Therapy for 6.5-7.5 years with recombinant insulin-like growth factor I inchildren with growth hormone insensitivity syndrome: A clinical research center study

Eight children with GH insensitivity syndrome were treated with recombinant human insulin-like growth factor I(IGF-I) (80-120 mug/kg sc twice daily) f or 6.5-7.5 yr. We previously reported that height velocity (HV) improved wi th treatment (from mean pretreatment HV of 4.0 cm/yr), to 9.3 cm/yr for the first year and 6.2 cm/yr for the second year. HV remained slightly below t his during the subsequent years (mean HV: 5.4, 5.5, 5.2, and 4.8 cm/yr duri ng years 3-6). Mean height so score before therapy was -5.6; and it improve d to -4.5, -4.4, and -4.2 after 2, 4, and 6 yr of therapy, respectively. Tr eatment was accompanied by gain in body weight and fat. Bone age advanced n ormally in the prepubertal patients, but it advanced more rapidly during th e latter years of treatment in those patients undergoing pubertal changes. The growth of spleen and kidneys (determined by ultrasound) was rapid in th e first 2-3 yr of therapy. More age-appropriate growth ensued, but six pati ents had a renal length for height more than 2 so above the mean at 6-7 yr of treatment. No major adverse changes in biochemical profile were observed . IGF-I-related hypoglycemia occurred early in treatment with the younger p atients, but this problem abated as treatment was continued. IGF-I therapy is effective in promoting statural growth in GH insensitivity syndrome pati ents, but the growth response is neither as intense nor as well-sustained a s the growth response to GH among children with GH deficiency.