This article is more than 5 years old. Information may no longer be current.
Panitumumab regimen improved OS in metastatic colorectal cancer
The addition of panitumumab to modified leucovorin, fluorouracil and oxaliplatin was associated with improved OS compared with a regimen of bevacizumab, modified leucovorin, fluorouracil and oxaliplatin in patients with untreated wild-type KRAS exon 2 metastatic colorectal cancer, according to study results.
Lee S. Schwartzberg, MD, FACP, of The West Clinic in Memphis, Tenn., and colleagues randomly assigned 278 patients with previously untreated wild-type KRAS exon 2 metastatic colorectal cancer (mCRC) in a 1:1 ratio to bevavcizumab (Avastin, Genentech) plus modified leucovorin, fluorouracil and oxaliplatin (mFOLFOX6) or panitumumab (Vectibix, Amgen) plus mFOLFOX6. PFS served as the primary outcome. OS and safety served as secondary outcomes.
Schwartzberg and colleagues also assessed treatment effects in an extended RAS analysis that included KRAS and NRAS exons 2, 3 and 4.
Both regimens conferred similar PFS. However, median OS was higher among patients who received panitumumab (34.2 months vs. 24.3 months; HR=0.62; 95% CI, 0.44-0.89).
Additionally, among patients in the wild-type RAS subgroup, PFS appeared longer in those treated with panitumumab (HR=0.65; 95% CI, 0.44-0.96; P=.029). Median OS in this subgroup was 41.3 months among those treated with panitumumab vs. 28.9 months among those treated with bevavcizumab (HR=0.63; 95% CI, 0.39-1.02).
“Patients who are wild-type by extended RAS analysis seem more likely to benefit from anti-EGFR therapy,” the researchers concluded.
Analysis of the randomized, phase 3 CALGB 80405 trial, designed to compare chemotherapy with cetuximab (Erbitux; Bristol-Myers Squibb, Lilly) or bevacizumab, may provide further support for this hypothesis, they wrote.
Disclosure: The researchers report employment or leadership positions with, stock ownership in, research funding/honoraria from and consultant/advisory roles with Amgen, as well as research funding and honoraria from Roche.