Human growth hormone releasing factor the latest target in lipodystrophy research

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A Canadian company has announced the start of a phase II trial in the United States to test the safety and efficacy of a synthetic version of human growth hormone releasing factor for the treatment of lipodystrophy in HIV-positive people.

Human growth hormone has been shown to reduce central fat accumulation in people with HIV lipodystrophy in several randomised studies, but concerns have been raised over its safety.

ThGRF has not been tested previously in HIV-positive people with lipodystrophy, but its developers believe that it may be able to do what human growth hormone appears to do – without the side-effects. Rather than directly replacing and boosting human growth hormone levels in a single injection each day, thGRF up-regulates the body’s own production of human growth hormone without over-riding the body’s own feedback mechanisms for regulating production of human growth hormone. Some experts believe that the injection of human growth hormone leads to an over-ride of this mechanism, resulting in disruption of glucose metabolism and the development of diabetes and elevated triglycerides. Both side effects have been observed in people with HIV lipodystrophy when treated with human growth hormone.

Glossary

hormone

A chemical messenger which stimulates or suppresses cell and tissue activity. Hormones control most bodily functions, from simple basic needs like hunger to complex systems like reproduction, and even the emotions and mood.

lipodystrophy

A disruption to the way the body produces, uses and distributes fat. Different forms of lipodystrophy include lipoatrophy (loss of subcutaneous fat from an area) and lipohypertrophy (accumulation of fat in an area), which may occur in the same person.

phase II

The second stage in the clinical evaluation of a new drug or intervention, in which preliminary data on effectiveness and additional information about safety is collected among a few hundred people with the disease or condition.

cholesterol

A waxy substance, mostly made by the body and used to produce steroid hormones. High levels can be associated with atherosclerosis. There are two main types of cholesterol: low-density lipoprotein (LDL) or ‘bad’ cholesterol (which may put people at risk for heart disease and other serious conditions), and high-density lipoprotein (HDL) or ‘good’ cholesterol (which helps get rid of LDL).

diabetes

A group of diseases characterized by high levels of blood sugar (glucose). Type 1 diabetes occurs when the body fails to produce insulin, which is a hormone that regulates blood sugar. Type 2 diabetes occurs when the body either does not produce enough insulin or does not use insulin normally (insulin resistance). Common symptoms of diabetes include frequent urination, unusual thirst and extreme hunger. Some antiretroviral drugs may increase the risk of type 2 diabetes.

The company, Theratechnologies Inc, developed the product ThGRF, as a treatment for type II diabetes. The company reports that phase II studies in adult diabetics indicated that the product was safe and associated with significant reductions in cholesterol compared to placebo, as well as significant reductions in glycosylated hemoglobin (HbA1c) when dosed at 1mg per day. HbA1c is a marker of overall control of gylcemia.

The HIV Lipodystrophy study, headed by Steven Grinspoon of Massachusetts General Hospital and Julian Falutz of Montreal General Hospital, will examine the effect of daily subcutaneous injections of 1mg or 2mg of ThGRF or placebo on truncal and abdominal fat in HIV-positive individuals with lipodystrophy. The study will also look at the effect on other measures of body fat and muscle mass, cholesterol levels, bone mineral density and insulin sensitivity. It will recruit 60 patients at centres in the United States and Canada.

Further information

Theratechnologies; information on ThGRF