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Sustained Treatment With Tesamorelin Needed to Keep Belly Fat Off
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15th Conference on Retroviruses and Opportunistic Infections
February 3-6, 2008
Boston
Mark Mascolini
People who lose visceral adipose tissue (VAT) and trunk fat with the growth hormone-releasing factor analog tesamorelin must keep injecting the drug to maintain those losses, according to results of a 26-week placebo-controlled extension of a randomized trial [1]. People who took tesamorelin for 26 weeks then switched to placebo for another 26 weeks regained trunk fat and abdominal subcutaneous adipose tissue.
The trial randomized 410 people with central fat accumulation while taking a stable antiretroviral regimen to 2 mg of subcutaneous tesamorelin daily or placebo for 26 weeks [2]. VAT measured by computed tomography dropped 15.2% in the 273 people taking tesamorelin while rising 5.0% in the placebo group (P < 0.001). At that point the investigators randomized 154 of the tesamorelin-treated people to continue treatment and 50 to switch to placebo. Everyone in the original placebo group started tesamorelin.
The resulting three groups--tesamorelin-tesamorelin (TT), tesamorelin-placebo (TP), and placebo-tesamorelin (PT)--matched closely in age (about 48 years), male-to-female ratio (88-to-12), body mass index (about 29 kg/m(2)), waist circumference (about 105 cm), and glucose (82% at or below 6 mmol/L) when the original study began. At study entry people in the TT group had slightly more VAT (181 + 75 cm(2)) than people in the TP group (174 + 72 cm(2)) or the PT group (175 + 78 cm(2)).
Among men in TT group VAT fell about 17% through 52 weeks (P < 0.05 versus baseline) but fell hardly at all over 52 weeks in TP men who switched to placebo at week 26. Among women in the TT group VAT fell about 24% through 52 weeks (P < 0.05 versus baseline) but only about 8% in the TP group (not significant).
People who took tesamorelin for 52 weeks lost about 1.25 kg of trunk fat on average (P < 0.001 versus baseline), whereas people who substituted placebo for tesamorelin at week 26 ended up with slightly more trunk fat at week 52 than at baseline. The TT group lost almost 2% of abdominal subcutaneous adipose tissue through 52 weeks (P < 0.05 versus baseline), whereas the TP group ended up with 1% more subcutaneous abdominal fat at week 52. Lean body mass rose almost 1.5 kg in the TT group after 52 weeks but hardly changed in the TP group. Limb fat did not change much in either group.
Triglycerides dropped significantly in both the TT and TP groups through 52 weeks, though more in the TT group (-0.58 + 0.15 mmol/L TT, P < 0.001; -0.35 + 0.16 mmol/L TP, P < 0.05). Total cholesterol also fell significantly in both groups, while the total-to-high density lipoprotein cholesterol ratio remained essentially unchanged through 52 weeks in both groups. Two people in the TT group (1.6%) and none in the TP group went from a normal glucose reading before treatment to type 2 diabetes, according to 2-hour oral glucose tolerance test results.
The body fat results indicate that 26 weeks of tesamorelin cannot maintain losses in VAT, subcutaneous abdominal tissue, or trunk fat through 1 year. Continuous therapy did keep fat off in this study, but an expensive antifat drug that must be injected daily may be a less-than-ideal remedy for central fat in people with HIV. The long-term consequences of growth hormone-releasing factor are unknown, though some experts fear a risk of pituitary hyperplasia or benign pituitary adenoma.
References
1. Falutz J, Allas S, Mamputu JC, et al. Data on 52-week safety and efficacy of tesamorelin, a growth hormone-releasing factor analogue, in HIV-infected patients with abdominal fat accumulation. 15th Conference on Retroviruses and Opportunistic Infections. February 3-6, 2008. Boston. Abstract 943.
2. Falutz J, Allas S, Blot K, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med. 2007;357:2359-2370.
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