Drug Helps Ease Fat Disorder in HIV Patients

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Because fat deposition is linked to the release of growth hormone from the pituitary gland, researchers have tried to give patients human growth hormone. Unfortunately, the side effects from the therapy were just too onerous for most patients to bear, Grinspoon said.

Enter tesamorelin, a synthetic version of a hormone that stimulates the patient's pituitary to produce its own natural growth hormone.

In the phase III trial, Grinspoon's group had 412 HIV patients (86 percent men) with lipodystrophy receive a daily injection of 2 milligrams of tesamorelin or a placebo for 26 weeks. They then used CT scans to track changes in visceral fat over six months, and measured patients' cholesterol and triglyceride levels.

"We had a very significant reduction in visceral fat on the order of 15 percent within the group, and all of the lipid [blood fat] parameters improved -- triglycerides, cholesterol, LDL cholesterol alone," Grinspoon said. All of this occurred without unhealthy alterations in blood sugar (something seen with growth hormone therapy). Patients also reported "improvement in body image, they felt less distressed," Grinspoon said.

Side effects noted in the growth hormone studies, such as swelling and joint pain, were not seen in this trial, he added. "We basically achieved a generally similar reduction in visceral adiposity -- something very close -- without the side effects," Grinspoon said.

The study has since been extended, he added, "suggesting that [tesamorelin] is relatively safe for 12 months at least."

Still, questions about long-term safety remain. Blackman noted that about half of patients taking tesamorelin developed antibodies to the drug, suggesting an immune reaction, and a few developed a kind of skin rash.

He also wondered if chronic stimulation of the pituitary gland might cause it to enlarge or even become malignant over time -- always a danger in HIV patients, whose immune deficiencies leave them more prone to cancer.

Finally, Blackman noted that a reduction in certain heart risk factors, such as cholesterol or triglyceride levels, isn't the same thing as saying that tesamorelin cut patients' risk of cardiovascular events or death. "It is, in my opinion, the most effective [agent] to date in decreasing abdominal fat, but I think that is all that we can say," he said.

Grinspoon agreed that larger, longer-term study is needed, and he noted that a second phase III trial is already set to begin. "If that one confirms the results of this one, then I am sure [Theratechnologies] will seek approval" from the FDA, he said.

More information

There's more on lipodystrophy at the Foundation for AIDS Research.