Pfizer suddenly released three important information about COVID-19 drug
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Pfizer suddenly released three important information about COVID-19 drug. You need to know something about Pfizer COVID-19 drug.
The new coronavirus has been suffering for a long time!
As of November 1, 2021, the number of deaths due to COVID-19 worldwide has exceeded 5 million . The actual number of deaths and secondary deaths is even higher.
However, in the game with the COVID-19 virus, mankind has gradually grasped the initiative.
In addition to the development of a series of highly protective COVID-19 vaccines, there have been breakthroughs in the treatment of COVID-19.
And the most noteworthy thing is undoubtedly the oral medicine for the treatment of early COVID-19 . Because this will completely change the treatment of COVID-19 and make it a simple and easy home treatment.
Pfizer’s antiviral drug Paxlovid has a big move
- November 5, 2021 , the USPfizer abruptly announced that its oral antiviral Paxlovid safe and effective for the treatment of 19-COVID .
- Compared with placebo, Paxlovid (PF-07321332) reduced the risk of hospitalization or death of high-risk adult patients who took the drug within 3 days of onset of symptoms by 89% ;
- During the 28-day follow-up period, there were no deaths in the Paxlovid treatment group , while there were 10 deaths in the control group.
As the results were better than expected, the study was terminated early .
On November 16, 2021, Pfizer suddenly released three important information about Paxlovid in a row.
In the early morning of November 16, Pfizer announced that it had reached an agreement with the United Nations Medicine Patent Pool (MPP) to authorize other pharmaceutical companies to produce Paxlovid for free , providing very cheap oral medicines to 95 low- and middle-income countries .
Subsequently, the US government announced that it would purchase 10 million courses of Pfizer’s Paxlovid drug . Although no details have been disclosed, the Washington Post reported that Pfizer’s Paxlovid drug costs nearly $500 per course of treatment .
If the price is true, it will be lower than the selling price of Merck’s anti-coronavirus drug Molnupiravir in the United States. Previously, the U.S. government purchased 3.1 million courses of Molnupiravir at a price of 2.2 billion U.S. dollars, and the price of each course of treatment was about 700 U.S. dollars; and the U.S. government also retained the priority right to purchase drugs for another 200 courses.
Finally, Pfizer finally revealed its main purpose: to require the US FDA to approve the emergency use authorization application for Paxlovid to treat COVID-19.
Pfizer’s operation also convinces us that in early 2022, humans will be able to use these highly effective anti-coronavirus drugs.
In order to systematically understand the existing anti-coronavirus drugs, the well-known medical website STAT specially published:
Regarding Pfizer and Merck’s anti- coronavirus drugs, you have to know the problem
1. Which effect is better?
- From the data has been published, Hui Rui drugs will be hospitalized / mortality risk reduction of 89 percent , while Merck drugs is reduced by 50% .
- But neither company disclosed its key detailed data, and the designs of the two trials were not exactly the same.
- When we take a closer look, we will find that 89% of Pfizer’s efficacy is based on taking the medicine within 3 days after the onset of the disease, while Merck takes the medicine within 5 days; and the antiviral
- treatment is definitely the sooner the better.
- When Pfizer’s drug was designed to be treated within 5 days of onset, the efficacy was reduced to 85% ; of course, it was also better than Merck’s drug.
In addition, according to laboratory data, the small molecule PF-07321332 in Pfizer Paxlovid has extremely high activity. The EC50 in Vero-E6 is only 74.5nM (0.0745uM) , while Merck’s blockbuster drug Molnupiravir is 0.22uM .
Moreover, Pfizer drug is actually a combination drug , which is PF-07321332 + protease inhibitor (the famous ritonavir); ritonavir is not a highly active antiviral drug, but an excellent antiviral drug The synergist, Cobicistat modified by ritonavir, regulates liver drug enzymes among many HIV drugs.
So our judgment is that Pfizer Paxlovid is slightly better than Merck’s Molnupiravir, but the common point of the two is: from the published research, the fatality rate of preventing COVID-19 has reached 100% curative effect.
2. Can Pfizer drugs be used in combination with Merck drugs?
When Pfizer first became ill with the efficacy of Paxlovid, we mentioned:
For Pfizer’s Paxlovid and Merck’s Molnupiravir , I quite hope that these two drugs can constitute a cocktail therapy . In fact, when HIV cocktail therapy appeared in 1995, it was also a combination of these two types of drugs, nucleosides + protease inhibitors that inhibit RNA synthesis.
STAT obviously also cares about this issue, thinking: “Yes” in theory, but “unlikely” in practice .
This is because these drugs are developed by different companies and there is no incentive to conduct combined therapy trials. However, other doctors and scientists, especially researchers from the National Institutes of Health or other institutions, can conduct clinical trials of the combination therapy.
But Michael Dolsten, head of Pfizer’s research and development, believes that Pfizer’s antiviral drug Paxlovid is sufficient to fight the new coronavirus and has a strong curative effect; it does not need to be combined with other drug treatments , and the combined treatment may increase potential side effects. (Oh, what a big tone. However, people really have data to support it.)
3. Can people with breakthrough infection use antiviral therapy?
This goes back to the European and American decision-making issues regarding drug indications: everything is based on data .
The clinical trials that have been completed are for people who are at high risk of serious illness; the same is true for Merck’s drug indications approved in the United Kingdom.
For people who have been vaccinated, the risk of hospitalization and death has been greatly reduced, so the need for antiviral drugs has decreased; at the same time, for this reason, oral drugs may not show efficacy in clinical trials. Therefore, previous clinical studies did not involve breakthrough infections.
Nevertheless, Pfizer is carrying out a series of clinical studies , including some breakthrough infections who have been vaccinated. This shows Pfizer’s confidence in its drugs.
One of Pfizer’s trials is for ordinary people to evaluate the effect of the drug on ordinary people who are not at high risk; it includes a group of patients who have been infected with the COVID-19 after being vaccinated . This is the most practical study . The Phase 2/3 clinical trial was launched in August.
Another preventive trial by Pfizer is aimed at the families of symptomatic patients with COVID-19 disease. They take the medicine immediately after close contact to see if they can prevent the close contact from being infected. The Phase 2/3 clinical trial was launched on September 27. Merck also launched a similar study.
4. Is the mechanism of action of the drug the same?
Obviously different. Both drugs interfere with the replication of the new coronavirus, but they interfere in different ways.
Simply put, Merck’s drug Molnupiravir is to adulterate the raw materials required for virus replication, so that the virus cannot replicate further.
Specifically, the active form of Molnupiravir is β-D-N4-hydroxycytidine (NHC) -triphosphate . The RdRp of the virus will mistakenly use NHC-triphosphate instead of cytidine triphosphate or uridine triphosphate as a catalyst. Substrate. NHC will make viral RNA replication and the incorporation of a large number of A G, mutations leading to RNA products .
Structural analysis of the RdRp-RNA complex containing the mutagenized product showed that NHC can form a stable base pair with G or A in the active center of RdRp, which explains how the drug evades proofreading and synthesizes mutant RNA.
Pfizer Paxlovid ‘s mechanism of action is equally simple.
The new coronavirus is an RNA virus. After entering the cell, it needs to use the cell’s protein to synthesize a long polypeptide chain containing a variety of functional proteins.
However, this long polypeptide chain needs to be cleaved by a protease before it can become a functional protein; the 3CL protease is the key to the new coronavirus to cut the long polypeptide chain.
The main component of Paxlovid, PF- 07321332, is an inhibitor of the new coronavirus 3CL protease. Therefore, its antiviral mechanism of action is different from Gilead’s Remdesivir and Merck’s Molnupiravir.
5. How do these two antiviral drugs compare with monoclonal antibodies?
- Regeneron, Eli Lilly, and Vir/GSK, etc. all have monoclonal antibodies authorized by the US FDA for the treatment of early COVID-19 patients to prevent the development of severe illness and death. Among them ,
- Regeneron’s monoclonal antibody reduces the risk of hospitalization/mortality by 70%, Eli Lilly’s is 87%, and Vir’s monoclonal antibody is 85% effective.
- However, these monoclonal antibodies require intravenous or intramuscular injection , so they usually require hospitalization.
- In addition, the treatment cost of monoclonal antibodies is higher , such as Regeneron’s monoclonal antibodies, which cost US$1,250 per dose.
While Pfizer and Merck oral medication is used a lot easier, and much cheaper price .
6. Will these drugs affect the patient’s DNA?
This question is actually for Merck’s Molnupiravir . As we mentioned earlier, the mechanism is to adulterate the virus in the replication process. Will it accidentally be incorporated into human gene replication?
In theory, it cannot be ruled out. But Merck has not found this risk in all existing studies.
However, UNC’s Swanstrom challenged this, believing that Merck’s test was insufficient. In August this year, his research group’s paper on the onset of disease indicated that a key metabolite of Molnupiravir may be changes in the animal’s DNA.
Therefore, this result makes people worry about the long-term side effects of Molnupiravir .
7. How many people will benefit from these new drugs?
According to the quarterly report, in 2021, Merck will be able to produce 10 million courses of Molnu piravir, and in 2022 it will be able to produce 20 million courses of Molnupiravir .
In addition, Merck also has licensed production in India of eight pharmaceutical companies Molnu piravir generics; Merck and the Medicines Patent Pool (MPP) jointly announced that it has signed a license agreement to promote the use of generic drugs, so that the world can be 105 low-income countries Use cheap drugs .
As for Pfizer ‘s drugs, in addition to authorizing other pharmaceutical companies to produce generic drugs, which can be sold at low prices in 95 low- and middle-income countries , by the end of 2021, 180,000 courses of drugs can be produced , and it will reach 50 million by 2022 . The course of medication.
According to data from the World Bank , China , Russia, Brazil, Mexico and other countries are middle-high-income countries.
In particular, it should be reminded that antiviral drugs, as a treatment plan used after infection , cannot replace vaccines as a preventive method used before infection .
That is to say, human beings are still inseparable from vaccines , and vaccination is still the basis for preventing COVID-19 infection.
Vaccine prevention and drug treatment together can constitute a double insurance for epidemic prevention.
Pfizer suddenly released three important information about COVID-19 drug
(source:internet, reference only)
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