Recently released data is prompting the revision of a large study comparing the use of Imclone Systems Inc.'s (IMCL) Erbitux and/or Genentech Inc.'s (DNA) Avastin together with chemotherapy in treating advanced colorectal cancer.
The move follows data released Saturday at the annual meeting of the American Society of Clinical Oncology in Chicago that found adding Erbitux to a treatment regimen that includes Avastin shortened the time until disease progression in similar patients, and those patients with a mutation of the KRAS gene fared notably worse.
The ongoing study, sponsored by the National Cancer Institute, will be temporarily suspended so that it can be amended to include only patients without mutation of the gene, said Study Chair Alan Venook, an oncologist with the University of California at San Francisco
The official amendment of the trial is pending, but will likely take place later this week.
"It will delay the study, but this will be the definitive study of Erbitux versus Avastin in colon cancer," he said, calling the revision an "obvious" move.
Erbitux had worldwide sales of $1.3 billion in 2007 and is approved to treat advanced colorectal and head and neck cancers. Avastin, with 2007 sales of $2.3 billion, is approved for advanced colorectal, lung and breast cancers.
The study was expected to complete enrollment in about nine months, but the revision will add about a year to that timeline, according to Dr. Venook.
It will have three arms, one that give patients a chemotherapy regimen along with Avastin, another that gives chemo with Erbitux, and a third that gives chemo along with both Avastin and Erbitux.
After treatment, patients will be evaluated periodically for 5 years and once a year thereafter.
Erbitux is an antibody that attacks cancer cells by latching onto, and therefore blocking, a growth-related trigger called epidermal growth-factor receptor, or EGFR, that occurs in some cancers. But a mutation in the KRAS gene effectively activates the pathway downstream from the drugs and apparently prevents it from turning off the signaling.
Avastin fights cancer growth by binding to and inhibiting Vascular Endothelial Growth Factor, or VEGF, a protein that is believed to play a critical role in the formation of new blood vessels.
Genentech is majority-owned by Roche Holding AG (RHHBY), which markets Avastin outside the U.S. Bristol-Myers Squibb Co. (BMY) markets Erbitux in North America and Merck KGaA (MRK.XE) markets it outside North America.