June 30, 2010
Abnormal levels of lipids -- cholesterol and triglycerides -- and blood sugar as well as unwelcome changes to body shape have occurred in some clinical trials, particularly trials of older anti-HIV drugs. To find out if raltegravir (Isentress) is associated with similar problems, researchers conducted a metabolic study comparing raltegravir-based regimens to ones based on efavirenz (Sustiva and in Atripla). After two years, they found that raltegravir was associated with minimal changes in levels of fats and sugar in the blood. Furthermore, no changes in body shape were detected with either study regimen.
A large randomized, placebo-controlled trial called Startmrk enrolled nearly 600 participants and randomly assigned them to receive regimens based on either raltegravir or efavirenz. All participants in this study received a combination of two other anti-HIV drugs as follows:
A fixed-dose combination of these two drugs is sold as Truvada.
Researchers conducted a metabolic sub-study of Startmrk with participants who received low-dose X-ray scans called DEXA. These are useful when objectively trying to assess changes in the body's composition of bone, muscle, fat and so on. Particular attention was paid to lipid levels in the blood of participants. In the metabolic sub-study, 55 people received raltegravir and 57 received efavirenz. All participants were from North America.
The profile of these participants at the start of the study was as follows:
After two years, on average there were relatively small increases in lipid levels in the blood of raltegravir users. Triglyceride levels even fell during the study.
In contrast, lipid levels rose to a larger degree among efavirenz users. Indeed, the difference in lipid levels between raltegravir and efavirenz users after two years was statistically significant for the following lipids:
Blood sugar levels rose slightly among raltegravir users but increased blood sugar levels were more common among efavirenz users. This difference was also statistically significant.
For the most part, increased lipid levels exceeded critical threshold levels only in the cases of LDL-C and triglycerides among some efavirenz users.
Changes in body fat were small and not significantly different between the two treatments.
Overall, the results from this metabolic sub-study suggest that after two years of treatment, raltegravir, when used with Truvada, had a minimal impact on lipid and sugar levels in the blood as well as on body shape.