Pfizer said Tuesday that clinical trials confirmed its Covid pill, a new type of antiviral treatment that should withstand the mutations seen with Omicron, drastically reduced hospitalizations and deaths among at-risk people by almost 90 percent.
The announcement came as a real-world study from South Africa showed two doses of the Pfizer-BioNTech vaccine was 70 percent effective in stopping severe illness from the new variant, a result called encouraging by researchers, though it represents a drop compared to earlier strains.
Data for the new pill, which hasn’t yet been authorized anywhere in the world, came from more than 2,200 volunteers, and backed up findings announced last month in an interim analysis.
The American drugmaker said its treatment, called Paxlovid, withstood the Omicron variant in lab-testing.
“This news provides further corroboration that our oral antiviral candidate, if authorized or approved, could have a meaningful impact on the lives of many,” Pfizer CEO Albert Bourla said in a statement, saying the new drug could “save lives.”
The trial showed that the pill reduced the need for hospitalization in high-risk adults with Covid-19 by 89 percent if the treatment was given within three days of symptom onset and by 88 percent if given within 5 days, according to the company.
Overall, there were 12 deaths in the placebo group who did not receive the drug and none in the drug group.
Side-effects were found at comparable rates between the treatment and placebo groups (23 percent and 24 percent, respectively), and were mostly mild.
There were also encouraging results from a trial among people at standard risk of developing severe Covid, the company reported, but that study is ongoing.
New type of drug
Paxlovid is a combination of two drugs — nirmatrelvir, a new experimental medicine, and ritonavir, an existing antiviral used against HIV. In total, 30 pills are taken over a period of five days.
Nirmatrelvir is known as a “protease inhibitor” and works by blocking the action of an enzyme the coronavirus needs to replicate. Ritonavir is administered to slow down the breakdown of nirmatrelvir inside the body, increasing its efficacy.
Because Paxlovid does not target the fast-mutating spike proteins that stud the surface of the coronavirus, scientists have hypothesized it should be more variant-proof than other treatments, such as synthetic antibodies infusions and antibodies triggered by most types of Covid vaccine.
Another Covid pill, Merck’s molnupiravir, has already been authorized in Britain and is pending authorization in the United States.
But final study results showed molnupiravir only reduced hospitalizations and deaths by a relatively disappointing 30 percent, and there are concerns over its safety. The company has recommended against molnupiravir’s use in pregnant women after animal studies raised concerns for fetuses.
Pfizer said it had shared its pill data with the US Food and Drug Administration as part of its submission for an emergency use authorization.
Real-world vaccine data
The news comes as the heavily-mutated Omicron variant continues spreading fast around the world, raising alarms about surges in severe cases and deaths.
Even if early data suggesting that the variant is milder in most people is confirmed, its increased transmissibility and ability to overcome prior immunity may negate this advantage, by virtue of infecting higher numbers of people.
Many high-income countries have stepped up their campaigns to get people booster shots in order to restore vaccine efficacy.
The latest research out of South Africa found that two doses of the Pfizer/BioNTech vaccine still offered high protection against serious illness.
“The double dose of Pfizer/BioNTech vaccine (shows) 70 percent effectiveness in reducing risk of hospitalization,” said Ryan Noach, the head of South Africa’s leading private health insurance company Discovery, which co-led the study.
Two doses of the vaccine offered 93 percent protection against earlier variants, according to the companies.
The study was based on the results of 78,000 PCR tests taken in South Africa between November 15 and December 7 and was conducted by Discovery along with the South African Medical Research Council (SAMRC).
It also found two doses were 33 percent effective against infection — a result that lines up with early data from the UK Health Security Agency, which experts say underscores the case for a third dose.
