The analysis indicates that patients with KRAS wild-type tumors bearing a BRAF mutation also benefit from Erbitux treatment; therefore, KRAS remains the only validated, clinically predictive marker of responsiveness to this drug.
The final Crystal data showed that in patients with KRAS wild-type tumors receiving Erbitux plus Folfiri, Median OS was 23.5 months compared to 20.0 months in those receiving chemotherapy alone. The risk of disease progression was reduced by 30.4%. The addition of Erbitux to Folfiri led to improvements in ORR and PFS.
Furthermore, the Crystal/Opus pooled analysis was designed to evaluate OS, PFS and ORR in the combined Crystal and Opus populations of patients with KRAS wild-type tumors.
In the study, the risk of death was reduced by 19% for patients receiving Erbitux plus chemotherapy compared to those receiving chemotherapy alone. The risk of disease progression was reduced by 34% for patients receiving Erbitux plus chemotherapy, compared to those receiving chemotherapy alone.
Aditionally, the updated results from the Opus study showed that in patients with KRAS wild-type tumors treated with Erbitux and chemotherapy (FOLFOX4), Median OS was 22.8 months compared to 18.5 months in the chemotherapy-alone arm. The risk of disease progression was reduced by 43.3%.
Claus-Henning Kohne, head of the department of oncology and hematology, said: “It is clear that overall survival is a critically important outcome in metastatic colorectal cancer, so it is extremely rewarding to achieve this result in patients with KRAS wild-type tumors. The analysis indicating that BRAF is not predictive for Erbitux efficacy is also of interest, as it confirms the current role of KRAS as the only clinically predictive biomarker for Erbitux.”
The study results were presented at the American Society of Clinical Oncology’s 2010 Gastrointestinal Cancers Symposium (ASCO-GI) in Orlando.