Researchers are also investigating whether the addition of pramlintide to insulin could improve the performance of a closed-loop system by reducing peak postprandial glucose excursions. Another line of investigation is seeking to determine whether a combination of insulin and glucagon through a dual-hormone infusion pump could reduce the risk of late postmeal and nocturnal hypoglycemia by feedback-controlled infusion of minidoses.
In addition, investigators are focusing on techniques to increase the rate of insulin absorption by warming the insulin site, using faster-acting insulins, and coformulating insulins with hyaluronidase to reduce the variability of absorption of rapid analogue insulins such as insulin lispro (Humalog) or insulin aspart (NovoLog).
But before closed-loop systems can be confidently used in the outpatient setting, several kinks still need to be worked out.
"The major obstacle, without a doubt in my mind, is that every safeguard must be in place to prevent injury to a patient due to insulin overdelivery as a result of a system error," Dr. Tamborlane said.
He disclosed serving as a consultant to Boehringer Ingelheim, Halozyme, Insuluine, LifeScan/Animas, Medtronic, Novo Nordisk, and Unomedical, and serving on the Novo Nordisk speakers bureau.