To get a drug approved in the US, companies must submit at least two studies to the Food and Drug Administration showing the medication is safe and effective.
So far, so good.
But what's to stop a company from commissioning four, five, six, or more studies and then only submitting the two that make their product look good -- ignoring anything that would hurt their chances of approval.
Well, according to a new study, not much. In fact, that appears to be exactly what drug companies are doing.
Over half of all supporting trials for FDA-approved drugs remained unpublished (more than) 5 years after approval. Pivotal trials and trials with statistically significant results and larger sample sizes are more likely to be published. Selective reporting of trial results exists for commonly marketed drugs.
The study in the Public Library of Science journal this week raises serious questions about how new drugs are approved. "We found that there was indeed a pattern that favorable studies were more likely to be published than unfavorable trials,'' Ida Sim, associate professor of internal medicine at UCSF and the lead author of the study told Bloomberg.
The study says bluntly, "a pivotal trial in which the new drug does no better than an old drug is less likely to be published than one where the new drug is more effective, a publication bias that could establish an inappropriately favourable record for the new drug in the medical literature."
In other words, the researchers are saying, the companies publish what makes them look good.