The agency is considering two antiviral pills that have proved to be highly effective. Why is it still dragging its feet?
The agency is considering two antiviral pills that have proved to be highly effective. Why is it still dragging its feet?
A s the Delta variant surges in various locales and the new Omicron variant expands around the globe, public officials are beginning to reimpose Covid-19 restrictions. The Food and Drug Administration, though, seems to lack the same sense of urgency.
The agency is considering two new antiviral pills that have been found to cut Covid-19 hospitalizations and deaths in people treated soon after they become symptomatic. If authorized, the pills would enable early Covid-19 to be treated at home with a five-day course of treatment — a marked improvement upon the treatments that are presently on offer.
The only currently FDA-authorized antiviral for Covid-19, Remdesivir, must be administered intravenously in a hospital setting, making it burdensome and expensive to use. Monoclonal antibodies — laboratory-produced molecules that block the virus that causes Covid-19 from attaching to human cells — have been granted FDA emergency-use authorizations (EUA), but are costly, difficult to manufacture, and also require intravenous administration.
The most promising of the new oral antivirals is Pfizer’s Paxlovid. The company halted a trial of the drug when an interim analysis demonstrated an 89 percent reduction in risk of hospitalization or death compared with placebo in nonhospitalized high-risk adults with Covid-19. Pfizer applied for an EUA a month ago on November 16, 2021.
The company has announced that a final analysis has confirmed the drug’s high effectiveness with the added bonus that it appears to be effective against Omicron. A second clinical trial in low-risk, unvaccinated people, as well as in vaccinated people at high risk for Covid-19 complications, found that Paxlovid cut hospitalizations by 70 percent compared with placebo. Yet the FDA has still not scheduled a meeting of its advisory committee to review the Paxlovid EUA.
Pharmaceutical companies Merck and Ridgeback Biotherapeutics announced that their investigational oral antiviral drug Molnupiravir reduced the risk of hospitalization or death by about 50 percent compared with placebo for patients with mild or moderate Covid-19 back on October 1, 2021. A phase III study of the drug was stopped early, when an independent monitoring board concluded the drug was so effective that it would be unethical to continue giving a placebo.
The drug was found to be safe and effective and approved for use in the United Kingdom on November 4. A few days later, Bangladesh authorized four companies to manufacture and distribute generic versions of the drug. By November 19, the European Medicines Agency advised national authorities considering authorization that Molnupiravir could be used to treat adults with Covid-19 who are at increased risk of developing severe Covid-19.
While Merck and Ridgeback applied to the FDA for an EUA on October 11, the FDA delayed consideration for more than six weeks, deciding to take the extraordinary step of convening an outside expert advisory committee on November 30.
By the time the committee met, a final analysis of the data showed that Molnupiravir decreased the risk of Covid-19 complications by 30 percent — down from the original 50 percent figure in the interim analysis. Nevertheless, the committee narrowly voted to recommend granting the drug emergency authorization by a vote of 13 to ten. The FDA has yet to authorize the pill.
Side effects for both new pills were similar in people who received the study medicines or the placebo and were mostly mild. There are no known serious safety concerns for Paxlovid.
Molnupiravir presents a different story since its mechanism of action — incorporating itself into the virus’s genetic material and inducing mutations that block its ability to replicate — raised concerns that the drug could cause mutations leading to birth defects or tumors in humans. None of the animal or human studies, thus far, have documented this risk. Nevertheless, the European Medicines Agency sensibly recommended against using the drug during pregnancy and advised women who can become pregnant to use effective contraception during treatment and for four days after the last dose. The FDA could easily recommend similar restrictions on use here.
We are now almost two years into a pandemic that has killed nearly 800,000 Americans. Two new medications that are inexpensive, easy to administer, and safe for most people could significantly mitigate any additional illness and death. But that will only be possible if the FDA moves with more alacrity than it has demonstrated to date.