New COVID treatments are coming. Will they help combat the omicron onslaught?

Omicron is already changing how medicine fights COVID-19.

Although it only became widespread across the United States in the past week, doctors, pharmacists and drug companies said they need different tools against the new variant. 

Two well-used monoclonal antibodies are unlikely to be effective against omicron. In their place, the government accelerated authorization of two antivirals that can be taken right after diagnosis to prevent illnesses from becoming severe.

The Food and Drug Administration on Wednesday authorized use of Pfizer's Paxlovid, a series of pills, taken at home that prevent nearly 90% of severe COVID-19 among those at high risk. On Thursday, the FDA authorized use of a second antiviral, molnupiravir, which appears to prevent progression to severe disease about 30% of the time.

"As we face omicron, the nation's medicine cabinet of treatments gives us more options to protect the American people," said Jeff Zients, the White House Coronavirus Response Coordinator. "We have tools to keep people safe and we will continue to use them."

The challenge will be to get antivirals to the people who need them.

Paxlovid takes 6 to 8 months to manufacture, and though deliveries will begin almost immediately, only 265,000 treatment courses will be available through the end of January, Zients said in a Wednesday news conference.

Ten million doses of molnupiravir are ready to be packaged and distributed, and hundreds of thousands of doses should be available within days, according to Merck, which makes the drug along with Ridgeback Biotherapeutics.

"It's always good to have more tools to fight against COVID-19," said pediatrician Ilan Shapiro, medical director of federally qualified health clinic AltaMed in East Los Angeles. But, he added, "it's one thing to have it approved and another to get access to it."

COVID-19 infections have climbed 36% in the past week, and some project a huge increase in cases over the next few weeks, perhaps exceeding the surge this time last year. Although omicron may cause less severe disease than its predecessors, many high-risk people are likely to become infected. 

The Paxlovid approval is particularly welcome, a number of doctors said, because their main tool to keep people out of the hospital has been rendered useless by omicron.

"In New York, we've stopped scheduling monoclonal infusions," said Dr. Daniel Griffin, chief of infectious diseases for ProHealth Care, which provides services at 300 locations in and around New York City.

Monoclonal antibodies, drugs derived from people whose immune systems successfully fought off COVID-19, have been extremely effective at keeping high-risk infected people from developing severe disease. But now that drug and a similar one from Eli Lilly, which both target the spike protein on the surface of the virus, aren't expected to work against the heavily mutated omicron variant. 

Griffin said his colleagues are scrambling to get sufficient doses of a third monoclonal antibody, sotrovimab, which targets a different spot on the virus and appears to still work against omicron but is in short supply.

"We have maybe 2,000 doses in all of downstate New York," he said, noting he may have to decide whether to give his share of those sotrovimab doses to high-risk patients who have not been vaccinated, or to those who received two or three shots but may not be fully protected because of weakened immunity. 

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Doctors in Boston have similar concerns.

"We don't have enough – not to keep up with the numbers (of new cases)," said Dr. Rajesh Gandhi, an infectious disease specialist at Massachusetts General Hospital. "One thing we're deeply concerned about – the number of patients is going up so quickly – as to whether there's going to be enough sotrovimab to keep up is uncertain."

GlaxoSmithKline, which makes the drug along with Vir Biotechnology, is "working with urgency and exploring options to expand our supply capacity," according to spokesperson Kathleen Quinn.

In June, the companies showed that sotrovimab reduced by 79% the risk of requiring hospitalization for more than a day or dying from any cause within a month compared to placebo.

The government has spent $1 billion buying doses of sotrovimab to provide at no cost to people who need it. Like other monoclonals, it is expected to run about $2,100 per treatment course.

Like most of the monoclonal antibodies, sotrovimab is given through a 30-minute infusion, which has been difficult to deliver during the pandemic because it requires dedicated facilities where highly infectious COVID-19 patients can be kept away from others. 

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Both Griffin and Gandhi are eager to get access to Paxlovid. "That could be a very timely, attractive way to treat people, especially those at high risk for progression," Gandhi said.

They were less enthusiastic about molnupiravir, which is aimed at the same high-risk group, but said they would use it if they had no better option. In authorizing the drug, the FDA specified that it should be used in high-risk people "for whom alternative COVID-19 treatment options authorized by the FDA are not accessible or clinically appropriate."

Molnupiravir was shown to be 30% effective at preventing severe disease, after looking to be 50% effective in an earlier analysis. 

"We were disappointed and a little surprised" the drug didn't turn out to be more effective, Griffin said.  

Many people are at higher risk for severe disease if infected, including those over 65, people with obesity, diabetes or lung disease, and those with compromised immune systems. 

Paxlovid is also most effective if given within three to five days of COVID-19 symptoms starting.

It could be challenging for people to take their symptoms seriously enough to get tested, receive test results, get a prescription for the drug and begin taking it – all within five days. 

Some pharmacies with medical clinics plan to immediately provide prescriptions for people who test positive. Griffin said his own organization expects to offer same-day home delivery of antivirals to people who qualify.

"If there's a drug out there, we're ready to try to make this happen really quickly," he said.

Paxlovid was shown to reduce the risk of hospitalization by 89% if given within 3 days of symptoms beginning and 88% if given within 5 days. Antivirals are most effective if given during the stage of infection when a virus is rapidly replicating.

The FDA authorized Paxlovid to be used by anyone age 12 and up who is infected with the virus that causes COVID-19 and is at high risk for severe disease. 

It is given as pills to be swallowed twice a day for 5 days – 30 pills in all. The drug was shown to be safe in a trial totaling more than 1,200 volunteers, half of whom received a placebo.

Pfizer is conducting additional trials of Paxlovid in adults at low risk for severe disease and in people who have been exposed to an infected person but have not tested positive themselves.

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On Nov. 18, Pfizer announced it had agreed to provide 10 million doses of Paxlovid to the U.S. government for $5.3 billion or $530 a dose. Zients said the government is working with Pfizer to increase the volume and reduce the drug's manufacturing time.

Paxlovid is not appropriate for people who have severe kidney problems or cirrhosis of the liver or who cannot interrupt medications that should not be taken at the same time. Those people would be good candidates for molnupiravir, Dr. John Farley, director of the Office of Infectious Diseases in the FDA’s Center for Drug Evaluation and Research said in a Thursday news conference.

"We feel that molnupiravir will be an important treatment option and very appropriate for a number of patients," he said.

Molnupiravir is intended to be used only in adults, because it may interfere with bone and cartilage growth, and not during pregnancy, because animal studies suggest it may harm the fetus.

During a late November FDA advisory committee, meeting several members also worried aloud about the potential for molnupiravir, if widely used and not taken as directed, to drive evolution of the virus, making vaccines and other therapies less effective. The drug, which according the FDA should to be taken twice a day for 5 days for a total of 40 capsules, works by introducing errors into virus’s genetic code that stops the virus from replicating.

Paxlovid also stops the virus from making copies of itself, but works in a different way, blocking an enzyme needed for replication. 

Five leading pharmacists groups complained to the FDA Wednesday that they should be allowed to prescribe antivirals, just as they order and dispense other oral drugs and deliver COVID-19 shots.

"Time is of the essence. Requiring patients to make an appointment with another prescriber just to get a prescription that their pharmacist will fill adds time, cost, and inconvenience but most concerning of all, it could cause hospitalizations and even deaths," the groups argued.

 While molnupiravir is less effective than Paxlovid, doctors and pharmacists said they would consider it.

"There are a lot of question marks still to answer, however, If I had nothing else to provide to a patient that was at high risk, that's a risk-reward discussion with a patient," said Michael Ganio, senior director of Pharmacy Practice and Quality at the American Society of Health-System Pharmacists. "That decision may lean in favor of molnupiravir if it was available."

Convalescent plasma might also be useful to help keep infected people out of the hospital, a team from Johns Hopkins University said Tuesday. Although the blood product has been controversial and shown ineffective among hospitalized patients, it reduced hospitalizations by 50% in a trial of 1,200 volunteers, half of whom received a placebo. 

Researchers from the Johns Hopkins Bloomberg School of Public Health, Johns Hopkins Hospital and Johns Hopkins University Medical School, said convalescent plasma should be part of the toolkit for keeping people out of the hospital and encouraged the FDA to quickly authorize the blood product.

Convalescent plasma, derived from the blood of recently infected or vaccinated people, contains natural antibodies that can help fight off infection, they said.

While the blood product may be effective, Griffin and Ganio both said they worry about how feasible it will be to deliver convalescent plasma in the midst of an outbreak. Also, the plasma will likely be derived from people who have been recently vaccinated, Griffin noted, which might pose an ethical problem for people who oppose vaccination.

Meanwhile, hospitals in Los Angeles, "are getting slowly packed" with COVID-19 patients, Shapiro said. "It looks very closely like what we saw in December last year."

Contact Karen Weintraub at kweintraub@usatoday.com.

Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.