There's nothing like hearing the results of studies directly from those who actually conducted the research. It is these women and men who are transforming HIV treatment and care. In this interview, you'll meet one of these impressive HIV researchers and read an explanation of the study she is presenting at CROI 2008.

I am Marta Boffito from Chelsea Westminster Hospital in London. We administered ritonavir [RTV, Norvir] once daily, 100 mg, and twice daily, 100 mg [to HIV-uninfected volunteers].¹ We followed them for two weeks, and then the volunteers underwent a washout [a period during which the volunteer is not receiving the study drug at all] and then swapped -- a patient who was a once-daily subject took twice daily, and vice versa -- in order to assess changes in cardiovascular risk markers and lipids.

Marta Boffito, M.D., Ph.D.

We observed that, over two weeks, HDL [high-density lipoprotein cholesterol levels] and CD36 decrease for both doses of ritonavir, while an increase in triglycerides was significant only when you give ritonavir once a day.

Obviously, the limitation of the study is that this is a group of volunteers who took the drug for only two weeks. However, we really wanted to assess the relationship between ritonavir exposure and the changes in lipids or other markers. We did see a correlation between ritonavir area under the curve and decrease in HDL or decrease in triglycerides.

Do you know if this study has ever been done before?

There was a similar study published in HIV Medicine where they gave ritonavir twice daily, and also Kaletra [lopinavir/ritonavir, LPV/r], to healthy volunteers. They saw changes in lipids.² Our main aim, honestly, was to measure other markers. We're also, at the moment, running research with other markers. CD36 was the first one, but hopefully we'll have more results with other markers to see if ritonavir actually changes [them].

Are you continuing this study?

Yes.

How much longer do you think you'll continue the study?

The study is finished, the physical study, but the analysis at the laboratory is ongoing, because we're looking for other markers, CD36-like, which may be altered in the presence in ritonavir. We're doing microarrays in the lab, and hopefully we'll have some results by June. We're looking at a lot of molecules that may be expressed following the addition of ritonavir.

Thank you.

This transcript has been lightly edited for clarity.

Footnotes

1. Boffito M, Collot-Teixeira S, De Lorenzo F, et al. Plasma exposure of 100 mg once and twice daily decreases HDL and CD36 expression but only twice-daily dosing increases triglycerides: Potential effect of RTV on cardiovascular disease. In: Program and abstracts of the 15th Conference on Retroviruses and Opportunistic Infections; February 3-6, 2008; Boston, Mass. Abstract 930.
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2. Shafran SD, Mashinter LD, Roberts SE. The effect of low-dose ritonavir monotherapy on fasting serum lipid concentrations. HIV Medicine. November 2005; 6(6): 421-425.