Clinical trial with porcine des-Phe B1 insulin. A comparative study with unmodified insulin on therapeutical efficacy, biological activity and immunogenicity.

Studies have been carried out in insulin-dependent diabetics of porcine Des-pheB1 insulin, which is an insulin analogue obtained by removal of the N-terminal aminoacid of the B chain. The therapeutic activity of Des-phe insulin (regular and semilinte preparations) was tested in a group of 24 insulin-dependent diabetics and compared with the unmodified parent compound. Both types of insulin, Des-phe and unmodified were chromatographically purified preparations. The mean daily blood glucose profile obtained with Des-phe insulin was slightly higher than that of unmodified preparations, while the mean blood glucose and the "M" index of Schlichtkrull were similar. The biological activity of regular Des-phe and its unmodified parent compound was evaluated in 6 further insulin-dependent diabetics, with the aid of an artificial endocrine pancreas. The insulin requirement to achieve an optimal metabolic control was 10% less with Des-phe insulin than with the unmodified preparation. The immunogenicity of Des-phe and unmodified insulins, tested by measuring plasma insulin antibody titres in diabetic patients either newly or already insulin treated, was comparable. However the binding capacity of 125I-Des-phe insulin to preexisting antibodies seemed to be less than that of unmodified 125I-insulin in patients previously treated with unmodified insulin. Finally Des-phe appeared able to correct promptly and completely the insulin-induced lipodystrophy of three insulin-dependent diabetics.