ERBITUX Data Demonstrate Improvements In Response Rate And Progression-free Survival In Wild Type K-ras Metastatic Colorectal Cancer Patients

NEW YORK -- ImClone Systems Incorporated today announced data from the Phase II OPUS study that show that the addition of ERBITUX(R) (cetuximab) to FOLFOX chemotherapy significantly improves both response rate and progression-free survival over FOLFOX alone in the first-line treatment of metastatic colorectal cancer (mCRC) patients whose tumors do not have mutations of the K-Ras oncogene (K-Ras wild-type). The study results have been published on the American Society of Clinical Oncology (ASCO) web site, www.asco.org, and will be presented at the ASCO Annual Meeting in Chicago on Saturday, May 31, 2008 at 1:15pm.

The OPUS study is a randomized first-line Phase II study of 337 patients comparing ERBITUX plus FOLFOX to FOLFOX alone in epidermal growth factor receptor (EGFR)-expressing mCRC patients who have not previously been treated. Oxaliplatin-based chemotherapy regimens, including FOLFOX, are used in the majority of first-line colorectal cancer patients in the U.S. Response rate, the OPUS study's primary endpoint, was found to be 46% in the ERBITUX-plus-FOLFOX arm compared with 36% in the FOLFOX-only arm (P = .064). When the wild type K-Ras patients are selected from the population, the response rate in the wild type K-Ras group increased to 61% in the ERBITUX-plus-FOLFOX arm compared with 37% in the FOLFOX-only arm (P = .01). With regard to the progression-free survival endpoint, the risk of disease progression was reduced by 43% (hazard ratio = 0.57; P = .02) by the addition of ERBITUX to FOLFOX chemotherapy in wild-type K-Ras patients. The OPUS study was conducted by Merck KGaA, Darmstadt, Germany.

In several recent clinical studies, screening patients for the K-Ras biomarker has been shown to be a highly effective tool in determining which patients will respond better to a particular cancer therapy. The non-mutated, or "wild type," K-Ras gene is expressed in about 65 percent of mCRC patients.

"ERBITUX has been shown to provide statistically and clinically improved outcomes in unselected metastatic colorectal cancer patient populations as a monotherapy and in combination therapy," said Eric K. Rowinsky, M.D., Executive Vice President and Chief Medical Officer of ImClone. "This data set is part of a growing body of scientific evidence that demonstrates that identifying individuals with the wild type K-Ras oncogene can serve to consistently improve outcomes for metastatic colorectal cancer patients receiving ERBITUX."

"We are encouraged by these promising results for the wild type K-Ras patients in the first-line OPUS study and we and our partners will continue to evaluate the potential of ERBITUX in treating colorectal cancer patients in earlier stage settings," said John H. Johnson, Chief Executive Officer of ImClone. "This K-Ras analysis, combined with other metastatic colorectal cancer studies in which we are evaluating the role of the K-Ras biomarker, are encouraging as we begin to see more tangible evidence of the potential of personalized cancer care."

About ERBITUX(R)

ERBITUX is a monoclonal antibody (IgG1 Mab) designed to inhibit the function of a molecular structure expressed on the surface of normal and tumor cells called the epidermal growth factor receptor (EGFR, HER1, c-ErbB-1). In vitro assays and in vivo animal studies have shown that binding of ERBITUX to the EGFR blocks phosphorylation and activation of receptor-associated kinases, resulting in inhibition of cell growth, induction of apoptosis, and decreased matrix metalloproteinase and vascular endothelial growth factor production. In vitro, ERBITUX can mediate antibody-dependent cellular cytotoxicity (ADCC) against certain human tumor types. No anti-tumor effects of ERBITUX were observed in human tumor xenografts lacking EGFR expression. EGFR is part of a signaling pathway that is linked to the growth and development of many human cancers, including those of the head and neck, colon and rectum.

ERBITUX, as a single agent, is indicated for the treatment of EGFR- expressing mCRC after failure of both irinotecan-and oxaliplatin-based regimens. ERBITUX, as a single agent, is also indicated for the treatment of EGFR-expressing mCRC in patients who are intolerant to irinotecan-based regimens.

Copyright Business Wire 2008