The two new antiviral pills from the American drug companies Merck and Pfizer, against Covid-19 are expected to help in the fight against coronavirus, when they become widely available.
Meanwhile, the extent of their use in different groups of patients is under investigation. Initially, the pills showed great promise in adults diagnosed with Covid-19 infection, while examining whether they can prevent infection in healthy people exposed to the coronavirus.
The following is a summary of what is already known, as well as a first comparison of the pills, according to Reuters.
* Which pill “works” best?
Clinical trial data from both companies show that the Pfizer pill is more effective, but the company has not yet released the full data. According to Pfizer, the pill reduces by 89% the risk of hospitalization or death of high-risk patients with Covid-19, if administered within three days of the onset of symptoms, and by 85% if administered within five days .
Merck had earlier (October 1) announced that its own pill reduces the risk of serious illness or death by 50% in patients at risk of severe disease if the drug is administered within the first five days after the onset of symptoms, but did not evaluate efficacy if the pill is given earlier, within the first three days.
The Pfizer pill is branded Paxlovid, while the Merck Lavgevrio pill, at least in the UK where it was approved for release.
* Why are these two pills important?
Although there are several vaccines available worldwide to prevent Covid-19, treatment options for those who already have coronavirus are still limited. To date, patients who have not yet been hospitalized but are at risk for severe Covid-19 can only take antibody drugs, which are expensive, not widely available, and are given intravenously in hospitals.
* How do the new pills “work”?
Both are given for five days in two doses: Pfizer three pills in the morning and three in the evening, while Merck four in the morning and four in the evening.
The Pfizer pill belongs to the class of protease inhibitors and blocks an enzyme that the coronavirus needs to multiply in the patient's body. According to the company, the virus may not gradually become resistant to the new drug, which is given in combination with another, ritonavir, an older antiviral that potentiates the action of protease inhibitors (but can cause gastrointestinal side effects and ” interference ”with other drugs).
The Merck pill activates a biological mechanism that aims to cause errors in the genetic code of the coronavirus. Because it causes random genetic mutations in the virus, it is difficult in this case, according to the company, for the virus to become resistant to the drug.
* What do we know about the safety of pills?
The two companies have so far provided limited data, but have expressed confidence in the safety of the new treatments. Pfizer reported that about 20% of patients in clinical trials – one in five – had some side effects, mostly mild. Serious side effects were reported in 1.7% of patients who took the pill (compared to 6.6% of those who took placebo or placebo!).
Merck reported that 12% of patients who took the pill had side effects. Other drugs in the same class as the new pill have been linked in the past to birth defects in animals. Merck assured that similar studies of her new drug for a longer period of time and in higher doses than those used in humans, show that her pill does not cause birth defects or cancer.
* What about the supply of pills?
The two companies said they were working to expand the global availability of their pills. Pfizer said it expects to produce more than 180,000 treatment series by the end of 2021 and at least 50 million by 2022. Merck expects to produce 10 million treatment series by the end of 2021 and at least 20 million by 2022.
* How much do they cost;
In the US, both vaccines and Covid-19 treatments are provided free of charge by the US government, while other countries negotiate prices with both companies. Merck has struck a deal with the United States to supply 1.7 million series of treatments, at a total cost of $ 1.2 billion, or about $ 700 for each series (that is, for each “pack of pills for five days”). Britain has struck a deal for 250,000 series of Pfizer pills, but at an undisclosed price.