The U.S. Food and Drug Administration will no longer require two rigorous clinical trials for most new drugs and novel health products, according to a Wednesday article in the New England Journal of Medicine by FDA Commissioner Marty Makary and Deputy Commissioner Vinay Prasad. Going forward, the agency’s “default position” will be to approve drugs based on a single study, reflecting advances in medical research and a push to reduce regulatory delays.

Makary, who took office in April, has enacted a series of measures to streamline FDA procedures, including requiring staff to use artificial intelligence in reviews and offering one-month assessments for medications deemed critical to national interests. He and Prasad wrote that modern drug research is “increasingly precise and scientific,” making the old two-trial standard unnecessary in many cases. They predict the change will produce a surge in drug development.

Former FDA drug center director Janet Woodcock said the move aligns with trends dating back to the 1990s, when single trials were increasingly accepted for rare or life-threatening conditions. Woodcock noted that the new policy will mainly affect treatments for common diseases, as cancer and rare-disease drugs have already often been approved based on one trial.

The two-study requirement originated in the 1960s to ensure results could be reproduced, but in recent years roughly 60 percent of first-of-a-kind drugs have been cleared on a single trial. Makary and Prasad argue that modern science and supporting evidence now allow regulators to move more quickly without the second study.

The policy contrasts with the FDA’s recent actions on vaccines and gene therapies. Last week, the agency initially rejected Moderna’s new mRNA flu shot application, citing insufficient clinical data, before agreeing to review it after an additional study. Prasad has also required more evidence for several experimental gene therapies, a stance that has unsettled biotech investors and highlighted tension between the agency’s speed-focused leadership and its divisions’ caution.

Woodcock emphasized that the impact of the policy depends on its implementation. “Since the agency’s approach is unclear, and the industry is already baffled, I don’t think this adds any illumination,” she said, cautioning that companies will need to see how the FDA applies the new one-trial standard in practice.