Cho, Sang Kyu

3525 Background: Recent clinical trials support regorafenib dose optimization (ReDO), a combination therapy with trifluridine/tipiracil and bevacizumab (TAS-BEV), and fruquintinib (FRUQ) for the treatment of refractory metastatic colorectal cancer (mCRC). This study evaluated relative cost-effectiveness of ReDO, TAS-BEV, and FRUQ for mCRC from a payer perspective in the United States. Methods: A Markov model was constructed to estimate total costs and quality-adjusted life years (QALY) for each treatment. In the base case, clinical parameters were obtained from the ReDOS study for ReDO, the SUNLIGHT study for TAS-BEV, and the FRESCO study for FRUQ. Economic parameters were obtained from IBM Micromedex RED BOOK for treatment costs and from the Centers for Medicare & Medicaid Services and the Agency for Healthcare Research and Quality for health care resource use. Incremental cost-effectiveness ratio (ICER) was used to evaluate relative cost-effectiveness of treatments. Model robustness was checked with deterministic (DSA) and probabilistic sensitivity analysis (PSA). A subgroup analysis was performed in patients with and without previous use of anti-VEGF therapy, but using the FRESCO-2 study for FRUQ because OS and PFS for this subgroup was unavailable in the FRESCO study. Results: In the base case, ReDO provided a higher QALY at a lower cost than TAS-BEV and FRUQ. During the first two months following treatment initiation, TAS-BEV had a higher total cost ($67,862) than ReDO ($44,695) and FRUQ ($48,688), partly due to the cost of managing neutropenia and using concomitant granulocyte colony stimulating factors (GCSF). The base case results were robust in DSA and PSA. Most influential parameters determining relative cost-effectiveness were related to treatment cost and effectiveness. In patients with previous anti-VEGF therapy, ReDO provided a higher QALY at a lower cost (0.571 QALY; $86,694) than TAS-BEV (0.490 QALY; $148,784) and FRUQ (0.411 QALY; $101,236). In patients without previous anti-VEGF therapy, TAS-BEV had a higher QALY (0.755 vs 0.571) and a higher cost ($232,701 vs $86,694) than ReDO, resulting in an ICER of $790,988 per QALY. Conclusions: ReDO was cost-effective compared with TAS-BEV and FRUQ, regardless of previous use of anti-VEGF therapy. In the base case, ReDO had a lower treatment cost than TAS-BEV and FRUQ, especially during the first month of dose optimization. TAS-BEV had the highest total cost, partly due to the cost of managing neutropenia and GCSF use. [Table: see text]

e18367 Background: Regorafenib at 160mg daily 21/28 days is a standard therapeutic option in patients with metastatic colorectal cancer. However, the cost of treatment and management of its side-effects is more than the cost-effectiveness threshold for oncology drugs in US and many countries around the world. ReDOS (Regorafenib Dose Optimization Study), is a randomized phase II trial in refractory mCRC and established that weekly dose escalation of regorafenib over the conventional dosing is superior in the composite endpoint of safety and efficacy. We explored the impact of the new dosing strategy on CE of regorafenib. Methods: A Markov model was constructed to compare costs and effectiveness of regorafenib (standard), regorafenib (ReDOS), and best supportive care (BSC). Model inputs for clinical efficacy and safety were from the CORRECT trial for regorafenib (standard) and BSC, and the ReDOS study for regorafenib (ReDOS). The incremental cost-effectiveness ratios (ICERs) were reported to compare treatments. Model robustness was checked with univariate and probabilistic sensitivity analyses. The model used a US payer’s perspective with 5% annual discount rate, and all costs were measured in 2018 US dollars. Results: Regorafenib (ReDOS) dominated regorafenib (standard), producing higher quality-adjusted life years at a lower cost. When compared to BSC, regorafenib (ReDOS) resulted in the ICER of $112,705 while regorafenib (standard) resulted in the ICER of $384,687. The most influential parameters on the ICERs were efficacy and health state utility parameters under univariate sensitivity analysis. In probabilistic sensitivity analysis using cost-effectiveness acceptability curves, regorafenib (ReDOS) was more cost-effective than regorafenib (standard) and BSC in 70% of repetition at the willingness-to-pay threshold of $120,000 per QALY (Quality-Adjusted Life Year) and 98% at a WTP threshold of $150,000. Conclusions: Based on the outcomes demonstrated in the ReDOS study, the dose optimization strategy of regorafenib results in favorable cost-effectiveness under a typical US willingness-to-pay threshold of $150,000 per QALY.