Coverage of 2007 CROI (Conference on Retroviruses and Opportunistic Infections)

February 25–28, 2007, Los Angeles, CA

Newer results on Sustiva vs. Viramune

February 28, 2007

At the 14th Conference on Retroviruses and Opportunistic Infections (CROI) on Monday, a large study reported comparing anti-HIV regimens including the two widely used drugs Sustiva (efavirenz) and Viramune (nevirapine), both in the NNRTI class, found that more people taking Sustiva achieved undetectable viral loads, maintained them longer and were more adherent to their regimens. Whether the better performance of the Sustiva regimen was due to the drug or to the better adherence by those using it is unclear.

This was not a randomized, controlled study. Rather, it was a retrospective review of medical charts. This leaves the study more open to confounding factors and more difficult to interpret. However, this was one of the largest comparative studies of these drugs. Whatever its limitations, it appears to confirm other findings that suggest the superiority of Sustiva.

The researchers looked at medical records for over 2,800 people and followed people for an average of 2 years. Nearly twice as many people took Sustiva compared to Viramune. The researchers examined how many people were able to achieve undetectable viral loads, how quickly their viral loads were lowered, how long they maintained undetectable viral loads, and how adherent they were to their regimens.

On all counts, people taking Sustiva had better outcomes. Researcher Jean Nechega of Johns Hopkins reported that people in the study who took Sustiva were more likely to be adherent. Adherence was measured using pharmacy records. This may be explained, at least in part, by Sustiva requiring only one dose a day, while Viramune is usually taken twice a day. For people who were highly adherent (defined as taking more than 70% of their doses), over twice as many people (69% vs. 31%) achieved undetectable viral loads. Importantly, people taking Sustiva tended to maintain viral suppression longer.

This study was done in South Africa. Over two-thirds of the participants were women. Around 5% of the women in the study had taken Viramune before to prevent mother-to-child transmission. People taking Sustiva did better regardless of pre-treatment viral load, or CD4+ cell count.

This study adds to the long-running debate about the relative value of these two drugs. A study, called the 2NN study, compared them head-to-head and found that they performed fairly equally. Other analyses have tended to favor Sustiva. Sustiva is contraindicated in pregnancy, because it might harm the developing baby, but otherwise tends to be well tolerated. Viramune is widely used to prevent mother-to-child transmission, but is hampered by uncommon, yet severe side effects.