In patients with previously untreated metastatic colorectal cancer (mCRC), the goal of treatment is likely to influence choice of first-line therapy, as suggested in ESMO 2016 guidelines previewed at WCGIC 2015. We conducted an exploratory analysis of the efficacy of first-line modified FOLFOX6 (mFOLFOX6) plus panitumumab or bevacizumab in patients with RAS wild-type (WT)/BRAF WT mCRC based on the aim of treatment: cytoreduction or disease control.
PEAK (NCT00819780) was an open-label randomised phase II trial of first-line panitumumab + mFOLFOX6 vs bevacizumab + mFOLFOX6. Using baseline characteristics, patients with RAS WT/BRAF WT mCRC were retrospectively classified into groups according to treatment goal: Cytoreduction group (liver-limited disease [LLD] and/or symptoms) or Disease-control group (asymptomatic with non-liver-limited metastases [with or without liver metastases]). Patients with an Eastern Cooperative Oncology Group (ECOG) score of 1 were considered to have tumour-related symptoms; those with ECOG 2 were excluded as they were not considered fit enough to meet ESMO criteria.
The analysis included 155 patients with RAS WT/BRAF WT mCRC, of whom 83 were in the Cytoreduction group and 72 were in the Disease-control group. Median PFS and OS were numerically longer with panitumumab + mFOLFOX6 vs bevacizumab + mFOLFOX4 in both groups (Table).
|Cytoreduction group (n = 83)|
|Panitumumab (n = 42)||12.7||36.8|
|Bevacizumab (n = 41)||10.6||29.0|
|HR (95% CI)||0.66 (0.43-1.06)||0.78 (0.46-1.33)|
|Disease-control group (n = 72)|
|Panitumumab (n = 35)||13.1||46.1|
|Bevacizumab (n = 37)||11.5||31.3|
|HR (95% CI)||0.71 (0.43-1.18)||0.60 (0.33-1.07)|
This exploratory analysis suggests that first-line treatment with mFOLFOX6 provides longer PFS and OS when combined with panitumumab than when combined with bevacizumab in patients with RAS WT/BRAF WT mCRC whether the aim of treatment is cytoreduction or disease control. These results are consistent with data from the PRIME study presented elsewhere at this congress (Taieb et al.) using two definitions of ‘symptomatic’, based on ECOG and patient-reported outcomes.
Clinical trial identification
Legal entity responsible for the study
F. Rivera: Acted on advisory boards and received research funding from Amgen, Sanofi, Merck-Serono and Roche. M. Peeters: Received research funding and acted in consultancy/advisory roles for Amgen and received research funding and participated in symposia for Merck Serono J-Y. Douillard: Honoraria/consulting/advisory roles for Amgen, Bayer, Roche, Merck; Research funding from Merck Serono; Travel/accommodation/ expenses from Amgen, Bayer, Roche, Merck. J. Taieb: Honoraria/consultigng/advisory role for Roche, Amgen, Merck, Lilly, Sanofi, Celgene, Sirtex R. Koukakis: Employee of Amgen Ltd. G. Demonty: Employee of Amgen (Europe) GmbH. S. Siena: Member of advisory boards or steering committees or principal investigator for Amgen, Bayer, Boehringer Ingelheim, Celgene, Genentech, Ignyta, Merck, Merrimack, Novartis, Pfzer, Roche, and SanofiAventis.