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# Treatment Effect Influences FDA Approval Decisions: Study
- URL: https://www.fdaweb.com/treatment-effect-influences-fda-approval-decisions-study/
- Published: 2019-09-12T12:00:00.000Z
- Updated: 2026-09-15T01:49:34.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5144989

Researchers from several universities around the world say that the size of therapeutic effects in alternative methods of FDA evaluation of breakthrough therapy drugs correlates with FDA approval without requiring randomized clinical trials. Writing in an open access article [posted](https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2749563?ref=fdaweb.com) online, the researchers say the magnitude of treatment effects was about 2.5-fold higher among treatments that were approved based on non-randomized clinical trials than among treatments that required further testing in randomized clinical trials. They found that only 1% to 2% of the drugs approved by FDA based on non-randomized clinical trials displayed “dramatic effects.”

“No clear threshold of magnitude of treatment effect above which FDA would not request further randomized clinical trials was found,” the article says.