A novel, extended, long-acting recombinant human growth hormone (rhGH) used to treat adults with growth hormone deficiency (AGHD) may help potentially lower the number of GH treatments to 2 times per month, according to recent results from a phase 2 trial published in the European Journal of Endocrinology.
“Traditional GHD treatment includes the use of daily subcutaneous injections of rhGH. However, this schedule is too frequent to be convenient for many patients, raising concerns about poor adherence to treatment, which can lead to reduced efficacy,” Cheol Ryong Ku, MD, PhD, from the Yonsei University College of Medicine in Seoul, Republic of Korea, and colleagues wrote in their study. “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.”
GX-H9, a novel, extended, long-acting rhGH fused to hybrid Fc (hyFc), is made up of human immunoglobulin D and human immunoglobulin G4. The half-life of GX-H9 increases through the expansion of size from its fusion to hGH, which reduces renal clearance. “IgG4 further increases the half-life of GX-H9 via neonatal Fc receptor-mediated endocytosis and recycling of the Fc-fusion protein,” the authors explained.
To test the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of weekly and every other week (EOW) GX-H9 dosage, Ku and colleagues performed a randomized, open-label, active-controlled and dose-escalation phase 1B/2 study, which included 45 AGHD patients from 16 endocrinology centers in Europe and Korea. Inclusion criteria were an insulin tolerance test result of <3.0 ng/mL peak GH, or a combination GH releasing hormone and arginine stimulation test with peak GH <4.0 ng/mL; minimum 3 months of stable hormone replacement therapies; and an insulin-like growth factor 1 (IGF-1) standard deviation <−1.