Pharmaceutical company Pfizer has received permission to conduct clinical trials in Russia to test the effectiveness of a new drug to prevent coronavirus. We are talking about the drug Paxlovid, which consists of a protease inhibitor and ritonavir.
In Russia, studies are already underway to determine its effectiveness in treating symptomatic coronavirus in people who have been in contact with a sick person (prevention), as well as its effectiveness in treating people with low and high risk of progression of the disease, according to the Registry of Clinical Trials Approvals.
The newspaper “Vedomosti” on November 16 drew attention to the drug trials for prevention. In early November, Pfizer announced the “impressive efficacy” of Paxlovid in the treatment of coronavirus. At the same time, the company announced that it was temporarily suspending trials (including in Russia) in order to immediately submit documents to the U.S. Food and Drug Administration (FDA) for product and drug quality control. This is because it is considered unethical to give patients with potentially life-threatening diseases a placebo during a pandemic.
The study of people at risk of the severe form in Russia began on September 30, the study of the mild form on October 19, and they will officially end in March 2022. Trials of the drug for prevention began on November 12 and, according to the registry, will be completed in March 2023.
“The year of completion of research is written with a reserve, it is a long period that means nothing. If the drug is really good and positive results come earlier, then the dossier will be submitted earlier,” commented Ilya Yasny, head of scientific expertise at the venture pharmaceutical fund Inbio Ventures, on the possibility of the drug appearing in Russia, as reported by the BBC.
A total of 90 people over the age of 18 from the Moscow region, St. Petersburg, Ekaterinburg, Smolensk, Barnaul and other cities will participate in the Russian drug test for prevention. A representative of Pfizer told “Vedomosti” that seven thousand people from different countries, including Russia, are participating in the trials of Paxlovid. If local regulatory authorities approve the drug, the company plans to introduce it to the markets of all these countries, said the source from the publication.
Foreign vaccines, including Pfizer’s, are not available in Russia, and the coronavirus is mainly treated with drugs of unproven efficacy. These include umifenovir (“Arbidol”), favipiravir, remdesivir, hydroxychloroquine and interferon alpha. In public statements, representatives of the Russian authorities refer to the principle of reciprocity in the recognition of vaccines by different countries. The process of approval of the Russian vaccine “Sputnik V” by the World Health Organization is delayed, and its deadlines are constantly postponed.
In October the organization resumed the process, but so far nothing is known about the results. According to the latest data, the Russian Direct Investment Fund expects the WHO to approve “Sputnik” by the end of this year.
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Paxlovid is a direct acting antiviral drug that targets the protease enzyme that is part of the coronavirus proteins. The drug prevents the virus from synthesizing proteins, which in turn prevents the virus from fully developing in the body.
In clinical trials, Paxlovid has shown a relative reduction of 89% in the likelihood of hospitalization with Covid-19. Molecular biologist Irina Yakutenko points out on her YouTube channel that this is a relative rather than an absolute reduction. In other words, scientists in the Paxlovid trials compared the number of hospitalizations and patient deaths to the total number observed.
Interim results from the Phase 2/3 studies are presented in the Company’s press release. More than one thousand adults participated in the studies. All had positive test results for the coronavirus and symptoms of the disease at the start of the studies. The participants were randomly divided into two equal groups. One group received Paxlovid orally every 12 hours for five days and the other group received a placebo.
Among those who started treatment within three days of symptom onset, 0.8% (3/389) were hospitalized within 28 days of study entry, and there were no deaths. In comparison, 7% (27/385) of patients who received placebo were hospitalized and seven people ultimately died. A similar picture was observed in people who received treatment within five days of symptom onset: 1% (6/607) of the drug group were hospitalized up to 28 days, with no deaths. Meanwhile, 6.7% (41/612) in the placebo group were hospitalized, including 10 deaths.
Adverse events occurred in 19% of the Paxlovid group and 21% of the placebo group, the majority of which were mild, Pfizer reported. People in the drug group were less likely to experience serious adverse events (1.7% vs. 6.6% in the placebo group) or drop out of the study due to adverse events (2.1% vs. 4.1%).
This is not the first drug of its kind. A similar development, molnupiravir, was approved in the UK in early November through a partnership between Merck and Ridgeback Biotherapeutics. This drug also targets the proteins of the coronavirus, preventing it from spreading in the human body. Merck claims the tablet is equally effective against all variants of Covid-19, both existing and those that may emerge in the future.
Trial data showed that molnupiravir reduced the number of hospitalizations by 50% in at-risk patients and significantly reduced mortality (using absolute probability, i.e., how often the event occurred during the trial). Overall, 7.3% of patients taking the drug were hospitalized or died within 30 days of taking it. The same occurred in 14.1% of patients who received a placebo. None of the study participants were vaccinated. The United Kingdom has already ordered 480,000 courses of the drug, which is expected to be delivered by the end of the year. In the United States, 1.7 million doses of molnupiravir have been ordered, and the country is in the process of obtaining an additional 1.4 million doses. A five-day course costs $700. The United States will therefore spend $2.2 billion to procure this drug. The price of Paxlovid will be similar to that of Molnupiravir, as previously stated by Pfizer. So, this drug is quite expensive and not all countries and patients will be able to afford it.
Research suggests that both drugs should be taken in the early stages of the disease to prevent progression. Can we say that when an effective drug against coronaviruses is available, vaccination will not be necessary? “No, both vaccination and medication are needed,” says Yasny. “Because vaccination works 95% of the time.” “If a vaccinated person gets sick, they will actually need medication, because it reduces the chances of being hospitalized by 10 times,” he says. “And on the other hand, if a person is not vaccinated, there will be many more cases of people getting sick. Someone will still end up in the hospital,” he explains. Some people will not develop an immune response to the vaccine, and medication will also be very useful for such people, Yasny concludes.