Abstract 927: Real-world (RW) biomarker characteristics and clinical outcomes in pre-treated non-MSI-H/dMMR metastatic colorectal cancer (mCRC) patients
Authors: Amonkar Mayur M. , Sura Sneha , Desai Kaushal , Jain Rishi , Liu Zhimei , Niehoff Nicole , Wilson Thomas W. , Patton Gregory , Cosgrove David 
Published: March 2024

Introduction: Given sparse RW evidence, we assessed biomarker characteristics & clinical outcomes in community oncology practices among pre-treated non-MSI-H/dMMR mCRC patients.

Methods: This retrospective cohort study used structured & chart review data from iKnowMed, The US Oncology Network electronic health record data & included non-MSI-H/dMMR adult mCRC patients pre-treated with standard of care (SoC) chemo who initiated subsequent systemic anticancer treatment (SACT), best supportive care (BSC) or neither from 1/1/2016 - 12/31/2021. Index date for SACT users was the regimen start date post SoC chemo & for patients on BSC & no SACT/BSC, it was last chemo administration date. Patients were followed from index date until 8/31/2022 for overall survival (OS) & real-world progression-free survival (rwPFS). KM analyses assessed outcomes, overall & stratified by treatment, RAS status & metastasis sites.

Results: Of mCRC patients with &gt;2 visits, 70.9% received MSI/MMR testing. In 292 eligible chart review patients, 69.5% received SACT in pre-treated setting (regorafenib 14.8%, trifluridine/tipiracil (TAS-102) 12.3%, other 72.9%), 28.8% received BSC & 1.7% neither. 76.7% reported KRAS/NRAS testing with 60.7% wild-type & 39.3% mutant. Common metastasis sites were liver-only (44.2%), liver & lung (10.3%) & lung-only (8.9%). Median (range) duration of follow-up was 5.2 (2.7, 10.0) months for regorafenib, 5.3 (2.5, 8.6) for TAS-102 & 10.7 (5.3, 18.0) for the other treatments group. Median OS was 7.4 (95% CI: 5.8, 8.8) months & median rwPFS was 3.5 (95% CI: 3.2, 4.3) months (outcomes data in Table).

Conclusions: 29.1% pre-treated, mCRC patients did not receive guideline recommended MSI/MMR testing, highlighting the need to improve testing. Outcomes varied by treatment, RAS status, & metastatic sites. The modest RW clinical benefit for SoC regorafenib & TAS-102, was consistent with trials & other RW studies; all highlighting an unmet need.

Cohorts Median (95% CI) OS (months) Median (95% CI) rwPFS1 (months) Overall 7.4 (5.8, 8.8) 3.5 (3.2, 4.3) Regorafenib 5.6 (3.1, 9.7) 2.4 (1.8, 3.0) TAS-102 5.9 (3.4, 8.6) 3.0 (2.1, 3.4) Other SACT2 12.8 (9.8, 17.2) 4.9 (3.7, 5.8) BSC 2.4 (1.8, 3.2) - RAS mutation Wild-type 8.6 (6.6, 11.5) 4.0 (3.3, 4.9) Mutant 5.4 (3.4, 9.5) 3.2 (2.1, 4.6) Metastatic sites Liver only 8.0 (5.7, 11.7) 3.9 (3.0, 4.9) Lung only 17.0 (7.8, 35.6) 7.9 (3.3, 10.5) Liver & lung only 5.4 (2.4, 7.2) 3.5 (2.1, 5.4) Other 6.7 (4.1, 9.4) 3.2 (2.7, 3.9) Abbreviation: CI: confidence interval, TAS-102: trifluridine/tipiracil, OS: overall survival, rwPFS: real-world progression-free survival, SACT: systemic anticancer treatment 1Overall rwPFS was calculated among patients receiving subsequent SACT only (n = 203) 2Top 2 “other SACT” included irinotecan- or oxaliplatin-based treatment

Citation Format: Mayur M. Amonkar, Sneha Sura, Kaushal Desai, Rishi Jain, Zhimei Liu, Nicole Niehoff, Thomas W. Wilson, Gregory Patton, David Cosgrove. Real-world (RW) biomarker characteristics and clinical outcomes in pre-treated non-MSI-H/dMMR metastatic colorectal cancer (mCRC) patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 927.