By Sam Boughedda
U.S. regulators ordered Pfizer (NYSE:PFE) to test the impact of an extra course of Paxlovid in people who experience a rebound in Covid-19 following treatment, Bloomberg reported Friday.
Bloomberg stated the drug will go through a further study after reports of the "mysterious phenomenon" continue to rise.
The report states that according to a letter from the regulator to Pfizer dated August 5, Pfizer has been told to produce initial results of a randomized trial of an extra course of the drug by September 30, 2023, with the letter also describing changes in Paxlovid's emergency authorization.
Fiona Rutherford and Robert Langreth, writing for Bloomberg, said the FDA confirmed the letter in an email, with Pfizer said to be working with the regulator to "finalize a protocol to study patients who may be in need of retreatment." The formal plan for the trial is expected to be finalized this month.
There have been various cases of viral infection, symptoms, or both after an initial course of Paxlovid since the spring.
U.S. President Joe Biden is one such case. Biden, who has had two Covid vaccine boosters, tested positive for Covid-19 in late July before testing positive again at the start of August.
Bloomberg said that in a separate memo on August 5, the FDA said it began discussions with Pfizer in May regarding a new retreatment study following numerous reports of rebound cases.