Evaluation of Fiasp® (Fast Acting Insulin Aspart) in 670G Hybrid Closed-Loop Therapy

Phase 4

Completed

Brief Summary: This is a pilot outpatient study conducted at Stanford to obtain preliminary data on how Fiasp® works in a closed-loop system and to determine if any changes need to be made to the 670G pump to optimize the use of Fiasp®.

Detailed Description: This will be a randomized cross-over blinded study and to see how the 670G pump responds to the introduction of Fiasp® insulin. Subjects enrolled in the study will have a 2 week period of optimization with weekly assessments of their Carelink download before entering the blinded phase of the study. They will use their usual home insulin during the optimization phase. They will then be started on their first blinded insulin (aspart or Fiasp®) which they will use for 2 weeks, before they cross-over to the other insulin.

Recruitment & Eligibility

Inclusion Criteria

Clinical diagnosis of type 1 diabetes and using 670G pump for at least 1 month, and willing to have the 670G pump downloaded into a Carelink Clinical research database.
The diagnosis of type 1 diabetes is based on the investigator's judgment; C-peptide level and antibody determinations are not needed.
Age ≥18 years
Using Novolog or Fiasp® insulin at time of enrollment
Willing to use Fiasp® insulin
Total daily insulin dose is at least 0.3 units/kg/day
Usual carbohydrate intake is at least 60 grams a day, and willing to have at least 25 grams of carbohydrates for breakfast
For females, not currently known to be pregnant
An understanding of and willingness to follow the protocol and sign the informed consent
Willing to have photographs taken of their infusion sites
Willing to download their 670G pump every 1-2 weeks to a research Carelink account
Willingness to answer a brief online questionnaire every 2 weeks
Must be able to understand spoken or written English
For subjects participating in Part 2 of this study they will need to be using Fiasp® as part of their usual care
Hemoglobin A1c between 6 and 10% at the time of enrollment

Exclusion Criteria

Pregnant or lactating females
No hypoglycemic seizure or loss of consciousness in the past 6 months
Severe episode of DKA in the 6 months prior to study enrollment that was unrelated to an infusion set failure
No known cardiovascular events in the last 6 months
No active proliferative diabetic retinopathy
Known tape allergies
Current treatment for a seizure disorder
Cystic fibrosis
Active infection
A known medical condition that in the judgment of the investigator might interfere with the completion of the protocol
Inpatient psychiatric treatment in the past 6 months
Presence of a known adrenal disorder
If on antihypertensive, thyroid, anti-depressant or lipid lowering medication, with lack of stability on the medication for the past 2 months prior to enrollment in the study
Abuse of alcohol
Dialysis or renal failure
Known eGFR <60%

Note: Adequately treated thyroid disease and celiac disease do not exclude subjects from enrollment.

Arm && Interventions

Group	Intervention	Description
Fiasp then Novolog	Fiasp	Following a 2-week run-in period for pump-setting adjustments and monitoring, participants 1 will use Fiasp insulin for 2 weeks, followed by Novolog insulin for 2 weeks. Both the subject and the investigator will be blinded to which group the subject is assigned.
Novolog then Fiasp	Fiasp	Following a 2-week run-in period for pump-setting adjustments and monitoring, participants 1 will use Novolog insulin for 2 weeks, followed by Fiasp insulin for 2 weeks. Both the subject and the investigator will be blinded to which group the subject is assigned.
Fiasp then Novolog	Novolog	Following a 2-week run-in period for pump-setting adjustments and monitoring, participants 1 will use Fiasp insulin for 2 weeks, followed by Novolog insulin for 2 weeks. Both the subject and the investigator will be blinded to which group the subject is assigned.
Novolog then Fiasp	Novolog	Following a 2-week run-in period for pump-setting adjustments and monitoring, participants 1 will use Novolog insulin for 2 weeks, followed by Fiasp insulin for 2 weeks. Both the subject and the investigator will be blinded to which group the subject is assigned.

Primary Outcome Measures

Name	Time	Method
Percentage of Time in Range: Sensor Glucose Readings <70 mg/dl	7 days (during 2nd half of 2-week intervention period)	Percentage of time in range (days) as a measure of hypoglycemia.
Percentage of Time in Range: Sensor Glucose Values Between 70-180 mg/dl	7 days (during 2nd half of 2-week intervention period)	Measured as percentage of time in range (days).

Secondary Outcome Measures

Name	Time	Method
Mean Sensor Glucose in mg/dl	7 days (during 2nd half of 2-week intervention period)	Mean sensor data over the second week of using a randomized, blinded insulin.