After an advisory committee to the US Food and Drug Administration (FDA) votes on whether to approve a new medicine, the standard mantra is that the agency doesn't have to follow its panel's advice, but, by and large, it does. However, according to a new analysis from Prevision Policy, a Washington, DC–based healthcare policy group, over the past four years the FDA has followed its committees' advice only 76% of the time.

Although the FDA ignores its advisors almost a quarter of the time, the analysis revealed that the agency has overturned a 'no' vote from its panels only three times since 2007, and in every case the reversal was for a product already on the market but seeking new indications, not for a new molecular entity. In other words, “a 'no' is going to stick for a new product,” says Ramsey Baghdadi, an analyst with Prevision Policy in Washington, DC. “But if you get a 'yes', you've got a 25% chance that it could be reversed based on those hard data points.”