What is the principle of action of the new funds from COVID-19
Pfizer, an American company, has tested a new drug, paxloid, which can be used to treat COVID-19 at home. Its effectiveness (88%) inspired US President Joe Biden to deliver the winner’s real speech at a press conference. “We are accelerating our way out of the pandemic,” he told reporters. The only answer is the FDA – the Food and Drug Administration, which must authorize the use of the drug. We asked Nikolai Kryuchkov, Ph.D., immunologist, to comment on the event in the world of pharmacology.
Despite the fact that the pills have not yet received the “go” from the FDA, the UK and Australia have already agreed on their supply to their citizens. And they pushed them to this publication on the preliminary results of the study. The experiment involved 775 adult patients who took two paxlovid tablets twice a day for five days. As a result, the number of hospitalized patients and deaths decreased in this group compared to the control group, where they took placebo, by 88 percent. Of those who took the drug, less than 1 percent of patients needed hospitalization with zero deaths. In comparison, in the control group, 7 percent of patients were hospitalized and seven people died.
“Paklovid is an original drug that really shows great efficacy in clinical trials,” says Nikolai Kryuchkov. – However, before its appearance, one might say, raised an information wave, another drug, which was announced a few days earlier by other pharmacists. This is also an effective antiviral drug, molnupiravir, for which the UK regulator approved earlier than the FDA. However, unlike pakslovid, it is less effective, it reduces the rate of hospitalizations and deaths by only 50 percent.
Both of these drugs are not really very new. They were created more than ten years ago as anti-influenza drugs.
– What is their principle of operation?
– The mechanism of molnupiravir is that it disrupts the synthesis of the viral RNA chain in the cell and inserts defective nucleotides there, forming mutations. Thus, the virus loses its ability to reproduce. Paklovid is a protease inhibitor. Protease is an enzyme that a virus needs at the stage of forming whole particles during its reproduction. That is, the drug inhibits (slows down) the action of the protease, which also disrupts the process of virus multiplication inside the cell. The methods are different – the goal is the same.
Since influenza and many other viruses have protease, paxlovid was originally developed as a universal remedy.
– Why did scientists place their stake on Pasclovid now? After all, there are many other universal antiviral agents.
– A substance similar to it several years ago was shown to be effective in infectious peritonitis in cats. This disease is also caused by a coronavirus infection. Therefore, the developers decided that it could also work on other coronaviruses. It was prepared first for MERS, which was not widely used. Now that the SARS-CoV-2 pandemic has arrived, it has proven to be the most effective. But I think that by the end of all the necessary clinical trials, the gap between the two counter-leader leaders will be smaller, for example, 50 and 70 percent effectiveness.
– What active drugs are they similar in effectiveness?
– There is no such. Even in spite of the fact that favipiravir used today in clinics is close in principle of action to molnupiravir (it also violates the genome of the virus), you cannot put it next to it. As well as other remedy – remdesivir.
– Strong drugs can have significant side effects. What is the difference between pakslovid and molnupiravir?
– Of course, there are side effects, I can’t name them now. But the frequency of their occurrence is no more than 3-4 percent of cases.
– Are there any Russian developments for this kind of strong antiviral agents?
– No. It’s good that at least we managed to create vaccines. It must be understood that drugs of this level are not created from scratch. The Americans have long had patents for similar compounds.
What is good for a cat is death