FOLFIRINOX-R study design: a phase I/II trial of FOLFIRINOX plus regorafenib as first line therapy in patients with unresectable RAS-mutated metastatic colorectal cancer

Abstract

Background The chemotherapy triplet FOLFOXIRI combined to the anti-VEGF antibody bevacizumab is an option in selected patients with metastatic colorectal cancer. In this setting, RAS-mutated metastatic colorectal cancer do not benefit the same from treatment than RAS-wildtype metastatic colorectal cancer do. Together with its antiangiogenic properties, the tyrosine-kinase inhibitor regorafenib has also anti-proliferative activities whatever the RAS status is. The present trial aims at studying the safety and the efficacy of regorafenib in combination with FOLFIRINOX – a chemotherapy triplet using a different dosing schedule than FOLFOXIRI - in patients with RAS-mutated metastatic colorectal cancer. Methods FOLFIRINOX-R is a prospective, multicentric, non-randomised, dose-finding phase 1–2 trial. The primary endpoints are the determination of the maximum tolerated dose, the recommended phase 2 dose, and the proportion of patients achieving disease control at 48-weeks. Phase 1 follows a 3 + 3 design (12 to 24 patients to be included). Sixty nine patients will be necessary in phase 2, including 5% non-evaluable ones, with the following assumptions, one-stage Fleming design, α = 5%, β = 20%, p0 = 35% and p1 = 50%. Key eligibility criteria include Eastern Cooperative Oncology Group Performance Status of ≤1 and RAS-mutated metastatic colorectal cancer not amenable to surgery with curative intent and not previously treated for metastatic disease. FOLFIRINOX (oxaliplatin 85 mg/m2, folinic acid 400 mg/m2, irinotecan 150–180 mg/m2, 5-fluorouracil: 400 mg/m2 then 2400 mg/m2 over 46 h) is administered every 14 days. Regorafenib (80 to 160 mg, as per dose-level) is administered orally, once daily on days 4 to 10 of each cycle. Discussion FOLFIRINOX-R is the first phase I/II study to evaluate the safety and efficacy of regorafenib in combination with FOLFIRINOX as frontline therapy for patients with RAS-mutated metastatic colorectal cancer. Trial registration EudraCT: 2018-003541-42; ClinicalTrials.gov: NCT03828799.

A narrative review of genetic factors affecting fluoropyrimidine toxicity

“…However, tumors that display activating mutations in KRAS or BRAF negate the efficacy of agents targeting EGFR, and in these cases FP-based chemotherapy (doublet or triplet) is frequently used in combination with anti-VEGF therapy (e.g., Bevacizumab). For highly aggressive mCRC, as occurs with BRAF mutations, four component FP-based regimens FOLFOXIRI and FOLFIRINOX are used ( 22 ). FOLFIRINOX was also recently shown to be a preferred option for adjuvant chemotherapy of pancreatic cancer ( 23 ), and to be an effective option in patients with advanced gastroesophageal adenocarcinoma ( 24 ).…”