People with central nervous system (CNS) side effects, who switched from Sustiva (efavirenz) plus two nucleoside reverse transcriptase inhibitors (NRTIs) to Intelence (etravirine) plus two NRTIs, had a significant reduction in those side effects. These data were reported in a scientific poster presentation Monday, July 19, at the International AIDS Conference (IAC), being held July 18 to 23 in Vienna.

U.S. treatment guidelines recommend Sustiva, a non-nucleoside reverse transcriptase inhibitor (NNRTI), as a preferred option for first-line antiretroviral (ARV) therapy. While Sustiva can cause CNS side effects—including insomnia, vivid dreams, daytime grogginess and nervousness—they subside in most people who take the drug. Unfortunately, they can persist in a minority.

For these individuals, other recommended treatment options include the integrase inhibitor Isentress (raltegravir) or a Norvir (ritonavir)–boosted protease inhibitor. Some providers, however, prefer to save Isentress as an option for people who are heavily treatment experienced. In addition, boosted protease inhibitors can increase triglycerides and other lipids. As an alternative to Isentress and PIs, Laura Waters, MD, from the Chelsea and Westminster Hospital in London, and her colleagues explored switching people from Sustiva to Intelence, a second-generation NNRTI.

For the study, Waters's team enrolled 38 HIV-positive men on a Sustiva regimen who had significant and persistent CNS side effects. Twenty of the men added Intelence to their regimen, but switched from Sustiva to a Sustiva placebo for 12 weeks—called the immediate switch, or IS, group. The other 18 were randomized to continue receiving their Sustiva regimen, but added an Intelence placebo for 12 weeks—called the delayed switch, or DS, group. After 12 weeks, all of the men in the DS group then received Intelence, and those in the IS group stopped taken the Sustiva placebo.

Waters and her colleagues found that switching to Intelence resulted in a significant reduction in CNS side effects. The percentage of those in the IS group with moderate to severe CNS side effects dropped from 90 percent to 60 percent after 12 weeks. Meanwhile, the number of people with significant CNS side effects dropped only from 88.9 percent to 81.3 percent in those in the DS group. Specifically, people in the IS group had a much more significant reduction in insomnia, abnormal dreams and nervousness.

While the reduction in side effects in those switching to Intelence was significant and points to a reasonable Sustiva alternative, the authors point out that not every side effect subsided and not all of the participants saw improvement. They conclude that some CNS side effects might not actually be caused by Sustiva and that further research in this area is warranted.