Treatment Patterns and Real-World Clinical Outcomes in Patients with Advanced Endometrial Cancer Who Are Microsatellite Instability (Msi)-High or Are Mismatch Repair Deficient (dmmr) in the United States

Objectives. Microsatellite instability-high (MSI-H) and deficient DNA mismatch repair (dMMR) status have emerged as actionable biomarkers for advanced endometrial cancer (aEC). The objective of this study was to as-sess clinical outcomes and treatment patterns among MSI-H/dMMR aEC patients who had disease progression following prior systemic therapy (FPST) in the US.Methods. Endometrial Cancer Health Outcomes (ECHO) was a retrospective, medical chart review study of patients with MSI-H/dMMR aEC who had disease progression between 07/01/2016 and 12/31/2018 FPST and were not candidates for curative surgery. Data on patient demographics, clinical and treatment characteristics, and clinical outcomes were collected. Kaplan-Meier analyses were performed to estimate real-world progression-free survival (rwPFS) and overall survival (OS), stratified by drug class.Results. A total of 124 eligible patients who initiated second-line chemotherapy +/- bevacizumab or immuno-therapy were included. Mean age was 61.4 years at aEC diagnosis and 86.3% of patients were stage IIIB-IV. Median rwPFS and OS were 4.0 months (95% CI: 2.0-9.0) and 7.0 months (95% CI: 5.0-18.0), respectively, among 21 pa-tients who received chemotherapy +/- bevacizumab, and 29.0 months (95% CI: 18.0-NE) and not reached (95% CI: 30.0-NA), respectively, among 103 patients who received immunotherapy. Most patients (n = 92) received pembrolizumab; among these patients, rwPFS and OS were 29.0 months (95% CI: 18.0-NE) and 30 months (95% CI: 30.0-NA), respectively.Conclusions. Real-world evidence suggests that pembrolizumab monotherapy provides considerable clinical benefits and has become the standard of care for MSI-H/dMMR aEC patients FPST who are not candidates for curative surgery in real-world settings.(c) 2022 Merck Sharp & Dohme LLC., a subsidiary Merck & Co., Inc., Rahway, NJ, USA and The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).