Outcome of a four-year randomized study of daily versus three times weekly somatropin treatment in prepubertal naive growth hormone-deficient children. Genentech Study Group.

A comparison was made of the growth responses of prepubertal naive GH-deficient children who were randomly assigned to receive 0.3 mg/kg.week recombinant human GH administered either daily (QD) or three times weekly (TIW) over 4 yr. The effects of the two regimens on annual growth velocity, change in height SD score, bone maturation, and age at onset of puberty are presented as the mean +/- SD. During each of the 4 yr, the annual growth velocity was significantly greater in the QD vs. TIW group. At 48 months, the mean total gain in height was 9.7 cm greater in the QD group (38.4 +/- 5.5) than that in the TIW group 28.7 +/- 3.2; P = 0.0002). The mean height SD score at the end of each year was significantly greater in the QD group. After 4 yr, the total gain in height SD score was 3.2 +/- 1.2 in the QD group compared to 1.5 +/- 0.5 in the TIW group (P = 0.0003). The height SD score at 4 yr was 0.2 in the QD group (pretreatment, -2.9) compared to -1.4 in the TIW group (pretreatment, -2.9). After 4 yr of rhGH treatment, the increment in bone age was similar in the QD (4.9 +/- 1.0 yr) and TIW (4.8 +/- 1.1 yr) groups. The change in height age minus the change in bone age was more favorable in the QD (1.2 +/- 0.8 yr) than in the TIW (0.0 +/- 0.9 yr) group (P = 0.003). The mean age at onset of puberty in boys was the same in the QD (13.2 yr) and TIW (13.0 yr) groups (P = 0.71), and the mean bone age at the start of puberty was also similar (11.5 in QD and 11.3 in TIW groups; P = 0.66). The advantages of QD rhGH treatment in prepubertal GH-deficient children after 4 yr were additional gains of 1.7 height SD score and 9.7 cm in height over those treated with the TIW regimen (P = 0.0002).