Insulin delivery by implantable pumps.

We have developed a neutral human insulin (Hoe 21 GH) which is stabilized for use in implantable roller pumps. After extensive in vitro tests and animals experiments this preparation was selected for a clinical trial in humans. Twenty remote-controlled insulin pumps (Siemens AG) were implanted into insulin-dependent Type I diabetic patients for a one-year feasibility trial in four centres. The total observation time was 18.2 patient years. Three pumps had to be prematurely explanted after 101, 141 and 236 days. Blood glucose was measured by self-monitoring with 5.5 (1-17) values per day. 62.9% of these were in the range 3.33-8.88 mM. 3.25 glucose values per patient month were in the hypoglycemic range (lower than 2.78 mM) and 2.6 symptomatic hypoglycemias were reported per patient month, of which 0.22 per patient year required medical attention. The median HbA1c level was 7.6% at base line (5.9%-9.1%, 10-90% percentile) and 7.0% at the end of the trial (5.7%-8.3%, 10-90% percentile) (p < 0.05). Although some technical and clinical problems were observed, the study showed that the combination of this dosing device and a stabilized insulin preparation was a successful approach to the treatment of insulin-dependent patients.