Phase II Trial of Target-guided Personalized Chemotherapy in First-line Metastatic Colorectal Cancer

Purpose: The aim of this study was to investigate the feasibility and efficacy of personalizing treatment of patients with advanced untreated colorectal cancer (CRC). Patients and Methods: Patients with untreated metastatic CRC, performance status 0-1, and candidates for systemic chemotherapy were eligible. Tumor tissues were analyzed for KRAS, BRAF, and PI3K mutations and expression of topoisomerase-1 (Topo-1), excision repair cross-complementing gene 1 (ERCC1), thymidylate synthase (TS), and thymidine phosphorylase (TP). Patients with Topo-1 expression received irinotecan, whereas patients with negative Topo-1 and ERCC1 expression received oxaliplatin. Otherwise, patients received physician's choice of treatment. If TS was positive, no fluoropyrimidine was administered and if negative, 5-flurorouracil if TP was negative, or capecitabine if TP was positive. KRAS-mutated patients were treated with bevacizumab, whereas KRAS-native received cetuximab. The primary endpoint of the study was progression-free survival (PFS). Results: A total of 74 patients were enrolled and 67 received personalized treatment including irinotecan (n = 27), oxaliplatin (n = 16), FOLFIRI (n = 12), and FOLFOX (n= 12). Thirty-eight patients received cetuximab and 29 bevacizumab. With a median follow-up time of 18.3 months (95% confidence interval [CI], 4-36), the overall median PFS was 8.3 months (95% CI, 6.9-9.7), representing a 12-month PFS rate of 36.5% (95% CI, 25-48). Overall clinical benefit, including response rate and disease stabilization, was 86% (95% CI, 73%-97%). The overall median survival was 21 months (95% CI, 11-40). Conclusions: Real-time target-guided personalized first-line treatment of patients with advanced CRC is feasible but, with the approached used, did not result in a clear improvement in PFS to warrant phase III testing.