Better growth outcomes in GH-deficient children treated younger than 2 years of age.

Background: Limited data are available on the growth response to growth hormone (GH) treatment in very young children with GH deficiency (GHD). In the present analysis, we compared clinical outcomes after GH treatment in children with GHD aged <2 and ≥2 years at the start of GH treatment. Methods: We analysed pooled data from two observational studies of paediatric patients who received Norditropin® treatment: NordiNet® IOS (NCT00960128) and the ANSWER Program (NCT01009905). Patients with GHD, who remained pre-pubertal after 1 year of treatment, were grouped by age at treatment start (<2 years; ≥2 years). The primary effectiveness outcome was change in height standard deviation score (SDS) after 1 and 10 years. We also investigated the frequency of non-serious adverse drug reactions (ADRs), serious ADRs and serious adverse events (SAEs). Results: In total, 507 and 7,486 children initiated treatment at <2 and ≥2 years of age, respectively. Height SDS (mean change (SD) from baseline) improved after 1 year of treatment in both groups and was greater in children initiating treatment at <2 years than in those initiating treatment at ≥2 years (1.4 (1.2) and 0.75 (0.5), respectively); these findings were sustained after 10 years of treatment (3.2 (1.7) and 2.2 (1.3), respectively). SAEs were more frequent in children initiating treatment at <2 years vs ≥ 2 years (3.3 vs 0.67%, respectively). Conclusions: Children aged <2 years at GH treatment initiation had better height outcomes, but more SAEs, after 1 and 10 years of GH treatment compared to children starting GH at age ≥2 years. Trial registration: NordiNet® IOS, ClinicalTrials.gov NCT00960128; ANSWER Program, ClinicalTrials.gov NCT01009905. Plain language summary: Data from two large studies showed that children with growth hormone deficiency (GHD) who began treatment with Norditropin® under 2 years of age had better growth than those first treated at or above 2 years of age, but also had more side effects. This highlights the value of early diagnosis, treatment and close monitoring of children with GHD.