Here’s a link to the original publication. It is in PLOS one, an open access journal that should be accessible for everybody.
Basically, one of the defences of our body against viral infections is a mechanism by which infected cells commit suicide (apoptosis) to halt virus propagation. Successful viruses, amongst them HIV, have evolved ways to block the trigger for this defensive suicide. The drugs tested render the trigger more sensitive, thus escaping the block and allowing infected cells to die. It is an interesting approach to therapy, however, it remains to be seen how this behaves in intact organisms, where not all cells are equally accessible to the drug. As in cancer therapy, you have to hit every single affected cell without killing too many normal cells, to kill 99.99% of the affected cells is not enough. Whether the therapeutic window (the difference between the lowest dose needed to be effective and the highest dose tolerated by the patient) is wide enough needs to be seen. On the other hand, if you also kill 10% of the healthy cells in cell culture, you barely notice it - in a patient, this would cause very severe side effects. Especially since in an intact organism, the different cell types may show different sensitivities to the drug.