March 22-28 2021
Clofazimine: a new, effective treatment?
The mortality rate from COVID-19 is about 2%. But today there is no really effective treatment that is specific to infections from a coronavirus. Remdesivir is the principal treatment used to shorten recovery times. However, it is does not work well in severe cases and needs to be administered intravenously.
What about other treatment options? Clofazimine was originally a drug against tuberculosis, then against leprosy, two diseases caused by bacteria. Chinese researchers at the Li Ka Shing Faculty of Medicine and at the University of Hong Kong have recently demonstrated that Clofazimine can also work against COVID-19.
The researchers first showed, using different cellular models, that replication in SARS-CoV-2 and in MERS-CoV (another coronavirus that caused an epidemic several years ago) could be reduced using Clofazimine. They then studied its mechanism and showed that the drug targeted several stages of the viral cycle:
- it blocks viral and cellular membrane fusion activity mediated by the surface viral spike (S) protein and so inhibits entry the entry of the virus into cells.
- it enables reduction of replication of the RNA viral genome (as does Remdesivir).
After these first in vitro results, the scientists evaluated the effectiveness of the treatment in vivo, using a hamster model. They were thus able to show that Clofazimine has a prophylactic and therapeutic activity against SARS-CoV-2, lessening the virus’ replication and reducing inflammatory deregulation. The researchers recommended its use in combination with small dose of Remdesivir, creating a synergistic action to reduce the viral charge, without increasing toxicity for the cells.
This can be represented as:
The prophylactic and therapeutic effect of Clofazimine against SARS-CoV-2 is real, particulary when combined with Remdesivir. At the current time this latter drug is the benchmark treatment against COVID-19, but its effectiveness is relative. It is therefore necessary to find other effective treatments. Complementary studies on Clofazimine would be useful since this molecule seems promising. It is administered orally and is inexpensive, which are two important advantages, notably for developing countries where access to health care is limited.