Prognosis

Pfizer’s Covid Drug Fails to Show Benefit as Preventive Therapy

Boxes of Pfizer Inc.’s Paxlovid antiviral medication.

Photographer: Kobi Wolf/Bloomberg
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Pfizer Inc. slid in extended trading after its Covid-19 treatment failed a late-stage study testing it as a way to prevent infections.

The drug, Paxlovid, failed to meet its primary goal of significantly reducing the risk of Covid-19 infection in adults exposed to the virus through a household contact, Pfizer said in a statement Friday. The drug reduced risks by about a third compared with a placebo, which didn’t meet the threshold for statistical significance.