On Thursday, the Food and Drug Administration’s independent panel of experts recommended full approval of Pfizer’s Covid-19 antiviral tablet Paxlovid for individuals at high risk but cautioned against potentially dangerous drug interactions.
As per CNBC, those over the age of 50 or those with medical disorders, such as high blood pressure or diabetes, that place them at a higher risk for hospitalization or death from Covid are encouraged to undergo therapy.
In December 2021, the FDA made Paxlovid available for emergency use in adolescents and adults at high risk. Pfizer submitted an application for the drug’s full clearance in June 2022, but the FDA prolonged the evaluation period in December. Typically, but not always, the agency follows the advice of its advisory groups. In May, it is expected to make a final decision.
Richard Murphy, chief of infectious diseases at the Veterans Affairs White River Junction Medical Center, stated, “Outside of oxygen, Paxlovid has likely been and continues to be the single most critical treatment tool during this pandemic.”
The panel, which voted 16-1 to recommend full approval, based on three mid- to late-stage clinical trials involving more than 6,000 patients in 21 countries conducted by Pfizer. In the EPIC-HR study, persons at high risk who were unvaccinated and had no history of Covid infection were evaluated. An FDA evaluation of the company’s data revealed that Paxlovid reduced the probability of hospitalization or death by 86% in those treated within five days of symptom onset and by 89% in those treated within three days of symptom onset.
“I found the efficacy evidence to be clear and persuasive,” said Dr. Sankar Swaminathan, chief of the infectious diseases division at the School of Medicine at the University of Utah.
Dr. Adaora Adimora, a professor in the department of infectious diseases at the University of North Carolina School of Medicine, referred to the risk reduction in Pfizer’s trials as “clinically meaningful” for the majority of individuals and the general population at a time when the United States continues to see thousands of Covid cases per week. Nationally, the Centers for Disease Control and Prevention record over 200,000 instances of Covid every week.
However, advisers concurred that significant adverse events owing to medication interactions, including Paxlovid, constitute a major safety issue. Dr. David Hardy, an adjunct clinical professor of medicine at the University of Southern California, stated, “I would like to underline that we emphasize the need of risk mitigation to prescribers, primary care physicians, and other prescribers in terms of drug-drug interactions.”
“That is where I believe we may run into difficulties,” he added, “where they would run into trouble giving this medicine without a clear understanding of how ritonavir [one of the pharmaceuticals in Paxlovid] interacts with other medications.”
More than half of Medicare and Veterans Affairs patients who are eligible for Paxlovid are taking drugs that interact with Paxlovid, according to an FDA examination of safety surveillance data. The FDA study noted that around 74% of Paxlovid prescriptions were written by adult primary care practitioners who may not have experience monitoring the potential harmful medication interactions.
As of late January, the FDA’s division of surveillance and epidemiology had received 271 complaints of significant adverse events possibly caused by Paxlovid medication interactions, including 147 hospitalizations and six fatalities. The FDA stated that immunosuppressants, which are commonly used to treat HIV and organ transplant patients, caused the most issues.
Swaminathan stated, however, that drug interactions must be “addressed and minimized.” Earlier in the conference, FDA staff indicated that interactions might be possibly handled by modifying the dosage of some prescriptions, enhancing patient monitoring, and ensuring that product labels alert prescribers and patients of potential drug interactions.
Paxlovid is comprised of two medications: nirmatrelvir, which inhibits a crucial enzyme that the Covid virus requires to proliferate, and ritonavir, which enhances the first medication’s antiviral properties. Individuals who experience Covid symptoms within five days of taking Paxlovid lower their chance of hospitalization or death. Patients must take three Paxlovid tablets twice day for five days to complete a full course of treatment.
According to federal data, more than 12 million courses of Paxlovid have been distributed to pharmacies across the United States, and 1.3 million doses are available nationwide. According to Jim Rusnak, Pfizer’s chief development officer for internal medicine, about 10 million patients in the U.S. and 14 million globally have been treated with the drug.
In 2022, its first year on the market, Paxlovid sales soared to $18.9 billion, but Pfizer anticipates a 58% decrease to $8 billion in 2023. The lone vote against Paxlovid was cast by Terry Gillespie, an Illinois patient representative from Plainfield. Gillespie expressed concern that doctors may not know when to administer the antibiotic, adding that he had a Covid infection four to five times but was never prescribed Paxlovid.
Gillespie remarked, “I don’t think the doctors truly know how to use it.” Following the vote, Swaminathan stated that he had a “worrisomely high number” of patients whose physicians discouraged them from taking Paxlovid out of fear of rebound Covid instances. After early recovery, this is when patients experience a recurrence of Covid symptoms or a positive test.
“I am concerned that there is a lack of knowledge in the medical community and that individuals are actively discouraged from taking a life-saving treatment,” he said. President Joseph Biden and his former chief medical advisor, Dr. Anthony Fauci, appeared to have recovered from Covid after taking the antiviral cocktail before testing positive again shortly after the introduction of Paxlovid in 2021.
Swaminathan stated that there is a “dramatic acceptance” in the media that Paxlovid produces rebound instances that are “possibly worse” than what patients experienced before taking the treatment, despite the lack of data to back this opinion.
Dr. Lindsey Baden, leader of the group and director of Brigham and Women’s Hospital, noted that new research indicates Paxlovid-induced rebound cases are “not the biology of what is happening.” “Until very recently, and even some of the facts provided today, I was unable to comprehend its meaning. So, we see statistics in real time that are organized and instructive,” stated Baden.
In a review of Pfizer’s clinical trials by the FDA, rebound rates varied from 10% to 16%, “with no evidence of a greater rate of symptom rebound or moderate symptom rebound” in individuals who took Paxlovid versus placebo. According to the agency’s staff, this was true regardless of the severity of the sickness or whether the omicron variety or an earlier strain was predominant.
