Companies rarely adequately disclose the rationale for drug rejections, shows a US Food and Drug Administration (FDA) analysis of complete response letters. Press releases not only often omit key details about rejections — such as the need for more clinical trials or increased mortality in the treatment arm of a trial — but also sometimes state a rationale for rejection that bears no similarity to that included in regulatory complete response letters.

In the study, a team of FDA researchers compared 61 complete response letters that were issued between 2008 and 2013 to the press releases that these rejections triggered (BMJ 350, h2758; 2015). The press release statements matched only 93 of 687 (14%) of the statements actually made in complete response letters. Out of 32 complete response letters that called for new clinical trials, only 19 (59%) of the associated press releases reported this recommendation. Out of 7 complete response letters noting higher mortality rates in treated patients, only 1 (14%) press release disclosed this problem.

The analysis also found that in 11 cases (18%), companies did not issue a press release about the complete response letter. A further 13 (21%) press releases did not include any statements that matched the statements included in the complete response letter. And 22 (26%) press releases noted rationale that could not be matched to that of the complete response letter.

In 2010, the FDA had proposed disclosing complete response letters to the public, but drew criticism because of the potential to violate trade secrets and confidential information. “Our analysis found that the FDA's reasons for not approving marketing applications for new molecular entities are not being fully conveyed to the public,” the authors now write. “The potential benefits of publicly disclosing the agency's detailed rationale for refusing approval include better informing the development of new drugs, facilitating a richer public health discourse, and counteracting misconceptions regarding FDA's reasons for denial of applications.”

The analysis also found that applications under priority review were less likely to receive complete response letters than those under standard review. Drug applications that were referred to advisory committees were marginally more likely to receive complete response letters than were applications that didn't go to committee (unless the advisory committee voted favourably on the drug).