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Tenofovir and Abacavir Similarly Beneficial for Treatment-Related Lipoatrophy in HIV: Presented at ICAAC

By Paula Moyer

WASHINGTON, DC -- December 19, 2005 -- Switching from a thymidine analog to either tenofovir disoproxil fumarate (Viread) or abacavir (Ziagen) will equally benefit patients with HIV who lose limb fat, according to findings presented here at the 45^th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).

Although the 2 regimens reduced lipoatrophy similarly, tenofovir may be less likely to cause blood lipid changes than abacavir, said principal investigator Graeme Moyle, MD, associate director of HIV research, Chelsea and Westminster Hospital, London, United Kingdom. "Fewer tenofovir patients initiated lipid-lowering therapy," he said in a presentation on December 17^th.

The investigators conducted the study to address the concern that reducing fat lipoatrophy by replacing a thymidine analog may be associated with deleterious lipid changes and other safety issues. They assessed lipid levels at baseline and at study end in patients who had participated in a randomized, open-label, 48-week study in which they were treated with either tenofovir or abacavir instead of a thymidine analog.

The study -- known as the Randomized Abacavir Viread Evaluation (RAVE) Study -- involved 105 HIV-positive patients who used 1 of 2 thymidine analogs (zidovudine or stavudine). The subjects were randomized in an open-label manner to be switched either to 300 mg of abacavir twice daily or 300 mg of tenofovir 4 times daily. Eligible patients were also on highly active antiretroviral therapy, had moderate to severe lipoatrophy, had not been treated with either of the replacement drugs, and had a current viral load of less than 50 copies/mL.

Among the patients, 71 were taking stavudine and 34 were taking zidovudine before the switch to the thymidine analog. After the switch, 52 were taking tenofovir and 53 were taking abacavir. By the end of the study, both groups showed a significant increase in limb fat over baseline (P < .01). The investigators noted that the 2 study arms had similar results.

Median baseline fasting lipid levels for the 2 groups in the in the tenofovir group and the abacavir group were as follows: total cholesterol 5.6 mmol/L and 3.3 mmol/L, respectively; high-density lipoprotein (HDL) 1.3 mmol/L for both groups; low density lipoprotein (LDL) 3.3 mmol/L and 3.0, respectively; triglycerides levels 2 mmol/L and 1.7mmol/L, respectively.

Median lipid levels improved somewhat over baseline in patients who switched to tenofovir. In those patients, the total cholesterol dropped a median of 0.1 mmol/L, as did the LDL, and the HDL dropped a median of 0.01 mmol/L. Triglycerides decreased a median of -0.17mmol/L.

Lipid levels were unchanged in patients treated with abacavir, the investigators noted.

In patients on stavudine who were randomized to tenofovir, median total cholesterol levels declined from a baseline of 5.9 mmol/L to 5.4 mmol/L at study end. In such patients who were switched to abacavir, the total cholesterol was 5.4 mmol/L at both points.

In individuals on zidovudine, the investigators documented small increases in median total cholesterol levels in both treatment groups. In such patients, median total cholesterol in the tenofovir group increased from 4.9 mmol/L to 5.1 mmol/L at the end of the study; in the abacavir group, the median levels were 5.3 mmol/L at baseline and 5.9 mmol/L at week 48.

The study was funded by Gilead Sciences, which manufactures Viread.


[Presentation title: Lipid Changes in a Randomized, 48-Week Open-Label Comparative Study of Tenofovir Viread vs Abacavir As Substitutes for a Thymidine Analogue in Persons With Lipoatrophy: the RAVE Study. Abstract: H-340]

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