Participants receiving the new Merck integrase inhibitor MK-0518 experienced no significant increases in total cholesterol and triglycerides in a phase IIB dose-ranging study in treatment-naïve patients, presented on Wednesday at the Forty-Sixth Interscience Conference on Antimicrobial Agents and Chemotherapy in San Francisco.
The study compared four doses of MK-0518 with efavirenz in 184 treatment-naïve individuals also receiving tenofovir and 3TC. Preliminary twenty-four week efficacy results were presented last month at the Sixteenth International AIDS Conference in Toronto.
MK-0518 inhibits the activity of integrase, an HIV enzyme that allows the virus to insert its genetic material into the DNA of human T-cells. Preliminary results have shown that the drug is highly effective in suppressing HIV replication in both treatment-naïve and highly treatment-experienced patients.
Baseline lipid levels were comparable across the five study arms, at around 160mg/mL for total cholesterol and between 110 and 155mg/dL for triglycerides.
After 24 weeks on treatment very slight declines in lipid levels were observed in the MK-0518 recipients at all doses (with the exception of HDL cholesterol), but in the efavirenz group all lipid levels rose. The only statistically significant difference was seen in LDL cholesterol, where the efavirenz group had an increase of approximately 5mg/dL whilst slight declines were seen at all MK-0518 doses (p
Teppler H et al. Differential effects of MK-0518 and efavirenz on serum lipids and lipoproteins in antiretroviral therapy-naïve patients. 46th ICAAC, San Francisco, abstract H-265a, 2006.