Amgen Statement on Additional Biomarker Analysis Beyond KRAS From Completed Phase 3 Study

RAS Mutation Status Beyond KRAS may be Predictive of Negative Outcomes in Patients Receiving Panitumumab Plus FOLFOX

THOUSAND OAKS, Calif. (April 17, 2013) – New biomarker findings are available based on a prospective analysis of a previously completed Phase 3 study (PRIME '203) of panitumumab plus FOLFOX (an oxaliplatin-based chemotherapy) versus FOLFOX alone in patients with previously untreated wild-type KRAS metastatic colorectal cancer (mCRC). Results of the primary analysis of this study have been previously reported.1 In this new biomarker analysis, "RAS mutations" refers to mutations in exons 2, 3, and 4 of KRAS and NRAS and "KRAS mutations" refers to the common mutations in exon 2 (codons 12 or 13) of KRAS.

In this analysis, patient tumor samples with wild-type KRAS status were assessed for additional RAS mutations. The additional mutations in RAS were associated with inferior progression-free survival and overall survival in patients who were administered panitumumab in combination with FOLFOX chemotherapy versus FOLFOX alone. No new toxicities were identified. These results suggest that RAS mutation status beyond KRAS may be predictive of negative outcomes in patients receiving panitumumab plus FOLFOX in mCRC.

Amgen is communicating this important new safety information to investigators. Amgen is also working with regulatory agencies globally regarding appropriate safety communication and the outcomes of this analysis to the healthcare community.

These results will be presented at the American Society of Clinical Oncology (ASCO) 2013 Annual Meeting.  ASCO has granted an exception to its Abstract Policy so that physicians and patients may begin to make treatment decisions based on the new information.  This exception and the abstract can be viewed online at:

About Vectibix® (panitumumab)

In the United States, Vectibix is indicated as a single agent for the treatment of epidermal growth factor receptor (EGFR)-expressing, metastatic colorectal carcinoma (mCRC) with disease progression on or following fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy regimens. The effectiveness of Vectibix as a single agent for the treatment of EGFR-expressing, metastatic colorectal carcinoma is based on progression-free survival. Currently, no data demonstrate an improvement in disease-related symptoms or increased survival with Vectibix.

Vectibix is not indicated for the treatment of patients with KRAS mutation-positive mCRC or for whom KRAS mCRC status is unknown. Retrospective subset analyses of metastatic colorectal cancer trials have not shown atreatment benefit for Vectibix in patients whose tumors had KRAS mutations in codon 12 or 13.

For additional information about Vectibix and full prescribing information, please visit


  1. Douillard JY, Siena S, Cassidy J, et al: Randomized, phase III trial of panitumumab with infusional fluorouracil, leucovorin, and oxaliplatin (FOLFOX4) versus FOLFOX4 alone as first-line treatment in patients with previously untreated metastatic colorectal cancer: the PRIME study. Journal of Clinical Oncology. 28:4697-705, 2010.