Last week, Merck and Company announced that an experimental pill they are working on to treat COVID-19 early in the course of the disease to keep patients from becoming seriously ill or dying is proving safe and effective. After discussion with the FDA, it and Merck felt the results were so good they decided to close additional enrollment to the trial. They will finish out the study in approximately November and then present the results and ask for approval for emergency authorization. Production of the pills has already started so as to be ready for rapid distribution when approved.
This is the first easy-to-use treatment specifically for COVID. It is a pill that when taken as prescribed early in the course of symptoms will decrease the risk of hospitalization and death by about 50%.
The drug is called malnupiravir. It is in oral form and easily taken at home. It must be started within five days of the onset of symptoms. This makes it important for people who have symptoms consistent with COVID-19 to get tested immediately (there is now a national backlog of testing, slowing down availability of results) and see their doctor at the onset. Treatment is eight pills daily for five days. This is very much like oral medication people use at early onset of influenza.
Along with the widespread use of vaccines and monoclonal antibodies, this can make COVID-19 a manageable disease. We would be able to go from pandemic to endemic. Merck has stated it will license malnupiravir for generic production for use in low income countries.
Currently treatment for COVID-19, while much better than it was in the initial months of the pandemic, is somewhat limited to monoclonal antibodies in those with the disease who are not yet hospitalized, dexamethasone for use in very sick hospitalized patients, respiratory support such as ventilators and oxygen, and supportive care for other manifestations of the disease.
Monoclonal antibodies are used in similar situations but they are not as readily available, they require intravenous infusion and they are significantly more expensive than the pills will be. Nonetheless they have been found to be about 70% effective. Lack of availability of this treatment and the high expense keeps it from being widely used, and almost not used at all in low income countries. Dexamethasone is used in very sick hospitalized patients to counteract the body’s massive immune system response which is actually the immediate cause of the pneumonia. In fact, the body’s attempt to get rid of the virus causes the lungs to be filled up with fluid and inflammatory cells thereby blocking the ability to transfer oxygen.
In the Merck study, 1,400 high-risk, unvaccinated patients were enrolled. Some patients received the malnupiravir and others received placebo. The active drug so far shows a 50% lower rate of severe illness and mortality than the placebo. After seeing this initial data, Merck, with the agreement of the FDA, felt there was no need to continue to enroll participants in the study, and it would be inappropriate to continue to give people a placebo.
Other companies are also working on developing a pill to treat COVID. So far the most promising ones are being produced by Pfizer and by Roche. All the drugs affect the virus’s ability to replicate itself in the host cell.
One potential drawback of the treatment is that people might use having a treatment as a reason not to get vaccinated. That is not a good idea. The studies of vaccination show it is very highly effective in preventing disease and malnupiravir is only 50% effective. That is very good for antiviral oral medication but would still allow the spread of the underlying virus in the population.
Finally, we have some real cause to celebrate and a way to bring down the risks of death in unvaccinated individuals.