A new study suggests that an immunosuppressive drug that treats multiple sclerosis (MS) may also be effective protecting against HIV infection. Fingolimod (Gilenya), which is approved by the FDA to treat MS flare-ups, may also block HIV and reduce the latent reservoir, according to a study by researchers at the George Washington University (GW) and published in PLOS Pathogens.

"While antiretroviral drugs have been effective in treating HIV thus far, drug resistance, negative side effects of antiretroviral therapy, and its varying efficacy underscore the need to develop alternative treatment and prevention options," said Alberto Bosque, PhD, MBA, assistant professor of microbiology, immunology, and tropical medicine at the GW School of Medicine and Health Sciences, in a press release. "For the first time, our research team found that by targeting the receptors to the signaling molecule Sphingosine-1-phosphate (S1P), we could effectively block HIV infection and cell-to-cell transmission of the virus and consequently reduce the seeding of the latent virus in the test tube."

Among the most persistent challenges in eradicating HIV is the latent reservoir of infected cells that may reactivate, which are not specifically targeted by current antiretroviral therapies, according to the study. The researchers said that finding a treatment that can target HIV infection and decrease the latent viral reservoir would have a positive effect on the approximately 40 million people worldwide living with the virus.

Fingolimod acts as a functional antagonist of S1P receptors. Through observing human immune cells, the study authors found that HIV infection was blocked by targeting S1P receptors with the immunosuppressive medication. Further, the researchers noted that fingolimod affected the HIV life cycle at multiple levels.

First, fingolimod decreased the surface density of the HIV receptor in T-cells, which inhibits viral binding and fusion, according to the study. Second, the researchers found that fingolimod activates the antiviral restriction factor SAMHD1, which caused a decrease in levels of total and integrated HIV.

"We believe this compound may be a promising novel therapy for HIV treatment and prevention," Bosque said in the press release.

Reference
MS Drug May be Used to Inhibit HIV Infection and Reduce Latent Reservoir. George Washington University. https://smhs.gwu.edu/news/ms-drug-may-be-used-inhibit-hiv-infection-and-reduce-latent-reservoir. Published August 13, 2020.