The molnupiravir, Merck’s antiviral drug initially developed to combat seasonal flu, has given excellent results in the phase 3 trials of the experimentation as an anticovid therapy: Merck states this in a press release which, however, it is important to emphasize, is not supported by studies external to the company. The drug, which is taken at the onset of the first symptoms of covid for five days twice a day, has been shown to be highly effective in reducing the risk of hospitalization and death, and also appears to work against the gamma, delta and mu variants.
“The discovery of an effective, safe and inexpensive antiviral would be a big step forward in the fight against covid,” said Peter Horby, an infectious disease expert at Oxford University. “Molnupiravir had shown promising results in laboratory studies, but the real litmus test was the patient tests: many drugs fail during this step, so the results we have today are really encouraging.”
Risks halved. What emerges from the trial, conducted on a group of 775 unvaccinated patients and with at least one risk factor for severe covid, is that taking molnupiravir would halve the chances of being hospitalized, and would also reduce deaths. In the control group (where no patient had taken the drug), 53 hospitalizations and 8 deaths were recorded, compared to 28 hospitalizations and zero deaths in the group of patients undergoing antiviral therapy.
How does it work? To combat SARS-CoV-2, the coronavirus that causes covid, molnupiravir mimics two RNA bases, cytosine or uracil, which induce mutations in the viral genome and stop replication, killing the virus. The antiviral acts in a targeted way, deceiving the virus but not human cells, which are therefore not affected by the treatment.
The name “molnupiravir” is inspired by Mjölnir, the hammer used by Thor, son of Odin, the Norse and Germanic deity corresponding to Jupiter / Zeus. Will this new antiviral drug be able to “break down” the SARS-CoV-2 coronavirus?
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More comfortable and cheaper. One of the most interesting aspects of molnupiravir is the fact that it comes in the form of ten tablets that the patient takes directly from home. In fact, if it is true that other effective therapies already exist to fight covid, such as monoclonal antibodies, the plasma of the recovered or remdesivir – the only drug so far approved by the US FDA (Food and Drug Administration) – it is equally true that they are all treatments that must be administered intravenously in the hospital. Another non-negligible aspect is the economic one: a complete treatment of molnupiravir costs about $ 700 – not pennies, but certainly much less than monoclonals ($ 2,100) or remdesivir ($ 3,100).
Prevention is better than cure. Although it is legitimate to rejoice at the first results of the Merck antiviral, we must not forget that it is a treatment, and not one prophylaxis: our best weapon to defeat covid remains vaccines, which prevent infection and stop the spread of the virus, as well as masks, distancing and control and isolation of the infected.
A useful tool in the poorest countries. Molnupiravir could instead become an effective weapon, at least temporarily, to fight the coronavirus in the poorest countries, where vaccination rates are still very low. Merck said it will differentiate prices by trying to benefit the least economically viable states, and that it has already signed a licensing agreement with five generic drug companies in India to increase production of the antiviral. Molnupiravir is also much easier to transport and store than medicines that need to be given by transfusion, and could therefore easily reach more remote areas.
Race against time. Merck plans to apply to the FDA for emergency approval of molnupiravir: in the meantime, the US government has already pledged to buy 1.7 billion doses for $ 1.2 billion. However, there are other pharmaceutical companies that are developing antivirals: Pfizer has recently started the last phase of the studies of two different antiviral tablets, and Roche of Switzerland is also developing a similar drug. “In the future we hope to be able to have a medicine that people can buy at the pharmacy and take at the first suspicious symptom, so as to hit the covid coronavirus as soon as possible,” concludes Janet Scott (University of Glasgow), who is collaborating with the development of another antiviral called favipiravir.