medwireNews: Weekly injection of a pegylated recombinant human growth hormone (PEG-rhGH) has proved effective in a study of Chinese children with GH deficiency (GHD).

The publication details results from a phase II study, which established the superiority of the 0.2 mg/kg per week dose over the 0.1 mg/kg per week dose, and of a phase III study, which established the efficacy of the higher PEG-rhGH dose relative to standard daily rhGH.

In fact, it was slightly more effective, with the average height velocity after 25 weeks of treatment being 13.41 cm/year with PEG-rhGH 0.2 mg/kg and 12.55 cm/year with daily rhGH 0.25 mg/kg per week, from a baseline of 2.3 cm/year in both groups.

The phase III study included 228 patients taking PEG-rhGH and 115 taking daily rhGH. Their average ages were 11.30 and 11.77 years, respectively, and their baseline corrected height standard deviation scores (SDSs) were –4.18 and –4.06. In both studies, GHD was defined as peak GH below 7 ng/mL in two stimulation tests.

The patients’ insulin-like growth factor (IGF)-1 SDS values also increased more in the PEG-rhGH group than the daily rhGH group, from a baseline of around –1.80, but remained at or below 0, on average. The researchers therefore believe this to indicate greater efficacy, rather than being a cause for concern.

IGF-1 levels breached the upper limit of normal on two consecutive occasions in 7.5% of the PEG-rhGH group and 4.3% of the rhGH group, which was not significantly different.

“In clinical practice, dose reduction would be recommended for these patients”, note Xiaoping Luo (Huazhong University of Science and Technology, Wuhan, China) and co-researchers in the European Journal of Endocrinology.

The researchers found the safety profile of PEG-rhGH to be consistent with that generally reported for long-acting GH, except for an increased incidence of peripheral oedema, at 11.4% versus 1.7%, among patients taking daily rhGH. However, they stress that most cases were mild and resolved without need of treatment interruption. There were no incidences of injection-site lipoatrophy.

The team notes that longer studies, which include monitoring of anti-GH (but not anti-PEG) antibodies, are ongoing.

By Eleanor McDermid

Eur J Endocrinol 2017; Advance online publication

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