $1.16 billion versus $980 million, a continued savings of more than $184 million annually. Similar savings were seen with panitumumab.

Conclusion: The increased societal cost of expanded RAS testing versus standard approved KRAS exon 2 testing was inconsequential when compared with the amount of money saved by not treating the additional 18% of patients who harbor additional RAS mutations (beyond exon 2) with anti-EGFR therapy.

Keywords: Antineoplastic agents; Colorectal neoplasms/drug therapy; Drug costs; Human; KRAS protein.

Figure 1.

Patients with metastatic colorectal cancer with either standard KRAS testing (exon 2) versus expanded testing (KRAS exon 2, 3, 4; NRAS exon 2, 3, 4). Figure shows the different distribution of mutated versus wild type tumors based on type of testing with associated cost of the test and the EGFR inhibitor. The scenario in this figure is that the standard testing cost was $197 and the expanded testing cost was 30 times that amount, or $5,910. The total costs of getting cetuximab or panitumumab include the cost of the drug and the test. Abbreviations: C, cetuximab; mCRC, metastatic colorectal cancer; P, panitumumab; WT, wild type.