It can be a tough thing for people with growth hormone deficiency to manage the condition, considering the typical need for daily injections. However, results from a Phase 2 clinical trial show that a long-acting growth hormone can help reduce the inconvenience of treatment.
The results of the trial conducted by Korean researchers and published in the European Journal of Endocrinology showed that GX-H9, a recombinant human growth hormone (rhGH), can reduce frequency of treatment to just two times per month among adult patients.
The current standard of treatment for growth hormone deficiency (GHD) involves daily injections of synthetic growth hormone. If they had an option, many patients would easily avoid the inconvenience and discomfort that come with daily treatment. Findings from this new trial will certainly be of interest to such people.
GX-H9 is an innovative rhGH featuring human immunoglobulins D and G4. It utilizes hybrid Fc (hyFc) technology, which helps to significantly extend its half-life. This also lowers renal clearance.
The study authors noted that the inclusion of IgG4 further prolongs the half-life of the recombinant growth hormone through “neonatal Fc receptor-mediated endocytosis and recycling of the Fc-fusion protein.”
Results of the trial, which also featured Genotropin, suggested that GX-H9 may be a capable replacement for daily treatments.
“Long-acting rhGH preparations not only allow less frequent injections, but also improve compliance by reducing the inconvenience of daily injections and potentially contribute to improving the efficacy of GH treatment,” Cheol Ryong Ku, one of the study authors said.
The researchers tested the efficacy and safety of GX-H9 in open-label, randomized, active-controlled trials with dose escalations. The trials had 45 adult patients selected from 16 endocrinology centers in Korea and Europe as subjects. The ages of these persons were between 20 and 65 years.
The subjects had either childhood-onset growth hormone deficiency or adult growth hormone deficiency (AGHD). Each one had received growth hormone treatment at least one month prior to the study.
Among the inclusion criteria used in the Phase 1B/2 clinical trial were regular hormone replacement treatments for at least three months; peak GH levels lower than 3.0 ng/mL on an insulin tolerance test, and a standard deviation lower than -1 for insulin-like growth factor-1 (IGF-1).
Patients were randomly assigned, 15 each, to three treatment groups, with treatment starting with the first. Those in Group 1 received 0.1 mg/kg of GX-H9 every week; Group 2 got 0.2 mg/kg every other week (EOW), while Group 3 was given 0.3 mg/kg EOW or a 6 ug/kg dose of Genotropin.
The different doses of the long-acting growth hormone and daily use of Genotropin led to considerable rise in IGF-1 levels. The peak was reached between 48 and 72 hours after administration.
The researchers observed dose-dependent increases in mean peak GH levels as a result of a single dose of GX-H9. This led them to reduce the dose for those in Group 3 to 0.2 mg/kg.
Mean IGF-1 response to GX-H9 remained above the baseline for 168 hours, the intended dose interval, for those in Group 1. It was 336 hours for subjects who received the long-acting hormone every other week in Groups 2 and 3.
A bigger Phase 3 clinical trial is currently being planned, according to the study authors.
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