• Successful Substitution of Protease Inhibitors with Sustiva (Efavirenz) in Patients with Undetectable Plasma HIV-1 RNA Levels -- Results of a Prospective, Randomized, Multicenter, Open-label Study (DMP 266-049)
  Slide Session 475
  Authored by A. Rachlis, S. Becker, J. Gill, E. Dejesus, G. Pierone, L. Kirkland, S. Kooshian, D. Farina, N. M. Ruiz, L. Bessen, S. Villano

This study is one of the largest done to date, in which 300 people on a protease inhibitor-based combination either stayed on their protease inhibitor or were switched instead to efavirenz (Sustiva). People were on their protease inhibitor for an average of 20 months, and all had a viral load <50 when the switch was done. Most were on either indinavir (44%) or nelfinavir (30%). This study supports the results of other similar studies done to date.

By week 24, there were some patients who discontinued the Sustiva -- with the anticipated 3% who stopped Sustiva due to side effects, similar to other large studies of this agent. However, over time, 12% stopped their protease inhibitor due to side effects. In follow up, there was similar viral suppression in both arms, with a few viral rebounds seen on both arms. However, after six months, there was some separation showing more rebounds occurring on those who stayed on their protease inhibitor. After the substitution, there was no change in the total cholesterol, but a small increase in the HDL ("good") cholesterol was noted on Sustiva, confirming previous observations. Further, the researchers showed that adherence was easier on sustiva with 21% reporting miss one or more doses, while 38% reported at least one missed dose when on the protease inhibitor.

This large study confirms the results of every other study done so far on the ability to switch from a protease inhibitor to a non-nucleoside. At this point, we have successfully shown that there is anticipated success in maintaining viral suppression, and for those who find difficulties on their protease inhibitor, they can confidently consider the non-nucleoside class as an alternative to it. There, however, can be side effects on the new agent, and these must be anticipated when any switch is considered. In addition, the nucleoside component of the regimen must be fully potent, with no anticipated underlying resistance, in order to maximize the success of this switch.