The study was done in America. Currently, long-term safety and efficacy data on pediatric patients treated with Norditropin® (somatropin rDNA origin) are being collected through a registry called American Norditropin Studies: Web-Enabled Research (ANSWER).
By October 2010, data were collected from 8,359 treatment-naïve pediatric patients who had isolated/idiopathic growth hormone deficiency (GHD; n=4,454), multiple pituitary hormone deficiency (MPHD; n=387), small for gestational age (SGA; n=461), idiopathic short statue (ISS; n=758), and Turner syndrome (TS; n=435).
The change from baseline in height standard deviation scares (ΔHSDS) were analyzed at years 1, 2, and 3.
At the start of growth hormone (GH) treatment, patients with MPHD (mean age 7.4±5.44 years), SGA (mean age 8.5±3.84 years), and TS (mean age 8.6±4.08 years) were generally younger than patients with other diagnostic categories. GHD mean was age 10.8±3.51 years, and for ISS, the mean age was 11.2±3.07.
Patients with MPHD and GHD had the lowest mean peak GH levels at baseline (MPHD: 3.1±3.03 ng.mL; GHD: 5.3±2.76 ng/mL). This is in comparison to other diagnostic categories; ISS had a mean peak GH level of 17.0±20.03 ng/mL, and SGA had a mean peak GH level of 13.8±12.63 ng/mL.
There were limited gender difference in DHSDS found across the diagnostic categories; a significant effect was observed in patients with GHD and SGA at year 1 (male>female; p=0.022).
Looking at pubertal status for patients with GHD, the best DHSDS at the third year was seen in patients were stayed in a prepubertal stage during the entire treatment period (1.51±0.86); this is compared to patients who were already pubertal when they began treatment (1.26±0.68) or patients who transitioned into the pubertal stage during the study (1.24±0.65).
Stratifying by age at beginning of treatment, younger patients demonstrated greater DHSDS than older patients—this is for all diagnostic categories for males and females. The overall DHSDS at year 3 for males <11 years old was 1.39±0.83; for males at least 11 years old, the overall DHSDS was 1.13±0.66 (p<0.0001). For females <10 years old, the overall DHSDS at year 3 was 1.26±0.88; for females at least 10 years, the overall DHSDS was 1.10±0.78 (p=0.0089). There were similar results at years 1 and 2.
The researchers stress that this data emphasize the importance of starting GH treatment at a younger age; the study showed that 3 years after starting GH treatment, a better growth response was seen in younger and prepubertal children.