Key clinical point: Initial phase 2 results do not support combining pembrolizumab to neoadjuvant chemoradiotherapy after 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) treatment of locally advanced rectal cancer (LARC), despite being safe.
Major finding: The mean neoadjuvant rectal (NAR) score was not significantly different among patients treated with vsvs without pembrolizumab (difference, 2.55; P = .26). Grade 3/4 adverse events were slightly higher in patients receiving pembrolizumab vsvs those not (48.2% vsvs 37.3%).
Study details: Findings are from an open-label, phase 2 trial including 185 patients with stage II/III LARC at high risk for metastatic disease who were eligible for sphincter-sparing surgery. Patients were randomly assigned to receive FOLFOX (6 cycles) followed by chemoradiotherapy with (n=90) or without (n=95) intravenous pembrolizumab for up to 6 doses before surgery.
Disclosures: The study was supported by the National Cancer Institute and Merck. Some of the authors including the lead author reported receiving personal fees, grants, honoraria, and/or serving as a consultant and/or on advisory boards for various sources.
Source: Rahma OE et al. JAMA Oncol. 2021 Jul 1. doi: 10.1001/jamaoncol.2021.1683 .