Nivolumab in patients with DNA mismatch repair-deficient/microsatellite instability-high (dMMR/MSI-H) metastatic colorectal cancer (mCRC): Long-term survival according to prior line of treatment from CheckMate-142.

Abstract

554 Background: Nivolumab (NIVO) provided durable responses (ORR, 32% per central assessment) and disease control (DCR, 64%) in pre-treated pts with dMMR/MSI-H mCRC (NCT02060188; Overman MJ et al Lancet Oncol 2017). NIVO was approved in the US for pts with dMMR/MSI-H mCRC who progress after standard chemotherapy (SC) with a fluoropyrimidine (F), oxaliplatin (Ox), and irinotecan (Iri). Here we present long-term survival and outcomes by prior chemotherapy with NIVO in CheckMate-142. Methods: Pts with dMMR/MSI-H mCRC received NIVO 3 mg/kg Q2W. The primary endpoint was ORR per RECIST 1.1. Other endpoints were DCR, DOR, PFS, OS, and safety/tolerability. Results: Of 74 pts evaluated, 53 had received F, Ox and Iri (group A); 21 pts had ≤ 2 SC regimens (group B). Median follow-up was 21 mo. Efficacy by central assessment is shown in the Table. In the 74 pts, ORR was 34%; CRs increased from 3% in prior database lock (DBL) to 9%. Numerically higher responses were noted in group B vs group A (Table). Grade 3–4 TRAEs were reported in 20% (all pts), 25% (group A), and 10% (group B) of pts. No treatment-related deaths were reported. Conclusions: NIVO continued to provide clinically meaningful durable responses and long-term overall survival in pts with dMMR/MSI-H mCRC. Of note, CR rate increased with longer follow-up. No new safety signals were reported with long-term follow-up. Enhanced responses in pts with ≤ 2 SC regimens support ongoing evaluation of NIVO combinations in first-line setting. Clinical trial information: NCT02060188. [Table: see text]