Background: A growing number of genomic alterations inform treatment of advanced/metastatic colorectal cancer (mCRC). However, use of comprehensive genomic profiling (CGP) is limited in the first-line (1L) setting. Based on the Tempus xT next-generation sequencing assay, we estimated the impact of expanded 1L CGP on the detection of currently actionable alterations in mCRC and associated diagnostic testing costs in a modeled US health plan setting.

Methods: A decision analytic model was used to compare testing scenarios over a two-year time horizon: current 1L testing with a mix of CGP and non-CGP diagnostics vs. replacing 20% of usual testing with Tempus CGP. The incidence of 1L mCRC, current testing rates, prevalence of actionable alterations, and test sensitivity were drawn from a literature review and clinical expert input. Currently actionable alterations included KRAS, NRAS, RAF, BRAF, dMMR/MSI, NTRK, RET, EGFR, HER2, MET, PIK3CA and POLE1. Cost components included initial and repeat testing, physician-associated and administrative costs. Opportunities for genomically-informed therapy or clinical trials were assessed under each testing scenario. A forward looking scenario, with additional informative alterations, was also explored.

Results: In a hypothetical five million-member health plan, with 50% Medicare and 50% commercial insurance, 1,112 incident cases of mCRC (22 per 100,000 patients) are expected in a typical year. Among these cases, 566 (51%) are expected to undergo 1L molecular diagnostic testing, with 55 projected to undergo repeat testing upon progression within the next year. Based on current real-world testing rates, there are an expected 521 missed opportunities for genomically informed treatment (47% of the incident mCRC population), with 442 missed due to lack of testing and 79 due to testing without CGP. Replacing 20% of usual testing with Tempus CGP in the modeled scenario was associated with up to a $0.003 per member per month (PMPM) testing cost increase and an additional 15.5 patients with an opportunity for genomically-informed care (12.7 patients for guideline-recommended treatment and 2.8 for a clinical trial). The number needed to test (NNT) with Tempus CGP versus the usual mix of testing was 7.8 1L patients to identify one actionable alteration. Scenario analyses projecting the advent of additional genomically-informed treatments and clinical trials resulted in smaller numbers needed to test.

Conclusions: Replacing 20% of usual testing with Tempus CGP is associated with a small incremental testing cost but can identify actionable alterations for a meaningful number of patients. For every eight 1L mCRC patients tested with Tempus CGP rather than the usual mix of molecular testing, one additional patient is expected to be identified as having currently actionable alterations.

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