In a few weeks, perhaps before many Americans are done decorating for the holidays, the US could have access to a new antiviral pill from Merck that is expected to change the deadly trajectory of the COVID-19 pandemic — with a second option from Pfizer that will follow shortly after.
Now, under federal investigation, both pills are being praised by doctors with infectious diseases not amenable to superlatives.
“This is really a game changer,” said Daniel Griffin, an infectious disease and immunology expert at Columbia University. “This is up there with vaccines. It is not a replacement for vaccines; we still want to get people vaccinated. But boy, this is just another great tool to have.”
The new regimens, which require taking 30 or 40 pills over five days, have been shown to dramatically reduce hospitalizations and prevent deaths in adults with mild to moderate COVID who are at risk for serious illness because of their age or underlying conditions. But experts say the success of the treatments depends on one uncertain factor: whether high-risk patients infected with COVID can be tested — and then treated — quickly enough to make a difference.
“Early, accessible testing and access to the results in a time frame that allows us to make a decision will really be the key to these drugs,” said Erica Johnson, chair of the Infectious Disease Board of the American Board of Internal Medicine. . “It puts the responsibility on our public health strategy to make it available.”
In clinical trials, molnupiravir, the antiviral drug developed by Merck & Co. and Ridgeback Biotherapeutics, administered to unhospitalized, unvaccinated, high-risk adult patients within five days of their first COVID symptoms. Pfizer’s product, Paxlovid, was tested in similar patients as early as three days – just 72 hours – after the onset of symptoms.
Results of the Merck study, last released month, showed that the drug reduced the risk of hospitalizations by about 50% and completely prevented deaths. It will be reviewed on Nov. 30 by a federal Food and Drug Administration advisory panel. Pfizer officials, who filed for emergency clearance from the FDA for their drug on Nov. 16, Paxlovid said it would reduce the risk of hospitalizations and deaths by 89%. Both drugs work by interfering with the way the COVID virus reproduces, although they do so at different points in the process.
But those promising results assume the drugs can be delivered in the limited time used in the studies, a proven challenge in getting antiviral treatments to real patients. Similar drugs can prevent serious flu consequences if given early, but Research shows that only about 40% of high-risk patients during five recent flu seasons sought medical attention within three days of becoming ill.
“That’s just not human nature,” said Kelly Wroblewski, director of infectious disease programs for the Association of Public Health Laboratories. “If you snort, you wait to see if it gets worse.”
Even as patients seek early care, access to COVID testing has been wildly variable since the start of the pandemic. Testing capacity in the US continues to be plagued by a host of issues, including supply chain bottlenecks, staff shortages, periodic spikes in demand, and results that can take hours or much longer.
PCR or polymerase chain reaction tests, the gold standard to detect SARS-CoV-2, may require scheduled appointments at medical offices or emergency care centers, and patients often wait days to hear the results. Rapid antigen tests are faster but less accurate, and some healthcare providers are hesitant to rely on them. Over-the-counter tests that can be used at home provide quick results, but are hard to find in stores and stay expensive. And it’s not yet clear how those results would be confirmed or whether they would be accepted as grounds for treatment.
“Get ready,” Griffin said. “You don’t want to call someone four days later and say, ‘Ooh, you’re out the window now,’ and the efficacy of this oral medication has been lost due to difficulties on our side getting those results.”
The situation is expected to improve after a bid by the Biden administration to invest $3 billion in rapid tests, including $650 million to increase production capacity for rapid tests. But it can take months for the change to show.
“Deliveries will get better, but it will be slow,” said Mara Aspinall, co-founder of Arizona State University’s biomedical diagnostics program, writing a weekly newsletter monitoring the national testing capacity.
If getting tests is going to be difficult, getting doses of the antiviral drugs is expected to be more difficult, at least initially. The federal government has agreed to purchase approximately 3.1 million courses of molnupiravir for $2.2 billion, which amounts to approximately $700 per course of treatment. The Biden administration plans to announce a deal to pay $5 billion for 10 million courses of the Pfizer drug, paying about $500 per course of treatment. according to The Washington Post.
Doses of the drugs distributed by the federal government would go to states and patients for free. But only a fraction of the planned inventory will be available to get started, said Dr. Lisa Piercey, the Tennessee health commissioner, who was part of a small group of state health officials working on the distribution plans.
In one scenario, in which 100,000 courses of the Merck drug will be available as early as Dec. 6, Piercey said Tennessee would receive only 2,000 patient courses, while the state averages more than 1,200 new cases per week. Deciding which sick patients get those scarce supplies will be “a deliberate stab in the dark,” Piercey said.
U.S. Department of Health and Human Services officials have said the antiviral treatments will be distributed through the same state-based system approved for monoclonal antibody treatments. The lab-made molecules, delivered via IV infusion or injection, mimic human antibodies that fight the COVID virus and reduce the risk of serious illness and death. Federal officials took over distribution in September, after a COVID surge in low-vaccination southern states led to: a run on national supplies. They are now assigned to states based on the number of recent COVID cases and hospitalizations and past use.
The antivirals will be cheaper than the monoclonal antibody treatments, which can cost the government about $1,250 per dose and infusion costs that cost patients hundreds of dollars in copays. The pills are much easier to use and pharmacies will likely be able to order and dispense them for home use.
Still, the antiviral pills won’t replace antibody treatments, said Dr. Brandon Webb, an infectious disease specialist at Intermountain Healthcare in Salt Lake City.
Questions remain about the long-term safety of the drugs in some populations. Merck’s molnupiravir works by causing mutations that prevent the virus from reproducing. The Pfizer treatment, which includes Paxlovid and low-dose ritonavir, an HIV antiretroviral drug, can cause interactions with other drugs or even over-the-counter supplements, Webb said.
As a result, the antivirals are unlikely to be used in children, people with kidney or liver disease, or pregnant people. They should be given to patients who are able to take multiple pills at once, a few times a day, and those patients should be monitored to make sure they are completing the therapy.
“We are on an interesting tightrope where we will try to identify suitable patients at an early stage to treat them with antivirals,” Webb said. “We just have to be agile and ready to run.”
KHN (Kaiser Health News) is a national newsroom that produces in-depth journalism on health issues. Together with Policy Analysis and Polling, KHN is one of the three most important operational programs on KFF (Kaiser Family Foundation). KFF is an endowed non-profit organization that provides information on health issues to the nation.