Clinical trial with authentic recombinant somatropin in Japan.

Recombinant somatropin, produced by recombinant DNA technology, was administered by injection in daily doses of 8 IU to six healthy young volunteers. Daily injection for 4 days did not cause any significant change in the results of physical examination, blood count or urinalysis. Non-esterified fatty acid levels increased significantly from 0.45 +/- 0.16 to 1.08 +/- 0.12 mEq/litre (mean +/- SEM) at 4 hours after the first injection (p less than 0.001). Plasma IGF-1 levels increased from 0.80 +/- 0.14 units/ml to 1.72 +/- 0.50, 3.22 +/- 1.02, 3.17 +/- 1.20 and 3.63 +/- 0.78 units/ml at 24 hours after each daily injection for 4 days (p less than 0.001). Plasma hGH reached peak levels at 3 hours after intramuscular injection of recombinant somatropin, 4 IU, and this peak value was 57.3 +/- 2.8 ng/ml. A total of 21 patients with pituitary dwarfism were also treated with recombinant somatropin for 6 months at a dose of 0.5 IU/kg/week. Their heights increased by 2.2-5.0 cm during the 6 months of treatment, which was calculated to be equivalent to 4.4-10.0 cm/year with a mean growth rate of 7.4 +/- 0.4 cm/year. Anti-hGH antibody with a titre of 10 was observed in two patients at the end of 6 months of treatment.