Antiviral Pills for COVID-19 Show Encouraging Results

Pfizer announced that its COVID-19 oral antiviral candidate, Paxlovid, significantly reduced hospitalization and death. This was based on an interim analysis of the results of a clinical study of non-hospitalized adult patients with COVID-19, who were at high risk of progressing to severe illness.

Paxlovid is specifically designed to be administered orally as a pill. So it can be prescribed at the first sign of infection or at first awareness of an exposure. This potentially helps patients avoid severe illness which can lead to hospitalization and death.

Pfizer hopes to eventually offer the pill to people to take at home before they get sick enough to go to the hospital, CNN reports. It would be given in combination with an older antiviral drug called ritonavir. The company hopes to receive Emergency Use Authorization from the U.S. Food and Drug Administration as soon as possible.

“Today’s news is a real game-changer in the global efforts to halt the devastation of this pandemic,” said Albert Bourla, CEO of Pfizer. “These data suggest that our oral antiviral candidate, if approved or authorized by regulatory authorities, has the potential to save patients’ lives, reduce the severity of COVID-19 infections, and eliminate up to nine out of ten hospitalizations.”

The study evaluated data from 1219 adults. The participants had a laboratory-confirmed diagnosis of COVID-19 within a five-day period with mild to moderate symptoms. And they were required to have at least one characteristic or underlying medical condition associated with an increased risk of developing severe illness from COVID-19.

The participants received Paxlovid or a placebo orally every 12 hours for five days. The results show an 89% reduction in risk of COVID-19-related hospitalization or death. 0.8% of the participants who received Paxlovid were hospitalized (with no deaths). This compares to 7% of the participants who received placebo and were hospitalized or died (with 7 deaths).

“I think it's a great day for humanity,” said Bourla in conversation with CNN.

Earlier this month, the UK medicines regulator approved Molnupiravir. It's a COVID antiviral developed by Merck and Ridgeback Therapeutics. This was reported in an article by biomedical technology professor Alexander Edwards, published in The Conversation.

Among adults with mild to moderate COVID, who were at risk of developing serious disease, molnupiravir cut the chances of being hospitalised or dying in half. Edwards explains the difference:

“Molnupiravir disrupts the replication of the virus. It mimics a building block of the virus’s genetic material, and so when the virus reproduces, gets incorporated into its RNA. This creates errors in its genetic code, and when enough of these build up, an “error catastrophe” stops the virus reproducing altogether… Paxlovid also stops viral replication, but in a different way. It works by binding to an enzyme - called a protease - to stop it from functioning. The coronavirus needs this enzyme to be functional in order to reproduce.”

Edwards adds that Molnupiravir should be taken as soon as possible following testing positive (and within five days of symptoms starting). And Paxlovid appears to be beneficial when administered within three to five days of symptom onset.