Researchers from the Georgia State University announced in early December the extremely promising findings of a coronavirus study looking at the MK-4482/EIDD-2801 drug, also known as molnupiravir. The new oral antiviral drug completely blocked virus transmission within 24 hours in ferrets. Developed by Merck and Ridgeback Biotherapeutics, molnupiravir popped up in various reports last year, and it was also the cause of some controversy last spring.
The drug was studied on humans and the preliminary conclusions of a Phase 2a randomized, double-blind, placebo-controlled trial have now been released. Incredibly, the medicine was able to cure infections from the novel coronavirus after only five days. This was only a secondary endpoint of this particular study, and the full conclusions have yet to be released.
Merck and Ridgeback announced the preliminary results during Science Spotlights at the 2021 Conference on Retroviruses and Opportunistic Infections (CROI 2021).
The Phase 2a trial enrolled 202 non-hospitalized adults who took the drug within 7 days of exhibiting COVID-19 signs or symptoms. All participants were later confirmed to have active coronavirus infections. The primary efficacy objective was the reduction in time to a negative PCR result, and samples were collected from patients periodically. Of the 182 participants who had an evaluable nasopharyngeal swab, 78 showed detectable virus levels at the baseline. The full study results are still blinded, and the researchers only presented findings from the secondary endpoint of reduction in time to negativity.
At day 5, there was a reduction (nominal p=0.001, not controlled for multiplicity) in positive viral culture in subjects who received molnupiravir (all doses) compared to placebo: 0% (0/47) for molnupiravir and 24% (6/25) for placebo.
“The secondary objective findings in this study, of a quicker decrease in infectious virus among individuals with early COVID-19 treated with molnupiravir, are promising and if supported by additional studies, could have important public health implications, particularly as the SARS-CoV-2 virus continues to spread and evolve globally,” Dr. William Fischer said in a statement.
It’s unclear when the final conclusions will be revealed, but molnupiravir is also the subject of other Phase 2 and Phase 2/3 trials. The researchers who led this particular trial did say that there were four serious adverse effects reported, but they were not found to be related to the drug.
Merck has also addressed the mutagenicity concerns from last year, conducting separate trials on animals to determine the risks. Here is an excerpt from the press release:
Merck has conducted a comprehensive nonclinical program to characterize the safety profile of molnupiravir. This program included assays such as Big Blue and PIG-a designed to provide a robust measure of a drug or chemical’s ability to induce mutations in vivo. Animals were administered molnupiravir for longer and at higher doses (mg/Kg) than those employed in human studies. The totality of the data from these studies indicates that molnupiravir is not mutagenic or genotoxic in in vivo mammalian systems.
Should the current Phase 2 and 3 trials confirm the safety and efficacy of molnupiravir, the drug might become the first COVID-19 medicine that can be administered orally to patients in order to treat their coronavirus infections at home.