The FDA's decision to expand Herceptin prescribing practices was expected in August, but the agency requested more information prior to its decision. However, according to Citigroup analysts, doctors across the country were already extensively prescribing Herceptin to early-stage breast cancer patients before the FDA gave approval.
Herceptin first entered the market in 1998 as a treatment for the 25 to 30 percent of breast cancer patients whose tumors generate a protein called HER-2. The drug was recommended for patients whose cancer had spread beyond the breast.
After Genentech announced last year that it had conducted a trial yielding positive results for the use of Herceptin in combination with chemotherapy in early-stage cancer patients, doctors began writing off-label prescriptions for the drug in such patients, prior to FDA approval.
Off-label prescribing is the practice of a physician prescribing a drug to treat a condition for which the FDA has not approved the drug. Essentially, once a drug is approved to treat one condition, it can then be legally prescribed to treat any other condition, despite lack of safety or effectiveness testing for treating unapproved conditions.
In the first nine months of 2006, U.S. sales of Herceptin increased by 84 percent from the same period in 2005, to $912 million. Citigroup says the FDA's approval of off-label prescriptions is unlikely to increase sales further, since doctors had already been prescribing the drug for early-stage patients.
Consumer health advocate Mike Adams, author of a critical cartoon on Herceptin, said, "The FDA's wink-and-nod tolerance of off-label prescribing makes a mockery of the entire drug approval process.
"Today's laws say that doctors can prescribe any drug for literally any condition, regardless of whether it has ever been approved or even tested for such conditions," he said. "To call this 'evidence-based medicine' is downright laughable."
A study appearing in the August issue of the Journal of Clinical Oncology found that Herceptin caused heart damage in 28 percent of its users.