Hocum, Brian

62 Background: Both Regorafenib (R) and Trifluridine/Tipiracil (T) ± BEV are widely used treatments for mCRC in later lines. This RW study evaluated optimal sequencing and associated outcomes among patients who initiated R and T in sequential lines of therapy (LOT) between LOT1-LOT6 within community oncology settings in the US. Methods: A retrospective study utilizing electronic medical record data from The US Oncology Network examined adult patients with mCRC who initiated R and T ± BEV sequentially between 09/01/2015 and 11/30/2022 (index date), with follow-up until 05/31/2023. Treatment patterns, overall survival (OS) and time to next treatment (TTNT) after sequence were assessed overall, R first (R-T) and T first (T-R). Multivariable Cox regression adjusting for age, sex, ECOG, tumor stage, and prior medication, assessed the association of factors with OS and TTNT. Results: In total, 308 mCRC patients initiating R and T (R-T, 156 pts [140 R-T and 16 R-T+BEV]; T-R, 152 pts [136 T-R and 16 T+BEV-R]) met study criteria. Baseline demographic (mean age 63 yrs, males 55%) and clinical characteristics (70% colon cancer, 58% ECOG 0-1) were similar between the cohorts. Most patients initiated index therapies at the third line of therapy (LOT3) (49% R-T, 45% T-R). The median (IQR) sequence duration was 7.4 (5.6), 6.7 (4.4), and 7.0 (4.7) months, respectively in patients with R-T, T-R, and overall. The median (95% CI) OS was 12.8 (11.2, 14.1) months among R-T and 10.2 (8.8, 11.9) months among T-R patients. Compared to R-T, the adjusted HR for the T-R sequence was 1.2 (95% CI 0.9–1.6; p=0.2). The median (95% CI) TTNT was 9.3 (8.4, 10.3) and 8.6 (7.8, 9.4) months, for R-T and T-R, respectively; the adjusted HR was 1.1 (95% CI 0.8–1.4; p=0.62). Conclusions: Patients initiating R first appeared to have a longer duration of treatment and survival, although not statistically significant. The one-year median duration of survival in this real-world setting confirms the importance of access to these treatments in patients with mCRC and can inform physicians regarding the choice of medications while sequencing therapies in mCRC. Clinical outcomes among R-T and T-R mCRC patients. Variable Level R-T (± BEV)[N 1 = 156] T (± BEV) -R[N 1 = 152] Adjusted 3,4 HR 5 (95% CI)[R-T Reference] Effect OverallSurvival Months – median (95% CI) 12.8(11.2, 14.1) 10.2(8.8, 11.9) 1.20 (0.91, 1.58) 0.20 TTNT 2 Months – median (95% CI) 9.3(8.4, 10.3) 8.6(7.8, 9.4) 1.07 (0.83, 1.37) 0.62 1 Entire R-T and T-R cohorts are presented since 16 patients in each cohort initiated T+BEV. 2 Time To Next Treatment. 3 Overall Survival adjusting for age, gender, stage at diagnosis, ECOG, prior anti-VEGF treatment. 4 Time To Next Treatment adjusting for age, gender, stage at diagnosis, and line of therapy. 5 Hazard Ratio.

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]

163 Background: Testing for BRAF and KRAS/NRAS mutations, HER2 amplifications, and MSI/MMR status is a standard of care for all patients with mCRC. There are limited real-world (RW) data regarding biomarker testing patterns among robust patients who are candidates for multiple LOT. We evaluated biomarker testing patterns among patients treated in community oncology practices who initiated regorafenib (REGO) and/or trifluridine/tipiracil (FTD/TPI), predominantly in 3rd or later lines of therapy. Methods: A retrospective analysis utilizing electronic medical record data from The US Oncology Network examined adult patients with mCRC who initiated REGO and/or FTD/TPI between 09/01/2015 and 11/30/2022 with follow-up until 05/31/2023. The proportion of patients tested for various biomarkers was assessed. Results: A total of 2684 mCRC patients initiated REGO and/or FTD/TPI (including 895 pts receiving both) in any LOT during the study period. The mean age of patients at baseline was 62.9 years, of whom 54.9% were male, 1599 (59.6%) patients were White and 436 (16.2%) were underrepresented minorities (Black or Hispanic/Latino). Patients were most commonly tested for KRAS mutations (75.2%) and least commonly for HER2 amplifications (22.6%). Age, gender, and race/ethnicity characteristics were similar between treatment subgroups, with 29.6% of minority and 23.1% of white patients not undergoing KRAS testing. Types of biomarkers tested and proportion of patients tested are reported in the table below. Conclusions: About one quarter of patients who were sufficiently robust to receive aggressive therapy did not undergo testing for KRAS, the oldest standard of care biomarker in CRC. We observed disparities by race/ethnicity. We also observed a correlation between rates of testing and treatment intensity, with patients who received both REGO and FTD/TPI having a higher rate of testing than those who received only one of the treatments. Understanding the pitfalls in biomarker testing will help pave the way for appropriate and equitable access to cancer care. [Table: see text]