Find us @


Pfizer announced that they are testing a second course of paxlapid People taking this new drug will have increased resistance to stopping abuse of opioid

An experimental drug was ahead of schedule; regulators were ordered to put the drug through further studies after reports grew with more cases of a mysterious phenomenon.



The (Bloomberg) US regulators mandated that Pfizer Inc. evaluate the effects of a second Paxlovid course among patients who suffer a rebound in Covid-19 after treatment, further examining the medication as reports of the puzzling phenomenon keep growing.

Most Check out Bloomberg

According to a letter the regulator sent to Pfizer on August 5, the business must present preliminary findings of a randomized controlled trial of a second course of the antiviral by September 30, 2023. The Food and Drug Administration acknowledged receipt of the letter, which details modifications to Paxlovid’s emergency permission, in an email.

According to an email from Pfizer spokesperson Kit Longley, the pharmaceutical company is “working with the FDA to develop a protocol to investigate patients who may be in need of retreatment,” and more information will be made available when it is. The agency stated that a formal plan for the clinical research is anticipated to be completed this month.

A five-day prescription of Paxlovid has replaced the competitor molnupiravir from Merck & Co. as the standard of care for high-risk individuals with Covid-19 due to its shown ability to lower hospitalization and mortality rates. But ever since the spring, several patients have complained of resurgences of viral infection, symptoms, or both, after they had run their course.

President Joe Biden was placed in seclusion for a second time in late July after testing positive for Covid-19 after taking Paxlovid and experiencing intermittent coughing. Anthony Fauci, a prominent medical advisor, too underwent Covid rebound after Paxlovid treatment.

The FDA stated in a separate memo dated August 5 outlining the revisions to the drug’s license that it had begun talking with Pfizer about a new retreatment study in May as a result of extensive media reports of rebound and of physicians already writing second courses of Paxlovid.

According to Paul Sax, an infectious disease specialist at Brigham and Women’s Hospital in Boston and alumnus of Harvard Medical School, the company’s outcomes timetable appears lengthy for a medicine that is so extensively used.

Since rebound is evidently widespread, annoying, and has uncertain clinical repercussions, he wrote in an email, “I’m hopeful that more prospective data will give us a clearer idea of risk factors and implications of rebound.”

After the recurrences were first revealed earlier this year, Pfizer Chief Executive Officer Albert Bourla himself advised a repeat course of the medication for those experiencing rebound. He stated in May that if virus levels increase again, “then you give a second course, like you do with antibiotics, and that’s it.”

Soon after, the FDA declared that there was “no evidence” that the additional treatment would be beneficial. Pfizer announced in late July that it was coordinating with the US to organize a trial for patients with rebound.

It is uncertain what causes rebound and how important it is medically. Although Pfizer said the viral load rebound phenomena only happened in about 2% of patients treated in its clinical trials of the medication and that the treatment was probably not to blame, more subsequent research have identified greater rates.

View More: Paxlovid and Other Covid-19 Treatments: A Comprehensive Guide

Over 5% of patients who got Paxlovid had an infection that returned within a month, according to a study conducted by researchers at Case Western Reserve University under the direction of Rong Xu. The study’s findings were published on the preprint server, and they show that nearly 6% of patients experienced a recurrence of symptoms during the same time frame.

Meanwhile, there is evidence that untreated Covid patients may experience rebound. According to data from a real-world study conducted by researchers at Harvard Medical School and other institutions and published on the preprint site on August 2, about 1 in 12 of these individuals saw a rebound of positive viral tests. The study discovered that 27% more patients experienced a relapse of symptoms after they had begun to improve. Rarely did someone have a rebound in their symptoms and virus load.

The business anticipates Paxlovid revenues for the entire year to be about $22 billion. This, along with the Covid vaccine it produces in collaboration with BioNTech SE, has completely changed the New York-based pharmaceutical company, which projects to generate up to $102 billion in total sales this year.

Most Take a look at Bloomberg Businessweek.