PRE-SUBMISSION MEETING PACKAGE
SECTION 4: PROPOSED PERFORMANCE TESTING PLAN
Solstice Lumina™ Continuous Glucose Monitoring System
Lumina C14 Implantable Sensor and Lumina R7 Wearable Reader/Transmitter
Sponsor: Solstice Biomedical Inc. 220 Westbrook Drive, Suite 400 Cambridge, MA 02142 United States
Parent Company: Solstice Biomedical Devices Ltd. Unit 14, Liffey Innovation Park Chapelizod, Dublin D20 FX72 Ireland
Prepared by: Calderwood & Harkness LLP 1401 K Street NW, Suite 900 Washington, D.C. 20005
In coordination with: Pinnacle Regulatory Consulting Group LLC 9500 Medical Center Drive, Suite 210 Rockville, MD 20850
Date of Preparation: For submission on or about June 16, 2025
Pre-Sub Meeting Target Date: August 14, 2025
CONFIDENTIAL AND PROPRIETARY NOTICE: This document and all attachments hereto contain confidential, proprietary, and trade secret information belonging to Solstice Biomedical Inc. and its parent company, Solstice Biomedical Devices Ltd. This document is submitted to the United States Food and Drug Administration, Center for Devices and Radiological Health (CDRH), solely for the purpose of the Pre-Submission (Q-Sub) meeting process and is not intended for public disclosure. This document is protected under 21 C.F.R. § 20.61(c) (trade secret and confidential commercial information), the Trade Secrets Act (18 U.S.C. § 1905), and Exemption 4 of the Freedom of Information Act (5 U.S.C. § 552(b)(4)). Any unauthorized use, reproduction, or distribution of this document is strictly prohibited.
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1. Introduction and Purpose
1.1 Purpose of This Section
This document constitutes Section 4 of the Pre-Submission (Q-Sub) meeting package submitted by Solstice Biomedical Inc. ("Solstice" or the "Sponsor") to the United States Food and Drug Administration ("FDA"), Center for Devices and Radiological Health ("CDRH"), Office of Health Technology 2 ("OHT2"), Division of Chemistry and Toxicology Devices. The Pre-Submission request is being filed pursuant to FDA's guidance document entitled "Requests for Feedback and Meetings for Medical Device Submissions: The Q-Submission Program" (most recently updated June 2023), and this Section 4 is submitted as an integral part of the complete Pre-Submission meeting package.
The purpose of this document is to outline in comprehensive detail the proposed non-clinical performance testing plan, biocompatibility evaluation strategy, electromagnetic compatibility ("EMC") and electrical safety testing program, software verification and validation ("V&V") approach, and cybersecurity assessment plan for the Solstice Lumina™ Continuous Glucose Monitoring ("CGM") System. The Lumina CGM System comprises two co-dependent device components: the Lumina C14 Implantable Sensor and the Lumina R7 Wearable Reader/Transmitter, along with associated software components as described further in Section 1.2, below.
Through this Pre-Submission package, Solstice respectfully requests FDA feedback on the adequacy and scope of the proposed testing plan to support a traditional 510(k) premarket notification submission covering both the Lumina C14 sensor and the Lumina R7 reader/transmitter as a unified system. Solstice intends to file a single 510(k) submission for the complete Lumina CGM System rather than separate submissions for the individual components, and the testing plan presented herein is designed to support that approach. Specific questions directed to FDA regarding the testing plan are set forth in Section 9 of this document.
Solstice has developed this testing plan in close consultation with its regulatory advisors at Pinnacle Regulatory Consulting Group LLC ("Pinnacle Regulatory"), its contract testing laboratory Whitmore Laboratories Inc. ("Whitmore"), and its legal counsel at Calderwood & Harkness LLP ("Calderwood & Harkness"). The testing plan has been informed by a thorough review of applicable FDA guidance documents, recognized consensus standards, predicate device submission histories, and relevant precedent in the CGM device space.
1.2 Device Overview Summary
The Solstice Lumina™ CGM System is a two-component continuous glucose monitoring system designed for use by persons aged 18 years and older who have been diagnosed with Type 1 or Type 2 diabetes mellitus. The system provides real-time, continuous glucose monitoring through the coordinated operation of an implantable sensor and a wearable reader/transmitter, and is intended to replace or supplement traditional fingerstick blood glucose monitoring. The two principal hardware components and their associated software components are described below.
Lumina C14 Implantable Sensor. The Lumina C14 is a subcutaneously implantable continuous glucose monitoring sensor designed for a 14-day (336-hour) wear duration. The sensor employs a fourth-generation enzymatic electrochemical biosensor incorporating Solstice's proprietary platinum-iridium electrode coating, designated PtIr-4G technology. The PtIr-4G electrode coating represents a significant advancement over conventional platinum electrode designs, providing enhanced signal stability, reduced oxygen dependency, and improved resistance to common electrochemical interferents. The C14 sensor operates across a measurement range of 40–400 mg/dL and provides glucose readings at five-minute intervals. The sensor requires a warm-up time of no more than 60 minutes from insertion to first reliable glucose reading. Glucose data is transmitted wirelessly from the C14 sensor to the R7 reader via Bluetooth Low Energy ("BLE") 5.2 radio communication. The C14 sensor is designed for single use and is inserted subcutaneously using an integrated, disposable applicator device. The sensor is affixed to the skin surface by means of a medical-grade adhesive patch.
Lumina R7 Wearable Reader/Transmitter. The Lumina R7 is a compact, wearable reader/transmitter device designed to be worn on the upper arm. The R7 receives BLE 5.2 data transmissions from the implanted C14 sensor and displays real-time glucose values, trend arrows indicating the direction and rate of glucose change, and 8-hour trend graphs on an integrated display screen. The R7 reader provides configurable hypoglycemia and hyperglycemia alerts with an alert latency of no more than five minutes from the time of sensor reading to user notification. Alerts are delivered through auditory, visual, and haptic modalities. The R7 reader also communicates with the Solstice Lumina™ mobile application (available on both iOS and Android platforms) via BLE, enabling remote data viewing, historical data logging, and cloud-based data sharing with healthcare providers. The R7 reader is powered by an internal rechargeable lithium-ion battery and is recharged via a USB-C connection to a medical-grade power supply.
Software Components. The Lumina CGM System incorporates four principal software components, each of which is subject to the software verification and validation plan described in Section 6 of this document:
(a) Lumina Firmware v3.4.2 — Embedded firmware residing on the C14 sensor, controlling glucose measurement acquisition, signal processing, calibration algorithms, and BLE data transmission.
(b) Lumina Reader OS v2.1.0 — Operating system software residing on the R7 reader, controlling display output, alert management, BLE communication with both the C14 sensor and the mobile application, user interface interactions, and data logging.
(c) LuminaPredict Algorithm v2.1 — A proprietary glucose prediction and trend calculation algorithm that processes raw electrochemical signal data from the C14 sensor to generate calibrated glucose values, rate-of-change calculations, and trend arrow displays. The algorithm resides on and executes within the R7 reader.
(d) Lumina Mobile App v1.0.3 — A companion mobile application available on both iOS (version 15.0 and later) and Android (version 12.0 and later) platforms, providing remote glucose value display, historical trend data, data export functionality, and connectivity to the Solstice Lumina™ cloud platform for data sharing with healthcare providers.
1.3 Predicate Context for Testing Strategy
The proposed testing plan has been developed to demonstrate substantial equivalence of the Solstice Lumina™ CGM System to the identified predicate devices in accordance with FDA's 510(k) requirements under Section 513(i) of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. § 360c(i)) and 21 C.F.R. Part 807, Subpart E.
Primary Predicate Device. Solstice has identified the NovaSense GlucoTrack NX-500 CGM System as its primary predicate device. The NX-500 was cleared by FDA on June 18, 2022, under 510(k) No. K211034. It is classified under product code QKQ (Electrode, Glucose, Subcutaneous), Class II, pursuant to 21 C.F.R. § 862.1355. The NX-500 system consists of a subcutaneously implantable enzymatic electrochemical glucose sensor with a 10-day wear duration and a handheld reader device that receives glucose data from the sensor via BLE wireless transmission. The NX-500 sensor employs a conventional platinum electrode design and transmits data using BLE 5.0 protocol.
Secondary Predicate (Reference Device). As a secondary predicate and reference device, Solstice has identified the NovaSense GlucoTrack NX-700 CGM System, cleared by FDA on March 7, 2024, under 510(k) No. K230489. The NX-700 is also classified under product code QKQ, Class II, pursuant to 21 C.F.R. § 862.1355. The NX-700 represents NovaSense's next-generation CGM platform, featuring a 14-day sensor wear duration (matching the Lumina C14), enhanced BLE 5.0 data transmission, and an updated glucose algorithm. The NX-700 continues to utilize a handheld reader form factor and a conventional platinum electrode design.
The proposed testing plan has been specifically designed to address the five key technological differences between the Solstice Lumina™ CGM System and the identified predicate devices, as follows:
(1) Sensor Wear Duration. The Lumina C14 sensor is designed for 14-day (336-hour) continuous wear, compared to 10-day wear for the primary predicate NX-500. The secondary predicate NX-700 also claims a 14-day wear duration. The testing plan includes extensive sensor drift and stability testing over the full 14-day wear period to demonstrate maintenance of accuracy throughout the extended wear duration.
(2) Electrode Material. The Lumina C14 sensor employs Solstice's proprietary PtIr-4G (platinum-iridium fourth-generation) electrode coating, in contrast to the conventional platinum electrode design used in both the NX-500 and NX-700 predicate devices. The PtIr-4G coating represents a significant technological difference, and the testing plan includes comprehensive analytical performance testing, interference testing, and biocompatibility evaluation of this novel material.
(3) BLE Version. The Lumina CGM System communicates via BLE 5.2 protocol, compared to BLE 5.0 used in the NX-700 secondary predicate and BLE 4.2 used in the NX-500 primary predicate. The testing plan includes wireless communication performance testing and coexistence testing to demonstrate reliable data transmission via the updated BLE 5.2 standard.
(4) Reader Form Factor. The Lumina R7 reader is designed as a compact, arm-worn wearable device, in contrast to the handheld reader form factor used in both predicate devices. This difference in form factor introduces considerations for skin contact biocompatibility, ergonomics, and wireless communication performance that are addressed in the testing plan.
(5) Glucose Prediction Algorithm. The Lumina CGM System uses the proprietary LuminaPredict Algorithm v2.1 for glucose value calculation, trend determination, and rate-of-change computation. This algorithm differs from the proprietary algorithms used in the NovaSense predicate devices. The testing plan includes comprehensive algorithm validation using independent clinical datasets.
Solstice notes that it has also identified, for purposes of corporate pedigree only, the Solstice GlucoStrip RX-200 Test Strip Reader, which was cleared by FDA on November 14, 2019, under 510(k) No. K192847. The GlucoStrip RX-200 is classified under product code NBW, Class II, and is not being cited as a predicate device for the purposes of demonstrating substantial equivalence of the Lumina CGM System. The GlucoStrip RX-200 is referenced solely to demonstrate Solstice's prior experience and established history of regulatory interactions with FDA in the glucose monitoring device space.
1.4 Contract Testing Laboratory
Solstice has engaged Whitmore Laboratories Inc. ("Whitmore") as its primary contract testing laboratory for the execution of the biocompatibility testing program, electromagnetic compatibility testing, and electrical safety testing described in this document. Whitmore's relevant credentials and engagement details are as follows:
Laboratory Name: Whitmore Laboratories Inc.
Address: 1625 Shady Grove Road, Suite 300, Gaithersburg, MD 20878
Accreditation: ISO/IEC 17025:2017 accredited laboratory, accredited by the American Association for Laboratory Accreditation (A2LA), Certificate No. 3847.01. Whitmore's scope of accreditation includes biological evaluation testing in accordance with the ISO 10993 series of standards, electromagnetic compatibility testing in accordance with the IEC 60601-1-2 standard, and electrical safety testing in accordance with the IEC 60601-1 standard. Whitmore is recognized by FDA as a testing laboratory for medical device submissions. A copy of Whitmore's current A2LA accreditation certificate is included as Appendix A to this document.
Key Contact: Dr. James Haverford, Director of Biocompatibility Testing
Engagement Date: March 3, 2025
Scope of Engagement: Whitmore has been engaged to perform all biocompatibility testing (ISO 10993 series), electromagnetic compatibility testing (IEC 60601-1-2), and electrical safety testing (IEC 60601-1) for the Lumina C14 sensor and Lumina R7 reader/transmitter. Whitmore will provide test reports suitable for direct inclusion in the 510(k) submission.
Regulatory consulting support for the design and development of all testing protocols described in this document has been provided by Pinnacle Regulatory Consulting Group LLC ("Pinnacle Regulatory"), under the direction of Dr. Sandra Ellison, Managing Director, and Thomas Greenbaum, Senior Regulatory Specialist. Pinnacle Regulatory has extensive experience advising CGM device manufacturers in the design of non-clinical performance testing programs for FDA submissions and has served as a regulatory consultant on more than thirty 510(k) submissions for continuous glucose monitoring and other in vitro diagnostic devices.
1.5 EU MDR Data Leveragability
An important consideration in the development of the proposed testing plan is the current regulatory status of the Lumina CGM System in the European Union. The Solstice Lumina™ CGM System has been commercially available in the EU since September 2024 and bears the CE marking under the European Medical Device Regulation (EU) 2017/745 ("EU MDR"). The relevant EU MDR certification details are as follows:
CE Certificate Number: MCA-2024-07319
Date of Issuance: September 12, 2024
Notified Body: Meridian Conformity Assessment GmbH, NB 0483
Classification: Class IIb (per Annex VIII, Rule 11 of the EU MDR)
In addition, Solstice Biomedical Devices Ltd. (the parent company) holds ISO 13485:2016 certification for the design, development, manufacture, and distribution of continuous glucose monitoring systems, certified by Meridian Conformity Assessment GmbH. Solstice's quality management system is maintained and audited in accordance with ISO 13485:2016 requirements.
The testing plan presented in this document has been developed with the express intention of leveraging, where FDA-acceptable, the technical file data that was generated to support the EU MDR CE marking. Significant performance testing, biocompatibility evaluation, and software verification data have already been generated as part of the EU MDR conformity assessment process, and Solstice believes that much of this data will be directly relevant and transferable to the FDA 510(k) submission. However, Solstice recognizes that there are certain FDA-specific requirements that may not be fully addressed by the existing EU MDR data package, and the testing plan includes supplemental testing to address identified gaps.
A key gap identified during the preliminary regulatory assessment is the potential need for additional extractable and leachable data specific to the PtIr-4G electrode coating. The chemical characterization data generated for the EU MDR technical file addressed extractables and leachables in accordance with ISO 10993-18, but Solstice's regulatory advisors have identified the possibility that FDA may require more extensive characterization of this novel electrode coating material, particularly given the updated FDA guidance on the use of ISO 10993-1 (September 2020 update). This gap is specifically addressed in Question 3 of the questions presented to FDA in Section 9, below.
Solstice also seeks FDA's confirmation, through this Pre-Submission process, that the general approach of leveraging EU MDR data supplemented by FDA-specific testing is an acceptable strategy for the planned 510(k) submission. This question is presented as Question 7 in Section 9.
2. Proposed Bench (Non-Clinical) Performance Testing
2.1 Overview of Bench Testing Scope
The proposed bench (non-clinical) performance testing program has been designed to comprehensively evaluate the safety and performance of both the Lumina C14 implantable sensor and the Lumina R7 wearable reader/transmitter under simulated and actual use conditions. The testing program is organized into five principal categories, each of which is described in detail in the subsections that follow:
(a) Sensor Accuracy and Analytical Performance — Comprehensive evaluation of the C14 sensor's measurement accuracy, linearity, precision, susceptibility to interference, stability over the full 14-day wear period, and consensus error grid analysis (Section 2.2).
(b) Reader/Transmitter (R7) Performance — Verification of R7 reader display accuracy, alert system functionality and latency, and sensor warm-up time performance (Section 2.3).
(c) Wireless Communication Performance — Evaluation of BLE 5.2 communication range and reliability, mobile application communication, and wireless coexistence (Section 2.4).
(d) Mechanical and Environmental Testing — Characterization of sensor insertion force, adhesive retention, environmental exposure resilience, shelf-life/accelerated aging, and water resistance (Section 2.5).
The testing program has been designed with reference to the applicable recognized consensus standards, CLSI guidelines, and FDA guidance documents identified in the References section (Section 10) of this document. Testing protocols have been developed in consultation with Pinnacle Regulatory and have been reviewed by Whitmore to ensure laboratory feasibility and alignment with accreditation scope.
The bench testing program described in this section is intended to complement, not replace, the clinical performance data that will be generated through the planned LUMINA-US clinical study (Protocol No. SBD-LUM-CL-001), which is described in Section 3 of the Pre-Submission meeting package (submitted separately). The bench testing program will provide a controlled, laboratory-based evaluation of the device's analytical performance under defined conditions, while the clinical study will provide in vivo performance data in the intended user population. Together, these data packages are expected to provide a comprehensive demonstration of the Lumina CGM System's safety and effectiveness for the purposes of the 510(k) submission.
2.2 Sensor Accuracy and Analytical Performance
2.2.1 In Vitro Accuracy Testing. Test Objective. The objective of this test is to evaluate the measurement accuracy of the Lumina C14 sensor across the full claimed measurement range (40–400 mg/dL) using reference glucose solutions in a controlled in vitro test environment. This testing is fundamental to the demonstration of analytical performance and represents a primary basis for the claim of substantial equivalence with the identified predicate devices.
Reference Standard. All reference glucose measurements will be obtained using a YSI 2900D Series Biochemistry Analyzer (or equivalent laboratory reference method meeting CLSI EP09 requirements), which is widely recognized by FDA as an acceptable reference standard for glucose measurement in CGM device evaluations.
Test Matrix. The in vitro accuracy assessment will evaluate sensor performance at the following glucose concentration levels, spanning the full measurement range: 40 mg/dL, 60 mg/dL, 80 mg/dL, 100 mg/dL, 120 mg/dL, 150 mg/dL, 200 mg/dL, 250 mg/dL, 300 mg/dL, 350 mg/dL, and 400 mg/dL. These eleven concentration levels provide comprehensive coverage of the clinically relevant glucose range, including the hypoglycemic range (40–70 mg/dL), the euglycemic range (70–180 mg/dL), and the hyperglycemic range (>180 mg/dL).
Sample Size. A minimum of 100 paired measurements (sensor reading paired with reference glucose measurement) will be obtained at each glucose concentration level, for a total of at least 1,100 paired data points across the measurement range. Paired measurements will be collected from sensors drawn from multiple manufacturing lots (minimum three lots) to ensure representative sampling.
Acceptance Criteria. The primary acceptance criterion is an overall Mean Absolute Relative Difference ("MARD") of no greater than 9.0% across all paired data points. This acceptance criterion is consistent with the performance thresholds established in FDA's guidance document "Integrated Continuous Glucose Monitoring Systems" (September 2023) and reflects the current state-of-the-art performance expectations for continuous glucose monitoring devices in the Class II regulatory pathway. Secondary acceptance criteria, stratified by glucose concentration range, will also be applied in accordance with the iCGM performance criteria.
Testing Conditions. Testing will be conducted in a controlled laboratory environment under simulated physiological conditions (temperature 37°C ± 1°C, phosphate-buffered saline at pH 7.4 ± 0.1). Sensors will be equilibrated in the simulated subcutaneous environment for a period consistent with the labeled warm-up time (≤ 60 minutes) prior to commencement of accuracy testing.
2.2.2 Linearity. Test Objective. The objective of this test is to demonstrate that the Lumina C14 sensor produces a linear response across the full claimed measurement range (40–400 mg/dL), thereby confirming that the sensor's electrochemical signal output is proportional to glucose concentration throughout the measurement range.
Test Method. Linearity testing will be conducted in accordance with CLSI EP06-A: Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach. Testing will employ a minimum of five glucose concentration levels spanning the measurement range, including levels near the lower limit (40 mg/dL), the midpoint (approximately 200 mg/dL), and the upper limit (400 mg/dL). Reference glucose concentrations will be prepared volumetrically using certified glucose standard solutions traceable to NIST reference materials.
Acceptance Criteria. The sensor response shall demonstrate a correlation coefficient (r²) of at least 0.99 over the 40–400 mg/dL measurement range, as determined by linear regression analysis. Polynomial regression analysis will also be performed to evaluate whether there are statistically significant deviations from linearity (nonlinear terms).
Statistical Analysis. The linearity assessment will include calculation of the linear regression equation, the coefficient of determination (r²), the standard error of the estimate, and the residual analysis for each concentration level. Any statistically significant deviations from linearity will be reported with an assessment of clinical significance.
2.2.3 Precision (Repeatability and Reproducibility). Test Objective. The objective of this test is to assess the within-sensor variability (repeatability) and between-sensor variability (reproducibility) of the Lumina C14 sensor's glucose measurements, thereby characterizing the precision of the measurement system.
Repeatability Testing. Repeatability will be assessed by obtaining multiple readings from the same sensor under identical test conditions at each glucose concentration level. A minimum of 20 replicate measurements per sensor per glucose concentration level will be obtained. Repeatability testing will be performed at a minimum of five glucose concentration levels spanning the measurement range.
Reproducibility Testing. Reproducibility will be assessed by comparing measurements obtained from multiple sensors drawn from different manufacturing lots (a minimum of three lots), tested under the same conditions and at the same glucose concentration levels. A minimum of ten sensors per manufacturing lot will be evaluated.
Acceptance Criteria. The acceptance criteria for precision are as follows:
• At glucose concentrations greater than 100 mg/dL: coefficient of variation ("CV") shall not exceed 5%.
• At glucose concentrations equal to or less than 100 mg/dL: the standard deviation of measurements shall not exceed 10 mg/dL.
These criteria are consistent with the precision requirements commonly applied to CGM devices and are aligned with the performance characteristics of the identified predicate devices.
2.2.4 Interference Testing. Test Objective. The objective of this test is to evaluate the potential for endogenous and exogenous substances commonly encountered in the intended patient population to interfere with the accuracy of glucose measurements obtained by the Lumina C14 sensor. Interference testing is particularly important for the Lumina C14 sensor given its novel PtIr-4G electrode coating, which may exhibit different susceptibility to electrochemical interferents compared to conventional platinum electrodes.
Test Method. Interference testing will be conducted in accordance with CLSI EP07-A3: Interference Testing in Clinical Chemistry (3rd Edition). Each potential interferent will be tested individually at its maximum expected therapeutic or physiological concentration, and the effect on glucose measurement accuracy will be assessed at a minimum of two glucose concentrations (one in the euglycemic range and one in the hyperglycemic range).
Substances to be Tested. The following endogenous and exogenous substances will be evaluated for potential interference:
• Medications: Acetaminophen (at maximum therapeutic serum concentration of approximately 30 mg/L), salicylic acid (at maximum therapeutic serum concentration of approximately 500 mg/L), hydroxyurea (at maximum therapeutic serum concentration), L-dopa (at maximum therapeutic serum concentration), and mannitol (at maximum therapeutic serum concentration).
• Vitamins and Supplements: Ascorbic acid (Vitamin C) (at concentrations up to 20 mg/dL, corresponding to megadose supplementation).
• Endogenous Substances: Dopamine (at physiological and therapeutic concentrations), uric acid (at elevated concentrations corresponding to hyperuricemia), and bilirubin (at concentrations corresponding to jaundice, up to 20 mg/dL).
• Hematocrit: Hematocrit will be evaluated across a clinically relevant range of 20% to 60%, encompassing both severe anemia and polycythemia.
• Sugars and Sugar Alcohols: Maltose, galactose, xylose, and icodextrin (a glucose polymer used in peritoneal dialysis solutions) will each be tested at their maximum expected physiological or therapeutic concentrations.
Acceptance Criteria. No tested substance shall produce a clinically significant bias in glucose measurement. Clinically significant bias is defined as follows:
• At glucose concentrations equal to or less than 100 mg/dL: bias shall not exceed ±10 mg/dL.
• At glucose concentrations greater than 100 mg/dL: bias shall not exceed ±10% of the reference glucose value.
These criteria are applied at the maximum expected therapeutic or physiological concentration of each tested substance and are consistent with the interference requirements set forth in FDA's iCGM guidance.
2.2.5 Sensor Drift / Stability Over 14-Day Wear. Test Objective. The objective of this test is to characterize the stability and accuracy of the Lumina C14 sensor over its full claimed 14-day (336-hour) wear period. Sensor drift — the gradual change in sensor accuracy over time due to biofouling, enzyme degradation, electrode surface changes, or other time-dependent phenomena — is a critical performance parameter for any CGM sensor, and is of particular importance for the Lumina C14 given its 14-day wear duration, which exceeds the 10-day wear duration of the primary predicate device (NovaSense GlucoTrack NX-500).
Test Design. Sensors will be placed in a simulated subcutaneous environment (temperature 37°C ± 1°C, phosphate-buffered saline at pH 7.4 ± 0.1) and continuously monitored over the full 336-hour wear period. Reference glucose measurements will be obtained at multiple time points throughout the wear period, with specific emphasis on the following critical evaluation periods:
• Day 1 (0–24 hours): Evaluation of initial sensor equilibration and early accuracy performance.
• Day 7 (144–168 hours): Mid-wear evaluation to assess onset and progression of any drift.
• Day 14 (312–336 hours): End-of-wear evaluation to confirm maintenance of accuracy at the conclusion of the labeled wear period.
In addition to these critical evaluation periods, reference measurements will be obtained at regular intervals (minimum every 12 hours) throughout the 14-day wear period to generate a comprehensive time-course profile of sensor accuracy.
Testing Conditions. Testing will be conducted under simulated subcutaneous conditions, as described above. To better simulate in vivo conditions, the test setup will incorporate periodic challenges with varying glucose concentrations to simulate the dynamic glucose fluctuations that occur during normal daily activities, meals, and exercise in patients with diabetes.
Acceptance Criteria. The following acceptance criteria will be applied:
• The overall MARD across all time points throughout the 336-hour wear period shall not exceed 9.0%.
• There shall be no statistically significant increase in MARD from Day 1 to Day 14, as determined by appropriate statistical analysis (paired t-test or non-parametric equivalent, with significance level α = 0.05).
• The MARD at Day 14 (calculated from data collected during hours 312–336) shall not exceed 10.0%.
Sample Size. A minimum of 30 sensors from at least three manufacturing lots will be evaluated in the sensor drift study to ensure adequate statistical power for detecting clinically meaningful drift.
2.2.6 Consensus Error Grid Analysis. Test Objective. The objective of this analysis is to assess the clinical accuracy of the Lumina C14 sensor by applying the Clarke Error Grid Analysis (or, if appropriate, the consensus Surveillance Error Grid) to all paired sensor-reference glucose data points generated from the in vitro accuracy testing program.
Methodology. All paired sensor-reference data points from the in vitro accuracy testing (Section 2.2.1) and the sensor drift study (Section 2.2.5) will be plotted on the Clarke Error Grid. Each data point will be classified into one of the five Clarke Error Grid zones (A through E) based on the clinical significance of the measurement error.
Acceptance Criteria. The following acceptance criteria will be applied:
• A minimum of 99% of all paired data points shall fall within Zones A and B of the Clarke Error Grid (i.e., clinically accurate or clinically acceptable measurements).
• No more than 1% of data points shall fall in Zone C.
• No data points shall fall in Zones D or E (clinically dangerous measurement errors).
Stratified Analysis. In addition to the overall error grid analysis, data will be presented stratified by glucose concentration range:
• Hypoglycemic range: glucose ≤ 70 mg/dL
• Euglycemic range: glucose 70–180 mg/dL
• Hyperglycemic range: glucose > 180 mg/dL
The stratified analysis will provide FDA with a detailed view of sensor accuracy across the clinically critical glucose concentration ranges.
2.3 Reader/Transmitter (R7) Performance Testing
2.3.1 Display Accuracy. Test Objective. The objective of this test is to verify that the Lumina R7 reader accurately displays glucose values, trend arrows, and 8-hour trend graphs that are consistent with the data transmitted from the Lumina C14 sensor. This testing ensures that no errors are introduced during data transmission, processing, or rendering on the R7 reader display.
Test Design. Known glucose values spanning the full measurement range (40–400 mg/dL) will be transmitted from the C14 sensor (or from a BLE signal simulator configured to emulate the C14 sensor's data output) to the R7 reader. The glucose values displayed on the R7 reader screen will be compared against the transmitted values to verify accuracy. Testing will include:
• Verification of numeric glucose value display accuracy across the full measurement range.
• Verification of trend arrow directionality, including confirmation that the correct trend arrow (rising rapidly, rising, stable, falling, falling rapidly) is displayed for each simulated rate-of-change condition.
• Verification of trend arrow threshold accuracy, ensuring that arrows transition correctly at the defined rate-of-change thresholds.
• Verification of 8-hour trend graph display, including visual accuracy and temporal axis scaling.
Acceptance Criteria. The R7 reader shall display glucose values, trend arrows, and trend graphs that are 100% consistent with the data transmitted from the C14 sensor, with no display errors, truncation, rounding errors, or rendering artifacts.
2.3.2 Alert System Validation. Test Objective. The objective of this test is to validate the functionality of the configurable hypoglycemia and hyperglycemia alert system on the Lumina R7 reader, including verification of alert latency, threshold accuracy, and alert modality functionality.
Alert Latency Testing. The time elapsed from the generation of a sensor reading indicating an alert condition to the delivery of the alert notification to the user will be measured under multiple conditions. Acceptance criterion: alert latency shall not exceed five minutes from the time of the sensor reading that triggers the alert condition.
Alert Threshold Testing. The alert system will be tested at multiple configurable alert thresholds to verify correct triggering behavior:
• Hypoglycemia alert thresholds: 55 mg/dL, 60 mg/dL, and 70 mg/dL
• Hyperglycemia alert thresholds: 180 mg/dL, 200 mg/dL, 250 mg/dL, and 300 mg/dL
For each threshold setting, testing will verify that the alert is triggered when the sensor reading crosses the threshold (rising above for hyperglycemia, falling below for hypoglycemia) and is not triggered when the sensor reading is within normal range. Testing will also evaluate the behavior of the alert system at glucose values near (within ±5 mg/dL of) the configured thresholds to assess for false alarm rates and missed alarms.
Alert Modality Testing. Each of the three alert modalities (auditory, visual, and haptic) will be tested independently and in combination to verify proper functioning:
• Auditory alerts: verification of alarm tone generation, volume level adequacy, and alarm tone distinctiveness from other device sounds.
• Visual alerts: verification of screen alert display, color coding, and alert message content.
• Haptic alerts: verification of vibration alert generation and perceptibility.
2.3.3 Warm-Up Time Verification. Test Objective. The objective of this test is to verify that the Lumina C14 sensor achieves operational readiness within the claimed warm-up time of no more than 60 minutes from the time of subcutaneous insertion to the generation of the first reliable glucose reading.
Test Design. The warm-up time will be evaluated under multiple ambient temperature conditions to assess the effect of environmental temperature on sensor equilibration:
• 15°C (representing cool environmental conditions, such as a physician's office in winter)
• 25°C (representing standard room temperature)
• 37°C (representing body temperature; accelerated equilibration expected)
Sensors will be inserted into simulated subcutaneous tissue at each temperature condition, and the time from insertion to first glucose reading meeting accuracy criteria (within ±15% of reference value for glucose >100 mg/dL, or within ±15 mg/dL for glucose ≤100 mg/dL) will be recorded.
Sample Size. A minimum of ten sensors per temperature condition will be evaluated.
Acceptance Criteria. At all tested ambient temperature conditions, the sensor warm-up time shall not exceed 60 minutes for any tested sensor.
2.4 Wireless Communication (BLE 5.2) Testing
2.4.1 Communication Range and Reliability. Test Objective. The objective of this test is to verify reliable BLE 5.2 data transmission between the Lumina C14 implanted sensor and the Lumina R7 reader/transmitter under intended use conditions and across the expected range of user scenarios.
Test Design. Communication performance will be evaluated at distances ranging from 0 meters (direct contact) to 10 meters, in increments of 1 meter. At each distance, testing will be performed under multiple device orientations and body positions (e.g., arm at side, arm raised, lying on side with reader between body and bed surface) to simulate real-world use conditions. Key parameters to be measured include:
• Packet error rate (PER): the percentage of transmitted data packets that are received with errors or are lost in transmission.
• Data throughput: the effective data transmission rate under each test condition.
• Connection stability: the ability to maintain a continuous BLE connection without dropouts or disconnections.
• Reconnection time: the time required to re-establish a BLE connection following a temporary signal interruption.
Acceptance Criteria. The packet error rate shall not exceed 0.1% at distances of 6 meters or less, which represents the typical maximum expected separation distance between the sensor (implanted in the abdomen) and the reader (worn on the upper arm) during intended use. At distances of 6 to 10 meters, the packet error rate shall not exceed 1.0%.
2.4.2 Communication with Mobile Application. Test Objective. The objective of this test is to verify reliable BLE communication between the Lumina R7 reader and the Solstice Lumina™ mobile application (Lumina Mobile App v1.0.3) on both iOS and Android platforms.
Test Design. The R7 reader's BLE communication with the mobile application will be evaluated on a representative set of iOS and Android device models, including:
• iOS devices: iPhone 13, iPhone 14, iPhone 15 (representing iOS versions 16, 17, and 18)
• Android devices: Northgate & Co. Galaxy S23, Severin Industries Pixel 7, Northgate & Co. Galaxy A54 (representing Android versions 13 and 14)
Testing will verify data integrity for all transmitted glucose values and trend data, including:
• Numeric glucose values (verification of exact match between R7 display and mobile app display)
• Trend arrow information
• Historical trend data (8-hour trend graphs)
• Alert notifications forwarded from R7 reader to mobile app
• Timestamp accuracy for all data elements
Acceptance Criteria. Data transmitted from the R7 reader to the mobile application shall be 100% accurate and complete, with no data corruption, truncation, or loss. Alert notifications shall be forwarded from the R7 reader to the mobile application with a latency of no more than 30 seconds.
2.4.3 Coexistence Testing. Test Objective. The objective of this test is to evaluate the ability of the Lumina CGM System's BLE 5.2 communication to coexist with other common wireless devices and radio frequency environments without degradation in glucose data transmission accuracy or latency.
Test Design. The Lumina CGM System will be operated in a simulated multi-device wireless environment that includes the following common interfering sources:
• Wi-Fi access points (802.11b/g/n/ac, 2.4 GHz and 5 GHz)
• Other BLE devices (e.g., wireless headphones, fitness trackers, smartwatches)
• Cellular devices (4G LTE and 5G NR)
• Microwave ovens (2.45 GHz)
Testing will evaluate glucose data transmission accuracy, alert delivery latency, and connection stability in the presence of each interfering source individually and in combination.
Acceptance Criteria. No degradation in glucose data transmission accuracy or alert delivery latency shall be observed in the presence of common interfering wireless signals. Specifically:
• Glucose data transmission accuracy: no discrepancies between sensor-reported and reader-displayed glucose values.
• Alert latency: alert delivery time shall remain ≤ 5 minutes in all tested coexistence scenarios.
• Connection stability: no BLE disconnections lasting more than 30 seconds in any tested coexistence scenario.
2.5 Mechanical and Environmental Testing
2.5.1 Sensor Insertion Force Testing. Test Objective. The objective of this test is to characterize the insertion force required for subcutaneous placement of the Lumina C14 sensor using the integrated disposable applicator device. This testing supports the evaluation of user safety and usability associated with the sensor insertion process.
Test Design. Insertion force will be measured using a calibrated force gauge or universal testing machine during simulated sensor insertion into an appropriate skin simulant. The test will characterize peak insertion force, sustained insertion force, and the force profile throughout the insertion stroke. Testing will be performed across multiple manufacturing lots (minimum three lots) and multiple applicator devices per lot (minimum ten devices per lot) to characterize lot-to-lot variability.
Acceptance Criteria. Insertion force values will be reported for characterization purposes. The mean peak insertion force shall be within an acceptable range that is consistent with comfortable, user-manageable insertion (i.e., consistent with predicate device insertion forces).
2.5.2 Adhesive / Retention Testing (C14 Sensor). Test Objective. The objective of this test is to evaluate the adhesion of the Lumina C14 sensor's skin-contact adhesive over the full 14-day wear period under varying skin conditions and activity levels, ensuring that the sensor remains securely attached throughout the intended wear duration.
Test Design. Adhesive performance will be evaluated under the following conditions:
• Skin conditions: dry skin, moist skin (post-shower), oily skin (application of common skin lotions or sunscreens).
• Activity levels: sedentary, moderate physical activity, vigorous physical activity (simulated through mechanical stress testing of the adhesive bond).
• Environmental conditions: exposure to water immersion (simulating bathing), elevated humidity, and perspiration.
Accelerated aging testing will be performed in accordance with ASTM F1980: Standard Guide for Accelerated Aging of Sterile Barrier Systems for Medical Devices to assess adhesive performance following simulated shelf-life storage.
Acceptance Criteria. The adhesive shall maintain secure sensor attachment for the full 14-day wear period under all tested conditions. No sensor detachment or significant adhesive failure shall occur during the wear period.
2.5.3 Environmental Exposure Testing (R7 Reader). Test Objective. The objective of this test is to evaluate the mechanical and environmental resilience of the Lumina R7 wearable reader/transmitter under the range of environmental conditions that may be encountered during intended use, storage, and transport.
Test Design. The R7 reader will be subjected to the following environmental exposure tests, conducted in accordance with applicable IEC and MIL-STD standards:
• Temperature cycling: Operating temperature range (10°C to 40°C) and storage temperature range (-20°C to 55°C) per IEC 60068-2-14.
• Humidity: Operating humidity range (10% to 95% relative humidity, non-condensing) per IEC 60068-2-78.
• Altitude: Simulated altitude testing per IEC 60068-2-13.
• Vibration: Random and sinusoidal vibration testing simulating transportation and daily use per IEC 60068-2-6 and IEC 60068-2-64.
• Drop testing: Free-fall drop testing from heights representative of accidental drops during daily use (1.0 meter onto concrete surface) per IEC 60068-2-31.
Acceptance Criteria. The R7 reader shall continue to operate within specified performance parameters, including display accuracy, alert functionality, and BLE communication, following exposure to all tested environmental conditions. No structural damage, display failure, or battery compromise shall occur during or after environmental testing.
2.5.4 Shelf Life / Accelerated Aging (C14 Sensor). Test Objective. The objective of this test is to support the shelf-life claims for the Lumina C14 sensor through accelerated aging testing, supplemented by real-time aging data.
Test Design. Accelerated aging testing will be performed in accordance with ASTM F1980: Standard Guide for Accelerated Aging of Sterile Barrier Systems for Medical Devices. Test samples will be subjected to accelerated aging conditions based on the Arrhenius reaction rate model, using a temperature of 55°C and a Q₁₀ factor of 2.0. The duration of accelerated aging will be calculated to simulate the claimed shelf life (anticipated to be 18 months from date of manufacture). Aged sensors will be evaluated for sterility maintenance, packaging integrity, sensor accuracy, and sensor drift performance.
Real-time aging studies will be conducted in parallel, with sensors stored at labeled storage conditions (2°C to 30°C, <90% relative humidity) and evaluated at periodic intervals (e.g., 3, 6, 12, and 18 months).
Acceptance Criteria. Sensors subjected to accelerated aging equivalent to the claimed shelf life shall meet all sensor accuracy and performance acceptance criteria specified in Section 2.2. Sterile barrier system integrity shall be maintained as demonstrated by sterility testing of aged units.
2.5.5 Water Resistance (R7 Reader). Test Objective. The objective of this test is to verify the water resistance of the Lumina R7 reader at the claimed Ingress Protection ("IP") rating.
Test Design. Ingress protection testing will be performed in accordance with IEC 60529: Degrees of Protection Provided by Enclosures (IP Code). The R7 reader will be tested at the claimed IP rating (anticipated IP67 or equivalent) to verify resistance to water ingress during daily activities such as hand washing, perspiration, and incidental water exposure.