Clinical Assessment of a Novel Microprobe Array Continuous Glucose Monitor for Type 1 Diabetes
Condition: Diabetes Mellitus
MeSH terms: Diabetes Mellitus
Study type: Interventional

Summary: 
      The purpose of the study is to assess the safety and efficacy of the Imperial College
      Microprobe Array Continuous Glucose Sensor in healthy volunteers and in subjects with type 1
      diabetes.
    

Detailed description: 
      Continuous knowledge of ambient glucose levels will be of benefit to patients with T1DM,
      especially those with troublesome hypoglycaemia. Existing monitors require skin puncture to
      access interstitial fluid and sense its glucose content. Despite their clinical benefits,
      their use is associated with discomfort and their accuracy is questionable in hypoglycaemia.
      The development of a painless continuous glucose monitor is regarded as the top research
      priority by patients with diabetes. A novel continuous glucose monitoring device has been
      developed at Imperial College based on microprobe technology. It consists of a small,
      wearable patch (~1 cm2), the size of a conventional postage stamp, containing microscopic
      projections (microprobes) that penetrate only the outermost skin layer. It accesses
      interstitial fluid to sense its glucose content without stimulating skin nerve fibres or
      reaching blood vessels within skin layers. The microprobe surface has the consistency of
      sandpaper. It is pushed into the skin with an applicator allowing it to penetrate through the
      skin layers and access the interstitial fluid in a minimally invasive manner. The device is
      disposable and optimum performance will be assessed over five days. The advantages of
      microprobe technology have been demonstrated in other clinical situations and include
      painless insertion, absence of bleeding and a low infection risk. The large surface area
      utilised in our microprobe device has the potential to improve device sensitivity and
      accuracy. Pre-clinical validation tests have demonstrated the ability of the device to
      respond accurately to variable glucose concentrations and to penetrate the outermost skin
      layer without fracture. We aim now to further develop the device through clinical studies in
      non-diabetic subjects and subjects with type 1 diabetes to allow painless accurate continuous
      glucose monitoring.

      The study will recruit 16 non-diabetic subjects and 20 subjects with type 1 diabetes.

      It will be conducted over four phases;

      oPhase 1 will assess safety, as a primary outcome, and efficacy, as a secondary outcome, in
      non-diabetic subjects over six hours in the clinical research facility where the device will
      be fitted and a cannula inserted for venous sampling every 15 minutes to measure venous blood
      glucose (YSI). Safety will be assessed with regards to skin inflammation and pain. Efficacy
      will be assessed in this phase by assessing magnitude of current measured by the microprobe
      array sensor and comparison of measured ISF glucose concentrations to simultaneous venous
      blood glucose samples (YSI).

      oPhase 2 will also assess safety, as a primary outcome, and efficacy, as a secondary outcome,
      in non-diabetic subjects over a period of 24 hours. The first six hours in the clinical
      research facility (same as phase 1), then subject will be allowed to go home with the device
      to assess safety over that period.

      oPhase 3 aims to assess efficacy of the device as a primary outcome and safety as a secondary
      outcome. This will be in subjects with type 1 diabetes over 24 hours as inpatients. Efficacy
      will be assessed mechanically (by the ability to penetrate the stratum corneum) and
      functionally (by the ability to accurately sense ISF glucose). The derived ISF glucose levels
      will be compared with simultaneous venous glucose samples (YSI) and with a commercially
      available CGM device (iPro2, Medtronic). Assessment of microprobe penetration of the stratum
      corneum will be performed using confocal microscopy, optical coherence tomography and in skin
      biopsies.

      oPhase 4 aims to assess efficacy of the device as a primary outcome and safety as a secondary
      outcome. This will be in subjects with type 1 diabetes over 5 days in ambulatory situation.
      Efficacy will be assessed by comparing microprobe sensor derived ISF glucose levels against
      ISF glucose levels measured using a commercially available CGM device (iPro2, Medtronic).
    

Intervention name(s): Microprobe glucose sensor
Intervention type(s): Device
Intervention description(s): Assessment of safety and accuracy of a novel continuous glucose monitor based on microprobe technology.
Other intervention name(s): Microprobe Array Continuous Glucose Monitor
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: Diabetes; Continuous Glucose Monitoring; Microprobes