What tesamorelin is, and why Europe did not approve it

Tesamorelin is a stabilised analogue of growth-hormone-releasing factor. Like sermorelin, it acts one step up: it is not growth hormone, but something that makes the pituitary release its own.

Unlike almost everything else in this catalogue, it has phase 3 trials behind it, with an endpoint measured by imaging rather than by impression.

What was measured, and in whom

The population studied is specific and worth keeping in view: patients with HIV on antiretroviral therapy and abdominal fat accumulation. Not healthy adults.

• Visceral fat. In the pooled analysis of two multicentre, double-blind, placebo-controlled trials, visceral adipose tissue fell at week 26 in the treated group and not in placebo, with a treatment effect of −15.4% [2].
• And subcutaneous fat did not move. This is the most interesting finding and the one that sets the compound apart: the reduction was selective for the visceral compartment, while abdominal subcutaneous fat was preserved [2].
• Metabolic profile. Triglycerides and the cholesterol/HDL ratio fell against placebo, and IGF-I rose [2]. A later analysis explicitly linked the visceral fat reduction to the improved metabolic profile [3].
• At week 52, with the safety extension, the visceral fat reduction was maintained [2][1].

The two agencies, and why both have to be told

In the United States it is approved. It is marketed as EGRIFTA and appears in the US agency's register as a prescription product [5].

In Europe it is not. And not for lack of trying: the marketing authorisation application was submitted and withdrawn on 21 June 2012, once the committee for human medicines had already evaluated the documentation and drawn up its lists of questions. The European agency itself records that, at the time of withdrawal, the committee was of the opinion that the benefits of Egrifta did not outweigh its risks [4].

Telling only the American half of this story would give a European reader a false impression. The same dossier, examined by two agencies, ended up in two different places.

What has not been studied

There are no trials of tesamorelin in healthy people for body composition, performance or recovery. All of the above was measured in a population with a specific alteration of fat distribution, tied to their antiretroviral treatment.

This page describes published literature. It is not medical information, it does not describe a therapeutic use, and it does not replace any healthcare professional.

What to look at when comparing suppliers

• HPLC purity for the specific batch, with a certificate you can read before buying.
• Identity confirmation by mass spectrometry: it is a modified analogue, and the modification is exactly what distinguishes it from other fragments of the same hormone.
• A real cold chain, and verified net content of the vial rather than the nominal figure.