The U.S. has given the green light for Pfizer’s anti-Covid pill. U.S. Drug Agency FDA announced Emergency Use Authorization (Eua) for U.S. Company’s Paxlovid Drug, Nirmatrelvir and Ritonavir Tablets packaged together, for the Treatment of Sars-CoV-2 Infection. It is approved for mild to moderate COVID-19 cases in adults and children over 12 weighing at least 40 kilograms, at high risk of progression to severe disease, including hospitalisation and death.
Paxlovid is available only by prescription – the FDA specifies – and therapy must be started as soon as possible after diagnosis, within five days from the onset of symptoms.
The treatment is given as 3 tablets, 2 of nirmatrelvir and one of ritonavir, to be taken together twice a day for five days, for a total of 30 tablets.
“Today’s authorisation introduces the first anti-Covid-19 treatment to be taken orally”, representing “an important step forward in the fight against this pandemic”, said Patrizia Cavazzoni, head of the Center for drug research and evaluation of the FDA. With the okay to the pill, she adds, “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 at high risk of progression to severe Covid.”
Pfizer Paxlovid pills: effectiveness
In November 2021, Pfizer announced the results of its clinical trials for Paxlovid. This drug is produced in the form of tablets for oral administration.
The trials were carried out on unvaccinated coronavirus patients who were at high risk of hospitalisation due to health problems (heart disease, diabetics, etc.).
There were six hospitalisations and zero deaths among the 607 trial participants who took Paxlovid. Among the 612 patients taking a placebo, 41 hospitalisations and ten deaths were recorded.
When the drug is prescribed within three days after the onset of symptoms of coronavirus, the drug shows effectiveness against hospitalisation and mortality at the level of 89%. If treatment is started within five days of the onset of symptoms, this rate drops to 85%.
The course of treatment with Paxlovid consists of taking 30 tablets for five days. There are no details on the side effects of Pfizer Paxlovid pills yet.
Effectiveness against COVID-19 variants like Omicron
Paxlovid has nothing to do with spike protein, in which multiple mutations have been identified in the omicron variant. The drug is an inhibitor of the viral protease 3CL, which inhibits the intracellular replication of viral RNA at the stage of proteolysis.
Thus, based on the mechanism of action, there is reason to believe that Paxlovid will retain its effectiveness in relation to omicrons. There is evidence that in vitro Paxlovid is effective against all previously identified variants of SARS-CoV2: alpha, beta, gamma, delta, lambda and mu. In vitro studies have shown that Paxlovid also effectively inhibits the 3CL protease of the omicron variant.