An experimental drug that researchers hope will cast a lifeline to HIV patients who have exhausted first-line treatment has shown early promise in long-awaited trials, The Lancet reports on Saturday.
Etravirine, also called TMC125, is designed as an alternative for patients who are resistant to a class of drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs).
An international consortium of doctors has been testing etravirine on NNRTI-resistant patients in two 48-week trials, the third and final phase of a long and complex process to assess new drugs for safety and effectiveness.
The volunteers in the DUET 1 and 2 trials are divided into two groups. Half receive etravrine and half a dummy, lookalike pill, a placebo.
In addition, all receive two standard anti-HIV drugs from a different treatment class, known as protease inhibitors, and also take selected NNRTIs.
The benchmark of success for helping patients with resistance problems is a "viral load" -- a count of the human immunodeficiency virus (HIV) which causes AIDS) -- to below 50 viruses per millilitre of blood.
At the 24-week point in the two trials, 56 and 62 percent of patients in the etravirine group had achieved this goal, The Lancet paper says. Among the "placebo" group, the rate was 39 and 44 percent.
Side effects were "mild or moderate" in severity, with generally little difference between the etravirine-takers and the placebo group.
Etravirine, made by a Belgian firm, Tibotec, has been closely followed by AIDS campaigners.
Antiretroviral drugs, as drugs to combat HIV are known, can save people with the AIDS virus, although they are not a cure.
But the longer a patient receives these drugs, the likelier it is that he or she will develop resistance problems as the virus mutates. In the case of NNRTIs, HIV can sidestep existing drugs with just a tiny mutation in a single amino acid.
The treatment options narrow further if a patient is found to suffer bad side effects from these powerful molecules.
The hope for etravirine is that it will open up a new front against resistant virus and raise the genetic barrier to developing resistance.