Dr Gabriel UguruMERCK, a drug giant announced on Friday 1 October 2021 that it had developed a pill against COVID-19 called molnupiravir. It would be the first oral antiviral medication for COVID-19, if approved. The drug according to released data, which had not been peer-reviewed, targets the viral protease, an enzyme used by the virus to replicate itself (i.e. make copies of itself). In other words, the drug is a protease inhibitor. What the drug does is to introduce copying errors during viral RNA replication, making it impossible for the virus to multiply in the body. Remember that Coronavirus works by taking control of your protein machinery and reprogramming it to start making copies of itself. So this drug does almost the opposite by disrupting the viral replication. COVID-19 vaccines work by targeting the spike protein outside of the virus. This spike protein is used for attachment and gaining entrance into your cells in order to cause infection.
The drug showed effectiveness even against new variants of the virus, including the highly transmissible Delta strain; and is especially attractive for use in unvaccinated or immunocompromised patients. It may also serve as an alternative choice to vaccination for those afraid of needles. The drug needs to be taken within five days after Coronavirus symptoms develop. The drug requires a course of twice daily intake for five days, for it to be effective. The drug like most discoveries in science whereby a set objective leads to a different one, was originally designed for treatment of influenza but is now being trialled for use against COVID-19.
In the trial of the drug, molnupiravir, 775 patients from different countries participated in the study. These patients tested positive for COVID-19 and were within the first five days of showing symptoms. Additionally, they also had one risk factor of either obesity, heart disease, old age or were diabetics. These risk factors meant that they were likely to become seriously ill and in danger of hospitalisation.
During the trial, 7.3% of the 775 people who participated, were either hospitalised or died after 30 days, compared to 14.1% of those given placebo or dummy pill. Within the first 30 days of the trial however, non of the participants receiving the drug died compared to eight deaths amongst those given placebo pill.
The shortcoming of the drug so far, is that the limited timeframe of 5 days within which to start the treatment will present a problem. This is because, many people may not receive a confirmed diagnosis of COVID-19 within the 5-day window. This means that the drug is only good for the first few days of infection or should be deployed preventatively before the virus infects the lungs and the rest of the body.
Caution though, there were side effects, which the company played down because they were slightly more pronounced in the placebo group. All the same, earlier study of the drug did not show any marked health benefit to patients who were already hospitalised with severe COVID-19!
Merck, whose shares rose almost 9% at the start of trading in New York after the announcement, are currently making plans to apply to the US Food and Drug Administration (FDA) for emergency use authorisation to enable the drug to be deployed in the US. Dr Anthony Fauci, chief medical adviser to US President Joe Biden, hailed the results as “very good news”, but urged caution until the FDA reviews the data.
But the US had already placed an order for 1.72 million courses of the drug worth $1.2B pending the FDA approval of the drug. This approximates to $700 per course of treatment or $70 per pill. Phew! Other countries, including the UK, have agreed deals with Merck. Licensing deals allowing generic manufacturers to supply the drug to low- and middle-income countries have also been concluded.
Other companies like Pfizer and Roche, are also carrying out trials of their own antiviral tablets. Pfizer is developing two antivirals with one antiviral in a tablet form to be taken at home, and another an intravenous infusion for patients suffering from more severe cases of the disease as to require hospitalisation. Both antiviral interventions are premised on protease inhibition of the important viral enzyme. The trial which started in March this year is at its final phase.
Roche in collaboration with Atea Pharmaceutical are trialling an oral antiviral pill called AT-527. In the ongoing trials, the drug substantially reduces the viral load in hospitalised patients compared to those patients on placebo pill.
A UK company called Sunairgen are also developing an inhaled interferon treatment for COVID-19. In this method, the company are focusing on interferon, important in activating the wider immune response that prevents the virus from replicating (multiplying). At the moment the virus suppresses the production of interferon beta, thereby weakening the immune system, which otherwise would have been deployed against it. If this important protein is deployed back in the lung where the virus causes most damage, the expected result is that effective prevention of the virus from causing infection would be achieved.
In the USA aside from vaccines, monoclonal antibodies given by intravenous infusions are also being deployed in the fight against the virus. An antiviral drug called remdesivir has been approved for use against COVID-19 in the US but there has been no evidence that the drug is effective in hospitalised patients.
It must be borne in mind that the Coronavirus pandemic has so far cost 4.7 million lives worldwide. This figure is not inclusive of other indirectly Coronavirus-associated deaths.
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