When a group of Yale School of Medicine researchers embarked on a study in the spring of 2020, they were not thinking about the loss of smell and taste that is a defining sign of COVID-19.
The researchers, led by infectious diseases specialist Joseph Vinetz, MD, were interested in identifying whether an oral medicine used to treat pancreatitis could decrease the viral load (the quantity of virus in your body) of SARS-CoV-2 and improve symptoms in persons newly diagnosed with COVID-19.
As of this writing, the paper has not yet appeared in a peer-reviewed journal but is available on a preprint site. The study found that the drug, named camostat mesylate or mesilate (CM was developed in Japan as a protease inhibitor in the 1980s), had little effect on viral load.
However, the researchers were surprised to find that it provided a distinct type of benefit.
“The patients who received the drug didn’t lose any sense of smell or taste. That was a ‘wow’ factor ” Dr. Vinetz confirms.
This is significant since anosmia, or a loss of smell and loss of taste are both prominent COVID-19 symptoms. As the virus disappears, many people’s senses recover. For others, though, the effect lasts in various degrees. (Those symptoms can still arise with the omicron version, but not as frequently as they have with the previous variants.)
Dr. Vinetz says he became interested in camostat mesylate after reading a paper published in Cell in April 2020 that showed how this drug could prevent SARS-CoV-2 from infecting cells.
Within three days of enrolling in Phase II randomized trial, 70 patients tested positive for COVID-19. For seven days, participants took the drug four times a day.
Although the trial was terminated after it became evident that the primary goal of lowering viral load was not being met, the researchers believe the unexpected findings of loss of smell and taste warrant further investigation.
“My daughter had COVID a year ago and she still has trouble smelling and tasting things,” adds Dr. Desir. “This drug seems to be able to modulate that loss of smell and taste. It has very few side effects and has been studied extensively. This could be the type of treatment that is given to someone with COVID at the onset of the infection.”
The doctors feel that if the medicine is approved for this use, it will be a game-changer.
“It wouldn’t be an expensive medication. Our idea was that everyone would take it if they were diagnosed because it’s hard to predict who will lose their sense of smell or taste, and it’s better to prevent it than to wait for it to happen,” adds Dr. Desir.
There were further benefits to this medicine since the study found that those who received it reported significant improvements in fatigue compared to those who received a placebo.
“People who got camostat mesylate in the trial started feeling less tired and better overall after day four, which was statistically different from the placebo group,” says Dr. Vinetz. “And there were essentially no adverse effects in the camostat mesylate group.”
It’s unclear whether camostat mesylate can help someone who has lost their sense of taste or smell regain it, he says.
“More studies would help us with that,” Dr. Chupp says.
A Phase III clinical trial and an application to the Food and Drug Administration (FDA) for emergency use authorization would be required for camostat mesylate to be approved for use in avoiding COVID-19-related loss of taste or smell. Dr. Chupp emphasizes that all of this will take time.
Despite this, the doctors are optimistic that their unexpected discovery may help in the fight against COVID-19.
“A drug such as camostat mesylate presents an opportunity,” says Dr. Chupp.
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