In November 2010, Tesamorelin was approved by the US Food and Drug Administration to reduce excess abdominal fat in HIV-infected patients with lipodystrophy. This condition occurs as a result of HIV infection itself and antiretroviral therapy.
What is Tesamorelin?
Tesamorelin is also known as (TH9507). It is a synthetic growth hormone-releasing factor agonist that stimulates the production and release of endogenous growth hormone. It consists of the 44 amino acids of Human Growth Hormone Releasing Hormone (GHRH) with the addition of a trans-3-hexenoic acid group. It is also more potent and stable than GHRH and resistant to cleavage by the enzyme dipeptidyl aminopeptidase.
In animal experiments, it significantly reduced visceral adipose tissue (VAT). Tesamorelin was found to reduce triglycerides and total cholesterol in test subjects with lipodystrophy when used with antiretroviral therapy for HIV infection. Tesamorelin is also being evaluated as a therapy for insulin resistance, obesity, and nonalcoholic fatty liver.
Structure of Tesamorelin
Molecular Formula: C221H366N72O67S
Molecular weight: 5136 g/molS
Mechanism of Action
Tesamorelin binds and stimulates human GHRF receptors with similar efficacy to endogenous GHRF. Growth hormone-releasing factor is a hypothalamic peptide that acts on the somatotropic cells of the pituitary gland to stimulate the synthesis and pulsatile release of endogenous growth hormone, which is both anabolic and lipolytic. GH exerts its effects on a variety of target cells, including chondrocytes, osteoblasts, myocytes, hepatocytes, and adipocytes, by interacting with specific receptors, stimulating the production of insulin arbitration factor1 (IGF1) and a variety of pharmacodynamic effects.
Studies show that the main mechanism of action of tesamorelin is lipolysis. Lipolysis is the breakdown of lipids and triglycerides, which are fats found in the body. Generally, lipids and triglycerides are stored in the body to be used later as energy. However, a high value for either can increase your risk for heart disease.
A study was planned on 806 Antiretroviral Therapy (ART) treated HIV patients with excess fat in the abdominal area. The patients were given tesamorelin (2mg) or placebo subcutaneously daily. After 26 weeks of treatment, the patients already getting placebo were switched to tesamorelin (2mg) for the next 26 weeks. The treatment of patients already getting tesamorelin was continued for another 26 weeks. The study’s observations concluded that the treatment with tesamorelin decreases Visceral Adipose Tissue (VAT) and maintains the reduction for up to 52 weeks, maintains abdominal adipose tissue, improves lipids and body image, and is generally well-tolerated without any significant clinical changes in glucose parameters1.
Administration of Tesamorelin
Tesamorelin injections are given under the skin. The medicine is in the form of a powder that should be mixed with a diluent (liquid) before use. This mixture must not be stored for later and should be used immediately. The injections are given once a day subcutaneously in the concentration of 2mg. The injection should not be given in the same place two times in a row.
Blood tests need to be done often to ensure that the medicine is effective and not causing any side effects. Please take note that the injections should not be given into scar tissue or bruised skin or directly into the navel (that is, the belly button). The Tesamorelin powder vials should be stored in a refrigerator and not in a freezer.
Any allergic reactions like swelling on lips, face, throat, or tongue; difficulty breathing, or hives.
If any serious side effects are observed, then the use of tesamorelin should be stopped immediately, and a doctor should be consulted. The serious side effects include:
– Pain in legs or arms
– Stiffness or pain in joints or muscles
– Swelling in feet, ankle, and hands
– Numbness or wrist pain
– Tingling or numbness in fingers or hands
– Symptoms (like increased urination, increased thirst, dry mouth, hunger, drowsiness, fruity breath odor, blurred vision, dry skin, weight loss) indicating high blood sugar
– Fluttering in the chest or pounding heartbeat
Some less serious side effects can also be observed. They include:
– Night sweats
– Insomnia (sleep problems)
– Depressed mood
– Muscle spasm
– Itching or mild rash
– Upset stomach, vomiting, nausea
– Redness, swelling, itching, bruising, pain, bleeding, or any other type of irritation on the site where tesamorelin is injected
Tesamorelin therapy can cause glucose intolerance and increase the risk of type 2 diabetes, so it is contraindicated during pregnancy. It is also contraindicated during pregnancy (Category X) as it can harm the fetus. It is also contraindicated in patients with hypothalamic-pituitary axis disorder due to pituitary tumor, radiation to the head and pituitary gland.
1. Falutz J, Mamputu JC, Potvin D, Moyle G, Soulban G, Loughrey H, Marsolais C, Turner R, Grinspoon S. Effects of tesamorelin (TH9507), a growth hormone-releasing factor analog, in human immunodeficiency virus-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data. J Clin Endocrinol Metab. 2010 Sep;95(9):4291-304
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