A Clinical Study of the Performance of a Glucose Blinding Protein-Based Continuous Glucose Monitor (GBP CGM) (SMA002)

University of Virginia

Status and phase

Completed

Phase 2

Conditions

Type 1 Diabetes Mellitus

Treatments

Device: GBP CGM

Study type

Interventional

Funder types

Other

Industry

Identifiers

NCT01469715

15696

Details and patient eligibility

About

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.

Full description

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.

Enrollment

16 patients

Sex

All

Ages

21 to 65 years old

Volunteers

No Healthy Volunteers

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.