The U.S. "new patient" and "transfer" studies.

The large-scale clinical trials of human insulin (recombinant DNA) in the United States consisted of a "New Patient" study and a "Transfer" study. The "New Patient" study involved 101 patients (38% type I) who have never received insulin and who were treated with human insulin and followed for 6 mo using NPH insulin alone or in combination with Neutral Regular Insulin (NRI). Shortly after treatment, serum glucose and total glycohemoglobin concentration fell. No patients developed insulin lipoatrophy or insulin allergy. Two patients developed insulin hypertrophy; in one, it was transient. Intradermal tests to varying dilutions of human insulin did not change over 6 mo. In addition, there was no evidence of development of antibodies to Escherichia coli polypeptide. Two-hundred-and-forty-three patients, 91% of whom had type I diabetes, were transferred in a controlled double-blind study from mixed beef-pork or purified pork insulin (PPI) either to human insulin or back to their previous insulin treatment and followed for 3 mo. While insulin dosage did not change, there was a slight increase in fasting serum glucose and a statistically significant increase in fasting ketonuria. There was no change in the frequency of the complications of insulin treatment. These limited data are consistent with the conclusion that NPH human insulin is slightly shorter acting than its animal insulin counterparts. Overall, human insulin is a safe, effective insulin.