Lifecare ASA

Regulatory Filings • Mar 6, 2024

DYNAMIC INTERFERENCE TESTING RESULTS WITH THE DEXCOM G7 CONTINUOUS GLUCOSE MONITORING DEVICE IN COMPARISON TO DEXCOM G6

Background

Continuous glucose monitoring (CGM) by means of needle sensors is becoming a standard measure in routine care of patients with type 1 and type 2 diabetes mellitus. Little is known, however, about the reaction of the glucose oxidasebased sensor technology to potentially interfering nutritional or pharmaceutical substances. Here, we report on results obtained with Dexcom G6 and Dexcom G7 needle sensors with our in-vitro dynamic interference testing method.

Results

Interference (%bias at the highest concentration tested from baseline, G6/G7) was seen with the following substances: acetaminophen: >100%/>100%, hydroxyurea: >100%/>100%, dithiothreitol: -18%/-11%, ethyl alcohol 12%/12%, galactose: 17%/21%, gentisic acid: 18%/27%, L-cysteine: -25%/-12%, L-dopa: 11%/14%, mannose: 20%/15%, methyldopa: 14%715%; N-acetylcysteine: 18%/14%, and uric acid: 33%/32%. In addition, G7 signals were also influenced by xylose (14%, G6: 7%).

Conclusions

Pfützner Science & Health Institute, Diabetescenter and Practice, Haifa-Allee 20, 55128 Mainz,, Tel: +49 61 31 – 5884640, Fax: +49 61 31 – 5884644, www.pfuetzner-mainz.com Pfützner A, Jensch H, Cardinal C, Srikanthamoorthy G, Riehn E, Thomé N. Laboratory Protocol and Pilot Results for Dynamic Interference Testing of Continuous Glucose Monitoring Sensors. J Diabetes Sci Technol. 2022:19322968221095573.doi: 10.1177/19322968221095573. PMID: 35549522.

The Dexcom G7 sensor showed a similar interference pattern as previously observed with G6. There does not seem to be a major difference in the next generation G7 sensor technology compared to G6. The clinical relevance of our findings for routine care should now best be investigated in appropriately designed clinical studies.

Methods

Three sensors from each sensor generation were exposed to substance gradients from zero to supraphysiological concentrations generated by HPLC-pumps at a stable glucose concentration of 200 mg/dL. YSI Stat 2300 Plus was used as the glucose reference method. Interference was assumed if the CGM needle sensors showed a mean bias of more than ±10% from baseline with a tested substance at any given substance concentration.

Pfützner A., Kuhl C., Setford S., Jensch H., Weingärtner L., Grady M., Holt E., Thomé N., Mainz, Germany; Inverness, UK, Malvern, PA, Wiltz, Luxembourg; Bergen, Norway

Reference:

Fig.1 CGM: Dynamic interference test method. Table 1. interfering substances Fig.2 Dexcom G6 & G7 interference by 13 substances

Acknowledgements:

This project received financial support from the European Union's Horizon 2020 research and innovation program under grant agreement No 951933 (ForgetDiabetes) and also from LifeScan Global Corporation, Malvern, PA, USA.

Substance	Maximum Concentration tested	Bias over baseline		Type of substance
		G6	G7
Acetaminophen	20 mg/dL	>100%	>100 %	drug
Dithiothreitol	6 mg/dL	-18%*	-11%*	drug
Ethyl-alcohol	316 mg/dL	+12%	+12%	drug, nutrient
Galactose	300 mg/dL	+17%	+21%	nutrient
Gentisic acid	100 mg/dL	+18%*	+27%*	drug
Hydroxyurea	9.12 mg/dL	>100%	>100%	drug
L-Cysteine	5 mg/dL	-25%*	-12%*	nutrient
L-Dopa	0.75 mg/dL	+11%	+14%	drug
Mannose	300 mg/dL	+20%	+15%	nutrient
Mesalazine	0.136 mg/dL	+0%*	+0%*	Drug
Methyldopa	2 mg/dL	+14%	+15%	drug
N-Acetyl-cysteine	55.4 mg/dL	+18%	+32%	Drug
Uric acid	23.5 mg/dL	+33%	+32%	endogeneous
Xylose	399 mg/dL	+7%	´+14%	nutrient

*: sensor fouling after the experiment