Background: Emerging therapies such as closed-loop (CL) glucose control, also known as artificial pancreas (AP) systems, have shown significant improvement in type 1 diabetes mellitus (T1DM) management. However, demanding patient intervention is still required, particularly at meal times. To reduce treatment burden, the automatic regulation of glucose (ARG) algorithm mitigates postprandial glucose excursions without feedforward insulin boluses. This work assesses feasibility of this new strategy in a clinical trial.

Methods: A 36-hour pilot study was performed on five T1DM subjects to validate the ARG algorithm. Subjects wore a subcutaneous continuous glucose monitor (CGM) and an insulin pump. Insulin delivery was solely commanded by the ARG algorithm, without premeal insulin boluses. This was the first clinical trial in Latin America to validate an AP controller.

Results: For the total 36-hour period, results were as follows: average time of CGM readings in range 70-250 mg/dl: 88.6\%, in range 70-180 mg/dl: 74.7\%, <70 mg/dl: 5.8\%, and <50 mg/dl: 0.8\%. Results improved analyzing the final 15-hour period of this trial. In that case, the time spent in range was 70-250 mg/dl: 94.7\%, in range 70-180 mg/dl: 82.6\%, <70 mg/dl: 4.1\%, and <50 mg/dl: 0.2\%. During the last night the time spent in range was 70-250 mg/dl: 95\%, in range 70-180 mg/dl: 87.7\%, <70 mg/dl: 5.0\%, and <50 mg/dl: 0.0\%. No severe hypoglycemia occurred. No serious adverse events were reported.

Conclusions: The ARG algorithm was successfully validated in a pilot clinical trial, encouraging further tests with a larger number of patients and in outpatient settings.