A weekly injection of an HIV antibody boasted a 98 percent success rate in battling the virus among participants in a small study. Researchers at the biotechnology company CytoDyn conducted a Phase IIb trial of the antibody, called PRO 140, as a solo treatment among 40 HIV-positive individuals.The antibody works similarly to daily oral Selzentry (maraviroc), blocking HIV from connecting to the CCR5 coreceptor on the surface of CD4 cells. But the weekly injectable is less toxic and has fewer side effects. Ninety-eight percent of the study participants maintained control of HIV for four weeks. All of the 14 participants who stayed in the study through the six-month point kept their virus suppressed. CytoDyn is embarking on a Phase III trial of PRO 140 as part of a combination regimen including daily antiretrovirals, and the company hopes to receive U.S. Food and Drug Administration approval in 2017.