Weekly growth hormone on course for phase III in children

By Eleanor McDermid, Senior medwireNews Reporter

A long-lasting formulation of human growth hormone (hGH) appears to be as effective as standard daily treatment in paediatric patients with growth hormone deficiency (GHD), researchers reported at the European Society of Paediatric Endocrinology annual meeting in Dublin, Ireland.

During 6 months of treatment, the 32 GHD children randomly assigned to receive weekly treatment with the long-lasting formulation achieved a growth velocity similar to that seen in nine children given standard daily hGH treatment.

“This is a significant and encouraging piece of work,” Martin Savage, Emeritus Professor of Paediatric Endocrinology from Barts and the London School of Medicine & Dentistry, UK, told medwireNews.

He said that the height velocities seen in the study “are of a level to be expected in treatment of naïve GHD subjects, indicating that GHD subjects are essentially responsive to this weekly therapy.”

Children in the control group received 0.034 mg/kg per day of genotropin – equivalent to a weekly hGH dose of 0.24 mg/kg – and achieved an annualised height velocity of 14.6 cm/year. Children given the long-lasting formulation achieved annualised height velocities of 12.2, 12.3 and 13.6 cm/year with weekly doses equivalent to hGH 0.18, 0.35 and 0.48 mg/kg, respectively. There were no significant differences between the groups.

The average height velocity standard deviation score (SDS) rose from about –3.0 at baseline to between +3.2 and +5.5 at the 6-month follow-up, with no significant differences between groups. As anticipated, younger children and those with lower peak GH levels at baseline had the best growth responses.

The hGH used in the study is fused to a naturally occurring C-terminal peptide (hGH-CTP), which extends its half-life so that it can be given as a weekly, rather than a daily, injection. Presenter Ron Rosenfeld (Oregon Health and Science University, Portland, USA) also noted that, as CTP is naturally occurring, the hGH-CTP preparation is likely to be non-immunogenic.

The children’s insulin-like growth factor (IGF)-1 SDS rose from about –2.0 to 0.0, with a dose-dependent response seen for the three hGH-CTP doses.

Savage said these normal IGF-1 levels indicates an absence of supraphysiological IGF-1 generation. “In terms of future metabolic safety parameters, this is important and reassuring”, he said, adding: “Height velocity values at 12 and 24 months are awaited.”

Rosenfeld said that the team plans a phase III trial to commence in 2015.

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