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August 30, 2007

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domg

"..which has to be a good move"?
The American medical journalist & researcher commenta:
"In the clinical trial that led to the approval of Tykerb, patients who took Tykerb plus the oral chemotherapy drug Xeloda had on average two months longer before their disease progressed than those taking Xeloda alone. How important is this?

Of course, two months more with stable disease is still two months worth having. But there is something missing from this picture - information about actual survival. Extending the time to progression is not the same thing as prolonging the length of time a patient is likely to live.

Clinical trials are frequently set up with an independent review board in place that can perform an interim analysis of the data and decide if one of the approaches under examination is doing significantly better than another. If so, the trial may be prematurely terminated and, for ethical reasons, the better treatment may then be offered to all the participants. This is precisely what happened in the Tykerb trial.

By terminating the trial, the oversight committee also served the interests of the drug company, which was able to "quit while it was ahead," i.e., while the trial data still looked highly positive. Naturally, it is important for oversight committees in clinical trials to worry about the ethics of withholding a drug that might prove effective. But what about the ethics of approving and administering a drug to tens of thousands of women before there is data showing that it has a positive effect on their survival?

Most doctors and breast cancer advocates seemed happy enough to have another new drug to treat advanced breast cancer. But the lack of survival information left at least one advocacy group disappointed. Barbara A. Brenner, executive director of Breast Cancer Action, reminded the FDA in a March 5 letter that it is overall survival, rather than a temporary stay of disease progression, that gives a truer picture of a cancer drug’s efficacy.

"The FDA should not approve drugs that have not shown either a survival benefit or improved quality of life for breast cancer patients with metastatic disease," Brenner’s letter read in part.

It will be encouraging if further analysis reveals that Tykerb does extend overall survival. However, it seems unlikely that this will be tested or reported any time soon. But without evidence of prolongation of survival in advanced breast cancer, we have to question the real value of this treatment.

As Barbara Brenner says, the real bottom line is increased survival. Will drugs such as Tykerb really help patients spend more quality time with their loved ones? Such questions are rarely asked, much less answered, by FDA panels and officials who are often under considerable pressure to approve a new drug. Despite the existence of rules that require drug companies to carry out extended (phase IV) studies after a drug has been approved, these rules are very seldom enforced. Effectively, this lowers the standard of approval considerably, and in effect turns the population at large into guinea pigs for the long term safety and effectiveness tests that should have been conducted before the drug was ever launched."

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