UK study finds HIV drugs could be repurposed to treat age-related macular degeneration, now untreatable in up to 90% of cases

Drugs that have been used for the last 30 years to treat HIV and AIDS could also be used to treat age-related macular degeneration in the eye and other inflammatory disorders, says a University of Kentucky news release.

The "landmark study" was led by Dr. Jayakrishna Ambati, professor and vice chair of UK's Department of Ophthalmology and Visual Sciences and has been published in the journal Science.

Age-related macular degeneration is a progressive condition that is untreatable in up to 90 percent of patients and is a leading cause of blindness in the elderly worldwide. There are two forms of AMD, wet and dry.  Wet AMD has several therapies available, which are not always successful. Dry AMD has no approved treatments.

The most widely used class of anti-HIV drugs are thought to work as a treatment for HIV/AIDS patients because of how they target a specific enzyme that is critical for the replication of HIV. The drugs are nucleoside reverse transcriptase inhibitors.

The study found "NRTIs prevented retinal degeneration in a mouse model of dry AMD," the release reports. The toxic molecule that causes dry AMD requires the same enzyme to fulfill its life cycle as the enzyme that is responsible for replicating HIV; NTRIs target that enzyme. Surprisingly, the study found that NRTIs target it indirectly, by blocking an immune pathway, says the release.

"Repurposing of NRTIs could be advantageous, for one, because they are very inexpensive," Benjamin Fowler, the lead author and a postdoctoral fellow in the Ambati lab, said in the release. "Moreover, through decades of clinical experience, we know that some of the drugs we tested are incredibly safe. Since these NRTIs are already FDA-approved, they could be rapidly and inexpensively translated into therapies for a variety of untreatable or poorly treatable conditions."