July 24 (UPI) -- Roughly one in four drugs approved by the U.S. Food and Drug Administration had at least one reviewer express concerns over their use, according to an analysis published Friday by JAMA Network Open.
Of 174 drugs approved by the agency between 2011 and 2015, 35 passed muster despite disagreement over requirements for post-approval safety evaluations or wording on their labels, the researchers said.
Twelve, or 7%, received approval even though at least one of the reviewers objected, while 10, or just under 6%, were allowed to go to market despite of concerns over the types of patients for whom they should be used, they said.
"We don't know whether these disagreements represent a red flag [regarding the safety of the drugs]," co-author Matthew Herder, director of the Health Law Institute at Dalhousie University in Canada, told UPI.
The internal debate, however, is a "good thing" because it is an indication of stringency of the review process, he said.
The data for every drug evaluated by the FDA is, in most cases, reviewed by dozens of agency executives and scientists, Harder and his colleagues said.
In addition to assessing safety and effectiveness information gleaned from clinical trials, reviewers evaluate drug labels for accuracy and set parameters for marketing, according to the FDA.
Agency reviewers also establish guidelines for large-scale clinical trials that may be conducted after a drug is approved to ensure that it is still safe.
Of the drug approvals reviewed by Harder and his colleagues, the most common conditions they were designed to treat were cancer, with 46 medications, and infectious diseases, with 27.
The FDA was the first major regulatory agency to issue approval for 118 medications during that period, said the researchers, who took on the analysis because of the U.S. agency's "influence ... on other regulators," including its counterpart north of the border, Health Canada.
There were 155 registered disagreements on the 174 approved drugs, Harder and his colleagues said.
Among the 12 cases of disagreement over the drug's approval, 11 of the products were ultimately cleared for use with a "post-marketing requirement" or a risk evaluation and management strategy, they said.
"Disagreements about whether to approve a drug ... and whether to place any restrictions on its use -- are relatively common at the FDA, which reveals how complex these regulatory decisions can be," Harder said.
"The problem, however, is that these disagreements may soon disappear, because in the last year or so, the FDA has changed how it documents and carries out its reviews" by, among other things, no longer reporting objections from reviewers publicly, he said.