USE OF RECOMBINANT HUMAN GROWTH-HORMONE IN CHILDREN WITH CHRONIC RENAL-INSUFFICIENCY - AN UPDATE

Growth retardation is common in children with chronic renal insufficie ncy (CRI). Now that dialysis and renal transplantation (TX) have becom e life sustaining, permanent stunted growth and adult short stature of ten occurs. Thus, efforts to enhance growth using recombinant human gr owth hormone (rhGH) have been undertaken in three groups of patients: chronic renal failure (CRF) prior to dialysis, end-stage renal disease (ESRD) on some form of dialysis; and following TX (post-TX) in whom g rowth retardation persists. Our initial study was in CRF. Eleven males , ages 2.5-16.3 years, with height standard deviation scores (SDS) of >2.0 below the mean, have been treated with rhGH for 18-48 months. rhG H was started in a dose of 0.125 mg/kg three times a week in the first 8 patients and subsequently changed to daily dosing (0.053 mg/kg/day) within the first 24 months. To date, overall, growth velocity (GV) in creased from 5.4 +/- 2.2 to 8.9 +/- 1.6, 7.5 +/- 1.8, 7.5 +/- 1.6 and 6.9 +/- 0.9 cm/year in those completing 12 (n = 11), 24 (n = 9), 36 (n = 7), and 48 (n = 3) months. The mean height SDS increased from >3.0 to < 1. 5 below the mean with 1 patient reaching the 50th centile. Dia lysis was initiated in 2 patients, a frequency not different from that expected over time in children with this degree of CRF. In the others , calculated creatinine clearance did not change, and no significant a dverse effects were noted as a consequence of the rhGH treatment. Thus , rhGH increases GV and facilitates catch-up growth in CRF. Following the initiation of our study in CRF, a US national multicenter double-b lind placebo-controlled study of rhGH in CRF was begun. The reported 2 -year results of that study support our initial findings of a signific ant increase in GV and improvement in height SDS score over baseline i n the rhGH-treated group as compared with placebo over the 2 years of the study. Our experience with rhGH in ESRD patients on continuous cyc ling peritoneal dialysis (CCPD) is less extensive. Of 5 children with marked growth failure (SDS -4.68) on CCPD for longer than 1 year, 2 ex perienced an increase in GV, and 1 maintained growth to achieve a gain in height SDS score. These data suggest that, while some children may be helped by rhGH even when ESRD occurs, treatment appears to be more effective when begun at an earlier degree of CRI. Our experience in p ost-TX patients includes 13 children with short stature or slow growth in whom rhGH was initiated 14-92 months post-TX and given, to date, f or 12 (n = 13), 24 (n = 9) and 36 (n = 2) months. GV increased in the first 2 years of treatment as did the height SDS of some patients. How ever, the older age and pubertal status of many of these patients make s growth analysis more difficult. These data and those reported by oth ers worldwide support the efficacy of rhGH therapy in increasing growt h velocity and improving height SDS in patients with CRI. Final height outcome and long-term safety data are not yet known.