FDA OKs High-Tech Colon Cancer Treatment
Erbitux Shrinks Tumors, Delays Progression
Feb. 12, 2004 -- The FDA approved Erbitux, the very drug at the heart of the Martha Stewart stock-sale controversy. This first-of-its-kind treatment is for colon cancer that has spread to other parts of the body.
Erbitux is a unique type of treatment called a monoclonal antibody and is the first such treatment for colon cancer. Antibodies are the body's natural defense against foreign substances, such as infection or cancer cells. Monoclonal antibodies are produced in a laboratory to target a very specific portion of foreign substances. Because of their precision, ideally treatment is more effective and has fewer side effects.
The FDA has approved Erbitux to treat colon cancer in combination with another colon cancer drug irinotecan, or alone if patients cannot tolerate irinotecan. Erbitux is shot into a vein.
Although treatment with Erbitux has not been shown to extend patients' lives in clinical trials, it was shown to shrink tumors in some patients and delay tumor growth, especially when used as a combination treatment.
Researchers say Erbitux works by targeting a natural protein called "epidermal growth factor receptor" (EGFR) on the surface of cancer cells, interfering with their growth.
"Erbitux is the second drug approved by the FDA that targets EGFR. The first was Iressa, approved last year for lung cancer," medical oncologist Harold Burstein, MD, PhD, tells WebMD. Burstein is a specialist on WebMD's Cancer Treatments and Advances message board and oncologist at the Breast Oncology Center at Dana-Farber Cancer Institute in Boston.
The drug has been tested in patients with tumors that contain EGFR and who failed treatment with irinotecan or other chemotherapy drugs. The combination treatment of Erbitux and irinotecan shrank tumors in 23% of patients and delayed tumor growth by approximately four months. For patients who received Erbitux alone, the tumor shrank in 11% and tumor growth was delayed by 1 1/2 months.
"While it is not clear if Erbitux helps patients live longer or better, it can shrink tumors in some patients," says Burstein.
"What is quite exciting is to see how the field of colorectal cancer treatment has evolved in recent years that clearly can provide benefit to patients. Now we need to figure out how best to use these many drugs -- alone, in combination, in sequence, and in whom. Those are good challenges to have."
The FDA first evaluated Erbitux in December 2001 after its manufacturer ImClone submitted an application for approval. The FDA rejected Erbitux in December 2001, saying that important safety and effectiveness data were missing. Prosecutors say Martha Stewart lied about unloading her ImClone shares at that time after she received inside information and then tried to obstruct an investigation.
In their new request for approval, Imclone submitted the results of a large, well-run trial that included 329 patients as well as the results of the earlier two studies. For the studies submitted in their original 2001 request for approval, ImClone successfully collected substantial amounts of missing information from hospital records and other sources.