Clinical trial results of Zytiga, a new drug from Johnson & Johnson, showed incredible promise in the fight of prostate cancer. Shortly after the findings were presented at the year’s biggest cancer conference, a statistician raised concerns that the clinical trial had been stopped prematurely, which gave the impression the drug was more effective than it is. Helping to decide when clinical trials should stop or continue are data safety monitoring boards. DSMBs watch for emerging side effects, evidence that the drug does not work, or that the drug is so effective that it is no longer ethical to give patients a placebo. Statisticians are concerned over a recent trend by DSMBs to stop trials early. There’ve been times when stopped-early studies proved the benefits of several new drugs, but, in the case of Zytiga, the results were not far more statistically significant than normal.

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