Parminder S Aujla

SACRAMENTO (TIP): Leprosy drug clofazimine, which is on the World Health Organization’s List of Essential Medicines, holds promise as at-home treatment for Covid-19, according to a Nature study co-authored by an Indian American scientist. The FDA approved drug exhibits potent antiviral activities against SARS-CoV-2 and prevents the exaggerated inflammatory response associated with severe Covid-19, it shows, according to a press release.

Based on these findings, a Phase 2 study evaluating clofazimine as an at-home treatment for Covid-19 could begin immediately, suggest scientists at Sanford Burnham Prebys Medical Discovery Institute and the University of Hong Kong. “Clofazimine is an ideal candidate for a Covid-19 treatment. It is safe, affordable, easy to make, taken as a pill and can be made globally available,” says co-senior author Sumit Chanda.

“We hope to test clofazimine in a Phase 2 clinical trial as soon as possible for people who test positive for Covid-19 but are not hospitalized,” says Chanda, PhD, professor and director of the Immunity and Pathogenesis Program at Sanford Burnham Prebys, La Jolla, California.

“Since there is currently no outpatient treatment available for these individuals, clofazimine may help reduce the impact of the disease, which is particularly important now as we see new variants of the virus emerge and against which the current vaccines appear less efficacious.”

Clofazimine was initially identified by screening one of the world’s largest collections of known drugs for their ability to block the replication of SARS-CoV-2, the release says.

Chanda’s team previously reported in Nature that clofazimine was one of 21 drugs effective in vitro, or in a lab dish, at concentrations that could most likely be safely achieved in patients.

In this study, the researchers tested clofazimine in hamsters—an animal model for Covid-19 —that were infected with SARS-CoV-2, the release says.

The scientists found that clofazimine lowered the amount of virus in the lungs, including when given to healthy animals prior to infection (prophylactically).

The drug also reduced lung damage and prevented “cytokine storm,” an overwhelming inflammatory response to SARS-CoV-2 that can be deadly.

Clofazimine also worked synergistically with remdesivir, the current standard-of-care treatment for people who are hospitalized due to Covid-19, when given to hamsters infected with SARS-CoV-2.

These findings suggest a potential opportunity to stretch the availability of remdesivir, which is costly and in limited supply, the release said.

In July 2020 Sumit Chanda shared more about his team’s race to find a treatment for Covid-19, according to the release from Sanford Burnham Prebys Medical Discovery Institute.

A Phase 2 trial evaluating clofazimine in combination with interferon beta-1b as a treatment for people with Covid-19 who are hospitalized is ongoing at the University of Hong Kong, the release said.

Interferon beta-1b is an immunoregulator that is given as an injection and is currently used to treat people with multiple sclerosis.

“Our data suggests that clofazimine should also be tested as a monotherapy for people with Covid-19, which would lower many barriers to treatment,” says Chanda.

“People with Covid-19 would be able to simply receive a regime of low-cost pills, instead of traveling to a hospital to receive an injection.”

Clofazimine was discovered in 1954 and is used to treat leprosy. Its promise for treating Covid-19 was discovered by high-throughput screening of more than 12,000 existing drugs from the ReFRAME drug library.