Phase II Study of Trifluridine/tipiracil (TAS-102) Therapy in Elderly Patients with Colorectal Cancer (T-CORE1401): Geriatric Assessment Tools and Plasma Drug Concentrations As Possible Predictive Biomarkers

The current study aimed to determine the efficacy of trifluridine/tipiracil for elderly patients with advanced colorectal cancer. This single-arm, open-label, multicenter, phase II study included elderly patients aged 65 years or more who had fluoropyrimidine-refractory advanced colorectal cancer and received trifluridine/tipiracil (70 mg/m2, days 1–5 and 8–12, every 4 weeks). The primary endpoint was progression-free survival (PFS), while secondary endpoints included overall survival (OS), overall response rate (ORR), toxicities, association between efficacy and geriatric assessment scores, and association between toxicity and plasma drug concentrations. A total of 30 patients with a mean age of 73 years were enrolled. Median PFS was 2.3 months (95% confidence interval, 1.9–4.3 months), while median OS was 5.7 months (95% confidence interval, 3.7–8.9 months). Patients had an ORR of 0%, with 57% having stable disease. Grade 4 neutropenia was observed in 13% of the patients. Patients with a higher G8 score (15 or more) showed longer PFS than those with a lower G8 score (median 4.6 vs. 2.0 months; p = 0.047). Moreover, patients with grade 3 or 4 neutropenia showed higher maximum trifluridine concentrations than those with grade 1 or 2 neutropenia (mean 2945 vs. 2107 ng/mL; p = 0.036). The current phase II trial demonstrated that trifluridine/tipiracil was an effective and well-tolerated option for elderly patients with advanced colorectal cancer. Moreover, geriatric assessment tools and/or plasma drug concentration monitoring might be helpful in predicting the efficacy and toxicities in elderly patients receiving this drug. UMIN000017589, 15/May/2015 (The University Hospital Medical Information Network)