Hyaluronidase Effect on Infusion Set Life

The investigators would like to see if the use of hyaluronidase will improve insulin infusion
set survival and improve the onset of insulin action. The investigators will also assess the
accuracy of the Dexcom G4P sensors with extended site use beyond the 7 day FDA approved time
frame.

The use of sensor information combined with the knowledge of infused insulin from pump
therapy could potentially help us detect when an infusion set is beginning to fail.
Information from the sensor function to the point of failure, and sensor function in response
to Tylenol may allow us to develop special formulas to determine when a sensor is not working
well. This will be very important for creating an artificial pancreas.

You are invited to participate in a research study to see if the use of hyaluronidase will
improve insulin infusion set survival and improve the onset of insulin action. The
investigators will also assess the accuracy of the Dexcom G4P sensors with extended site use
beyond the 7 day FDA approved time frame. Eligible subjects are those with type 1 diabetes
who wear an insulin pump.

Thirty subjects will be enrolled. Fifteen patients from each of the two sites: Stanford
University and University of Colorado.

Inclusion Criteria:

1. Clinical diagnosis of type 1 diabetes for at least one year and using an insulin pump
for at least 3 months

2. Total daily insulin dose of at least 0.4 units/kg/day

3. The diagnosis of type 1 diabetes is based on the investigator's judgment; C peptide
level and antibody determinations are not needed.

4. Age 12 to 45 years

5. Hemoglobin A1c level less than or equal to 10%

6. Willingness to infuse 1 ml of hyaluronidase (Hylenex) into the insulin infusion set
after insertion on day 1 and day 3 of the week they are assigned to use hyaluronidase

7. Willingness to use a Silhouette or Comfort insulin infusion set throughout the study.
The set includes the Duo Infusion Tubing for infusion of hyaluronidase (Hylenex).

8. Willingness to eat the same breakfast each morning for the first two weeks of the
study

9. Willing to take two 500mg tablets of Tylenol Regular Strength and monitor glucose
levels at ½, 1, 2, 4, 6, and 8 hours later.

10. For females, not currently known to be pregnant

11. An understanding of and willingness to follow the protocol and sign the informed
consent

12. Must be able to understand spoken or written English

Exclusion Criteria:

1. Diabetic ketoacidosis in the past 6 months

2. Severe hypoglycemia resulting in seizure or loss of consciousness in the 6 months
prior to enrollment

3. Known tape allergies

4. Current treatment for a seizure disorder

5. Cystic fibrosis

6. Active infection

7. A known medical condition that in the judgment of the investigator might interfere
with the completion of the protocol such as the following examples:

8. Inpatient psychiatric treatment in the past 6 months for either the subject or the
subject's primary care giver (i.e., parent or guardian)

9. Presence of a known adrenal disorder

10. If on antihypertensive, thyroid, anti-depressant or lipid lowering medication, lack of
stability on the medication for the past 2 months prior to enrollment in the study

11. Abuse of alcohol

12. Use of an OmniPod insulin infusion pump

13. Pregnant or lactating females