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Updated CRYSTAL: KRAS predictive of outcomes in CRC treated with cetuximab plus FOLFIRI
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2010 Gastrointestinal Cancers Symposium
Patients with wild-type KRAS metastatic colorectal cancer had superior objective response, OS and PFS with cetuximab plus FOLFIRI compared with patients assigned to FOLFIRI alone, according to updated results from the CRYSTAL trial.
“This final analysis confirms KRAS mutation status to be a predictive factor across all efficacy endpoints examined for cetuximab in combination with FOLFIRI,” said Eric Van Cutsem, MD, PhD, head of the division of digestive oncology at University Hospital Gasthuisberg in Leuven, Belgium. Van Cutsem presented results from a retrospective analysis of the phase-3 CRYSTAL trial at the 2010 Gastrointestinal Cancers Symposium in Orlando, Fla. Earlier results were presented at the 2008 ASCO Annual Meeting and published in The New England Journal of Medicine.
Almost 90% of patients in the intent-to-treat population were evaluable for KRAS mutation (n=1,063). Among those patients, 56% (n=666) had wild-type tumors.
Objective response for patients with wild-type KRAS randomly assigned to cetuximab (Erbitux, ImClone) plus FOLFIRI was 57.3% vs. 39.7% for those assigned to FOLFIRI alone (OR=2.07; P<.0001). Patients in the combination arm also had longer PFS (9.9 months vs. 8.4 months; HR=0.696; P=.0012) and OS (23.5 months vs. 20 months; HR=0.796; P =.009).
Van Cutsem said these findings remained consistent in patients with both wild-type KRAS/wild-type BRAF tumors. OS for patients assigned to the combination was 25.1 months vs. 21.6 months (HR=0.83; 95% CI, 0.687-1.004). PFS for these patients was 10.9 months with cetuximab plus FOLFIRI compared with 8.8 months (HR=0.679; 95% CI, 0.533-0.864). Objective response was 61.0% in the combination arm vs. 42.6%.
However, Van Cutsem said there was no statistically significant difference for response rate, OS or PFS between the study arms in patients with wild-type KRAS and mutant BRAF tumors.
“This analysis suggests BRAF mutation is a poor prognostic factor in first-line metastatic colorectal cancer,” he said. “BRAF mutation status does not appear to be a strong biomarker for the addition of cetuximab to FOLFIRI.” – by Jason Harris
For more information:
- Van Cutsem E. #281. Presented at: 2010 Gastrointestinal Cancers Symposium; Jan. 22-24, 2010; Orlando, Fla.
