Over the last two years, after researchers first discovered SARS-CoV-2, discussion surrounding the prevention of infection has primarily focused on the efficiency and safety of vaccines. With the threat of Omicron and other variants looming — the world worrying about a possible surge in cases — drug developers are now looking at an antiviral medication that can possibly be the answer to changing the trajectory of the COVID-19 pandemic: the Molnupiravir pill.
Molnupiravir was developed by pharmaceutical companies Merck, Sharp, and Dohme (MSD), and Ridgeback Biotherapeutics. It’s being hailed as a game-changer for being the first oral medication for COVID-19. It can be taken days after symptoms arise to prevent severe complications.
Molnupiravir, The COVID-19 Pill: What We Know So Far
In clinical trials that Merck conducted, they split 775 unvaccinated volunteers from 170 sites across the globe who had at least one risk factor for severe COVID-19 (obesity, aged over 60 years, diabetes, or heart disease) into two groups. The placebo group consisted of the people who would be getting a pill with no known effects, and the control group had people who would receive the Molnupiravir drug. The was a double-blind study. Neither the patients nor the doctor knew if they were getting the actual pill or the placebo. It also required a third party to oversee the trials.
The patients received four capsules twice a day for five days after the first COVID-19 symptoms. Merck recorded that the drug reduced the risk of hospitalizations and death down to 50% for patients who had a mild to moderate case. The hospital admitted only 28 of the participants taking Molnupiravir. On the other hand, there were 53 admissions from the placebo group. On the last day of the 29-day study, no deaths were recorded for the control group. The placebo had eight. The patients in both groups also experienced no severe side effects during the trials.
Merck reported that the pill performed so well this year that they had to stop the clinical trials. It was unethical that half the patients kept receiving placebo despite the overwhelmingly positive findings. They quickly asked the FDA to make the treatment available.
How Molnupiravir Works
An oral antiviral medicine that can alter the course of the SARS-CoV-2 developed this quickly during a global pandemic would be historical. This was possible because rNHC, the breakdown product of the coronavirus pill, was previously tested in other RNA viruses, like MERS-CoV. So, how does it work?
Before we learn the mechanisms behind Molnupiravir, we need to go back to how viruses invade our bodies and get us sick.
SARS-CoV-2 is made up of a genetic material called ribonucleic acid or RNA. Four nitrogenous bases, also called the building blocks, make up RNA: adenine, guanine, cytosine, and uracil. When the RNA virus enters our system, it binds itself with one of our cells. It makes copies of itself by binding its four bases to the cell’s building blocks: adenine, guanine, cytosine, and thymine. This replication process continues until the cell bursts from the high volume of new viral particles.
The individual takes the drug within five days after symptoms develop. Its breakdown product, rNHC, mimics two RNA bases, cytosine and uracil, and enters the infected cell. When the virus is looking for more building blocks to build a new strand, it accidentally uses the Molnupiravir’s bases and incorporates them.
The virus feeds off of building blocks that it thinks are the natural building blocks that it uses to make more of itself, only to find out later that it’s not. The structure of rNHC can’t stabilize, so the virus dies from incorporating the wrong building block into its chains.
Merck’s research suggested the drug took account of and would be effective against variants such as Delta, Gamma, and Mu.
Possible Side Effects of the Coronavirus Pill
Merck didn’t test the pill on pregnant women during the clinical trials. All participants also couldn’t have unprotected sex for a week after finishing their medication.
Previously, one study found mutations in animal cell structures treated with Molnupiravir. The trials’ participants reported no life-threatening side effects. But a question remains. If the drug can imitate building blocks to prevent RNA from making copies of itself, could it destroy or interfere with the host’s cellular replication processes?
We need further research and clinical trials to prove that the COVID-19 pill won’t interfere with RNA replication during embryo development and cause birth defects.
Molnupiravir and Vaccines
If and when science authorizes Molnupiravir for use, vaccination will remain crucial as the first line of defense. It prevents SARS-CoV-2 infection and slows down its spread.
While the coronavirus pill may be beneficial as a treatment for COVID-19, the vaccine prevents you from getting the disease in the first place. The drug might be effective for real-world cases. But people who receive the vaccine still have a much lower chance of infection, thus not requiring treatment at all.
The Future of the Pandemic and Monoclonal Antibodies
While not as convenient as taking an oral medication, another treatment that can alter the virus’s course is monoclonal antibodies. Monoclonal antibodies — which doctors administer through intravenous (IV) infusions — also reduce the risk of hospitalizations and deaths.
Because Molnupiravir and monoclonal antibodies can reduce severe complications caused by the disease, researchers might start looking into combining these two as a form of treatment and testing the synergistic impact they could have on SARS-CoV-2. Furthermore, if the Molnupiravir drug becomes a success, the company and the developers might start investigating if and how we can use the pill as prophylaxis. This is medication you can take immediately after exposure to someone who tested positive for COVID-19.
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