A new HIV med may provide backup for combos pummeled by viral mutations. The drug, Tibotec’s etravirine (TMC 125), will join Sustiva and Viramune in the
non-nuke class. And it seems to control HIV that’s grown resistant to those two drugs.

Sustiva and Viramune have long been major players in many HIV combos. But they can be a one-shot deal: When HIV mutates in certain ways, it can stop responding not only to the non-nuke you’re taking but to the other one as well.

Enter etravirine. In June, Tibotec’s Johan Vingerhoets, MD, reported that a study tested twice-daily etravirine against HIV with two such mutations. Labeled K103N and Y181C, they arise when combos including either Sustiva or Viramune fail and the virus develops high-level resistance to both. But etravirine worked as well in people whose HIV had K103N as in those without the mutation. In people whose virus had Y181C, the new non-nuke was about 40% less effective.

Richard D’Aquila, MD, of Vanderbilt University School of Medicine in Nashville, says the study results have meaning for people with resistance to either of the non-nukes. He adds that the Y181C mutation is linked more to Viramune than to Sustiva and that “Y181C is rarely seen in Sustiva-treated patients.”  

Etravirine, now in Phase III clinical trials, could be approved by early next year. Even if it delivers more for those who’ve been failed by Sustiva than for Viramune grads, everyone will get a little something from this resistance -resister.