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Tesamorelin (Egrifta SV): effects, use and side effects

Clinical review pending

Tesamorelin is approved in the US to reduce excess abdominal fat in HIV-associated lipodystrophy. What studies show about its effects, and which risks and monitoring matter.

In adults with HIV-associated lipodystrophy, tesamorelin can reduce excess fat in the abdomen. It is approved in the US for this purpose, but not for general weight loss. In studies, the effect lasted as long as treatment continued. After treatment stopped, abdominal fat increased again toward baseline levels.

What is tesamorelin?

Tesamorelin is sold under the brand name Egrifta. The drug is a synthetic, stabilized copy of growth hormone-releasing hormone (GHRH), known as an analog. The body’s own GHRH is made in the hypothalamus and signals the pituitary gland to release growth hormone.

In HIV-associated lipodystrophy, excess fat can build up deep inside the abdomen. Tesamorelin is used to reduce this fat. It was developed under the name TH9507 and approved in the US in 2010.

How does tesamorelin work?

Tesamorelin binds to GHRH receptors in the pituitary gland. This prompts the gland to release the body’s own growth hormone in individual bursts, following the natural pattern known as pulsatile release. As a result, insulin-like growth factor 1 (IGF-1) rises too.

Among other things, growth hormone promotes the breakdown of fat, a process called lipolysis. Fat in the abdominal cavity, also called visceral fat, responds especially strongly. So tesamorelin does not supply the body with growth hormone; it stimulates the body to release its own. That is how it reduces deep abdominal fat.

Studies in people with HIV-associated lipodystrophy reported the following changes in visceral adipose tissue [1]:

Group Change in visceral adipose tissue
Tesamorelin, after 6 months Reduction of about 11 percent
Tesamorelin, with continued treatment Reduction of nearly 18 percent
Placebo Barely changed

After treatment stops, visceral fat tends to increase again.

Is tesamorelin FDA-approved?

Yes. The US Food and Drug Administration (FDA) approved tesamorelin in 2010 as Egrifta [2]. Later formulations are marketed as Egrifta SV and Egrifta WR. Tesamorelin is injected under the skin every day; the medical term is subcutaneous injection.

What is tesamorelin prescribed for?

Tesamorelin is prescribed to reduce excess abdominal fat in people with HIV-associated lipodystrophy. It is not approved for general weight loss. It must not be used in the following situations:

  • during pregnancy,
  • in active cancer,
  • in a disorder of the pituitary’s hormonal control axis.

What side effects are possible?

The prescribing information lists the following common side effects, among others:

  • injection site reactions,
  • joint, muscle and limb pain,
  • swelling from fluid retention.

Doctors also need to watch for the following risks and changes during treatment:

Frequently asked questions

What is tesamorelin used for?

Tesamorelin (Egrifta SV) is FDA-approved to reduce excess abdominal fat in adults with HIV-associated lipodystrophy. Studies have also looked at the drug in people without HIV who have increased visceral fat [3] and in HIV-associated nonalcoholic fatty liver disease [4]. It has no FDA approval for these uses, however. Whether prescribing it outside the approved indication makes sense is a case-by-case decision for the treating doctor.

How long does it take for tesamorelin to reduce visceral fat?

In the pivotal phase III trials, visceral fat had decreased after 26 weeks of treatment compared with placebo, by a statistically significant and clinically meaningful amount. One of these trials enrolled 412 adults with HIV: on tesamorelin, visceral adipose tissue (VAT) fell by 15.2% [5], while on placebo it rose by 5.0% (p < 0.001). A pooled analysis of 806 adults found a treatment effect of about −15.4% at 26 weeks [6].

In an extension study, visceral fat moved back toward baseline levels after treatment stopped [7]. With continued use, the effect was maintained.

Does tesamorelin affect blood sugar?

Yes, tesamorelin can affect blood sugar regulation. Growth hormone counteracts the action of insulin: when growth hormone levels rise, cells can become less sensitive to insulin and fasting blood sugar can go up.

In a pooled analysis of the pivotal trials in 806 adults with HIV, tesamorelin was generally well tolerated. The glucose measures studied did not differ between the groups to a clinically meaningful degree [6]. A randomized 12-week trial in 53 adults with type 2 diabetes likewise found no significant differences between tesamorelin and placebo in fasting blood sugar [8] or in insulin response.

Even so, by week 26 of the clinical trials, more participants on tesamorelin reached an HbA1c of 6.5% or higher [9]: 5% versus 1% on placebo. HbA1c reflects longer-term blood sugar levels. That is why a doctor assesses glucose levels before treatment starts and checks them regularly during therapy.

How does tesamorelin differ from sermorelin?

Tesamorelin is a full-length GHRH(1-44) analog. A trans-3-hexenoyl modification at the N-terminus, one end of the molecule, stabilizes the drug. It makes it more resistant to breakdown by the enzyme DPP-IV [10]. Tesamorelin is FDA-approved for HIV-associated lipodystrophy. Several randomized controlled phase III trials showed that it reduces visceral fat.

Sermorelin, a GHRH(1-29) fragment, is shorter. It contains the shortest sequence needed for activity and is not stabilized at the N-terminus. Sermorelin currently has no FDA approval; its earlier approval as Geref ended after the product was discontinued. There are far fewer clinical data on sermorelin. No study comparing the two drugs head to head has been published so far.

Who should not use tesamorelin?

Tesamorelin must not be used in disorders of the hypothalamic-pituitary axis, the hormonal control system that links these two brain regions. Contraindications include an underactive pituitary gland (hypopituitarism), a pituitary tumor, previous radiation to the head, or a head injury.

The drug must also not be used in active malignant cancer, during pregnancy, or in people with known hypersensitivity to tesamorelin or its ingredients. Before prescribing it, the treating doctor carries out a thorough assessment of whether treatment is appropriate.

Does tesamorelin cause side effects?

Yes. In phase III trials, injection site reactions such as redness, itching and pain [9] were among the most frequently reported side effects. Also commonly reported were joint pain (arthralgia), pain in the limbs, muscle pain (myalgia), fluid retention in the arms or legs (peripheral edema), and abnormal sensations such as tingling (paresthesia).

These symptoms largely match the typical effects of growth hormone and the local reactions to injections under the skin. As a single adverse event, injection site reactions were reported most often.

Treatment can also disrupt blood sugar regulation and push IGF-1 levels above the reference range. Both changes need to be monitored. Hypersensitivity reactions occurred in 4% of study participants. If such a reaction occurs, contact a doctor right away.

How long does tesamorelin need to be used for the effect to last?

In a 12-month study with an extension phase, visceral fat stayed reduced with continued use of tesamorelin [7]. After treatment stopped, the amount of fat moved back toward baseline levels.

The results suggest that treatment has to continue for the effect to last. Whether the benefit of long-term use outweighs the risks is assessed by a doctor case by case. Metabolic monitoring, IGF-1 levels, and how the person responds to therapy overall all factor into that assessment.

Sources

  • Sources: FDA prescribing information for Egrifta; a randomized trial of tesamorelin in HIV lipodystrophy (Falutz et al., Journal of Acquired Immune Deficiency Syndromes, 2010, DOI: 10.1097/QAI.0b013e3181cbdaff 1 ), indexed on PubMed. This document is educational and does not constitute medical advice. Original reference