Now Pfizer’s pill, which works by a different mechanism, appears to have produced even better results in high-risk patients. The trial was stopped early by independent monitors because the effect was so impressive.
“We are really over the moon that we did see such high efficacy in this study. It has tremendous implications for patients globally,” said Annaliesa Anderson, chief scientific officer for Pfizer’s hospitals business unit, which includes its antiviral work.
In addition to the current trial in high-risk patients, Pfizer is also testing the drug in standard-risk patients, a study that included some vaccinated people who had breakthrough infections.
In a third large trial, Pfizer is exploring if the drug could be used as a prophylactic medicine for people who live with someone who has come down with Covid-19, meaning a person would take the drug to avoid contracting the virus.
Old Molecule
The pill was internally developed by Pfizer researchers in the U.S. and U.K. During the early pandemic shutdowns, the scientists agreed to come back to their labs in an urgent effort to develop anti-Covid pills, Anderson said. Company researchers “worked around the clock to design this molecule” in a highly-compressed timeframe, she said.
They dusted off an old experimental antiviral drug that Pfizer had developed after the original SARS epidemic, a coronavirus cousin to Covid-19 that killed about 800 people starting in late 2002. The old drug needed to be administered intravenously. But by July of last year, the Pfizer researchers tweaked the original molecule and came up with a new compound that turned out to be highly potent against Covid-19 and other coronaviruses in the test tube -- and could be used as a pill.
The Pfizer drug works to block a crucial enzyme that the Covid-19 virus needs to replicate. It is taken twice a day for five days and used in combination with a second medicine called ritonavir that helps the Pfizer compound stay in the bloodstream longer.
Pfizer said it planned to offer the antiviral therapy through a tiered pricing approach during the pandemic. High and upper-middle income countries will pay more than lower income countries, it said. The drugmaker didn’t say exactly how much it would charge.
A Pfizer spokesperson said the company currently expects to produce more than 180,000 packs of the drug by the end of this year, and anticipates making at least 50 million packs by the end of 2022, with 21 million produced in the first half of the year.
This article was provided by Bloomberg News.