This week, Theratechnologies Inc. began marketing a new medicine called tesamorelin (Egrifta)—licensed for the treatment of excess belly fat in some HIV-positive people. Tesamorelin causes the body to produce growth hormone and, as a result, most tesamorelin users can lose some degree of belly fat.
Summary
Tesamorelin is a small molecule that stimulates the brain to produce growth hormone. This hormone helps to reduce the amount of fat in the belly of some HIV-positive people. Tesamorelin does not affect the fatty layer just under the skin (subcutaneous fat) in the face or other parts of the body. Prior to prescribing tesamorelin, Health Canada requires physicians to request a CT scan of a patient’s abdomen to confirm the presence of excess belly fat. Tesamorelin is injected under the skin once daily. In clinical trials, participants who had previously lost belly fat while taking tesamorelin had belly fat return when they stopped taking the drug. In Canada, tesamorelin is expected to cost about $3,000 per patient per month.
Some notes on belly fat, growth hormone and HIV
The fat that accumulates within the belly is called visceral fat. In general, among adults, as the amount of belly fat increases, production of growth hormone decreases. Studies from the 1980s and early-to-mid-1990s suggested that some HIV-positive adults produced lower-than-ideal levels of growth hormone. This reduced production of growth hormone led to changes in the composition of the body—an accumulation of belly fat and a loss of some lean tissue (muscle).
About tesamorelin
Tesamorelin is a small molecule (called a peptide). This drug stimulates a gland in the brain, called the pituitary gland, to release growth hormone. Increased production of growth hormone can cause excess belly fat to diminish.
Clinical trials with HIV-positive people
Tesamorelin has been tested in more than 800 HIV-positive people in well-designed clinical trials. Many participants used tesamorelin for between six and 12 months. This usually resulted in a significant decrease in belly fat compared to placebo (fake tesamorelin). There was a small increase in muscle mass among tesamorelin users and no loss of subcutaneous fat. Levels of triglycerides, a fatty substance in the blood, decreased modestly among tesamorelin users.
When participants who had previously received tesamorelin were instead given placebo, all of the beneficial effects of tesamorelin disappeared.
The hormone insulin is used to help regulate blood sugar levels. After initiating therapy with tesamorelin, the body’s ability to respond to insulin may change. During clinical trials, participants who received tesamorelin were more likely to develop elevated levels of blood sugar because their bodies became less sensitive to the effects of insulin. However, among participants who took tesamorelin for up to one year, problems with blood sugar levels generally resolved.
Side effects
In clinical trials, tesamorelin was very well tolerated. Common but temporary side effects occurred at the site where tesamorelin was injected and could include the following:
- redness
- dryness
- itching
- swelling
- pain
Other side effects included the following:
- muscle pain
- joint pain
Uncommon side effects included the following:
- nausea
- vomiting
Warnings and precautions
1. Blood sugar
Persistently elevated blood sugar can foreshadow the development of pre-diabetes and diabetes.
Tesamorelin may cause abnormalities in the body’s ability to maintain stable and normal blood sugar (glucose) levels. Theratechnologies has made the following recommendations:
- Before starting tesamorelin therapy, doctors should assess their patients for pre-diabetes and diabetes.
- During tesamorelin therapy, regular monitoring of blood sugar levels is needed to ensure that patients do not develop pre-diabetes or diabetes.
- Doctors should exercise caution if tesamorelin-using patients develop pre-diabetes or diabetes, as Theratechnologies states: “Diabetes is a known cardiovascular risk factor.”
2. Cancer risk
Tesamorelin stimulates production of growth hormone and another hormone called insulin-like growth factor-1. These hormones can help some tumours grow. Although there have not been published reports of an increased risk of cancer among tesamorelin users, Theratechnologies makes the following recommendations:
- Patients with newly diagnosed or recurrent cancer(s) should not use tesamorelin.
- Any pre-existing cancer should be inactive and its treatment complete prior to initiating therapy with tesamorelin.
- For patients with a history of treated and stable cancers, “tesamorelin should be initiated only after a careful evaluation of the potential benefit of treatment relative to the risk of re-activation of the underlying [cancer].”
3. Women
Tesamorelin has caused harm to the fetuses of pregnant rats. It should not be used by women who are pregnant or who plan to become pregnant.
4. The immune system
In clinical trials, about 4% of participants who used tesamorelin developed hypersensitivity reactions affecting the skin, such as the following:
- itching
- redness
- flushing
- rash
Should such reactions—suspected or confirmed—occur, Theratechnologies advises patients to stop using the drug and immediately seek medical attention.
In clinical trials, about 50% of participants who used tesamorelin developed antibodies that attacked this drug. More than 80% of people with hypersensitivity reactions developed such antibodies. However, the presence of these antibodies did not alter the effectiveness of tesamorelin.
Experiments with rats and people have found that tesamorelin does not weaken the immune system.
5. Fluid build-up
As tesamorelin stimulates the release of growth hormone, fluid can sometimes accumulate, causing swelling in tissues, painful joints and carpal tunnel syndrome in wrists. Such side effects should be temporary or should resolve when treatment is stopped.
6. Special populations
Tesamorelin has not been studied in the following populations:
- people under the age of 18
- people over the age of 65
- people with liver injury or dysfunction
- people with kidney injury or dysfunction
Drug interactions
Tesamorelin does not appear to affect the activity of or the concentration of drugs used for the treatment of HIV.
However, tesamorelin does increase production of growth hormone and may increase the activity of enzymes in the liver that break down the following medicines:
- corticosteroids
- estrogen and testosterone
- anti-seizure drugs
- cyclosporine (Neoral, Sandimmune)
Theratechnologies advises that doctors may need to order blood tests to ensure that these drugs are within the expected range in tesamorelin-using patients.
Before starting tesamorelin
Talk to your doctor and pharmacist if you have or had any of the following health issues:
- cancer
- problems with blood sugar, including pre-diabetes and diabetes
- kidney problems
- liver problems
Dosage, use and effectiveness
Tesamorelin is meant to be taken at a dose of 2 mg per day in treatment-experienced HIV-positive adults with the following waist sizes:
- men with waist size 95 cm or greater
- women with waist size 94 cm or greater
Furthermore, prior to prescribing tesamorelin, Health Canada has asked doctors to request a CT scan to confirm that their patients have excess belly fat. The CT scan should find that visceral fat is greater than 130 cm2.
Also, prior to using tesamorelin, patients should have tried to reduce visceral fat by making changes to their diet and with exercise.
Not all HIV-positive people respond to tesamorelin therapy. Theratechnologies suggests that a decrease in waist size of 1 cm following six months of daily treatment “should be considered as the minimal acceptable decrease for a satisfactory response [to tesamorelin therapy].”
Tesamorelin should be kept refrigerated at temperatures between 2°C and 8°C and protected from exposure to light.
Tesamorelin is supplied as a powder and requires mixing with sterile water to reconstitute the drug.
One month’s supply of tesamorelin comes in boxed kits containing the following:
- 30 vials each containing 2 mg of tesamorelin
- 30 vials of sterile water for injection
- 30 syringes and needles
Theratechnologies has prepared brochures and videos to help patients learn how to prepare and inject tesamorelin. Contact the company (see the Access section below) to obtain these materials.
Before using tesamorelin, review the instructions on how to prepare the drug for injection with your health care provider. Practice the preparation of the drug with your doctor, nurse or pharmacist.
Access
Tesamorelin is licensed in Canada. However, it is not listed on federal, provincial or territorial formularies. Therefore, most people who will access tesamorelin will likely be able to do so because they have private drug insurance plans. Tesamorelin is expected to cost about $3,000 per patient per month. Most private insurance plans do not pay the full cost of medications, and so users are required to make up the difference with a co-payment.
Theratechnologies has a patient support program called Egrifta Support with a toll-free telephone number that patients can call to obtain assistance with the following:
- navigating their private insurance plan
- assistance with co-payments
- advice about using tesamorelin
- support and educational tools on how to prepare and inject tesamorelin
- follow-up support calls
People can contact Egrifta Support at:
1.844.788.1933
—Sean R. Hosein
REFERENCES:
- Theratechnologies. Egrifta. Product monograph. 26 March 2015. Available at: http://theratech.ca/en/content/canada
- Stanley TL, Grinspoon SK. Effects of growth hormone-releasing hormone on visceral fat, metabolic, and cardiovascular indices in human studies. Growth Hormone and IGF Research. 2015 Apr;25(2):59-65.