TREATMENT WITH GROWTH HORMONE-RELEASING HORMONE (GHRH) 1-44 IN CHILDREN WITH IDIOPATHIC GROWTH-HORMONE DEFICIENCY - A RANDOMIZED DOUBLE-BLIND DOSE-EFFECT STUDY

One hundred and eleven pre-pubertal children (70 boys, 41 girls, aged 2.5 to 14.3 years) with growth failure (height 2 SD below the mean for chronological age (CA) and height velocity (HV) below the 10th percentile for bone age) due to idiopathic growth hormone deficiency (peak plasma GH < 20 mUI/l to two standard provocative tests) were treated with GHRH 1-44 NH2. Patient stratification in two classes was performed according to body weight; in each class, patients were randomly allocated to one of seven GHRH doses, from 30 to 300 mug/day. GHRH was injected subcutaneously, every evening, for six months in a double-blind fashion. No relationship was found between the absolute or incremental HV during treatment and the dose (range from 1.3 - 23.1 mug/kg/day) of GHRH. However, HV (cm/year) increased from 3.8 +/- 0.1 (mean +/- SEM) before treatment to 6 +/- 0.2 during six months treatment and 47 patients (42%) increased their HV up to at least the mean normal HV for bone age (catch-up growth). Low titer antibodies to GHRH were found in 19 patients (17.1%) at six months; no adverse effect was observed. Our results suggest thal patients showing catch-up growth were older, had a height closer to the mean for chronological age and a slower pre-treatment height velocity. Failure to demonstrate a relationship between GHRH dose and changes in growth velocity might be explained by the combination of a placebo effect, insufficient frequency of GHRH administration and heterogeneity of the population.