Cetuximab plus FOLFOXIRI versus cetuximab plus FOLFOX as conversion regimen in RAS/BRAF wild-type patients with initially unresectable colorectal liver metastases (TRICE trial): A randomized controlled trial

Abstract

Background: It remains unclear whether intensification of the chemotherapy backbone in tandem with an anti-EGFR can confer superior clinical outcomes in a cohort of RAS/BRAF wild-type colorectal cancer (CRC) patients with initially unresectable colorectal liver metastases (CRLM). To that end, we sought to comparatively evaluate the efficacy and safety of cetuximab plus FOLFOXIRI (triplet arm) versus cetuximab plus FOLFOX (doublet arm) as a conversion regimen (i.e., unresectable to resectable) in CRC patients with unresectable CRLM.

Methods and findings: This open-label, randomized clinical trial was conducted from April 2018 to December 2022 in 7 medical centers across China, enrolling 146 RAS/BRAF wild-type CRC patients with initially unresectable CRLM. A stratified blocked randomization method was utilized to assign patients (1:1) to either the cetuximab plus FOLFOXIRI (n = 72) or cetuximab plus FOLFOX (n = 74) treatment arms. Stratification factors were tumor location (left versus right) and resectability (technically unresectable versus ≥5 metastases). The primary outcome was the objective response rate (ORR). Secondary outcomes included the median depth of tumor response (DpR), early tumor shrinkage (ETS), R0 resection rate, progression-free survival (PFS), overall survival (not mature at the time of analysis), and safety profile. Radiological tumor evaluations were conducted by radiologists blinded to the group allocation. Primary efficacy analyses were conducted based on the intention-to-treat population, while safety analyses were performed on patients who received at least 1 line of chemotherapy. A total of 14 patients (9.6%) were lost to follow-up (9 in the doublet arm and 5 in the triplet arm). The ORR was comparable following adjustment for stratification factors, with 84.7% versus 79.7% in the triplet and doublet arms, respectively (odds ratio [OR] 0.70; 95% confidence intervals [CI] [0.30, 1.67], Chi-square p = 0.42). Moreover, the ETS rate showed no significant difference between the triplet and doublet arms (80.6% (58/72) versus 77.0% (57/74), OR 0.82, 95% CI [0.37, 1.83], Chi-square p = 0.63). Although median DpR was higher in the triplet therapy group (59.6%, interquartile range [IQR], [50.0, 69.7] versus 55.0%, IQR [42.8, 63.8], Mann-Whitney p = 0.039), the R0/R1 resection rate with or without radiofrequency ablation/stereotactic body radiation therapy was comparable with 54.2% (39/72) of patients in the triplet arm versus 52.7% (39/74) in the doublet arm. At a median follow-up of 26.2 months (IQR [12.8, 40.5]), the median PFS was 11.8 months in the triplet arm versus 13.4 months in the doublet arm (hazard ratio [HR] 0.74, 95% CI [0.50, 1.11], Log-rank p = 0.14). Grade ≥ 3 events were reported in 47.2% (35/74) of patients in the doublet arm and 55.9% (38/68) of patients in the triplet arm. The triplet arm was associated with a higher incidence of grade ≥ 3 neutropenia (44.1% versus 27.0%, p = 0.03) and diarrhea (5.9% versus 0%, p = 0.03). The primary limitations of the study encompass the inherent bias in subjective surgical decisions regarding resection feasibility, as well as the lack of a centralized assessment for ORR and resection.

Conclusions: The combination of cetuximab with FOLFOXIRI did not significantly improve ORR compared to cetuximab plus FOLFOX. Despite achieving an enhanced DpR, this improvement did not translate into improved R0 resection rates or PFS. Moreover, the triplet arm was associated with an increase in treatment-related toxicity.

Trial registration: ClinicalTrials.gov Identifier: NCT03493048.

Fig 1. CONSORT diagram.

The safety population consisted of patients who received at least 1 line of chemotherapy. Loss to follow-up included individuals who were no longer contactable or available for further participation in a study, either because they withdrew before the end of the planned follow-up period or for other reasons that rendered them unreachable. FOLFOX, fluorouracil, leucovorin, and oxaliplatin; FOLFOXIRI, modified fluorouracil, leucovorin, oxaliplatin, and irinotecan; ICC, intrahepatic cholangiocarcinoma; MDT, multidisciplinary team; NED, no evidence of disease.

Fig 2. Tumor response comparisons between the 2 treatment arms in terms of (A) ORR and (B) ETS.

Not evaluable refers to patients in the ITT population who did not have at least 1 efficacy assessment. FOLFOX, fluorouracil, leucovorin, and oxaliplatin; FOLFOXIRI, fluorouracil, leucovorin, oxaliplatin, and irinotecan; OR, odds ratio; PR, partial response; SD, stable disease; PD, progressive disease; NE, not evaluated; ORR, objective response rate; ETS, early tumor shrinkage.

Fig 3

(A) Waterfall plot depicting the depth of tumor response in patients that had at least 1 efficacy evaluation. The blue and orange bars represent the percentage of tumor change from baseline for patients treated with cetuximab plus FOLFOXIRI and cetuximab plus FOLFOX, respectively. The dashed lines correspond to RECIST version 1.1 criteria, with PD indicating an increase of at least 20% in the sum of the diameters of target lesions from baseline, and PR defined as a minimum of 30% decrease in the sum of the diameters of target lesions from baseline. (B) Progression-free survival in the ITT population. FOLFOX, 5-fluorouracil, leucovorin, and oxaliplatin; FOLFOXIRI, 5-fluorouracil, leucovorin, oxaliplatin, and irinotecan; DpR, depth of response; IQR, interquartile range; ITT, intention-to-treat; PD, progressive disease; PR, partial response.