MGH cancer specialists propose new approval track for targeted drugs

08/11/04

'Selective approval' would require follow up studies to identify most appropriate patients

One of the most promising new strategies for cancer treatment is the development of drugs that directly target molecular abnormalities that lead to the growth of tumors. Several such drugs have received Food and Drug Administration (FDA) approval in recent years, but some have been controversial because the data on which they were approved did not clearly define which patients will most benefit from the new medications.

Writing in the July 29 New England Journal of Medicine, two specialists from the Massachusetts General Hospital (MGH) Cancer Center propose an expansion of the FDA's "fast-track" programs for drug approval. In their "Sounding Board" piece, Thomas Roberts Jr., MD, and Bruce Chabner, MD, call on the FDA to require pharmaceutical companies to carry out studies identifying the patients most likely to respond to a targeted-therapy drug, as a condition of the drug's approval.

"Throughout the 1980s members of the AIDS community were incredibly effective in influencing the FDA to allow easier access to antiretroviral drugs," says Roberts. "The resulting fast-track programs allow more rapid review and approval of drugs to treat many serious conditions that have no effective treatment."

While fast-track approval has opened up important therapeutic options for many patients, Roberts adds, without the detailed data provided by fully controlled clinical trials, physicians may not have information that clarifies who should or should not receive the medications. "With a new drug that costs $15,000, you don't want to shoot in the dark and just hope this patient will be the one in ten who will benefit. And since choosing one of these drugs means you may have to exclude a different one, you don't want to waste time with an agent that won't help that patient."

He and Chabner propose institution of a mechanism they call "selective approval," which could be piloted for cancer drugs and eventually used for medications treating other conditions. Under selective approval, targeted drugs could receive fast-track approval based on consistent antitumor responses in early clinical trials, provided that the sponsoring pharmaceutical company has begun studies designed to identify the patients most likely to respond to the therapy. The approval would be reviewed annually and could be withdrawn if the clarifying research were not completed. On the other hand, completion of controlled clinical trials would convert the approval to full status.

"The advent of targeted cancer reatments has brought great enthusiasm for what some refer to as personalized medicine," says Roberts, "but there has also been disappointment that so few of these individualized approaches have become available to patients. One of the FDA's fast-track programs, called accelerated approval, which looks at surrogates for clinical benefit [biomarkers] instead of waiting for definitive evidence of clinical benefit [e.g. improvement in survival time], is an important first step that we think should go further. The next step will require investing in the studies that will help us, as clinicians, better target therapies to the patients that will benefit the most."

Roberts is an instructor in Medicine at Harvard Medical School, and Chabner, clinical director of the MGH Cancer Center, is a professor of Medicine. Their report is supported by grants from the National Cancer Institute and the PhRMA Foundation.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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