Last week, the U.S. Food and Drug Administration (FDA) authorized two at-home antiviral treatment pills for COVID-19, marking a major milestone in the global fight against the virus that has disrupted the world for nearly two years.
Both medications, one developed by Pfizer (NYSE: PFE) and the other by Merck (NYSE: MRK) in partnership with Ridgeback Biotherapeutics, were authorized for emergency use by the FDA just one day apart--Pfizer on Wednesday, Merck on Thursday. The U.S. Centers for Disease Control and Prevention (CDC) is expected to authorize both treatments this week.
Pfizer's pill, named Paxlovid, is recommended for patients 12 years of age and older at high risk of developing severe disease to prevent both hospitalizations and death at a 89% effective rate. The FDA said the oral drug should be prescribed as soon as possible after COVID infection is detected and within five days of symptom onset.
A full course of Paxlovid is 30 pills: three pills taken twice daily alongside a low dose of a common HIV treatment, ritonavir, for five days. Ritonavir works by slowing a patient's immune system to allow the antiviral treatment to stay active longer.
Merck's pill, called molnupiravir, is recommended for adults with mild to moderate COVID infections who are at risk for severe disease as well. The treatment has a 30% effective rate at preventing hospitalizations and death. The agency said patients should being treatment within five days of symptom onset.
A full course of Merck's treatment is a total of 40 pills: four pills taken twice a day for five days. The FDA did not authorize Merck's pill for patients under the age of 18 due to potential adverse effects on bone and cartilage growth. The pill also may pose a risk to pregnant patients and their fetuses; the FDA recommends patients to use contraception while using Merck's treatment and for four days after their last dose.
The authorization marks a "major step forward" in the pandemic, Dr. Patrizia Cavazzoni, director of the FDA's Center for Drug Evaluation and Research, said in a statement on Wednesday.
"This authorization provides a new tool to combat COVID-19 at a crucial time in the pandemic as new variants emerge and promises to make antiviral treatment more accessible to patients who are at high risk for progression to severe COVID-19," Cavazzoni said.
The big advantage oral antiviral treatments have over current COVID drugs that require an IV or infection is that they can be taken at home without the need for a healthcare professional to administer. That in turn could help overwhelmed hospital systems this winter as infections are expected to continue to surge by preventing the severe disease and the need for hospitalization all together.
Pfizer said in a statement on Wednesday it is ready to start delivering Paxlovid doses in the United States immediately. Likewise, Merck said in a statement Thursday that it is ready to ship "hundreds of thousands" of molnupiravir courses within days and 1 million courses over the next few weeks in the U.S.
The U.S. has purchased 10 million courses of Pfizer's treatment in a $5 billion deal, and 3.1 million course of Merck's drug for $2.2 billion.