HOW WELL TESTED ARE NEW CANCER DRUGS?
Breast Cancer Action
With a certain amount of regularity a new cancer drug makes headlines, generating an enormous amount of hope as well as pressure to make the product swiftly available. In time, we usually learn that the drug’s benefit is much more modest than was originally portrayed in the media, and soon oncologists begin to prescribe the drug for other forms of cancer without waiting for clinical trials to prove its effectiveness.
Contrary to popular belief, drug companies are not required to prove that their drugs prolong survival. Until the mid-1980s, all cancer drugs were approved solely on the basis of what researchers call the "tumor response." In other words, a drug company needed only show that the drug caused a tumor to shrink, not necessarily to disappear.
Years ago, a change in the approval process was recommended by the FDA’s own Oncologic Drug Advisory Committee. The committee members, primarily cancer experts unaffiliated with any government agency, knew that tumor shrinkage often has little or no relation to survival. The committee proposed the novel idea that a drug company should be required to prove that a drug provided some benefit that was meaningful to the patient, such as increased survival or an improvement in symptoms. The committee argued further that the potential benefit of tumor shrinkage did not necessarily outweigh the substantial toxicity of cancer drugs.
This recommendation was made in the mid-1980s, but change at the FDA comes slowly, as a recent assessment of new drug approvals has demonstrated. From 1990 through 2001, the FDA approved 66 new cancer drugs. Prolonged survival was not proven for 48 drugs. And tumor response was the basis of approval for 35 drugs.
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