SYNERGY trial supports rhGH therapy for idiopathic short stature

By Eleanor McDermid
Horm Res Paed 2018; doi:10.1159/000491016
31 August 2018

medwireNews: The SYNERGY trial investigators report significant improvements in height velocity in South Korean children with idiopathic short stature (ISS) treated with daily recombinant human growth hormone (rhGH).

During the first 6 months of treatment, the average height velocity increased from 5.63 cm/year to 10.08 cm/year in 59 children with ISS who were randomly assigned to receive rhGH at a dose of 0.067 mg/kg per day.

Height velocity increased from 4.94 to 5.92 cm/year in the 30 children assigned to receive no treatment during this period, giving a significant difference between the groups of 3.47 cm/year, report Byung-Kyu Suh (The Catholic University of Korea, Seoul) and colleagues in Hormone Research in Paediatrics.

The children were all at least 5 years of age, were prepubertal, and had a height that was below the 3rd percentile for their age and sex, but with no diagnosed cause.

The average height standard deviation score (SDS) was –2.26 at baseline and improved by 0.59 during the 6 months of treatment, compared with 0.08, from –2.33 at baseline, in the control group, which was a statistically and clinically significant difference.

After an additional 6 months of treatment, the patients’ average height SDS had improved by 0.96. The patients in the control group switched to taking rhGH during this period and achieved a 0.62 improvement in height SDS.

“Although our data cannot be extrapolated to long-term height gains, the short-term responses to r-hGH in the first 6–12 months of treatment have correlated with long-term efficacy” in previous studies, say the researchers.

They therefore believe that “there is good reason to expect that the children treated with r-hGH in the SYNERGY study are likely to have a good chance of reaching an improved near-final height.”

Adverse events were rare and there were no new safety concerns. Insulin-like growth factor (IGF)-1 levels rose to 1.3 SDS after 12 months of treatment, and were greater than 2.0 SDS in 24% of patients and greater than 3.0 SDS in 5%. The team states that “this is comparable to the proportion of patients with supra-normal IGF-1 concentrations in other studies of high-dose r-hGH treatment.”

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