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Glucose Monitors and Glucose Sensing. Applications for the 21 st Century and Beyond The Quest for the Closed Loop. Why Glucose Sensing??. More “real time” assessment Ability to detect hypoglycemia and hyperglycemia at “odd” times

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glucose monitors and glucose sensing
Glucose Monitors and Glucose Sensing

Applications for the

21st Century and Beyond

The Quest for the Closed Loop

why glucose sensing
Why Glucose Sensing??
  • More “real time” assessment
  • Ability to detect hypoglycemia and hyperglycemia at “odd” times
  • Better administration and correlation of insulin dosages—less guessing
  • May uncover eating disorders and other issues related to stress, diet and exercise
  • Patient compliance with monitoring an issue– many do not like to “poke” fingers or other sites so often. Pain and discomfort, lack of blood obtained, lost strips, etc.
why glucose sensing3
Why Glucose Sensing??
  • Goal– Closing the Loop
  • An artificial pancreas
  • Provide accurate and specific data to control glucose levels – many individuals keep blood glucoses higher than optimal to avoid hypoglycemia
  • Fear of hypoglycemia in the middle of the night– not waking up
  • “Take the worry” out of diabetes treatment – Type 1 patients in particular; parents, children and physicians
optimal conditions for glucose measurement
Optimal Conditions for Glucose Measurement
  • Immediate availability of results and measurements
  • High frequency of measurements
    • Measurements every 2-5 minutes would be ideal
    • Ability to detect rapid rise or decline is necessity
  • Need quick signal stability after initiation or placement
  • Stability over prolonged period of time (>3 days necessary)
case for glucose sensing recent studies
Case for Glucose Sensing – Recent Studies
  • 23 patients participated – hospitalized and ambulatory
  • Both Type 1 and Type 2 individuals
  • Study lasted 72 hours (key time limit)
  • 75 capillary samples were obtained
  • Microdialysis subcutaneous monitoring system used
    • microdialysis catheter; extracorporeal electrochemical sensor
    • signal needed to be corrected for fluid transportation – 31 minutes (lag time)

Diabetes Care 24: 1696, 2001 Jungheim et al

results of study and conclusions
Results of Study and Conclusions
  • Studies showed no limitations to patients activity and only mild skin irritation
  • Difference between SCGM and capillary glucose was ~ 7-9 % over the full range (meter differences can be as much as 10 – 15 %)
  • Hypoglycemia was detected with SCGM but was missed 58-71% of the time by spot capillary measurements. This despite 5-7 or more measurements per day
  • No decay in sensitivity over the 72 hour period
  • SCGM could be useful in glucose control & therapy
glucose monitor development

Glucose Monitor Development

Race for the Closed Loop System, Painless, Continuous and the “Gold”

types of monitors in development
Types of Monitors in Development
  • Minimally invasive interstitial devices
  • Transcutaneous optical devices
  • Electrochemical sensing devices
    • subcutaneous
    • Implantable
  • Implantable optical sensors
physiology of interstitial fluid
Physiology of Interstitial Fluid
  • Extracellular fluid and flows through the capillary walls
  • Glucose levels in interstitial fluid ≠ blood glucose
  • Lag time could be ~ 10 to 20 minutes
  • Perspiration, oils and other environmental factors (lotions, etc.) can dilute the measurements and adversely affect the results as sample size is small
interstitial glucose sensor
Interstitial Glucose Sensor

Glucowatch Biographer 2

Cygnus Corp: www.glucowatch.com

advantages and limitations of glucowatch system
Advantages and Limitations of Glucowatch System

Non-invasive

Detects trends and patterns in glucose levels

readings every 10 minutes with up to 6/hour = 72 readings/monitoring session

Alerts patients to rapids changes in glucose levels

Less painful??

Computer download capable

? Ability to determine insulin or medication adjustmens

2 hour “warm-upperiod

Calibration is needed with each sensor use

Skin irritation with sensor and adhesive

Skipped readings possible with rapid changes in temperature, perspiration and if system is bumped or dislodged

If several readings in a row are skipped, the system must be recalibrated

Advantages

Limitations

use of glucowatch biographer 2
Use of Glucowatch Biographer 2
  • Intended for use in adults and children to detect trends and patterns in glucose levels
  • To detect and assess hyperglycemic and hypoglycemic patterns to help facilitate adjustments in therapy
  • To be used as an adjunctive device, to supplement, not replace, information obtained from traditional and standard home glucose monitoring devices!
glucowatch biographer 2
Glucowatch Biographer 2
  • Draws out interstitial fluid by reverse electroionophesis
  • Glucose interacts with Glucose Oxidase Membrane to form hydrogen peroxide which interacts with biosensor producing low electric current which is measured and analyzed
  • Glucowatch 2
    • Cost $599 to $799
    • Rebates can save $200 to $300
  • Auto sensor
    • Disposable transdermal pad
    • Changed every 14-15 hours
    • ~$4 each (2 needed) for each recording session
    • Concerns with calibration time, risk of infection and irritation
glucose collection with the glucowatch g2 biographer uses reverse iontophoresis

CATHODE

ANODE

Cl-, (ascorbate, urate)

Na+, neutral species (i.e., glucose)

Glucose Collection with the GlucoWatch®G2™ Biographer Uses Reverse Iontophoresis
  • Only small compounds pass through the skin.
    • No proteins (e.g., hemoglobin) in the extract
  • Glucose is collected at the cathode.
    • Interfering species (ascorbate and urate) collected at anode
  • The charge and size exclusion properties of reverse iontophoretic extraction will lead to a very “clean” sample.

Data on file, Cygnus Inc. 2002.

the automatic monitoring process with the glucowatch g2 biographer

† 3 min

‡ 7 min

† 3 min

‡ 7 min

† 3 min

‡ 7 min

† 3 min

‡ 7 min

The Automatic Monitoring Process with the GlucoWatch®G2™ Biographer *

A “RUNNING AVERAGE” PROVIDES READINGS EVERY 10 MINUTES

Internal measure

127 mg/dL

109 mg/dL

101 mg/dL

112 mg/dL

Displayed reading

118 mg/dL

105 mg/dL

107 mg/dL

TIME

3:10 pm

3:20 pm

3:30 pm

3:40 pm

* Following a 2 hour warm-up and calibration

† 3 min glucose collection

‡ 7 min glucose measurement

Data on file, Cygnus Inc. 2002.

glucowatch biographer home study clarke error grid analysis

Biographer Readings

60%

34%

1%

4%

0.1%

2996 paired points

ZONE

A

B

C

D

E

A

400

E

C

350

300

250

B

200

Biographer Readings (mg/dL)

150

D

D

B

100

50

E

C

0

0

100

200

300

400

One Touch® Profile®

GlucoWatch® Biographer Home Study – Clarke Error Grid Analysis

Slope = 0.95, Intercept = 12.6 mg/dL, r = 0.80

(A) Accurate. Biographer within 20% of finger-stick test result (or both below 70 mg/dL)

(B) Acceptable. Difference greater than 20% but Biographer would not lead to bad decision

(C) Might cause an over-correction of normal glucose levels. Finger-stick blood glucose test result in the normal range, but Biographer reading is high or low.

(D) Failure to detect a high or low glucose level. Biographer reading in the normal range, but finger-stick blood glucose test result is high or low

(E) Treatment error could occur. Biographer reading low when finger-stick blood glucose is high or Biographer reading high when finger-stick is low.

One Touch® Profile® * Glucose Readings (mg/dL)

* One Touch® Profile® – Johnson and Johnson, New Brunswick New Jersey

Data on file, Cygnus Inc. 2002.

studies of glucowatch vs meters
Studies of Glucowatch vs. Meters
  • Differences between interstitial fluid and blood glucose
  • Time lag: 17.2 minutes ± 7 minutes with Glucowatch
  • Time lag: 13 minutes with most blood glucose meters
  • With glucose increasing, changes were less as measured by Glucowatch as compared with blood
  • With glucose decreasing, changes were greater as measured by Glucowatch as compared with blood or meters
  • Conclusion: possible false hyperglycemia and false hypoglycemia if taken unilaterally

Kulcu et al:

ADA Meeting 2002

spectrx glucose sensing system
SpectRx Glucose Sensing System
  • Transdermal Biophotonic System
  • Fluid is collected through micropores
  • Laser system used on the outer layer of skin
  • Measured in a patch which contains a glucose sensor
  • Clinical trials are ongoing
  • Is not FDA approved at this time
  • Still similar to Glucowatch in that it provides information on trends and not necessarily real-time for treatment adjustments

SpectRx website: www.spectrx.com

spectrx glucose sensing system20
SpectRx Glucose Sensing System

Laser device on the skin surface

Patch with sensor system embedded

www.spectrx.com

pendragon glucose sensing system
Pendragon Glucose Sensing System
  • Uses electromagnetic waves
  • Attached to lower forearm similar to the Glucowatch
  • Performs measurements every minute but averaging occurs
recent study with pendra
Recent Study with PENDRA
  • 15 individuals without diabetes
  • Changes in microcirculation of the arms resulted in varying glucose values
  • Temperature changes, other environmental issues had to address via a complex calibration procedure
  • Conclusions:
    • Need to “fix” device appropriately to arm to avoid possible variations
    • Needs extensive physician and patient training to operate
    • Needs further studies prior to any extensive use in the clinical setting

Diabetes Technology and Therapeutics 6:435, 2004

continuous glucose monitoring system cgms
Continuous Glucose Monitoring System--CGMS
  • Basic Premise: Glucose + Oxygen = Gluconic Acid + H2O2
  • Reaction is submitted to an electrical current which is proportional to the glucose concentration which is measured
  • Enzymatic or Electrochemical Sensors are implanted in the subcutaneous tissue (under the skin)
  • Similar to the catheters used in insulin pump therapy
  • Short term use at present; reliability just 48 to 72 hours
mechanism of action of cgms
Mechanism of Action of CGMS

Enzymatic Reaction is measured by sensor in IF through skin

cgms system
CGMS System
  • Sensor is percutaneous an ~1mm in diameter
  • Measures an “average” glucose value every 5 minutes and is stored in the monitor
  • “Hard” wired system; worn externally
  • Requires calibration at 4-5 times per day, otherwise data is not able to be downloaded
  • Able to enter events on the monitor to assist with interpretation of results
  • 3 day use only at this time
  • Not “real time”—requires return to physician office for download and interpretation
cgms system31
CGMS System
  • Problems with encapsulation tissue which can cause errors in data collection
  • Anything implanted in the body over time becomes covered with a protein layer initially and then a collagen like layer
  • Encapsulation tissue is to protect the body from foreign objects which may be perceived as harmful and to isolate the object chemically (ie.—broken port in pulmonary artery)
  • This chemical isolation could decrease the sensitivity and response time of electrochemical subcutaneous systems such as CGMS
cgms reproducibility study metzger m et al diabetes care 25 1185 july 2002
Self monitoring of glucoses several times per day will leave “gaps”– large excursions can occur without patient knowledge

Hypothesis: to test the reproducibility of the CGMS in “real-life setting”

CGMS may be a tool that could alleviate this difficulty

System measures glucose concentration every 5 minutes for a 72 hour period

Preliminary Study– performed in Type 2 patients

~ 150 separate glucose tracings

Included healthy volunteers and patients on only metformin

Correlated with frequent blood glucose measurements

Noted exceeding high incidence of hypoglycemic events with no symptoms and not confirmed by simultaneous blood glucose measurements

Correlation coefficient –r=0.74

CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002
cgms reproducibility study metzger m et al diabetes care 25 1185 july 200233
CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002
  • “Real Life Study” was undertaken to determine accuracy and reproducibility of tracings utilizing the CGMS device
  • 11 patients involved in the study
  • 6 had Type 1 diabetes
  • 3 had Type 2 diabetes
  • 2 “healthy” volunteers with no history of DM
  • 10 male, 1 female
  • Placed on two glucose sensor devices simultaneously for a 3 day period with usual “normal” activity
cgms reproducibility study metzger m et al diabetes care 25 1185 july 200234
CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002
  • Protocol – Sensors were attached according to the manufacturer’s instructions
  • Sensors were placed in the abdominal SQ tissue 4-5 cm to the right or left of the umbilicus
  • Calibration and Initialization were performed and 1 hour was elapsed before first capillary glucose
  • Meal times were recorded
  • Capillary glucoses were done immediately post meals, during the night and early AM
  • Capillary glucoses were entered into the monitor within 5 minutes of determination
cgms reproducibility study metzger m et al diabetes care 25 1185 july 2002ea
CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002EA
  • Download was done upon completion and analysis was performed immediately
  • Anonymity was preserved
  • Each day was divided into 8 time intervals according to the meal times of the patient
  • Classifications:
    • A: Satisfactory
    • B: if all glucose values are between 80 –150
    • C: glucose > 150 during >1 hr., too low
    • D: glucose < 70 during >30 minutes or impossible to evaluate due to technical reasons
cgms reproducibility study metzger m et al diabetes care 25 1185 july 200236
CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002
  • D Classification was further subclassified:
    • D1: Low concordance between sensor and glucometer r < 0.8 or the difference is too high (28%)
    • D2: Insufficient number of meter glucose values entered for calibration
    • D3: Strong midnight shift: usual sensor glucose values post midnight. Usually secondary to insufficient number of calibration values.
  • Evaluations were analyzed by two different observers independently and concordance rates were determined
cgms reproducibility study metzger m et al diabetes care 25 1185 july 200237
CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002
  • Mean sensor not recording glucose values
    • 46 classified in the “D” group and not use of sensor: 60.4 ± 16.9 hours each patient
  • 432 single time intervals were initially evaluated
  • 78 (18%) were discarded for technical reasons
    • 32 due to interpretable
  • 139 paired sets of data were available for sensor-sensor comparison.
    • 92 from Type 1 patients
    • 30 from Type 2 patients
    • 17 from non-diabetes volunteers
cgms reproducibility study metzger m et al diabetes care 25 1185 july 200238
CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002
  • Concordance was seen in only 65% of the time periods
  • 25% noted glucose levels too high in one sensor and satisfactory in the other
  • 9% noted glucose levels too low with satisfactory levels in the other
  • 1 case noted: sensor 1 showed hyperglycemia, sensor 2 showed hypoglycemia
  • No difference between patients with DM and non DM
cgms reproducibility study metzger m et al diabetes care 25 1185 july 200239
CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002
  • Conclusions:
    • Accuracy and reproducibility is lower than previously thought
    • Differences were greatest between the 125 and 225 mg/dl range – most important area in treatment of patients with diabetes mellitus
    • Correlation between two simultaneous sensors was lower than that of capillary vs. sensor (r = 0.84 vs. 0.90)
cgms reproducibility study metzger m et al diabetes care 25 1185 july 200240
CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002
  • Conclusions:
    • 35% clinically important discrepancies between two simultaneous sensor tracings
    • Could result in incorrect clinical advice in 17% of patient cases
    •  RESULTS OBTAINED IN “REAL LIFE” SITUATIONS MUST BE INTERPRETED IN INDIVIDUAL CLINICAL TERMS
cgms reproducibility study metzger m et al diabetes care 25 1185 july 200241
CGMS– Reproducibility StudyMetzger, M. et al: Diabetes Care 25:1185, July 2002
  • Development of a reliable device for continuous glucose monitoring is of outmost importance in the treatment of diabetes
  • Future endeavors in this area must be rigorously evaluated in “real life” situations before release to the general public
  • Rebuttal from Medtronic —concerns in the above study: software used was earlier version, device was used for more than planned or approved
additional studies 2003
Additional Studies--2003
  • Armstrong and King: ADA Meeting 2003
  • 11 subjects: 2 No Diabetes, 6 Type 1, 3 Type 2
  • Measured Glucoses with 1 Touch Ultra 7 times per day
  • Wore 2 sensors (CGMS) concurrently for 3 days
  • Mean Sensor life: 67 hours
  • Used updated software
  • Found accuracy with newer software ~94%
  • Most of differences between modalities within 10%
  • Sensor-sensor differences less than previous study
rebuttal to metzger findings
Rebuttal to Metzger Findings
  • Expectations did not coincide with CGMS intended use
  • Study did not use Clarke error grid but was one of subjective assessment
  • Study did use updated software (Solutions 3.0)
  • Results are similar to those reported in the post-marketing studies (Diabetes Technology and Therapeutics, 2000)
  • CGMS is intended to “supplement, not replace, blood glucose information using standard monitoring devices”
  • CGMS, when used with home monitoring devices and HbA1C values can help optimize clinical management

Mastrototaro and Gross; Diabetes Care 26:256 2003

rebuttal to metzger findings44
Rebuttal to Metzger Findings
  • Solutions 3.0 software resolves most of the 18% rate of technical problems encountered in the study
    • Correction of the midnight shift
    • Improvement in the accuracy and reproducibility of the downloads
    • Improvement in the agreement between sensor and meter values

Mastrototaro and Gross; Diabetes Care 26:256 2003

rebuttal to metzger findings45
Rebuttal to Metzger Findings
  • CONCLUSIONS:
  • Results should be weighed against the encouraging results and conclusions from previous and evolving reports and research
  • ◙ Appears that this is a work in progress and should not be utilized as the sole clinical indicator! – should not be used at present as the

only source for change in treatment regimens

  • -Speakers judgment after reviewing literature
sample cgms reports
Sample CGMS Reports

Daily Report of Blood Glucoses

sample cgms reports47
Sample CGMS Reports

Modal Time Reports– Can be varied individually

sample cgms reports48
Sample CGMS Reports

Composite 3 day report for comparison

additional studies involving children
Additional Studies Involving Children
  • Accuracy of Glucowatch 2 system and CGMS in detecting hypoglycemia
  • Multi-center study
  • Involved the Children in Diabetes Research Network
  • 91 children enrolled
  • Ages 3-17
  • Patients were enrolled in a CRC-clinical research center for 24 hours

Diabetes Care 27:722-726 2004

glucowatch 2 vs cgms
Glucowatch 2 vs. CGMS
  • Patients used CGMS and Glucowatch 2 during each admission
  • 1/3 patients started CGMS 48 hours prior to admission
  • 1/3 patients started CGMS 24 hours prior to admission
  • 1/3 patients started CGMS on the day of admission
  • Each patient used 2 sensors for the G-watch 2 during the study– 2 hour overlap
  • 1 Touch Ultra meter used as calibration and control
glucowatch 2 vs cgms51
Glucowatch 2 vs. CGMS
  • Samples: every hour during the day every 30 minutes during the night
  • Hypoglycemia induction test: samples obtained every 5 minutes for 90 minutes
  • Adjustment of values for lag time: time involved in sampling the interstitial fluid measuring glucose as compared with blood
    • Glucowatch 2 Biographer– 17.5 minutes
    • CGMS – 2.5 minutes
glucowatch 2 vs cgms52
Glucowatch 2 vs. CGMS

Glucowatch 2 Biographer

~ 23 % of values were within reference range when glucoses were < 60 mg%

51% false alarms were detected with use

CGMS System

Both modified and original sensors noted < 50% detection within reference range (36 and 48 %)

58% to 60% false alarms were detected with use

Results of Study

study conclusions
Study Conclusions
  • Neither Glucowatch 2 nor CGMS is accurate in reporting glucose values in the hypoglycemic range
  • Accuracy of both devices is better when reference glucose levels are >100 mg/dl
  • Neither device is appropriate at this time for real time detection
  • Both systems are more likely to be of value in adjusting bolus and basal insulin doses in patients with consistently elevated glucoses and A1C levels
  • The accuracy of these early generation sensors is similar to the early generation meters (circa 1970s-early 1980s)
guardian home system
Guardian Home System
  • Sensor can be set to “alarm” at certain levels both high and low
  • Monitor can be placed up to 6 feet away; does not have to be worn
  • Monitor can store up to 21 days of data
  • Can be downloaded to personal computer
  • Still needs calibration similar to CGMS system
  • Alerts or alarms need to be verified with “finger stick” glucose
  • Cost is not set at present (~ $800- $1500 anticipated)
anticipated sample guardian report
Anticipated Sample Guardian Report

Reports similar to CGMS System

www.minimed.com

paradigm 522 system patient use
Paradigm 522 System– Patient Use
  • Consists of Glucose Sensor, Radio Transmitter and Pump receiver
  • Abstract presented at ADA 2004 (Orlando)
  • 9 Patients involved; Ages 10-21, Type 1 DM
  • Used CSII
  • Did 4 Blood Glucoses/day via HGM
  • Wore 7 sensors during the 3 week trial
  • A1C levels decreased 0.3%
  • Glucoses decreased average 20 mg%
  • Work in progress; Not available yet!!!
implantable subcutaneous systems

Implantable Subcutaneous Systems

Enzyme electrode system

Electrochemical device

dexcom subcutaneous sensor system
DexCom Subcutaneous Sensor System

Implantable Sensor device

Pager monitoring system

dexcom subcutaneous sensor system60
DexCom Subcutaneous Sensor System
  • Special bioprotective layer prevents foreign body reaction with sensor
  • Can measure glucoses ranging from 40 mg/dl to 700 mg/dl (2.2-38.9 mmol/L)
  • Recalibration every 20 days
  • 160 – 180 day lifespan for sensor
  • Still need to do HGM 2-3 times/day to initiate glucose algorithm
  • Easily implanted in subcutaneous tissue
  • Can be accomplished as outpatient procedure

Diabetes Care 27:734, 2004

Endocrinology Clinics NA 33:175, 2004

therasense navigator system
Therasense Navigator System
  • Interstitial System
  • Wireless system
  • Needs calibration 1-2 times per day
  • Readings every 1-2 minutes conceptualized
  • High and low glucose alarms to be incorporated
  • Currently experimental
  • Company not distributing info at this time
near infrared spectroscopy

Near Infrared Spectroscopy

Non-invasive techniques

sensys medical systems
Sensys Medical Systems

Endocrinology Clinics of NA 33: 163-173 2004

sensys medical systems64
Sensys Medical Systems
  • Measures glucose non-invasively via NIR spectroscopy
  • Device weighs less than 1.5 pounds
  • Fiber-optic head secured to the forearm
  • Still needs HGM for calibration
  • Various components such as sweat, fat, etc. can interfere with efficacy
  • Can use either volar or dorsal aspects of the forearm
  • Uses a rechargeable battery
  • Studies ongoing with patient use
open flow microperfusion systems

Open-flow Microperfusion Systems

ADICOL Project-Disetronic/Roche

Advanced Insulin Infusion with a Control Loop

adicol project disetronic roche
ADICOL Project –Disetronic / Roche
  • Inserted into the subcutaneous adipose tissue
  • Double lumen catheter
  • Acquires glucose readings every 30 minutes
  • Goal – subcutaneous glucose sensing/insulin delivery system
adicol project disetronic roche67
ADICOL Project –Disetronic / Roche

Large bore catheter

Readings only

every 30 minutes

Small study sample

with patient use

infrared spectroscopy

Infrared Spectroscopy

Animas Corporation Continuous Glucose Monitoring System

infrared spectroscopy69
Infrared Spectroscopy
  • Infrared light is absorbed by molecules
  • Each molecule has its own spectra (absorption characteristic)—similar to its own footprint
  • Theoretically-by measuring the absorbed light vs. wavelength, one could delineate the species and concentration
  • In reality– this is difficult
    • Water absorbs most IR light
    • Blood scatters light
    • Different species overlap in their spectra or footprint
spectra of water hemoglobin blood glucose
Spectra of Water, Hemoglobin, Blood & Glucose

Absorbance

0.042

0.040

0.038

0.036

0.034

0.032

Hemoglobin

0.030

0.028

0.026

0.024

0.022

0.020

0.018

0.016

0.014

0.012

0.010

0.008

0.006

0.004

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

Wavelength (microns)

Absorbance

0.062

0.060

Glucose

0.058

0.056

0.054

0.052

0.050

0.048

0.046

0.044

0.042

0.040

0.038

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

Wavelength (microns)

in vivo measurements in dog glucometer and sensor head vs time

350

300

250

200

150

100

50

0

11:38

12:07

12:35

13:02

In vivo Measurements in Dog: Glucometer and Sensor Head vs. Time

Glucometer

Sensor

Glucose Concentration (mg/dl)

13:41

14:09

14:36

15:03

15:33

16:00

16:39

17:08

17:34

18:02

Time

animas continuous system
Animas Continuous System
  • Has designed and built short term prototype and demonstrated stability in animals
  • Need to miniaturize system
    • Laser diodes under development
    • Telemetry developed
    • Electronics being modified and mostly developed
  • Clinical trials in humans projected to start 2005 or 2006. Projected as early Phase 2 studies with sites to be determined. No pediatric patients to be involved!
advantages of animas monitor
Advantages of Animas Monitor
  • Provides continuous reading of blood glucose without patient intervention
  • Measures glucose in blood as opposed to some other body fluid, e.g.interstitial fluid, ocular fluid
  • The encapsulation/ fibrin tissue has no effect on monitor accuracy
  • Provides direct access to blood, obviating loss and interference associated with light transmission through intervening tissues.
  • Sensor stays implanted for at least 5 years, limited by battery life. No percutaneous wires or cables are utilized.
what is the goal of these technologies

What is the Goal of These Technologies?

Development of a Closed Loop System– The Artificial Pancreas

*Put the Endocrinologist into

Early or Permanent Retirement

what has been accomplished
What Has Been Accomplished?
  • New Technology to determine patterns and facilitate changes in therapy
  • Prototypes for long term glucose monitoring
  • More awareness by patients and families regarding the importance of intensive therapy and “tight” control of blood glucoses
  • “Consumer driven” research for an artificial pancreas
  • More physicians are implementing intensive therapy with technology now available to compliment the treatment
final thoughts
Final Thoughts
  • No system at present is appropriate for a closed loop system
  • No system developed at present can replace the “finger stick” monitor for “real time” glucose values and treatment decisions
  • Presently, there are 50+ companies or individuals attempting to develop a continuous glucose monitoring system
  • EVENTUALLY, THAT DAY WILL ARRIVE!! WHEN, ONE ONLY KNOWS!