OBJECTIVES: Colorectal cancer (CRC) is the third most common cancer in the United States, with one-third of individuals developing metastatic CRC (mCRC). Treatment for Stage IV, third-line+ mCRC is largely palliative, with many patients resistant to therapy. Furthermore, guiding treatment selection (e.g. oxaliplatin/irinotecan/cetuximab re-challenges, regorafinib, trifluridine/tipracil) remains empirical. Xilis Micro-OrganoSpheresTM (MOS) platform is an emerging technology in therapy selection that uses microscale tumor-like structures developed from biopsy tissue and grown to retain structure, genetic alterations, gene expression, immune microenvironment, and histopathology from individual patients. We aimed to model the cost-effectiveness of a MOS-guided against standard provider selection for third-line treatment of mCRC patients.

METHODS: Using a combined decision tree and Markov model, we modeled the physician-guided approach (5% overall treatment response) against a MOS-guided treatment response (estimated 30% by key leaders) for the overall group. The model used a U.S payer’s perspective, an annual discount rate of 3%, and costs in 2021 U.S. Dollars. Parameters of transition probabilities between disease states, toxicity probabilities, quality of life, and costs were estimated from clinical trials, published literature, and/or expert input. Outcomes included quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) over eight months. Univariate sensitivity analyses were used to test the robustness of the model’s assumptions.

RESULTS: Compared to unguided provider selection with assumed 5% effectiveness, MOS-guided treatment with assumed 30% effectiveness resulted overall in 597 deaths avoided, an additional 3765.94 QALYs, and ICER of $27,253.46 per QALY. Sensitivity analysis showed that our model is sensitive to the assumed MOS effectiveness and its estimated effect on the probability of disease progression. In the sensitivity analysis, MOS remained the cost-effective strategy, with ICERs ranging $27,253.46/QALY to $43,725.43/QALY.

CONCLUSIONS: Considering a willingness-to-pay threshold of $100,000/QALY, MOS models a cost-effective treatment strategy when compared to current non-guided provider treatment selection for third-line mCRC.