Newly formulated GROWJECT is bioequivalent to the prior GROWJECT formulation and causes less injection-associated pain.

Daily treatment with subcutaneous injections of recombinant human GH can be physically and emotionally stressful for children and their caregivers owing to the pain caused by injection. In this study, 52 healthy male subjects were randomized to investigate the bioequivalence and compare the safety and injection-associated pain between the prior GROWJECT sc formulation and the new formulation, which contains less phosphate buffer. Single subcutaneous doses of each formulation were administered in a crossover manner. Adverse events were monitored throughout the study and subjects rated injection site pain on a 5-point scale. The 90% confidence intervals of the geometric least square means ratio for the area under the human GH concentration-time curve from 0 to 24 h and maximum concentration were 1.002-1.049 and 0.971-1.075 following 6 mg and 0.992-1.038 and 0.973-1.058 following 12 mg, respectively. No severe adverse events were observed. The mean pain score was significantly higher (i.e., less painful) with the new formulation than with the prior formulation regardless of the order of treatment. The new GROWJECT sc formulation was bioequivalent to the prior formulation and associated with less injection site pain.