icon-folder.gif   Conference Reports for NATAP  
  12th Conference on Retroviruses and Opportunistic Infections (CROI)
Feb 22-25, 2005
Boston, MA
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Switching off AZT or d4T to Tenofovir or Abacavir Improves Limb Fat After 48 weeks
  "A 48 week, randomized, Open-Label Comparative vstudy of Tenofovir vs Abacavir as Substitutes for a Thymidine Analogue in persons with Lipoatrophy & Sustained Virological Suppression on HAART"
Previously reported studies suggest that neither abacavir nor tenofovir is associated with lipoatrophy. At the Lipodystrophy Workshop in October 2005 David Nolan reported data from pilot studies showing that tenofivr & abacavir are not associated with mitochondrial DNA loss in fat cells. He provided study results showing patients who switched from AZT or d4T to TDF or ABC showed improvement in mtDNA. The MITOX & TARHEEL studies showed fat loss could improve after switching to ABC. And also at the Lipodystrophy Workshop week 120 results from the SOLO study showed that patients who were treatment-naïve and received abacavir+3TC along with either NFV or fosamprenavir/r were unlikely to develop fat loss., only 4-5% of patients who did not report lipoatrophy before starting SOLO reported fat wasting after 120 weeks.
The objective of this study reported by Graeme Moyle at the 12th CROI was to compare abacavir with tenofovir when substituted for AZT or d4T with regards to limb fat recovery, change in lipids and control of HIV RNA.
This study was a randomized, open-label, 48-week study of change in limb fat following substitution of AZT or d4T with ABC vs TDF in adults on HAART with moderate to severe lipoatrophy who are naïve to ABC & TDF with a current viral load <50 copies/ml. Limb fat was measured by dual-energy x-ray absorptiometry (DEXA); secondary endpoints included HIV RNA, adverse events, visceral fat mass (by CT Scan), and fasting metabolic parameters. Analysis was performed on an intent-to-treat basis ignoring treatment changes.
105 patients were randomized receiving d4T (n=71) or AZT (n=34): 53 to ABC, 52 to TDF. Limb fat mass was similar at baseline (mean: 3.7 kg in ABC & 3.9 kg in TDF). At week 48 there was a significant increase in limb fat in both groups from baseline values (p<0.01) but no difference between drug arms. Similar changes in visceral fat and subcutaneous fat by CT were observed. Virological suppression was similarly maintained between both groups. Discontinuation of of ABC was more common (n=6, including 3 hypersensitivity reactions) than TDF (n=1). Mean changes in total cholesterol, LDL, & triglycerides were 0.31, 0.10, and 0.46 mmol/L with ABC and -0.46, 0.25, and 0.49 mmol/L with TDF. Changes in each parameter through week 48 significantly favored TDF (p=0.01, 0.05, & 0.01, respectively). No significant difference between treatment groups observed in changes in bone mineral density scores by DEXA but there was a trend of BMD decline in TDF group.