Phase II study evaluating trifluridine/tipiracil + bevacizumab and capecitabine + bevacizumab in first-line unresectable metastatic colorectal cancer (mCRC) patients who are noneligible for intensive therapy (TASCO1): Results of the final analysis on the overall survival.
Authors: Van Cutsem Eric , Danielewicz Iwona , Saunders Mark P. , Pfeiffer Per , Argiles Guillem , Borg Christophe , Glynne-Jones Robert , Punt Cornelis J. A. , van de Wouw Agnes J. , Fedyanin Mikhail , Stroyakovskiy Daniil , Kroening Hendrik , Garcia-Alfonso Pilar , Wasan Harpreet Singh , Falcone Alfredo , Aubel Paul , Egorov Anton , Amellal Nadia , Moiseenko Vladimir 
Published: January 2021

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Background: Our phase II randomized study was conducted in patients with previously untreated unresectable mCRC not eligible to receive standard oxaliplatin- or irinotecan- based chemotherapy regimens. The results of the primary study analysis were reported earlier and demonstrated a promising efficacy in terms of progression-free survival (PFS) and an acceptable safety profile for the combination of trifluridine/tipiracil + bevacizumab (E. Van Cutsem et al. Ann. Oncol. 2020). Here we present the final end-of-study analysis on the overall survival (OS). Methods: Eligible patients were randomized in 1:1 ratio to receive either trifluridine/tipiracil administered orally at 35 mg/m²/dose bid from days 1-5 and days 8-12, and bevacizumab at 5 mg/kg on days 1 and 15 of a 28-day treatment cycle (TT-B), or capecitabine administered orally at 1250 or 1000 mg/m²/dose bid (according to the patient’s status) from days 1-14 and bevacizumab at 7.5 mg/kg on day 1 of a 21-day treatment cycle (C-B). Cycles were repeated until documented disease progression, unacceptable toxicity, or investigator’s/patient’s decision. Following the treatment discontinuation, all patients were followed for OS until the end-of-study, which was defined as the date of the withdrawal visit for the last patient. In the absence of death confirmation or for patients alive as of the end-of-study date, survival time was censored at the date of their last study follow-up. For the OS analysis the HR and the corresponding 2-sided 80% and 2-sided 95% CIs for TT-B versus C-B were estimated using a Cox proportional hazard model adjusting for the stratification factors based on IWRS data. OS was summarized using Kaplan-Meier curves and further characterized in terms of the median and survival probabilities at 6, 12, 18, and 24 months along with the corresponding 2-sided 80% and 2-sided 95% CI (Brookmeyer and Crowley CI for median and Kalbfleisch and Prentice CI for survival probabilities). Results: From April 2016 to March 2017, 153 patients were randomized and followed until end-of-study on September 1, 2020. Twenty-one patients, 11 from TT-B and 10 from C-B, were alive and censored for the analysis. Median OS was 22.31 months in TT-B and 17.67 months in C-B with HR 0.78 (95% CI, 0.55, 1.10). Survival probability at 18 months in TT-B was 0.62 (95% CI, 0.50, 0.72), and 0.47 (95% CI, 0.35, 0.57) in C-B. Conclusions: Our study demonstrated earlier a median PFS of 9.2 months for TT-B and 7.8 months for C-B when administered to patients with previously untreated unresectable mCRC ineligible for standard combination chemotherapy. The final study analysis performed on OS, the main secondary endpoint, provided further evidence for TT-B as a noteworthy valuable regimen in this population settings. Clinical trial information: NCT02743221.