Cancer drugs called HDAC inhibitors might hold one of the keys to an HIV cure, specifically by fighting latent virus hiding out in the viral reservoir. In a small safety and efficacy trial, Danish researchers gave three weekly injections of the HDAC inhibitor romidepsin to six HIV-positive people, all of whom were on anti-retrovirals (ARVs) and had an undetectable viral load at the outset. There were various signs that the drug succeeded in reversing latency of HIV-infected cells, causing them to begin replicating virus again (which makes the cells susceptible to ARVs, since HIV drugs can only go after replicating virus). The drug apparently inhibited enzymes that keep HIV tightly wound within an immune cell’s nucleus. Meanwhile, the levels of cell-associated HIV RNA in CD4 cells rose. Five of the participants developed a detectable viral load. However, readings of the total HIV DNA found in the participants’ CD4 cells showed no significant change, suggesting the viral reservoir didn’t take a hit from the treatment.