Is Selzentry (maraviroc) the next best pre-exposure prophylaxis, or PrEP, for HIV-negative individuals looking to avoid contracting the virus? A clinical trial dubbed NEXT-PrEP, which was announced in July, is looking to find out.   

Selzentry could be a useful alternative to Truvada, the only approved PrEP option, as it targets CD4 cells, not the virus. This potentially means less drug resistance—a concern for Truvada PrEP users who may need the drug, and others like it, if they later become infected.

Curiously, just one week after the clinical trial was announced, CDC scientists reported that maraviroc failed to protect monkeys from rectal infection with the virus. The results might not bode well for humans—only studies will tell—though NEXT-PrEP researchers say Selzentry doesn't work as well on monkey cells as it does on human cells.