The Food and Drug Administration (FDA) has asked Pfizer Inc. to test the effects of an additional course of its antiviral Paxlovid among people who experience a rebound in COVID-19 after treatment, the regulator said on Friday.
The drugmaker must produce the initial results of a randomized controlled trial of a second course of the antiviral by Sep. 30 next year, the FDA told Pfizer in a letter dated Aug. 5.
