A modified HIV drug reversed vision loss and paralysis in animal models of multiple sclerosis, according to a study funded by the National Institutes of Health. The experimental drug, kamuvudine-9, prevented activation of the inflammasome, a cellular alarm system in the brain and spinal cord that triggers cell death, researchers at the University of Virginia found.
Existing MS treatments aim to suppress the immune system's rogue B and T cells, which attack healthy nerve tissue. But while these drugs prevent relapses, they do not address damage already caused and broadly suppress immunity. The new approach targets the inflammasome instead, addressing a downstream effect of immune dysfunction that appears to drive the disease's most severe complications.
The researchers tested the drug in mice with MS-like disease. After symptoms appeared, they administered kamuvudine-9 for two weeks. Mice that received the drug recovered almost completely from motor impairment and vision loss, a recovery not seen in mice given a standard MS drug. The drug also protected nerve fibers and their insulating sheaths, the main conductors for signals in the brain and spinal cord.
The researchers supplemented animal studies with an analysis of insurance claims from patients receiving similar antiviral drugs called NRTIs to treat HIV or hepatitis B. Compared to patients not taking these medications, those receiving NRTIs were less likely to be diagnosed with MS and, if diagnosed, less likely to experience relapses. "Though NRTIs are different molecules, they too block inflammasome activation and the signal we detected here is exactly what we would expect to see if K-9 does one day prove effective in humans," said Jayakrishna Ambati, M.D., who led the University of Virginia work.
Kamuvudine-9 has already been tested in clinical trials for eye diseases including diabetic macular edema and thyroid eye disease. A similar drug, K-8, has shown promise in treating late-stage macular degeneration. The researchers said they hope to soon begin clinical studies of kamuvudine-9 for MS and other neurodegenerative diseases such as ALS. The study was published in Science Translational Medicine on September 23, 2026.