Saw this article about the integrity of health research in Nature today. The article is not specifically concerned with clinical trials for drugs, which are subject to additional regulatory scrutiny. However, the allegations are still quite interesting:
For more than 150 trials, [an editor for the journal Anesthesia] got access to anonymized individual participant data (IPD). By studying the IPD spreadsheets, he judged that 44% of these trials contained at least some flawed data: impossible statistics, incorrect calculations or duplicated numbers or figures, for instance. And 26% of the papers had problems that were so widespread that the trial was impossible to trust, he judged — either because the authors were incompetent, or because they had faked the data.
For years, a number of scientists, physicians and data sleuths have argued that fake or unreliable trials are frighteningly widespread […] Some, on the basis of their personal experiences, say that one-quarter of trials being untrustworthy might be an underestimate. “If you search for all randomized trials on a topic, about a third of the trials will be fabricated,” asserts Ian Roberts, an epidemiologist at the London School of Hygiene & Tropical Medicine.