There is a scarcity of data from randomised controlled trials on the association of growth hormone (GH) with gonadotrophin-releasing hormone agonists in idiopathic short stature (ISS), although this off-label use is common. We aimed to test whether delaying pubertal progression could increase near-adult height (NAH) in GH-treated patients with ISS.
Patients with ISS at puberty onset were randomised to GH with leuprorelin (combination, n = 46) or GH alone (n = 45). NAH standard deviation score (SDS) was the primary outcome measure. The French regulatory authority requested premature discontinuation of study treatments after approximately 2.4 years; patients from France were followed for safety.
Mean (s.d.) baseline height SDS was −2.5 (0.5) in both groups, increasing at 2 years to −2.3 (0.6) with combination and −1.8 (0.7) with GH alone. NAH SDS was −1.8 (0.5) with combination (n = 19) and −1.9 (0.8) with GH alone (n = 16). Treatment-emergent adverse events and bone fractures occurred more frequently with combination than GH alone.
Due to premature discontinuation of treatments, statistical comparison of NAH SDS between the two cohorts was not possible. During the first 2–3 years of treatment, patients treated with the combination grew more slowly than those receiving GH alone. However, mean NAH SDS was similar in the two groups. No new GH-related safety concerns were revealed. A potentially deleterious effect of combined treatment on bone fracture incidence was identified.