Among those who have signed are the Cochrane Collaboration - which analyses clinical data, and the Medical Research Council, which now makes publication a condition of all studies it funds.

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Two years ago, a panel rejected Xinlay, a prostate cancer drug from Abbott Laboratories, because the only evidence for its effectiveness came from after-the-fact analyses of two clinical trials.

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Pooled analyses of Avandia clinical trial data, she noted, pointed to more heart attacks occurring on Avandia than on either the placebo or with its main competitor, Actos, which is made by Takeda.

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Two years ago, a panel rejected Xinlay, a prostate cancer drug from Abbott Laboratories (nyse: ABT - news - people ), because the only evidence for its effectiveness came from after-the-fact analyses of two clinical trials.

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There are other types of analyses that fall between observational studies and the best clinical trials in their reliability.

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