Macimorelin for diagnosing growth hormone deficiency

The technology described in this briefing is macimorelin. It is used for diagnosing growth hormone deficiency (GHD) in adults.

The innovative aspects are that it is the only oral growth hormone stimulation test and does not rely on inducing hypoglycaemia to provide a growth hormone response.

The intended place in therapy would be as an alternative to all currently available GHD tests, including the insulin tolerance test in adults with GHD.

The main points from the evidence summarised in this briefing are from 2 studies (1 multicentre randomised crossover trial with a subgroup post-hoc analysis and 1 multicentre open-label study), which include a total of 237 people. They show that macimorelin is an effective and safe test for diagnosing adult growth hormone deficiency (AGHD) with accuracy comparable with other tests, including the insulin tolerance test.

Key uncertainties around the evidence are that there is only 1 randomised crossover trial, with a secondary analysis, and 1 study that had to be altered because the comparator was discontinued. Only 1 NHS trust was included in the randomised crossover trial, which was done in the US and across 25 sites in Europe.

Experts advised that macimorelin is less invasive than other GHD tests because it is taken orally, needs fewer blood samples, has a shorter procedure time, can be done in an outpatient setting and has fewer side effects. It can be used when the insulin tolerance test is contraindicated. They noted that further research is needed on its tolerability, the impact of body mass index on its effectiveness and its use when the insulin tolerance test is contraindicated.

The cost of macimorelin is about £421 per test (excluding VAT). The cost of standard care is between £439 and £470 per test.