P-95 Bevacizumab, irinotecan and biweekly trifluridine/tipiracil for pretreated metastatic colorectal cancer: MODURATE, a phase Ib study

Abstract

Treatment of refractory metastatic colorectal cancer (mCRC) with trifluridine/tipiracil yields some survival benefits. Trifluridine/tipiracil combined with bevacizumab or irinotecan suggested enhanced therapeutic effects in preclinical models. A phase Ib study combining standard trifluridine/tipiracil regimens with irinotecan resulted in better antitumor activity, accompanied by a high degree of febrile neutropenia. This phase Ib study of trifluridine/tipiracil, irinotecan, and bevacizumab in previously treated mCRC was conducted at two centers, Shizuoka Cancer Center and Aichi Cancer Center in Japan, and consisted of dose escalation (3+3 design) and expansion cohorts. Key eligibility criteria included histologically confirmed colorectal adenocarcinoma, failure or intolerant to fluoropyrimidine and oxaliplatin, no prior therapy with trifluridine/tipiracil and irinotecan, age of 20–75 years, and ECOG PS of 0–1. Patients received trifluridine/tipiracil (25–35 mg/m2 twice daily on days 1–5), irinotecan (150–180 mg/m2; day 1), and bevacizumab (5 mg/kg; day 1) every 2 weeks. The recommended phase II dose (RPTD) in the dose escalation cohort was administered to at least 15 patients in both cohorts. A total of 28 patients from two centers were enrolled between August 2016 and January 2020, comprising 18 in dose escalation cohort and 10 additional patients in expansion cohort. Five dose-limiting toxicities were observed in dose escalation cohort. RPTD was defined as trifluridine/tipiracil 35 mg/m2, irinotecan 150 mg/m2, and bevacizumab 5 mg/kg. Of the 16 patients who received RPTD, patients characteristics were as follows; median age (range), 64 (38-73) years; male/female, 11/5; PS 0/1, 13/3; right-/left-sided tumor, 1/15; median number of metastatic site (range), 2 (1-5); RAS mutant/wild-type, 9/7; uridine diphosphate glucuronosyltransferase 1A1 genotype wild/single hetero/double hetero or homo, 7/8/1; prior history of bevacizumab/anti-EGFR antibody, 6/4. The most common grade 3/4 adverse events were neutropenia (86%) and leukopenia (63%) without febrile neutropenia. No treatment-related death was observed. Dose reduction, delay, and discontinuation occurred in 94%, 94%, and 6% of patients, respectively. At a median follow-up time (range) of 417 (346–611) days, the overall response rate was 19%, with 3 patients achieving a partial response. The disease control rate was 75%, with an additional 9 patients exhibiting stable disease for >4 months duration in 5 patients. The median progression-free survival and overall survival were 7.1 (95% confidence interval [CI], 3.7–not reached [NR]) months and 21.7 (95% CI, 11.3–NR) months, respectively. Biweekly administration of trifluridine/tipiracil, irinotecan, plus bevacizumab may decrease febrile neutropenia with moderate antitumor activity in previously treated mCRC patients. Further investigation of this combination therapy is required.