How many studies haven’t started a year or more after approval?

When drugs are granted accelerated approval, drugmakers are required to follow up with studies to confirm those drugs’ clinical effectiveness. An NPR analysis found that over the past 30 years almost 42% of these confirmatory studies hadn’t started within a year.

Source: NPR analysis of FDA and NIH data (1992 to 2021)

Credit: Analysis by Sydney Lupkin/NPR. Graphic by Connie Hanzhang Jin/NPR