FDA Approves Erbitux and Vectibix Label Changes Regarding KRAS Status

The US Food and Drug Administration (FDA) has approved prescribing information changes to the “indication and usage” section of the labels for ImClone/Bristol-Myers Squibb’s Erbitux (cetuximab) and Amgen’s Vectibix (panitumumab), allowing the manufacturers to note that metastatic colorectal cancer trials have not shown a treatment benefit with use of epidermal growth factor receptor (EGFR) inhibitors in patients whose tumors have KRAS mutations in codon 12 or 13, and that these drugs are not recommended for the treatment of colorectal cancer in patients with these mutations. The FDA has also updated the “clinical studies” section of the labels to include results from retrospective analyses across seven randomized clinical trials with agents in this class. These label updates follow guidelines issued by the American Society of Clinical Oncology and the National Comprehensive Cancer Network back in January 2009, which recommended that all metastatic colorectal cancer patients be tested for KRAS variants before initiating treatment with an anti-EGFR antibody.

According to a statement issued by Sean Harper, chief medical officer and head of global development at Amgen, “With this label update, physicians can now eliminate anti-EGFR antibodies as a treatment option for patients with mutated KRAS tumors and redirect those patients to alternative therapies, avoiding unnecessary treatments in patients who are unlikely to benefit.” The statement also noted that the label update is “specific to the utility of KRAS as a biomarker for Vectibix used as a monotherapy.” The company is currently conducting two prospective phase III clinical trials in the combination chemotherapy setting that will assess the clinical utility of KRAS as a predictive biomarker in earlier lines of therapy in patients with metastatic colorectal cancer. Data from these trials are expected to be released in the third quarter of 2009.

It is estimated that about 35% of colorectal cancer patients have KRAS mutations, with the remainder having a nonmutated or wild type KRAS gene. Not using Erbitux as a first-line treatment for these patients could save about $600 million a year.