Actor Charlie Sheen revealed this month that he has achieved an undetectable viral load by taking PRO 140, an injectable HIV drug that's currently being studied, according to a report in the Daily Mail.
"It's impossibly amazing. Personally, I think about how I felt on the day and how I feel today. Wow. Talk about a transformation. One minute you're on the road to perdition, the next you're on the road to providence. It's amazing," Sheen told The Daily Mail.
PRO 140 is a special antibody that binds to the CCR5 co-receptor on the body's CD4 cells (the cells that HIV targets and takes over). The CCR5 co-receptor is a site on the surface of CD4 cells that is one of HIV's main entry points. PRO 140 fights HIV by blocking this entry point and preventing HIV from infecting healthy cells.
Sheen, who disclosed his HIV status in Nov. 2015, started taking PRO 140 as a study participant in a phase-3 clinical trial that is looking into the drug's safety and effectiveness in humans. In the study, the drug was given without any other HIV antiretroviral drugs to see whether PRO 140 alone was enough to fight HIV and maintain an undetectable viral load. Sheen has been a part of the study for eight months, according to The Daily Mail.
Last June, PRO 140's manufacturer, CytoDyn, reported phase-2b study results at the medical conference ASM Microbe 2016 in Boston. The results showed that, out of 15 study participants receiving weekly injections of PRO-140, 10 were able to stay on the treatment and maintain an undetectable viral load for over a year. PRO 140 did not fully suppress HIV in four other participants, while the last participant was able to maintain an undetectable viral load with PRO 140 but subsequently moved.
In terms of safety, the drug was generally well tolerated and there were no serious side effects experienced by the participants. Injection site reactions (pain or discomfort at the part of the body where the drug is injected) were mild and infrequent.
Here's a video from the drug developers showing how PRO 140 combats HIV:
The study administered PRO 140 once every week, but one dose can last up to two months, according to the video.