A Clinical Study of the Performance of a Glucose Blinding Protein-Based Continuous Glucose Monitor (GBP CGM)
A Clinical Study of the Performance of a Glucose Blinding Protein-Based Continuous Glucose Monitor (GBP CGM)
The purpose of this study is to assess the accuracy of the Becton Dickenson (BD) Technologies
 Glucose Binding Protein-Based Continuous Glucose Monitor (GBP CGM) in patients with Type 1
 diabetes during low (goal glucose 55 mg/dL), normal (80-140 mg/dL) and high (>180mg/dL)
 glucose levels over a 24 hour period. This will be achieved by monitoring blood sugar levels
 when a regular dinner meal is given, when a liquid breakfast meal (BOOST Original containing
 41 grams Carbohydrates (CHO), 4 grams fat, 10 grams protein) is given, when subcutaneous
 insulin is dosed to induce hypoglycemia to a goal of 55 mg/dL, and when a regular lunch meal
 is given. A Continuous Glucose Monitor (CGM) is an electronic device that measures and
 displays blood sugar (glucose) levels in the body throughout the day and night. The method
 being used to detect blood sugar in the investigational Glucose Binding Protein-Based
 Continuous Glucose Monitor (GBP CGM) is different than the method that is currently in use by
 commercially available models.

 Some sensors cannot tell the difference between glucose (sugar) and other substances such as
 Tylenol, aspirin or citric acid etc. Because they cannot tell the difference, they may give
 false readings. The GBP CGM is made to only recognize glucose in the body rather than other
 substances (e.g., Tylenol, aspirin, citric acid, etc.). As a result, the investigators expect
 the new GBP CGM to be more accurate at detecting low blood sugar levels than the current
 devices.
Development of accurate continuous glucose monitoring devices is critically important for the
 maintenance of strict glycemic control without increasing the risk for hypoglycemia and for
 the successful implementation of an artificial pancreas. Glucose binding protein-based (GBP)
 continuous glucose monitors offer several potential advantages over commercially available
 glucose oxidase based sensors. Unlike glucose oxidase based sensors, GBP sensors do not
 require establishment of an equilibrium reduction/oxidation reaction and are not as
 susceptible to interference from other compounds because they are engineered to recognize
 only glucose. As a result, GBP-based glucose sensors are exceptionally accurate at low blood
 glucose levels and have a faster warm-up time than glucose oxidase based systems. The
 principal idea of this proposal is to evaluate the accuracy and performance of a second
 generation glucose binding protein-based continuous glucose monitor (GBP CGM) developed by BD
 Technologies in subjects with type 1 diabetes, with emphasis on warm-up period after
 insertion, accuracy in hypoglycemic and hyperglycemic ranges, and lag time over a 24 hour
 period of sensor use. In order to accomplish this, the investigators will conduct a clinical
 trial consisting of 25.5-hour studies involving 15 subjects, each wearing one active and one
 mock (no GBP) device simultaneously during meals and induced hypoglycemia to observe a wide
 range of glucose values. The investigators envision that the glucose binding protein-based
 continuous glucose monitor will demonstrate minimal warm-up time after insertion, overall
 accuracy comparable to commercial glucose oxidase sensors with excellent performance in the
 hypoglycemic range and a nominal lag time to sensing a change in blood glucose.
Inclusion Criteria:

 -  Clinical diagnosis of type 1 diabetes mellitus for ≥1 year. For an individual to be
 enrolled at least one criterion from each list must be met.

 -  Criteria for documented hyperglycemia (at least 1 must be met):

 1. Fasting glucose ≥126 mg/dL - confirmed

 2. Two-hour oral Glucose Tolerance Tests (OGTT) glucose ≥200 mg/dL - confirmed

 3. HbA1c ≥6.5% documented - confirmed

 4. Random glucose ≥200 mg/dL with symptoms

 5. No data at diagnosis is available but the participant has a convincing history of
 hyperglycemia consistent with diabetes

 -  Criteria for requiring insulin at diagnosis (1 must be met):

 1. Participant required insulin at diagnosis and continually thereafter

 2. Participant did not start insulin at diagnosis but upon investigator review
 likely needed insulin (significant hyperglycemia that did not respond to oral
 agents) and did require insulin eventually and used continually

 3. Participant did not start insulin at diagnosis but continued to be hyperglycemic,
 had positive islet cell antibodies - consistent with latent autoimmune diabetes
 in adults (LADA) and did require insulin eventually and used continually

 -  Use of an insulin pump to treat his or her diabetes for at least six months prior to
 the study.

 -  Actively using a bolus calculator function with the current insulin pump with
 pre-defined parameters for glucose goal(s), carbohydrate ratio(s), and insulin
 sensitivity factor(s).

 -  Signed informed consent

 -  Age ≥21 and <65 years old

 -  Body mass index between 19 and 30 kg/m2, inclusive

 -  HbA1c ≤11%

 Exclusion Criteria:

 -  Uncontrolled arterial hypertension (diastolic blood pressure >90 mm Hg and/or systolic
 blood pressure >160 mm Hg)

 -  Impaired hepatic function measured as alanine aminotransferase or aspartate
 aminotransferase ≥three times the upper reference limit

 -  Impaired renal function measured as creatinine >1.2 times above the upper limit of
 normal

 -  Diabetic ketoacidosis in the past 6 months

 -  Severe hypoglycemia resulting in a seizure or loss of consciousness in the 12 months
 prior to enrollment

 -  Conditions which may increase the risk of induced hypoglycemia such as known coronary
 artery disease, congestive heart failure, history of any cardiac disorder or
 arrhythmia, history of a cerebrovascular event, history of migraines, seizure
 disorder, syncope, adrenal insufficiency, or neurological disease.

 -  Current use of medications containing >4000 mg acetaminophen per day.

 -  Current use of L-Monoamine oxidases (MAO) inhibitors.

 -  Known microvascular (diabetic) complications (other than diabetic non-proliferative
 retinopathy),such as history of laser coagulation, proliferative diabetic retinopathy,
 known diabetic nephropathy (other than microalbuminuria with normal creatinine) or
 neuropathy requiring treatment

 -  Known allergy to eggs

 -  Pregnancy, breast-feeding or intention of becoming pregnant

 -  Current or recent alcohol or drug abuse by patient history.