The coronavirus disease (COVID-19) treatment pill paxlovid is seen in boxes at the Misericordia hospital in Grosseto, Italy, on February 8, 2022.
Jennifer Lorenzini | reuters
Food and Drug Administration’s independent panel of advisors recommends full approval of Pfizer COVID-19 The antiviral pill Paxlovid for high-risk but potentially harmful drug interactions was flagged on Thursday.
Treatment is recommended for people above 50 years of age or suffering from medical conditions Like high blood pressure or diabetes which puts them at higher risk of ending up in hospital or dying from Covid.
The FDA made Paxlovid available for the first time in December 2021 for emergency use In high-risk individuals 12 years of age and older. pfizer submitted an application for full approval of the drug in June 2022, but the FDA extended its review Application period in December.
The agency usually follows the advice of its advisory committees but is not required to do so. A final decision on this is to be taken in May.
Richard Murphy, chief of infectious diseases at the Veterans Affairs White River Junction Medical Center, said, “I would say, other than oxygen, paxlovid has been and continues to be probably the most important treatment tool during this pandemic.”
The panel, which voted 16-1 to recommend full approval, drew on three of Pfizer’s mid- to late-stage clinical trials on paxlovid, which enrolled more than 6,000 patients in 21 countries .
‘Clinically meaningful’ risk reduction
A trial called EPIC-HR looked at high-risk adults who had not been vaccinated and had no prior COVID infection. According to an FDA review of the company’s data, the trial found that Paxlovid reduced the risk of hospitalization or death by 86% in adults treated within five days of the onset of symptoms, and by three days after the onset of symptoms. 89% decreased in those treated within.
“I thought the efficacy data was clear and reassuring,” said Dr. Shankar Swaminathan, chief of the department of infectious diseases at the University of Utah School of Medicine.
Professor in the Department of Infectious Diseases at the University of North Carolina School of Medicine, Dr. Adora Adimora called the risk reduction in Pfizer’s trials “clinically meaningful” for most individuals and the broader population, when the US still sees thousands. of covid cases each week. Nearly 200,000 Covid cases are reported weekly nationwide, according to Centers for Disease Control and Prevention,
But the consultants agreed that serious adverse reactions due to interactions between Paxlovid and other drugs are a significant safety concern.
This photo taken on July 31, 2022 shows a health worker taking a swab sample from a woman to test for the Covid-19 coronavirus at a swab collection site in Guangzhou in China’s southern Guangdong province. According to a study posted online Tuesday, about a third of people with Covid will have an improvement in their symptoms, regardless of whether they are treated with the antiviral paxlovid.
Str | AFP | Getty Images
“I would just stress that we underscore the importance of reducing risk for the prescriber, primary care, physician and other prescribers in the context of drug-drug interactions,” said Dr. David Hardy, University of Medicine An assistant clinical professor at the University of Southern California.
“That’s where I think we might get into trouble, I should say, where they would get into trouble prescribing this drug without a good understanding of what ritonavir is. [one of the medications in Paxlovid] does for other drugs,” he said.
drug interactions
More than half of paxlovid-eligible Medicare and Veterans Affairs patients are taking medications that have drug interactions with paxlovid, according to an FDA review of safety surveillance data. The FDA review noted that approximately 74% of Paxlovid prescriptions were from adult primary care physicians, who may not have experience managing potentially adverse drug interactions.
The FDA said its Office of Surveillance and Epidemiology registered 271 reports of serious adverse events potentially related to drug interactions with paxlovid, including 147 hospitalizations and six deaths, through the end of January. The most common drugs that caused problems were immunosuppressants, which are often used to treat HIV and organ transplant patients, the FDA said.
But Swaminathan said drug interactions should be “detectable and minimised”. FDA staff said earlier in the meeting that interactions were potentially managed by adjusting dosages of some drugs, increasing patient monitoring and ensuring product labeling informs prescribers and patients about potential drug interactions. May go.
Paxlovid consists of two drugs: nimritalvir, which blocks a key enzyme the Covid virus needs to replicate, and ritonavir, which boosts the first drug’s ability to fight infection.
Patients take paxlovid within five days of developing Covid symptoms to reduce the risk of hospitalization or death. To complete the full course of medication, patients should take three tablets of Paxlovid twice a day for five days.
More than 12 million courses of Paxlovid have been distributed to pharmacies across the US and 1.3 million doses available nationwide, according to federal data. About 10 million patients have been treated in the U.S. and 14 million worldwide, according to Jim Rasnak, Pfizer’s chief development officer for internal medicine.
sales of paxlovid to grow to $18.9 billion in 2022The first year it was available, Pfizer expects revenue to drop 58% to $8 billion in 2023.
rebound cases
The lone vote against Paxlovid was from Terry Gillespie, a patient representative from Plainfield, Illinois. Gillespie raised concerns about doctors not knowing when to prescribe the drug, noting that he had been offered paxlovid four to five times “but not once”.
“I don’t think doctors really know how to use it,” Gillespie said.
After the vote, Swaminathan said he had a “huge number of patients” whose doctors discouraged them from taking paxlovid because of fears of rebound Covid cases. This happens when patients see their Covid symptoms return or get a positive test after initially recovering.
“I am concerned that there is a lack of good understanding in the medical community and that patients may be discouraged from actually taking an effective drug that could save their lives,” he said.
Those case reports came shortly after Paxlovid entered the market in 2021 with Pres. Joe Biden And his former chief medical adviser, Dr. Anthony Fauci, recovered from Covid after taking an antiviral cocktail before testing positive again.
Swaminathan said there is a “dramatic acceptance” among the media that Paxlovid causes rebound cases and that they are “potentially worse off” than patients before taking the drug, despite a lack of data to support that belief.
Panel chairman and director of Brigham and Women’s Hospital, Dr. Lindsay Baden said emerging data indicates that the cases of rebound caused by paxlovid “are not the biology of what’s going on.”
Baden said, “Until recently, and even some of the data shared today, has helped me understand what this means. So we are seeing data in real time that are systematic and informative. “
An FDA review of Pfizer’s clinical trials found that the overall rate of rebound was between 10% and 16%, with “no evidence of a higher rate of asymptomatic rebound or moderate symptomatic rebound” among patients who received Paxlovid. compared to patients who received a placebo. regardless of patients’ risk of severe disease, or whether the Omicron variant or an earlier strain was dominant, according to agency staff.
More data needed on immunocompromised patients
Before the panel’s vote, FDA staff said more data is needed to determine whether immunocompromised people need a longer course of paxlovid beyond the traditional five days. They cited an overall lack of clinical trial data on the use of paxlovid in those people, noting that only 13 of more than 2,000 patients in the EPIC-HR trial had weakened immune systems.
FDA staff said that immunocompromised people may benefit more from a longer course of paxlovid because they are more prone to prolonged Covid infection. The Centers for Disease Control and Prevention states that immunocompromised patients can remain infectious for up to 20 days after symptom onset, and recommended Those patients are kept in isolation for at least 20 days. Roughly 7 million US adults are immunized, CDC Estimate,
Pfizer representatives highlighted the company’s ongoing efforts to research the use of paxlovid in immunocompromised patients. In September, the company began enrolling patients in a clinical trial examining different durations of paxlovid courses, including 10- and 15-day courses.
Dr. Paula Carvalho, a professor at the University of Washington, said she is “quite satisfied” with the company’s plan, but added that she hopes the clinical trials include the HIV population.
“I hope the study can be done in time, because we are in dire need of this information,” Carvalho said.