“We believe that dealing with the virus will require effective treatments for people infected with the virus or those who have been exposed to it, integrated with the effect of vaccines,” said the company’s chief scientist, Michael Dolsten.
Pfizer began developing its drug “PF-07321332” in March 2020, and is testing it with “ritonavir”, an anti-HIV drug that was reused for other purposes. The clinical test will include 2,660 adults, who will participate at the first signs of infection with Covid-19 or upon first learning of their exposure to the virus.
They will be randomly given either a combination of PF-07321332 and ritonavir, or a placebo twice a day for five or ten days. The goal is to evaluate the safety and efficacy of the drugs being studied, in preventing SARS-CoV-2 infection and the onset of symptoms by day 14.
Other companies are also testing oral antivirals against Covid, but Pfizer is the first drug specifically designed against the Corona virus, and it is known as a “protease inhibitor” and laboratory tests have shown that it disrupts the reproduction process of the virus itself. And if the treatment is proven to be effective on the ground of the trial, it is likely that it will only be effective in the early stages of infection.
By the time COVID has progressed to severe disease, the virus has stopped reproducing itself, and patients have an overactive immune response.