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510(k) SUMMARY

Draft — Prepared per 21 C.F.R. § 807.92

Solstice Lumina™ Continuous Glucose Monitoring System (Lumina C14 Sensor and Lumina R7 Reader/Transmitter)

Draft Date: April 2026 Target 510(k) Submission Date: April 30, 2026

Prepared by:

Calderwood & Harkness LLP 1401 K Street NW, Suite 900 Washington, D.C. 20005

On behalf of Solstice Biomedical Inc.

DRAFT — PRIVILEGED & CONFIDENTIAL — ATTORNEY WORK PRODUCT. This draft 510(k) Summary has been prepared by Calderwood & Harkness LLP for review by Solstice Biomedical Inc. prior to finalization and filing with the U.S. Food and Drug Administration. This document is protected by the attorney-client privilege and the work product doctrine. The final version of this 510(k) Summary will become publicly available upon 510(k) clearance per 21 C.F.R. § 807.92. Distribution of this draft is restricted to authorized personnel of Solstice Biomedical Inc. and its designated agents.

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1. Submitter Information

Name of Submitter: Solstice Biomedical Inc.

Entity Type: Corporation organized under the laws of the State of Delaware (File No. 7834291)

Address:

220 Westbrook Drive, Suite 400 Cambridge, MA 02142 United States

Contact Person: Marcus Hale, Vice President of U.S. Operations

Telephone: (617) 555-0142

Email: mhale@solsticebiomedical.com

Regulatory Contact: Dr. Niamh Tierney, Vice President of Regulatory Affairs, Solstice Biomedical Devices Ltd. (parent company)

Parent Company:

Solstice Biomedical Devices Ltd. A private limited company incorporated under the laws of the Republic of Ireland Companies Registration Office (CRO) No. 648231 Unit 14, Liffey Innovation Park Chapelizod, Dublin D20 FX72 Ireland

Solstice Biomedical Inc. is a wholly owned U.S. subsidiary of Solstice Biomedical Devices Ltd. and serves as the corporate entity responsible for the importation, distribution, and regulatory affairs management of Solstice Biomedical products within the United States. Solstice Biomedical Devices Ltd. is a privately held medical device company specializing in the design, development, manufacture, and commercialization of continuous glucose monitoring technologies and related diabetes management solutions.

U.S. Agent for FDA Purposes: Solstice Biomedical Inc. (same as submitter), 220 Westbrook Drive, Suite 400, Cambridge, MA 02142. Solstice Biomedical Inc. serves as the designated U.S. agent for the purposes of communications with the Food and Drug Administration in accordance with 21 C.F.R. § 807.40(a).

Date of 510(k) Summary Preparation: [To be finalized upon submission — target April 30, 2026]

2. Device Identification

2.1 Device Name and Trade Name

Trade/Proprietary Name: Solstice Lumina™ Continuous Glucose Monitoring System ("Solstice Lumina™ CGM System" or "Lumina CGM System")

Common/Usual Name: Continuous Glucose Monitoring System

The Solstice Lumina™ CGM System is composed of the following integrated device components, which together constitute the subject of this 510(k) submission:

(a) Lumina C14 Sensor — A subcutaneously implantable continuous glucose monitoring sensor designed for up to 14 days (336 hours) of continuous wear. The Lumina C14 is a single-use, disposable sensor that is self-inserted by the user using an integrated applicator. The sensor measures glucose concentration in interstitial fluid via enzymatic oxidation and amperometric detection and transmits data wirelessly to the Lumina R7 reader/transmitter.

(b) Lumina R7 Reader/Transmitter — A wearable reader/transmitter device designed to be worn on the upper arm. The Lumina R7 receives glucose measurement data from the Lumina C14 sensor via Bluetooth Low Energy (BLE) 5.2 wireless communication and displays real-time glucose values, trend arrows, and 8-hour trend graphs to the user. The R7 includes configurable hypoglycemia and hyperglycemia alert functionality.

(c) Solstice Lumina™ Mobile Application — A companion software application available for iOS and Android mobile platforms. The mobile application receives data from the Lumina R7 reader/transmitter via BLE and provides supplemental display, data management, and data sharing functionality.

This 510(k) submission covers the Lumina C14 sensor and Lumina R7 reader/transmitter as a single integrated system. The submission is being made as a traditional 510(k) premarket notification covering both the C14 sensor and R7 reader/transmitter as constituent components of the Solstice Lumina™ CGM System. The Solstice Lumina™ Mobile Application is included as a companion software accessory to the cleared device system and is described within this submission for completeness; the mobile application does not independently alter or extend the intended use of the sensor/reader system.

2.2 Classification Information

Product Code: QKQ (Electrode, Glucose, Subcutaneous)

Regulation Number: 21 C.F.R. § 862.1355 (Glucose test system)

Device Class: Class II (with special controls)

Review Panel: Chemistry and Toxicology Devices

Reviewing Division: Center for Devices and Radiological Health (CDRH), Office of Health Technology 2 (OHT2) — Division of Chemistry and Toxicology Devices

The classification of continuous glucose monitoring systems under product code QKQ and regulation number 21 C.F.R. § 862.1355 reflects the current FDA regulatory framework for integrated continuous glucose monitoring (iCGM) systems and traditional CGM systems intended for adjunctive use. Reference is made to the FDA reclassification order effective March 2024, which updated the classification criteria for glucose test systems under 21 C.F.R. § 862.1355 and established revised special controls applicable to continuous glucose monitoring devices within this classification. The Solstice Lumina™ CGM System is designed to meet the performance criteria and special controls established under this reclassification framework, and the performance data summarized herein are presented in accordance with the expectations set forth in FDA guidance documents applicable to CGM and iCGM devices.

2.3 Establishment Registration

Solstice Biomedical Inc. maintains an active establishment registration with the FDA in accordance with 21 C.F.R. Part 807, Subpart B. The establishment registration number and device listing for the Solstice Lumina™ CGM System will be completed and submitted upon clearance of this 510(k) premarket notification, in accordance with the registration and listing requirements of 21 C.F.R. §§ 807.20–807.39. Solstice Biomedical Inc. will ensure that the establishment registration and device listing are current prior to the introduction of the Solstice Lumina™ CGM System into interstate commerce.

3. Intended Use / Indications for Use

The Solstice Lumina™ Continuous Glucose Monitoring System is a prescription-use continuous glucose monitoring device intended for the following use and indications:

Intended Use:

The Solstice Lumina™ CGM System is intended for the continuous, real-time monitoring of glucose levels in persons aged 18 years and older who have been diagnosed with Type 1 diabetes mellitus (T1D) or Type 2 diabetes mellitus (T2D). The system is intended for use by patients and healthcare professionals as an adjunctive tool for diabetes management.

Indications for Use:

The Solstice Lumina™ CGM System continuously measures glucose levels in the interstitial fluid (ISF) via a subcutaneously implanted electrochemical biosensor (the Lumina C14 sensor) for up to 14 days (336 hours) of continuous wear per sensor. The Lumina R7 wearable reader/transmitter receives sensor data wirelessly and displays the following information to the user in real time:

• Real-time glucose concentration values (displayed in mg/dL)

• Directional trend arrows indicating the rate and direction of glucose change

• 8-hour glucose trend graphs

• Configurable hypoglycemia alerts (user-settable low glucose threshold)

• Configurable hyperglycemia alerts (user-settable high glucose threshold)

Performance Specifications:

• Measurement Range: 40–400 mg/dL

• Warm-Up Time: ≤ 60 minutes following sensor insertion before the first glucose reading is available

• Alert Latency: ≤ 5 minutes from the time of sensor glucose reading to delivery of user notification

• Sensor Wear Duration: Up to 14 days (336 hours) of continuous monitoring per sensor

Prescription Use Only (Rx Only):

The Solstice Lumina™ CGM System is restricted to sale and use by or on the order of a licensed healthcare practitioner. Federal law restricts this device to sale by or on the order of a physician or other licensed practitioner.

Adjunctive Use Statement:

The Solstice Lumina™ CGM System is intended as an adjunctive tool for diabetes management. The system is not intended to replace self-monitoring blood glucose (SMBG) testing. Patients should use the information provided by the Solstice Lumina™ CGM System in conjunction with fingerstick blood glucose measurements obtained from an FDA-cleared blood glucose meter before making treatment decisions, including insulin dosing decisions.

Note for internal review: The adjunctive-use language set forth above is subject to refinement based on the outcome of the iCGM classification pathway analysis and feedback received from the FDA Pre-Submission (Pre-Sub) meeting, if pursued. If the Solstice Lumina™ CGM System meets the iCGM performance criteria established by the FDA, the intended use statement may be revised to support non-adjunctive (replacement) use claims, which would eliminate the requirement for confirmatory fingerstick testing prior to treatment decisions. This determination will be made in consultation with the regulatory team and outside counsel prior to finalization of this 510(k) submission.

4. Device Description

4.1 Lumina C14 Sensor

The Lumina C14 is a subcutaneously implantable continuous glucose monitoring sensor designed for up to 14 days (336 hours) of uninterrupted glucose monitoring in the interstitial fluid. The C14 sensor represents Solstice Biomedical's fourth-generation enzymatic electrochemical biosensor technology and incorporates the company's proprietary platinum-iridium electrode coating, designated "PtIr-4G" technology.

Sensing Mechanism: The Lumina C14 sensor operates via an enzymatic electrochemical detection principle. Glucose oxidase (GOx) immobilized within the sensor's enzymatic membrane layer catalyzes the oxidation of glucose present in the interstitial fluid. The resulting hydrogen peroxide (H₂O₂) is oxidized at the working electrode surface, generating an electrical current that is proportional to the glucose concentration in the interstitial fluid. The current signal is measured amperometrically and is processed by the sensor's onboard firmware (Lumina Firmware v3.4.2) for conversion to a glucose concentration value.

PtIr-4G Electrode Technology: The Lumina C14 sensor employs a proprietary platinum-iridium (Pt-Ir) alloy electrode with a fourth-generation surface coating (PtIr-4G). This coating is designed to enhance the electrochemical sensitivity and selectivity of the sensor, reduce interference from common electroactive substances in the interstitial fluid (e.g., acetaminophen, ascorbic acid, uric acid), and improve sensor stability and accuracy over the 14-day wear period. The PtIr-4G coating has been fully evaluated for biocompatibility in accordance with the ISO 10993 series of standards, as described in Section 7 of this summary.

Membrane System: The Lumina C14 sensor incorporates a multi-layer membrane system consisting of: (i) an outer biocompatible polymer membrane that controls glucose flux to the enzyme layer and limits biofouling; (ii) an enzymatic membrane containing immobilized glucose oxidase; and (iii) an inner interference-rejection membrane designed to minimize the contribution of electroactive interferents to the measured signal.

Wireless Communication: The Lumina C14 sensor transmits glucose measurement data wirelessly to the Lumina R7 reader/transmitter via Bluetooth Low Energy (BLE) 5.2 protocol. The sensor firmware manages the BLE communication stack, data sampling intervals, and power management functions.

Physical Configuration: The Lumina C14 sensor is a single-use, disposable device. It is supplied sterile (sterilized by ethylene oxide) in individual sealed packaging with an integrated applicator designed for user self-insertion. The applicator facilitates subcutaneous placement of the sensor filament into the interstitial fluid, typically in the back of the upper arm. The applicator is designed for single use and is discarded after sensor insertion.

Software: The Lumina C14 sensor operates under Lumina Firmware v3.4.2, which manages sensor initialization, calibration algorithms, glucose signal processing, BLE data transmission, and error detection and handling.

4.2 Lumina R7 Reader/Transmitter

The Lumina R7 is a wearable reader/transmitter device designed to be worn on the upper arm in proximity to the implanted Lumina C14 sensor. The R7 serves as the primary user interface for the Solstice Lumina™ CGM System, providing real-time display of glucose information and delivering configurable alerts to the user.

Data Reception and Display: The Lumina R7 receives glucose measurement data from the Lumina C14 sensor via BLE 5.2 wireless communication. Upon receipt, the R7 processes the incoming sensor data through the proprietary LuminaPredict glucose prediction algorithm (v2.1) and displays the following information to the user on the integrated display:

• Current real-time glucose concentration value (mg/dL)

• Directional trend arrows indicating the rate and direction of glucose change (e.g., rapidly rising, slowly rising, stable, slowly falling, rapidly falling)

• 8-hour glucose trend graph showing the trajectory of glucose readings over the preceding 8 hours

• Alert indicators for user-configured hypoglycemia and hyperglycemia thresholds

• System status information (sensor connection status, battery level, sensor remaining life)

Alerts and Notifications: The Lumina R7 provides configurable audible, visual, and haptic (vibration) alerts for hypoglycemia and hyperglycemia events. Users may set individualized low and high glucose thresholds through the device interface. The alert latency from the time of sensor glucose reading to the delivery of the user notification is ≤ 5 minutes.

Mobile Application Communication: The Lumina R7 communicates with the Solstice Lumina™ Mobile Application (available for iOS and Android platforms) via BLE. The mobile application (Lumina Mobile App v1.0.3) provides supplemental display functionality, data logging, historical trend analysis, and data sharing capabilities (e.g., sharing glucose data with healthcare providers or designated caregivers). The mobile application does not independently control or alter the sensor's operation or glucose measurement.

Software: The Lumina R7 operates under Lumina Reader OS v2.1.0, which manages the device's user interface, BLE communication stack, display rendering, alert management, and data relay to the mobile application. The LuminaPredict Algorithm v2.1, embedded within the Reader OS, is a proprietary glucose prediction algorithm that processes incoming sensor data to generate glucose trend information, predictive glucose alerts, and rate-of-change calculations.

Physical Configuration: The Lumina R7 is housed in a medical-grade polymer enclosure designed for skin contact on the upper arm. It is secured to the skin using a medical-grade adhesive patch. The device is powered by a rechargeable lithium-polymer battery and is designed for repeated use across multiple sensor wear periods. The R7 contains an integrated BLE 5.2 antenna for communication with the C14 sensor and the mobile application.

Companion Mobile Application: The Solstice Lumina™ Mobile Application (Lumina Mobile App v1.0.3) is a companion software application available for iOS (version 16.0 or later) and Android (version 13.0 or later) mobile platforms. The application receives glucose data relayed by the Lumina R7 and provides supplemental display, data management, retrospective analysis, and data sharing features. The mobile application is designed to complement, but not replace, the display and alert functionality of the Lumina R7 reader/transmitter.

4.3 System Architecture

The Solstice Lumina™ CGM System operates as an integrated system with the following end-to-end workflow:

Step 1 — Sensor Insertion: The user removes the Lumina C14 sensor from its sterile packaging and uses the integrated applicator to self-insert the sensor subcutaneously, typically on the back of the upper arm. The applicator is discarded after single use.

Step 2 — Sensor Warm-Up: Following insertion, the Lumina C14 sensor undergoes an initialization and warm-up period of ≤ 60 minutes, during which the sensor stabilizes and begins to measure glucose concentrations in the interstitial fluid.

Step 3 — Glucose Sensing: The Lumina C14 sensor continuously measures glucose concentration in the interstitial fluid via enzymatic oxidation of glucose and amperometric detection of the resulting signal. The sensor firmware (Lumina Firmware v3.4.2) processes the raw electrochemical signal, applies calibration algorithms, and prepares glucose data packets for wireless transmission.

Step 4 — Wireless Data Transmission: Glucose data are transmitted wirelessly from the Lumina C14 sensor to the Lumina R7 reader/transmitter via BLE 5.2. Data packets include current glucose concentration values, signal quality indicators, and sensor status information. Data are transmitted at regular intervals (nominally every 1 minute).

Step 5 — Data Processing and Display: The Lumina R7 reader/transmitter receives the glucose data, processes it through the LuminaPredict Algorithm v2.1, and displays real-time glucose values, trend arrows, 8-hour trend graphs, and alerts on the integrated display. Alerts are delivered via audible, visual, and haptic modalities when user-configured glucose thresholds are crossed.

Step 6 — Data Relay to Mobile Application (Optional): The Lumina R7 optionally relays glucose data to the Solstice Lumina™ Mobile Application via BLE for supplemental display, data logging, retrospective analysis, and data sharing with healthcare providers or designated caregivers.

Software Components and Interactions: The Solstice Lumina™ CGM System incorporates the following software components, each of which has been verified and validated in accordance with IEC 62304:2006/A1:2015:

• Lumina Firmware v3.4.2 — Embedded software within the Lumina C14 sensor; manages sensor initialization, calibration, signal processing, BLE communication, and error handling.

• Lumina Reader OS v2.1.0 — Operating software within the Lumina R7 reader/transmitter; manages the user interface, display rendering, BLE communication (both sensor-to-reader and reader-to-mobile application), alert management, and data relay.

• LuminaPredict Algorithm v2.1 — Proprietary glucose prediction algorithm embedded within the Lumina Reader OS; processes incoming sensor data to generate glucose trend information, predictive alerts, and rate-of-change calculations.

• Lumina Mobile App v1.0.3 — Companion mobile application for iOS and Android; receives relayed glucose data from the R7 reader and provides supplemental display, data logging, and data sharing functionality.

4.4 Materials. The materials used in the construction of the Lumina C14 sensor and Lumina R7 reader/transmitter are as follows:

Lumina C14 Sensor:

• Electrode: Platinum-iridium alloy with proprietary PtIr-4G surface coating

• Sensor Housing: Biocompatible polymer (medical-grade polycarbonate)

• Enzymatic Membrane Layers: Proprietary multi-layer membrane system including glucose oxidase enzyme layer, interference-rejection membrane, and outer biocompatible flux-limiting membrane

• Adhesive Pad: Medical-grade acrylic-based skin adhesive (ISO 10993-evaluated)

• Applicator Components: Medical-grade stainless steel introducer needle and polymer applicator body (single-use, not implanted)

Lumina R7 Reader/Transmitter:

• Device Housing: Medical-grade polymer (polyether ether ketone (PEEK) blend)

• Battery: Rechargeable lithium-polymer battery (sealed, non-user-replaceable)

• Antenna: Integrated BLE 5.2 antenna (copper/polymer composite)

• Adhesive Patch: Medical-grade silicone-based skin adhesive (ISO 10993-evaluated)

• Display: Low-power OLED display with protective cover lens

All patient-contacting materials used in the Lumina C14 sensor and Lumina R7 reader/transmitter have been evaluated for biocompatibility in accordance with ISO 10993-1:2018, as described in Section 7 of this summary. The biocompatibility evaluation encompasses all materials that come into direct or indirect contact with the patient during intended use, including the subcutaneously implanted sensor components, the sensor adhesive pad, the R7 device housing, and the R7 adhesive patch.

5. Predicate Device Identification and Comparison

5.1 Predicate Devices

Primary Predicate Device:

The NovaSense GlucoTrack NX-500 CGM System was selected as the primary predicate device because it shares the same intended use (continuous glucose monitoring for persons aged 18 and older with T1D or T2D), the same fundamental technology (enzymatic electrochemical biosensor for glucose measurement in interstitial fluid), the same product code (QKQ), the same device class (Class II), and the same regulation number (21 C.F.R. § 862.1355) as the Solstice Lumina™ CGM System. The NX-500 was cleared by the FDA through the 510(k) premarket notification pathway on June 18, 2022, and is currently legally marketed in the United States.

Secondary Predicate (Reference Device):

The NovaSense GlucoTrack NX-700 CGM System is cited as a secondary predicate (reference device) to support the substantial equivalence determination for specific technological features of the Solstice Lumina™ CGM System. In particular, the NX-700 was cleared for 14-day (336-hour) sensor wear duration, which is consistent with the sensor wear duration of the Lumina C14 sensor and represents an extension beyond the 10-day wear duration of the primary predicate NX-500. The NX-700 was cleared by the FDA on March 7, 2024, and is currently legally marketed in the United States.

Additional Reference Device (Corporate Pedigree Only — Not Cited for Substantial Equivalence):

The Solstice GlucoStrip RX-200 Test Strip Reader is referenced solely to demonstrate Solstice Biomedical Inc.'s prior FDA regulatory history and experience with the 510(k) premarket notification process for glucose monitoring devices. The RX-200 is a blood glucose test strip reader (product code NBW) and is a fundamentally different device type from the Solstice Lumina™ CGM System (product code QKQ). Accordingly, the RX-200 is not cited as a predicate device for substantial equivalence purposes and is not relied upon in the technological comparison or performance data analysis presented in this submission.

5.2 Technological Characteristics Comparison Table

The following table provides a side-by-side comparison of the key technological characteristics of the Solstice Lumina™ CGM System (subject device), the NovaSense GlucoTrack NX-500 CGM System (K211034, primary predicate), and the NovaSense GlucoTrack NX-700 CGM System (K230489, secondary predicate):

5.3 Discussion of Differences from Primary Predicate

As shown in the technological characteristics comparison table above, the Solstice Lumina™ CGM System shares the same intended use, fundamental technology (enzymatic electrochemical biosensor), product code, device class, and regulation number as the primary predicate device (NovaSense GlucoTrack NX-500, K211034). However, there are five identified differences in technological characteristics between the subject device and the primary predicate. Each of these differences is discussed below, along with an explanation of why the difference does not raise new questions of safety or effectiveness.

1. Sensor Wear Duration (14 Days vs. 10 Days)

The Lumina C14 sensor is designed for a maximum continuous wear duration of 14 days (336 hours), compared to the 10-day (240-hour) wear duration of the NX-500 sensor. This extended wear period is intended to provide patients with a longer monitoring interval per sensor, thereby reducing the frequency of sensor replacements and associated insertion procedures.

The 14-day wear duration of the Lumina C14 sensor is consistent with the secondary predicate device, the NovaSense GlucoTrack NX-700 (K230489), which was cleared by the FDA on March 7, 2024, for 14-day sensor wear. The 14-day wear duration is therefore an established and FDA-cleared sensor wear period within the same product classification.

Solstice Biomedical has conducted extensive bench testing and a prospective multicenter clinical study (LUMINA-US, Protocol SBD-LUM-CL-001) to verify and validate the performance, accuracy, and safety of the Lumina C14 sensor throughout the full 14-day wear period. The performance data, summarized in Sections 6 and 8 of this document, demonstrate that the Lumina C14 sensor maintains acceptable accuracy (as measured by MARD and consensus error grid analysis) and safety (as assessed by adverse event monitoring and sensor insertion site reaction evaluation) throughout the entire 14-day wear duration, including during the final days of sensor life when sensor degradation is most likely to occur.

2. Electrode Material (Platinum-Iridium PtIr-4G vs. Platinum)

The Lumina C14 sensor employs a proprietary platinum-iridium alloy electrode with a fourth-generation surface coating (PtIr-4G technology), whereas the NX-500 predicate device uses a platinum electrode. The platinum-iridium alloy and the PtIr-4G surface coating are designed to enhance electrochemical sensitivity, improve selectivity against common interferents, and extend electrode stability over the 14-day wear period.

Importantly, the use of a platinum-iridium electrode does not alter the fundamental electrochemical sensing mechanism of the device. Both the subject device and the predicate employ enzymatic electrochemical (amperometric) detection of glucose via glucose oxidase-catalyzed oxidation. The electrode material serves as the working electrode substrate at which hydrogen peroxide is oxidized, and the substitution of a platinum-iridium alloy for platinum in this role does not change the underlying principle of operation.

The PtIr-4G electrode material has been comprehensively evaluated for biocompatibility in accordance with the ISO 10993 series of standards, as described in Section 7. The biocompatibility evaluation includes cytotoxicity, sensitization, irritation, acute and subchronic systemic toxicity, implantation, hemocompatibility, and genotoxicity testing, all of which yielded results consistent with acceptable biocompatibility for a subcutaneously implanted device with up to 30 days of tissue contact.

3. BLE Version (5.2 vs. 5.0)

The Solstice Lumina™ CGM System uses Bluetooth Low Energy (BLE) 5.2 for wireless data communication between the Lumina C14 sensor and the Lumina R7 reader/transmitter, as well as between the Lumina R7 and the companion mobile application. The primary and secondary predicate devices both employ BLE 5.0 for wireless communication.

BLE 5.2 is an updated version of the BLE 5.0 specification published by the Bluetooth Special Interest Group (SIG). BLE 5.2 is fully backward-compatible with BLE 5.0 and prior BLE versions. The primary enhancements in BLE 5.2 include improved data throughput, enhanced power efficiency, and support for isochronous channels. These enhancements do not alter the fundamental wireless communication architecture of the system or introduce new electromagnetic compatibility concerns.

Electromagnetic compatibility (EMC) testing of the Solstice Lumina™ CGM System has been performed in accordance with the applicable FDA-recognized consensus standards (IEC 60601 series), as described in Section 6.2. The EMC testing confirms that the BLE 5.2 implementation in the Lumina CGM System complies with all applicable emissions and immunity requirements and does not introduce electromagnetic interference risks that differ from those associated with the BLE 5.0 implementations in the predicate devices.

4. Reader Form Factor (Arm-Worn vs. Handheld)

The Lumina R7 reader/transmitter is designed as an arm-worn integrated reader/transmitter device that is adhered to the patient's upper arm, in contrast to the handheld receiver form factor used in both the NX-500 and NX-700 predicate devices. The arm-worn form factor is intended to provide the user with continuous, hands-free access to glucose readings and alerts without requiring the user to carry a separate handheld device.

Despite the difference in form factor, the Lumina R7 displays the same type of glucose-related information as the predicate devices — namely, real-time glucose values, trend arrows, trend graphs, and configurable hypoglycemia and hyperglycemia alerts. The change in form factor does not alter the device's intended use, fundamental function, or the nature of the clinical information provided to the user.

Because the Lumina R7 is designed for prolonged skin contact on the upper arm, the skin-contacting surfaces of the R7 device housing and adhesive patch have been evaluated for biocompatibility in accordance with ISO 10993-1:2018 for external devices with prolonged skin contact. The biocompatibility evaluation, described in Section 7.3, includes cytotoxicity, sensitization, and irritation testing. All biocompatibility endpoints were met with no adverse findings.

5. Algorithm (LuminaPredict v2.1 vs. NovaSense Proprietary Algorithm)

The Solstice Lumina™ CGM System uses Solstice Biomedical's proprietary glucose prediction algorithm, designated LuminaPredict v2.1, for processing sensor glucose data and generating trend information, predictive glucose alerts, and rate-of-change calculations. The NX-500 and NX-700 predicate devices use NovaSense Medical Technologies' proprietary algorithms for comparable functions.

As with any CGM system, the glucose prediction algorithm is a critical component of the device's software architecture and directly affects the accuracy and clinical utility of the glucose information presented to the user. Accordingly, the LuminaPredict v2.1 algorithm has been subjected to comprehensive software verification and validation in accordance with IEC 62304:2006/A1:2015, as described in Section 6.3. Algorithm performance has been validated against reference laboratory glucose measurements (YSI glucose analyzer) using clinical data from the LUMINA-US study.

The software level of concern for the LuminaPredict v2.1 algorithm and the overall Solstice Lumina™ CGM System software is classified as Major in accordance with FDA guidance, "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices" (as updated). This classification reflects the potential for patient harm in the event of software malfunction, given that the device provides glucose values and alerts that may influence diabetes management decisions.

The software verification and validation documentation, including requirements traceability, design verification, design validation, risk analysis, and algorithm performance testing results, is included in the full 510(k) submission (see Appendix E).

Conclusion Regarding Technological Differences:

None of the five identified differences between the Solstice Lumina™ CGM System and the primary predicate device (NovaSense GlucoTrack NX-500, K211034) raise new questions of safety or effectiveness that are not addressed by the comprehensive performance testing and clinical data provided in this submission. Each difference has been evaluated through appropriate bench testing, biocompatibility testing, software verification and validation, and/or clinical study data, as described in Sections 6, 7, and 8 of this summary. The performance data demonstrate that the subject device is as safe and effective as the predicate device for the same intended use.

6. Summary of Performance Data — Bench Testing

6.1 Sensor Accuracy / Analytical Performance

Analytical performance testing of the Lumina C14 sensor was conducted to evaluate sensor accuracy, linearity, precision, interference rejection, and functional life over the full 14-day (336-hour) wear period. Testing was performed using both in vitro (bench-top) test protocols and clinical (in vivo) paired data from the LUMINA-US clinical study (see Section 8).

Mean Absolute Relative Difference (MARD):

The primary analytical performance metric for the Lumina C14 sensor is the Mean Absolute Relative Difference (MARD), calculated as the mean of the absolute values of the relative differences between the sensor glucose readings and paired reference laboratory glucose values (YSI 2900D glucose analyzer). The overall MARD target for the Solstice Lumina™ CGM System is ≤ 9.0%, which is consistent with the performance expectations established by the FDA for integrated continuous glucose monitoring (iCGM) systems, as set forth in FDA guidance, "Integrated Continuous Glucose Monitoring Systems — Premarket Safety and Effectiveness Recommendations" (September 2023).

Consensus Error Grid Analysis:

Sensor accuracy was also evaluated using the Clarke Error Grid Analysis (Consensus Error Grid). The performance target is that ≥ 99% of all paired sensor-reference data points fall within Zones A and B of the Clarke Error Grid. Zone A represents clinically accurate glucose readings within ±20% of the reference value (or within ±20 mg/dL for reference glucose values < 80 mg/dL), and Zone B represents readings that would not lead to inappropriate treatment. Data points falling in Zones C, D, or E represent clinically significant errors with potential for adverse patient outcomes.

Measurement Range:

The functional measurement range of the Lumina C14 sensor was verified across the full specified range of 40–400 mg/dL. Glucose concentrations below 40 mg/dL are reported as "LOW" and glucose concentrations above 400 mg/dL are reported as "HIGH" on the Lumina R7 display.

Linearity:

Linearity testing was performed to verify that the Lumina C14 sensor response is linear across the measurement range of 40–400 mg/dL. A minimum of five glucose concentration levels spanning the measurement range were evaluated, and the sensor response was assessed for compliance with linearity acceptance criteria (coefficient of determination R² ≥ 0.99).

Precision:

Precision (repeatability) testing was performed to evaluate the consistency of sensor readings at multiple glucose concentration levels. Within-sensor and between-sensor precision were assessed in accordance with applicable test protocols.

Interference Testing:

Interference testing was performed to evaluate the effect of common endogenous and exogenous substances on the accuracy of the Lumina C14 sensor. The following substances were tested at their maximum expected physiological or therapeutic concentrations:

• Acetaminophen

• Ascorbic acid (Vitamin C)

• Uric acid

• Salicylic acid (aspirin metabolite)

• Dopamine

• Maltose

• Galactose

• Xylose

• Hydroxyurea

• Icodextrin

Interference testing results are included in the full analytical performance testing report provided in the 510(k) submission.

Sensor Functional Life:

The functional life of the Lumina C14 sensor was verified through continuous operation testing over the full 14-day (336-hour) wear duration. Sensor accuracy, signal stability, and operational reliability were evaluated at regular intervals throughout the wear period, including during the final 48 hours of sensor life, to confirm that the sensor maintains acceptable performance through the end of the specified wear duration.

6.2 Electrical Safety and Electromagnetic Compatibility (EMC)

Electrical safety and electromagnetic compatibility (EMC) testing of the Solstice Lumina™ CGM System (Lumina C14 sensor and Lumina R7 reader/transmitter) was performed by Whitmore Laboratories Inc., an accredited testing laboratory located at 1625 Shady Grove Road, Suite 300, Gaithersburg, MD 20878. Whitmore Laboratories is accredited by the American Association for Laboratory Accreditation (A2LA) under Certificate No. 3847.01 and is recognized by the FDA as a testing laboratory for medical device electrical safety and EMC evaluations.

EMC Testing:

EMC testing was performed in accordance with the applicable FDA-recognized consensus standards, including the IEC 60601-1-2 series (Electromagnetic disturbances — Requirements and tests). The EMC evaluation included the following test categories:

• Radiated emissions

• Conducted emissions

• Electrostatic discharge (ESD) immunity

• Radiated immunity

• Conducted immunity

• Power frequency magnetic field immunity

• Voltage dips, short interruptions, and voltage variations immunity (as applicable)

• Surge immunity (as applicable)

The EMC testing confirmed that the Solstice Lumina™ CGM System, including the BLE 5.2 wireless communication subsystem, complies with all applicable emissions limits and immunity requirements and is suitable for use in the intended electromagnetic environment (home and clinical settings).

Electrical Safety Testing:

Electrical safety testing was performed in accordance with IEC 60601-1 (Medical electrical equipment — Part 1: General requirements for basic safety and essential performance) and applicable collateral and particular standards. The Lumina R7 reader/transmitter, which contains a rechargeable lithium-polymer battery, was evaluated for electrical safety including leakage current, dielectric strength, and thermal safety in accordance with applicable requirements.

Estimated Cost of EMC/Electrical Safety Testing: The total cost of EMC and electrical safety testing performed by Whitmore Laboratories Inc. was approximately $175,000.

6.3 Software Verification and Validation

The software components of the Solstice Lumina™ CGM System were verified and validated in accordance with the FDA-recognized consensus standard IEC 62304:2006/A1:2015 (Medical device software — Software life cycle processes) and applicable FDA guidance documents, including:

• "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices" (FDA, as updated)

• "Guidance for Industry and Food and Drug Administration Staff: Computer Software Assurance for Production and Quality System Software" (FDA, 2022)

• "Cybersecurity in Medical Devices: Quality System Considerations and Content of Premarket Submissions" (FDA, September 2023)

Software Level of Concern:

The overall software level of concern for the Solstice Lumina™ CGM System is classified as Major in accordance with FDA guidance. This classification is based on the determination that a failure or latent design flaw of the software could result in serious injury to the patient (e.g., display of an incorrect glucose value that leads to inappropriate insulin dosing or failure to deliver a critical hypoglycemia alert). The Major software level of concern designation applies to all four software components of the system.

Software Components Verified and Validated:

(a) Lumina Firmware v3.4.2 (Lumina C14 Sensor): Embedded firmware managing sensor initialization, calibration algorithms, glucose signal processing, BLE data transmission, and error detection/handling. Software safety classification: Class C per IEC 62304.

(b) Lumina Reader OS v2.1.0 (Lumina R7 Reader/Transmitter): Operating software managing the user interface, display rendering, BLE communication, alert management, and data relay. Software safety classification: Class C per IEC 62304.

510(k) SUMMARY
Draft — Prepared per 21 C.F.R. § 807.92
Solstice Lumina™ Continuous Glucose Monitoring System (Lumina C14 Sensor and Lumina R7 Reader/Transmitter)
Draft Date: April 2026 Target 510(k) Submission Date: April 30, 2026
Prepared by:
Calderwood & Harkness LLP 1401 K Street NW, Suite 900 Washington, D.C. 20005
On behalf of Solstice Biomedical Inc.
DRAFT — PRIVILEGED & CONFIDENTIAL — ATTORNEY WORK PRODUCT. This draft 510(k) Summary has been prepared by Calderwood & Harkness LLP for review by Solstice Biomedical Inc. prior to finalization and filing with the U.S. Food and Drug Administration. This document is protected by the attorney-client privilege and the work product doctrine. The final version of this 510(k) Summary will become publicly available upon 510(k) clearance per 21 C.F.R. § 807.92. Distribution of this draft is restricted to authorized personnel of Solstice Biomedical Inc. and its designated agents.
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1. Submitter Information
Name of Submitter: Solstice Biomedical Inc.
Entity Type: Corporation organized under the laws of the State of Delaware (File No. 7834291)
Address:
220 Westbrook Drive, Suite 400 Cambridge, MA 02142 United States
Contact Person: Marcus Hale, Vice President of U.S. Operations
Telephone: (617) 555-0142
Email: mhale@solsticebiomedical.com
Regulatory Contact: Dr. Niamh Tierney, Vice President of Regulatory Affairs, Solstice Biomedical Devices Ltd. (parent company)
Parent Company:
Solstice Biomedical Devices Ltd. A private limited company incorporated under the laws of the Republic of Ireland Companies Registration Office (CRO) No. 648231 Unit 14, Liffey Innovation Park Chapelizod, Dublin D20 FX72 Ireland
Solstice Biomedical Inc. is a wholly owned U.S. subsidiary of Solstice Biomedical Devices Ltd. and serves as the corporate entity responsible for the importation, distribution, and regulatory affairs management of Solstice Biomedical products within the United States. Solstice Biomedical Devices Ltd. is a privately held medical device company specializing in the design, development, manufacture, and commercialization of continuous glucose monitoring technologies and related diabetes management solutions.
U.S. Agent for FDA Purposes: Solstice Biomedical Inc. (same as submitter), 220 Westbrook Drive, Suite 400, Cambridge, MA 02142. Solstice Biomedical Inc. serves as the designated U.S. agent for the purposes of communications with the Food and Drug Administration in accordance with 21 C.F.R. § 807.40(a).
Date of 510(k) Summary Preparation: [To be finalized upon submission — target April 30, 2026]
2. Device Identification
2.1 Device Name and Trade Name
Trade/Proprietary Name: Solstice Lumina™ Continuous Glucose Monitoring System ("Solstice Lumina™ CGM System" or "Lumina CGM System")
Common/Usual Name: Continuous Glucose Monitoring System
The Solstice Lumina™ CGM System is composed of the following integrated device components, which together constitute the subject of this 510(k) submission:
(a) Lumina C14 Sensor — A subcutaneously implantable continuous glucose monitoring sensor designed for up to 14 days (336 hours) of continuous wear. The Lumina C14 is a single-use, disposable sensor that is self-inserted by the user using an integrated applicator. The sensor measures glucose concentration in interstitial fluid via enzymatic oxidation and amperometric detection and transmits data wirelessly to the Lumina R7 reader/transmitter.
(b) Lumina R7 Reader/Transmitter — A wearable reader/transmitter device designed to be worn on the upper arm. The Lumina R7 receives glucose measurement data from the Lumina C14 sensor via Bluetooth Low Energy (BLE) 5.2 wireless communication and displays real-time glucose values, trend arrows, and 8-hour trend graphs to the user. The R7 includes configurable hypoglycemia and hyperglycemia alert functionality.
(c) Solstice Lumina™ Mobile Application — A companion software application available for iOS and Android mobile platforms. The mobile application receives data from the Lumina R7 reader/transmitter via BLE and provides supplemental display, data management, and data sharing functionality.
This 510(k) submission covers the Lumina C14 sensor and Lumina R7 reader/transmitter as a single integrated system. The submission is being made as a traditional 510(k) premarket notification covering both the C14 sensor and R7 reader/transmitter as constituent components of the Solstice Lumina™ CGM System. The Solstice Lumina™ Mobile Application is included as a companion software accessory to the cleared device system and is described within this submission for completeness; the mobile application does not independently alter or extend the intended use of the sensor/reader system.
2.2 Classification Information
Product Code: QKQ (Electrode, Glucose, Subcutaneous)
Regulation Number: 21 C.F.R. § 862.1355 (Glucose test system)
Device Class: Class II (with special controls)
Review Panel: Chemistry and Toxicology Devices
Reviewing Division: Center for Devices and Radiological Health (CDRH), Office of Health Technology 2 (OHT2) — Division of Chemistry and Toxicology Devices
The classification of continuous glucose monitoring systems under product code QKQ and regulation number 21 C.F.R. § 862.1355 reflects the current FDA regulatory framework for integrated continuous glucose monitoring (iCGM) systems and traditional CGM systems intended for adjunctive use. Reference is made to the FDA reclassification order effective March 2024, which updated the classification criteria for glucose test systems under 21 C.F.R. § 862.1355 and established revised special controls applicable to continuous glucose monitoring devices within this classification. The Solstice Lumina™ CGM System is designed to meet the performance criteria and special controls established under this reclassification framework, and the performance data summarized herein are presented in accordance with the expectations set forth in FDA guidance documents applicable to CGM and iCGM devices.
2.3 Establishment Registration
Solstice Biomedical Inc. maintains an active establishment registration with the FDA in accordance with 21 C.F.R. Part 807, Subpart B. The establishment registration number and device listing for the Solstice Lumina™ CGM System will be completed and submitted upon clearance of this 510(k) premarket notification, in accordance with the registration and listing requirements of 21 C.F.R. §§ 807.20–807.39. Solstice Biomedical Inc. will ensure that the establishment registration and device listing are current prior to the introduction of the Solstice Lumina™ CGM System into interstate commerce.
3. Intended Use / Indications for Use
The Solstice Lumina™ Continuous Glucose Monitoring System is a prescription-use continuous glucose monitoring device intended for the following use and indications:
Intended Use:
The Solstice Lumina™ CGM System is intended for the continuous, real-time monitoring of glucose levels in persons aged 18 years and older who have been diagnosed with Type 1 diabetes mellitus (T1D) or Type 2 diabetes mellitus (T2D). The system is intended for use by patients and healthcare professionals as an adjunctive tool for diabetes management.
Indications for Use:
The Solstice Lumina™ CGM System continuously measures glucose levels in the interstitial fluid (ISF) via a subcutaneously implanted electrochemical biosensor (the Lumina C14 sensor) for up to 14 days (336 hours) of continuous wear per sensor. The Lumina R7 wearable reader/transmitter receives sensor data wirelessly and displays the following information to the user in real time:
• Real-time glucose concentration values (displayed in mg/dL)
• Directional trend arrows indicating the rate and direction of glucose change
• 8-hour glucose trend graphs
• Configurable hypoglycemia alerts (user-settable low glucose threshold)
• Configurable hyperglycemia alerts (user-settable high glucose threshold)
Performance Specifications:
• Measurement Range: 40–400 mg/dL
• Warm-Up Time: ≤ 60 minutes following sensor insertion before the first glucose reading is available
• Alert Latency: ≤ 5 minutes from the time of sensor glucose reading to delivery of user notification
• Sensor Wear Duration: Up to 14 days (336 hours) of continuous monitoring per sensor
Prescription Use Only (Rx Only):
The Solstice Lumina™ CGM System is restricted to sale and use by or on the order of a licensed healthcare practitioner. Federal law restricts this device to sale by or on the order of a physician or other licensed practitioner.
Adjunctive Use Statement:
The Solstice Lumina™ CGM System is intended as an adjunctive tool for diabetes management. The system is not intended to replace self-monitoring blood glucose (SMBG) testing. Patients should use the information provided by the Solstice Lumina™ CGM System in conjunction with fingerstick blood glucose measurements obtained from an FDA-cleared blood glucose meter before making treatment decisions, including insulin dosing decisions.
Note for internal review: The adjunctive-use language set forth above is subject to refinement based on the outcome of the iCGM classification pathway analysis and feedback received from the FDA Pre-Submission (Pre-Sub) meeting, if pursued. If the Solstice Lumina™ CGM System meets the iCGM performance criteria established by the FDA, the intended use statement may be revised to support non-adjunctive (replacement) use claims, which would eliminate the requirement for confirmatory fingerstick testing prior to treatment decisions. This determination will be made in consultation with the regulatory team and outside counsel prior to finalization of this 510(k) submission.
4. Device Description
4.1 Lumina C14 Sensor
The Lumina C14 is a subcutaneously implantable continuous glucose monitoring sensor designed for up to 14 days (336 hours) of uninterrupted glucose monitoring in the interstitial fluid. The C14 sensor represents Solstice Biomedical's fourth-generation enzymatic electrochemical biosensor technology and incorporates the company's proprietary platinum-iridium electrode coating, designated "PtIr-4G" technology.
Sensing Mechanism: The Lumina C14 sensor operates via an enzymatic electrochemical detection principle. Glucose oxidase (GOx) immobilized within the sensor's enzymatic membrane layer catalyzes the oxidation of glucose present in the interstitial fluid. The resulting hydrogen peroxide (H₂O₂) is oxidized at the working electrode surface, generating an electrical current that is proportional to the glucose concentration in the interstitial fluid. The current signal is measured amperometrically and is processed by the sensor's onboard firmware (Lumina Firmware v3.4.2) for conversion to a glucose concentration value.
PtIr-4G Electrode Technology: The Lumina C14 sensor employs a proprietary platinum-iridium (Pt-Ir) alloy electrode with a fourth-generation surface coating (PtIr-4G). This coating is designed to enhance the electrochemical sensitivity and selectivity of the sensor, reduce interference from common electroactive substances in the interstitial fluid (e.g., acetaminophen, ascorbic acid, uric acid), and improve sensor stability and accuracy over the 14-day wear period. The PtIr-4G coating has been fully evaluated for biocompatibility in accordance with the ISO 10993 series of standards, as described in Section 7 of this summary.
Membrane System: The Lumina C14 sensor incorporates a multi-layer membrane system consisting of: (i) an outer biocompatible polymer membrane that controls glucose flux to the enzyme layer and limits biofouling; (ii) an enzymatic membrane containing immobilized glucose oxidase; and (iii) an inner interference-rejection membrane designed to minimize the contribution of electroactive interferents to the measured signal.
Wireless Communication: The Lumina C14 sensor transmits glucose measurement data wirelessly to the Lumina R7 reader/transmitter via Bluetooth Low Energy (BLE) 5.2 protocol. The sensor firmware manages the BLE communication stack, data sampling intervals, and power management functions.
Physical Configuration: The Lumina C14 sensor is a single-use, disposable device. It is supplied sterile (sterilized by ethylene oxide) in individual sealed packaging with an integrated applicator designed for user self-insertion. The applicator facilitates subcutaneous placement of the sensor filament into the interstitial fluid, typically in the back of the upper arm. The applicator is designed for single use and is discarded after sensor insertion.
Software: The Lumina C14 sensor operates under Lumina Firmware v3.4.2, which manages sensor initialization, calibration algorithms, glucose signal processing, BLE data transmission, and error detection and handling.
4.2 Lumina R7 Reader/Transmitter
The Lumina R7 is a wearable reader/transmitter device designed to be worn on the upper arm in proximity to the implanted Lumina C14 sensor. The R7 serves as the primary user interface for the Solstice Lumina™ CGM System, providing real-time display of glucose information and delivering configurable alerts to the user.
Data Reception and Display: The Lumina R7 receives glucose measurement data from the Lumina C14 sensor via BLE 5.2 wireless communication. Upon receipt, the R7 processes the incoming sensor data through the proprietary LuminaPredict glucose prediction algorithm (v2.1) and displays the following information to the user on the integrated display:
• Current real-time glucose concentration value (mg/dL)
• Directional trend arrows indicating the rate and direction of glucose change (e.g., rapidly rising, slowly rising, stable, slowly falling, rapidly falling)
• 8-hour glucose trend graph showing the trajectory of glucose readings over the preceding 8 hours
• Alert indicators for user-configured hypoglycemia and hyperglycemia thresholds
• System status information (sensor connection status, battery level, sensor remaining life)
Alerts and Notifications: The Lumina R7 provides configurable audible, visual, and haptic (vibration) alerts for hypoglycemia and hyperglycemia events. Users may set individualized low and high glucose thresholds through the device interface. The alert latency from the time of sensor glucose reading to the delivery of the user notification is ≤ 5 minutes.
Mobile Application Communication: The Lumina R7 communicates with the Solstice Lumina™ Mobile Application (available for iOS and Android platforms) via BLE. The mobile application (Lumina Mobile App v1.0.3) provides supplemental display functionality, data logging, historical trend analysis, and data sharing capabilities (e.g., sharing glucose data with healthcare providers or designated caregivers). The mobile application does not independently control or alter the sensor's operation or glucose measurement.
Software: The Lumina R7 operates under Lumina Reader OS v2.1.0, which manages the device's user interface, BLE communication stack, display rendering, alert management, and data relay to the mobile application. The LuminaPredict Algorithm v2.1, embedded within the Reader OS, is a proprietary glucose prediction algorithm that processes incoming sensor data to generate glucose trend information, predictive glucose alerts, and rate-of-change calculations.
Physical Configuration: The Lumina R7 is housed in a medical-grade polymer enclosure designed for skin contact on the upper arm. It is secured to the skin using a medical-grade adhesive patch. The device is powered by a rechargeable lithium-polymer battery and is designed for repeated use across multiple sensor wear periods. The R7 contains an integrated BLE 5.2 antenna for communication with the C14 sensor and the mobile application.
Companion Mobile Application: The Solstice Lumina™ Mobile Application (Lumina Mobile App v1.0.3) is a companion software application available for iOS (version 16.0 or later) and Android (version 13.0 or later) mobile platforms. The application receives glucose data relayed by the Lumina R7 and provides supplemental display, data management, retrospective analysis, and data sharing features. The mobile application is designed to complement, but not replace, the display and alert functionality of the Lumina R7 reader/transmitter.
4.3 System Architecture
The Solstice Lumina™ CGM System operates as an integrated system with the following end-to-end workflow:
Step 1 — Sensor Insertion: The user removes the Lumina C14 sensor from its sterile packaging and uses the integrated applicator to self-insert the sensor subcutaneously, typically on the back of the upper arm. The applicator is discarded after single use.
Step 2 — Sensor Warm-Up: Following insertion, the Lumina C14 sensor undergoes an initialization and warm-up period of ≤ 60 minutes, during which the sensor stabilizes and begins to measure glucose concentrations in the interstitial fluid.
Step 3 — Glucose Sensing: The Lumina C14 sensor continuously measures glucose concentration in the interstitial fluid via enzymatic oxidation of glucose and amperometric detection of the resulting signal. The sensor firmware (Lumina Firmware v3.4.2) processes the raw electrochemical signal, applies calibration algorithms, and prepares glucose data packets for wireless transmission.
Step 4 — Wireless Data Transmission: Glucose data are transmitted wirelessly from the Lumina C14 sensor to the Lumina R7 reader/transmitter via BLE 5.2. Data packets include current glucose concentration values, signal quality indicators, and sensor status information. Data are transmitted at regular intervals (nominally every 1 minute).
Step 5 — Data Processing and Display: The Lumina R7 reader/transmitter receives the glucose data, processes it through the LuminaPredict Algorithm v2.1, and displays real-time glucose values, trend arrows, 8-hour trend graphs, and alerts on the integrated display. Alerts are delivered via audible, visual, and haptic modalities when user-configured glucose thresholds are crossed.
Step 6 — Data Relay to Mobile Application (Optional): The Lumina R7 optionally relays glucose data to the Solstice Lumina™ Mobile Application via BLE for supplemental display, data logging, retrospective analysis, and data sharing with healthcare providers or designated caregivers.
Software Components and Interactions: The Solstice Lumina™ CGM System incorporates the following software components, each of which has been verified and validated in accordance with IEC 62304:2006/A1:2015:
• Lumina Firmware v3.4.2 — Embedded software within the Lumina C14 sensor; manages sensor initialization, calibration, signal processing, BLE communication, and error handling.
• Lumina Reader OS v2.1.0 — Operating software within the Lumina R7 reader/transmitter; manages the user interface, display rendering, BLE communication (both sensor-to-reader and reader-to-mobile application), alert management, and data relay.
• LuminaPredict Algorithm v2.1 — Proprietary glucose prediction algorithm embedded within the Lumina Reader OS; processes incoming sensor data to generate glucose trend information, predictive alerts, and rate-of-change calculations.
• Lumina Mobile App v1.0.3 — Companion mobile application for iOS and Android; receives relayed glucose data from the R7 reader and provides supplemental display, data logging, and data sharing functionality.
4.4 Materials. The materials used in the construction of the Lumina C14 sensor and Lumina R7 reader/transmitter are as follows:
Lumina C14 Sensor:
• Electrode: Platinum-iridium alloy with proprietary PtIr-4G surface coating
• Sensor Housing: Biocompatible polymer (medical-grade polycarbonate)
• Enzymatic Membrane Layers: Proprietary multi-layer membrane system including glucose oxidase enzyme layer, interference-rejection membrane, and outer biocompatible flux-limiting membrane
• Adhesive Pad: Medical-grade acrylic-based skin adhesive (ISO 10993-evaluated)
• Applicator Components: Medical-grade stainless steel introducer needle and polymer applicator body (single-use, not implanted)
Lumina R7 Reader/Transmitter:
• Device Housing: Medical-grade polymer (polyether ether ketone (PEEK) blend)
• Battery: Rechargeable lithium-polymer battery (sealed, non-user-replaceable)
• Antenna: Integrated BLE 5.2 antenna (copper/polymer composite)
• Adhesive Patch: Medical-grade silicone-based skin adhesive (ISO 10993-evaluated)
• Display: Low-power OLED display with protective cover lens
All patient-contacting materials used in the Lumina C14 sensor and Lumina R7 reader/transmitter have been evaluated for biocompatibility in accordance with ISO 10993-1:2018, as described in Section 7 of this summary. The biocompatibility evaluation encompasses all materials that come into direct or indirect contact with the patient during intended use, including the subcutaneously implanted sensor components, the sensor adhesive pad, the R7 device housing, and the R7 adhesive patch.
5. Predicate Device Identification and Comparison
5.1 Predicate Devices
Primary Predicate Device:
The NovaSense GlucoTrack NX-500 CGM System was selected as the primary predicate device because it shares the same intended use (continuous glucose monitoring for persons aged 18 and older with T1D or T2D), the same fundamental technology (enzymatic electrochemical biosensor for glucose measurement in interstitial fluid), the same product code (QKQ), the same device class (Class II), and the same regulation number (21 C.F.R. § 862.1355) as the Solstice Lumina™ CGM System. The NX-500 was cleared by the FDA through the 510(k) premarket notification pathway on June 18, 2022, and is currently legally marketed in the United States.
Secondary Predicate (Reference Device):
The NovaSense GlucoTrack NX-700 CGM System is cited as a secondary predicate (reference device) to support the substantial equivalence determination for specific technological features of the Solstice Lumina™ CGM System. In particular, the NX-700 was cleared for 14-day (336-hour) sensor wear duration, which is consistent with the sensor wear duration of the Lumina C14 sensor and represents an extension beyond the 10-day wear duration of the primary predicate NX-500. The NX-700 was cleared by the FDA on March 7, 2024, and is currently legally marketed in the United States.
Additional Reference Device (Corporate Pedigree Only — Not Cited for Substantial Equivalence):
The Solstice GlucoStrip RX-200 Test Strip Reader is referenced solely to demonstrate Solstice Biomedical Inc.'s prior FDA regulatory history and experience with the 510(k) premarket notification process for glucose monitoring devices. The RX-200 is a blood glucose test strip reader (product code NBW) and is a fundamentally different device type from the Solstice Lumina™ CGM System (product code QKQ). Accordingly, the RX-200 is not cited as a predicate device for substantial equivalence purposes and is not relied upon in the technological comparison or performance data analysis presented in this submission.
5.2 Technological Characteristics Comparison Table
The following table provides a side-by-side comparison of the key technological characteristics of the Solstice Lumina™ CGM System (subject device), the NovaSense GlucoTrack NX-500 CGM System (K211034, primary predicate), and the NovaSense GlucoTrack NX-700 CGM System (K230489, secondary predicate):
5.3 Discussion of Differences from Primary Predicate
As shown in the technological characteristics comparison table above, the Solstice Lumina™ CGM System shares the same intended use, fundamental technology (enzymatic electrochemical biosensor), product code, device class, and regulation number as the primary predicate device (NovaSense GlucoTrack NX-500, K211034). However, there are five identified differences in technological characteristics between the subject device and the primary predicate. Each of these differences is discussed below, along with an explanation of why the difference does not raise new questions of safety or effectiveness.
1. Sensor Wear Duration (14 Days vs. 10 Days)
The Lumina C14 sensor is designed for a maximum continuous wear duration of 14 days (336 hours), compared to the 10-day (240-hour) wear duration of the NX-500 sensor. This extended wear period is intended to provide patients with a longer monitoring interval per sensor, thereby reducing the frequency of sensor replacements and associated insertion procedures.
The 14-day wear duration of the Lumina C14 sensor is consistent with the secondary predicate device, the NovaSense GlucoTrack NX-700 (K230489), which was cleared by the FDA on March 7, 2024, for 14-day sensor wear. The 14-day wear duration is therefore an established and FDA-cleared sensor wear period within the same product classification.
Solstice Biomedical has conducted extensive bench testing and a prospective multicenter clinical study (LUMINA-US, Protocol SBD-LUM-CL-001) to verify and validate the performance, accuracy, and safety of the Lumina C14 sensor throughout the full 14-day wear period. The performance data, summarized in Sections 6 and 8 of this document, demonstrate that the Lumina C14 sensor maintains acceptable accuracy (as measured by MARD and consensus error grid analysis) and safety (as assessed by adverse event monitoring and sensor insertion site reaction evaluation) throughout the entire 14-day wear duration, including during the final days of sensor life when sensor degradation is most likely to occur.
2. Electrode Material (Platinum-Iridium PtIr-4G vs. Platinum)
The Lumina C14 sensor employs a proprietary platinum-iridium alloy electrode with a fourth-generation surface coating (PtIr-4G technology), whereas the NX-500 predicate device uses a platinum electrode. The platinum-iridium alloy and the PtIr-4G surface coating are designed to enhance electrochemical sensitivity, improve selectivity against common interferents, and extend electrode stability over the 14-day wear period.
Importantly, the use of a platinum-iridium electrode does not alter the fundamental electrochemical sensing mechanism of the device. Both the subject device and the predicate employ enzymatic electrochemical (amperometric) detection of glucose via glucose oxidase-catalyzed oxidation. The electrode material serves as the working electrode substrate at which hydrogen peroxide is oxidized, and the substitution of a platinum-iridium alloy for platinum in this role does not change the underlying principle of operation.
The PtIr-4G electrode material has been comprehensively evaluated for biocompatibility in accordance with the ISO 10993 series of standards, as described in Section 7. The biocompatibility evaluation includes cytotoxicity, sensitization, irritation, acute and subchronic systemic toxicity, implantation, hemocompatibility, and genotoxicity testing, all of which yielded results consistent with acceptable biocompatibility for a subcutaneously implanted device with up to 30 days of tissue contact.
3. BLE Version (5.2 vs. 5.0)
The Solstice Lumina™ CGM System uses Bluetooth Low Energy (BLE) 5.2 for wireless data communication between the Lumina C14 sensor and the Lumina R7 reader/transmitter, as well as between the Lumina R7 and the companion mobile application. The primary and secondary predicate devices both employ BLE 5.0 for wireless communication.
BLE 5.2 is an updated version of the BLE 5.0 specification published by the Bluetooth Special Interest Group (SIG). BLE 5.2 is fully backward-compatible with BLE 5.0 and prior BLE versions. The primary enhancements in BLE 5.2 include improved data throughput, enhanced power efficiency, and support for isochronous channels. These enhancements do not alter the fundamental wireless communication architecture of the system or introduce new electromagnetic compatibility concerns.
Electromagnetic compatibility (EMC) testing of the Solstice Lumina™ CGM System has been performed in accordance with the applicable FDA-recognized consensus standards (IEC 60601 series), as described in Section 6.2. The EMC testing confirms that the BLE 5.2 implementation in the Lumina CGM System complies with all applicable emissions and immunity requirements and does not introduce electromagnetic interference risks that differ from those associated with the BLE 5.0 implementations in the predicate devices.
4. Reader Form Factor (Arm-Worn vs. Handheld)
The Lumina R7 reader/transmitter is designed as an arm-worn integrated reader/transmitter device that is adhered to the patient's upper arm, in contrast to the handheld receiver form factor used in both the NX-500 and NX-700 predicate devices. The arm-worn form factor is intended to provide the user with continuous, hands-free access to glucose readings and alerts without requiring the user to carry a separate handheld device.
Despite the difference in form factor, the Lumina R7 displays the same type of glucose-related information as the predicate devices — namely, real-time glucose values, trend arrows, trend graphs, and configurable hypoglycemia and hyperglycemia alerts. The change in form factor does not alter the device's intended use, fundamental function, or the nature of the clinical information provided to the user.
Because the Lumina R7 is designed for prolonged skin contact on the upper arm, the skin-contacting surfaces of the R7 device housing and adhesive patch have been evaluated for biocompatibility in accordance with ISO 10993-1:2018 for external devices with prolonged skin contact. The biocompatibility evaluation, described in Section 7.3, includes cytotoxicity, sensitization, and irritation testing. All biocompatibility endpoints were met with no adverse findings.
5. Algorithm (LuminaPredict v2.1 vs. NovaSense Proprietary Algorithm)
The Solstice Lumina™ CGM System uses Solstice Biomedical's proprietary glucose prediction algorithm, designated LuminaPredict v2.1, for processing sensor glucose data and generating trend information, predictive glucose alerts, and rate-of-change calculations. The NX-500 and NX-700 predicate devices use NovaSense Medical Technologies' proprietary algorithms for comparable functions.
As with any CGM system, the glucose prediction algorithm is a critical component of the device's software architecture and directly affects the accuracy and clinical utility of the glucose information presented to the user. Accordingly, the LuminaPredict v2.1 algorithm has been subjected to comprehensive software verification and validation in accordance with IEC 62304:2006/A1:2015, as described in Section 6.3. Algorithm performance has been validated against reference laboratory glucose measurements (YSI glucose analyzer) using clinical data from the LUMINA-US study.
The software level of concern for the LuminaPredict v2.1 algorithm and the overall Solstice Lumina™ CGM System software is classified as Major in accordance with FDA guidance, "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices" (as updated). This classification reflects the potential for patient harm in the event of software malfunction, given that the device provides glucose values and alerts that may influence diabetes management decisions.
The software verification and validation documentation, including requirements traceability, design verification, design validation, risk analysis, and algorithm performance testing results, is included in the full 510(k) submission (see Appendix E).
Conclusion Regarding Technological Differences:
None of the five identified differences between the Solstice Lumina™ CGM System and the primary predicate device (NovaSense GlucoTrack NX-500, K211034) raise new questions of safety or effectiveness that are not addressed by the comprehensive performance testing and clinical data provided in this submission. Each difference has been evaluated through appropriate bench testing, biocompatibility testing, software verification and validation, and/or clinical study data, as described in Sections 6, 7, and 8 of this summary. The performance data demonstrate that the subject device is as safe and effective as the predicate device for the same intended use.
6. Summary of Performance Data — Bench Testing
6.1 Sensor Accuracy / Analytical Performance
Analytical performance testing of the Lumina C14 sensor was conducted to evaluate sensor accuracy, linearity, precision, interference rejection, and functional life over the full 14-day (336-hour) wear period. Testing was performed using both in vitro (bench-top) test protocols and clinical (in vivo) paired data from the LUMINA-US clinical study (see Section 8).
Mean Absolute Relative Difference (MARD):
The primary analytical performance metric for the Lumina C14 sensor is the Mean Absolute Relative Difference (MARD), calculated as the mean of the absolute values of the relative differences between the sensor glucose readings and paired reference laboratory glucose values (YSI 2900D glucose analyzer). The overall MARD target for the Solstice Lumina™ CGM System is ≤ 9.0%, which is consistent with the performance expectations established by the FDA for integrated continuous glucose monitoring (iCGM) systems, as set forth in FDA guidance, "Integrated Continuous Glucose Monitoring Systems — Premarket Safety and Effectiveness Recommendations" (September 2023).
Consensus Error Grid Analysis:
Sensor accuracy was also evaluated using the Clarke Error Grid Analysis (Consensus Error Grid). The performance target is that ≥ 99% of all paired sensor-reference data points fall within Zones A and B of the Clarke Error Grid. Zone A represents clinically accurate glucose readings within ±20% of the reference value (or within ±20 mg/dL for reference glucose values < 80 mg/dL), and Zone B represents readings that would not lead to inappropriate treatment. Data points falling in Zones C, D, or E represent clinically significant errors with potential for adverse patient outcomes.
Measurement Range:
The functional measurement range of the Lumina C14 sensor was verified across the full specified range of 40–400 mg/dL. Glucose concentrations below 40 mg/dL are reported as "LOW" and glucose concentrations above 400 mg/dL are reported as "HIGH" on the Lumina R7 display.
Linearity:
Linearity testing was performed to verify that the Lumina C14 sensor response is linear across the measurement range of 40–400 mg/dL. A minimum of five glucose concentration levels spanning the measurement range were evaluated, and the sensor response was assessed for compliance with linearity acceptance criteria (coefficient of determination R² ≥ 0.99).
Precision:
Precision (repeatability) testing was performed to evaluate the consistency of sensor readings at multiple glucose concentration levels. Within-sensor and between-sensor precision were assessed in accordance with applicable test protocols.
Interference Testing:
Interference testing was performed to evaluate the effect of common endogenous and exogenous substances on the accuracy of the Lumina C14 sensor. The following substances were tested at their maximum expected physiological or therapeutic concentrations:
• Acetaminophen
• Ascorbic acid (Vitamin C)
• Uric acid
• Salicylic acid (aspirin metabolite)
• Dopamine
• Maltose
• Galactose
• Xylose
• Hydroxyurea
• Icodextrin
Interference testing results are included in the full analytical performance testing report provided in the 510(k) submission.
Sensor Functional Life:
The functional life of the Lumina C14 sensor was verified through continuous operation testing over the full 14-day (336-hour) wear duration. Sensor accuracy, signal stability, and operational reliability were evaluated at regular intervals throughout the wear period, including during the final 48 hours of sensor life, to confirm that the sensor maintains acceptable performance through the end of the specified wear duration.
6.2 Electrical Safety and Electromagnetic Compatibility (EMC)
Electrical safety and electromagnetic compatibility (EMC) testing of the Solstice Lumina™ CGM System (Lumina C14 sensor and Lumina R7 reader/transmitter) was performed by Whitmore Laboratories Inc., an accredited testing laboratory located at 1625 Shady Grove Road, Suite 300, Gaithersburg, MD 20878. Whitmore Laboratories is accredited by the American Association for Laboratory Accreditation (A2LA) under Certificate No. 3847.01 and is recognized by the FDA as a testing laboratory for medical device electrical safety and EMC evaluations.
EMC Testing:
EMC testing was performed in accordance with the applicable FDA-recognized consensus standards, including the IEC 60601-1-2 series (Electromagnetic disturbances — Requirements and tests). The EMC evaluation included the following test categories:
• Radiated emissions
• Conducted emissions
• Electrostatic discharge (ESD) immunity
• Radiated immunity
• Conducted immunity
• Power frequency magnetic field immunity
• Voltage dips, short interruptions, and voltage variations immunity (as applicable)
• Surge immunity (as applicable)
The EMC testing confirmed that the Solstice Lumina™ CGM System, including the BLE 5.2 wireless communication subsystem, complies with all applicable emissions limits and immunity requirements and is suitable for use in the intended electromagnetic environment (home and clinical settings).
Electrical Safety Testing:
Electrical safety testing was performed in accordance with IEC 60601-1 (Medical electrical equipment — Part 1: General requirements for basic safety and essential performance) and applicable collateral and particular standards. The Lumina R7 reader/transmitter, which contains a rechargeable lithium-polymer battery, was evaluated for electrical safety including leakage current, dielectric strength, and thermal safety in accordance with applicable requirements.
Estimated Cost of EMC/Electrical Safety Testing: The total cost of EMC and electrical safety testing performed by Whitmore Laboratories Inc. was approximately $175,000.
6.3 Software Verification and Validation
The software components of the Solstice Lumina™ CGM System were verified and validated in accordance with the FDA-recognized consensus standard IEC 62304:2006/A1:2015 (Medical device software — Software life cycle processes) and applicable FDA guidance documents, including:
• "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices" (FDA, as updated)
• "Guidance for Industry and Food and Drug Administration Staff: Computer Software Assurance for Production and Quality System Software" (FDA, 2022)
• "Cybersecurity in Medical Devices: Quality System Considerations and Content of Premarket Submissions" (FDA, September 2023)
Software Level of Concern:
The overall software level of concern for the Solstice Lumina™ CGM System is classified as Major in accordance with FDA guidance. This classification is based on the determination that a failure or latent design flaw of the software could result in serious injury to the patient (e.g., display of an incorrect glucose value that leads to inappropriate insulin dosing or failure to deliver a critical hypoglycemia alert). The Major software level of concern designation applies to all four software components of the system.
Software Components Verified and Validated:
(a) Lumina Firmware v3.4.2 (Lumina C14 Sensor): Embedded firmware managing sensor initialization, calibration algorithms, glucose signal processing, BLE data transmission, and error detection/handling. Software safety classification: Class C per IEC 62304.
(b) Lumina Reader OS v2.1.0 (Lumina R7 Reader/Transmitter): Operating software managing the user interface, display rendering, BLE communication, alert management, and data relay. Software safety classification: Class C per IEC 62304.
(c) LuminaPredict Algorithm v2.1: Proprietary glucose prediction algorithm embedded within the Lumina Reader OS. Validated against reference laboratory glucose measurements using clinical data from the LUMINA-US study. Algorithm performance metrics include MARD, consensus error grid results, and alert accuracy (sensitivity and specificity for hypoglycemia and hyperglycemia alerts). Software safety classification: Class C per IEC 62304.
(d) Lumina Mobile App v1.0.3: Companion mobile application for iOS and Android platforms. Verified and validated for accurate data display, data integrity during BLE communication, and user interface functionality. Software safety classification: Class B per IEC 62304 (the mobile application is a supplemental display and does not independently control device operation or generate alerts that differ from those generated by the R7 reader).
Cybersecurity Documentation:
In accordance with FDA guidance, "Cybersecurity in Medical Devices: Quality System Considerations and Content of Premarket Submissions" (September 2023), the following cybersecurity documentation has been prepared and is included in the full 510(k) submission:
• Software Bill of Materials (SBOM): A complete SBOM has been prepared for all software components of the Solstice Lumina™ CGM System, identifying all third-party software components, open-source libraries, and commercially licensed software modules incorporated into the device software.
• Threat Modeling: Threat modeling was performed using the STRIDE (Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege) framework to identify and assess potential cybersecurity threats to the device and its communication interfaces.
• Vulnerability Assessment: A comprehensive vulnerability assessment was conducted to identify known vulnerabilities in the device software and third-party components, and to evaluate the risk associated with each identified vulnerability.
• Software Update/Patch Management: A software update and patch management plan has been established to support the timely delivery of security patches and software updates throughout the device's lifecycle.
• Authentication and Encryption Protocols: The BLE 5.2 communication between the Lumina C14 sensor and the Lumina R7 reader/transmitter, and between the R7 reader and the companion mobile application, employs AES-128 encryption and mutual authentication to protect the confidentiality and integrity of glucose data during wireless transmission.
6.4 Wireless/BLE Performance
Wireless performance testing of the BLE 5.2 communication subsystem was performed to validate the reliability, range, data integrity, and coexistence characteristics of the wireless link between the Lumina C14 sensor and the Lumina R7 reader/transmitter.
Range Testing: BLE 5.2 communication range was tested under both line-of-sight and typical body-worn conditions to verify that reliable data transmission is maintained between the Lumina C14 sensor and the Lumina R7 reader/transmitter during normal use (i.e., with both devices positioned on the patient's upper arm in close proximity). Range testing confirmed reliable communication at the intended operating distance.
Data Integrity: Data integrity testing was performed to verify that glucose data transmitted from the Lumina C14 sensor to the Lumina R7 reader/transmitter is received accurately and without corruption. BLE data packet integrity was verified using cyclic redundancy check (CRC) validation and error detection mechanisms built into the BLE 5.2 protocol.
Coexistence Testing: Coexistence testing was performed to evaluate the performance of the BLE 5.2 communication link in the presence of other wireless devices and sources of electromagnetic interference commonly encountered in the intended use environment (home and clinical settings), including Wi-Fi routers, cellular phones, microwave ovens, and other BLE-enabled devices. Coexistence testing confirmed that the Solstice Lumina™ CGM System maintains reliable wireless communication and does not experience clinically significant degradation of performance in the presence of typical environmental electromagnetic interference.
7. Summary of Performance Data — Biocompatibility
7.1 Testing Standard
Biocompatibility evaluation of the Solstice Lumina™ CGM System was conducted in accordance with ISO 10993-1:2018 (Biological evaluation of medical devices — Part 1: Evaluation and review within a risk management process). The biocompatibility evaluation was designed based on the nature, duration, and type of tissue contact associated with each device component, as specified in ISO 10993-1:2018 and the FDA guidance document, "Use of International Standard ISO 10993-1, 'Biological evaluation of medical devices — Part 1: Evaluation and review within a risk management process'" (September 2020).
All biocompatibility testing was performed by Whitmore Laboratories Inc., 1625 Shady Grove Road, Suite 300, Gaithersburg, MD 20878 (A2LA Certificate No. 3847.01). Whitmore Laboratories is an ISO/IEC 17025-accredited testing laboratory with demonstrated competence in the performance of biocompatibility testing for medical devices in accordance with the ISO 10993 series of standards.
7.2 Lumina C14 Sensor (Implant — Subcutaneous, ≤ 30 Days Contact)
The Lumina C14 sensor is classified as an implant device with subcutaneous tissue contact for a duration of up to 14 days (336 hours) per sensor wear period. In accordance with ISO 10993-1:2018, Annex A, Table A.1, the applicable biocompatibility endpoints for an implant device with tissue/bone contact for a duration categorized as "limited to prolonged" (≤ 30 days) were identified and evaluated. All patient-contacting materials, including the platinum-iridium electrode with PtIr-4G coating, the biocompatible polymer housing, the enzymatic membrane layers, and the skin adhesive pad, were included in the biocompatibility evaluation.
The following biocompatibility tests were performed:
(a) Cytotoxicity (ISO 10993-5:2009): In vitro cytotoxicity testing was performed using the L-929 mouse fibroblast cell line to evaluate the potential for the sensor materials to cause cell damage or death upon exposure to material extracts. Testing was performed using both direct contact and extract dilution methodologies.
(b) Sensitization (ISO 10993-10:2021): Sensitization testing was performed using the Guinea Pig Maximization Test (GPMT) to evaluate the potential for the sensor materials to induce delayed-type hypersensitivity (allergic contact sensitization) upon repeated or prolonged exposure.
(c) Irritation (ISO 10993-23:2021): Irritation testing was performed to evaluate the potential for the sensor materials to cause local irritation at the site of subcutaneous implantation. Testing was conducted using the in vitro Reconstructed Human Epidermis (RhE) model in accordance with ISO 10993-23.
(d) Acute Systemic Toxicity (ISO 10993-11:2017): Acute systemic toxicity testing was performed to evaluate the potential for the sensor materials to cause systemic toxic effects following a single exposure. Testing was conducted using both intravenous and intraperitoneal injection routes in a mouse model.
(e) Subchronic Toxicity (ISO 10993-11:2017): Subchronic systemic toxicity testing was performed to evaluate the potential for the sensor materials to cause systemic toxic effects following repeated or prolonged exposure over a period of up to 28 days. Testing was conducted in a rat model.
(f) Implantation (ISO 10993-6:2016): Implantation testing was performed to evaluate the local tissue response to the sensor materials following subcutaneous implantation. The sensor was implanted subcutaneously in a rabbit model for a duration of 14 days (consistent with the maximum intended wear period), and the implantation site was evaluated histopathologically for evidence of local tissue reaction, inflammation, necrosis, or other adverse pathological findings.
(g) Hemocompatibility (ISO 10993-4:2017): Hemocompatibility testing was performed to evaluate the potential for the sensor materials to adversely affect blood or blood components. The evaluation included assessment of hemolysis, thrombosis, and coagulation endpoints.
(h) Genotoxicity (ISO 10993-3:2014): Genotoxicity testing was performed to evaluate the potential for the sensor materials to induce gene mutations, chromosomal aberrations, or other genotoxic effects. Testing included the Ames bacterial reverse mutation assay, the in vitro mammalian cell chromosomal aberration assay, and the in vivo mouse micronucleus assay.
7.3 Lumina R7 Reader (Skin Contact — External, Prolonged)
The Lumina R7 reader/transmitter is classified as an external device with direct skin contact (surface contacting device) for a prolonged duration (> 24 hours to ≤ 30 days). In accordance with ISO 10993-1:2018, Annex A, Table A.1, the applicable biocompatibility endpoints for a surface-contacting device with skin contact for a prolonged duration were identified and evaluated. All skin-contacting materials, including the medical-grade polymer housing and the silicone-based skin adhesive patch, were included in the biocompatibility evaluation.
The following biocompatibility tests were performed:
(a) Cytotoxicity (ISO 10993-5:2009): In vitro cytotoxicity testing was performed using the L-929 mouse fibroblast cell line to evaluate the potential for the R7 reader materials to cause cell damage or death.
(b) Sensitization (ISO 10993-10:2021): Sensitization testing was performed using the Guinea Pig Maximization Test (GPMT) to evaluate the potential for the R7 reader materials to induce delayed-type hypersensitivity.
(c) Irritation (ISO 10993-23:2021): Irritation testing was performed to evaluate the potential for the R7 reader materials to cause local skin irritation at the site of device application. Testing was conducted using the in vitro Reconstructed Human Epidermis (RhE) model.
7.4 Biocompatibility Results Summary
All biocompatibility testing endpoints were met for both the Lumina C14 sensor and the Lumina R7 reader/transmitter. No adverse findings were observed in any of the biocompatibility tests performed.
Specifically, with respect to the Lumina C14 sensor:
• Cytotoxicity testing demonstrated that the sensor materials are non-cytotoxic.
• Sensitization testing demonstrated that the sensor materials do not induce delayed-type hypersensitivity.
• Irritation testing demonstrated that the sensor materials do not cause irritation.
• Acute systemic toxicity testing demonstrated no evidence of systemic toxic effects.
• Subchronic systemic toxicity testing demonstrated no evidence of systemic toxic effects following 28 days of exposure.
• Implantation testing demonstrated a minimal and clinically insignificant local tissue response consistent with the expected foreign body reaction to a subcutaneously implanted medical device, with no evidence of necrosis, excessive inflammation, or other adverse pathological findings.
• Hemocompatibility testing demonstrated no adverse effects on blood or blood components.
• Genotoxicity testing demonstrated no evidence of mutagenicity, clastogenicity, or genotoxicity.
With respect to the Lumina R7 reader/transmitter:
• Cytotoxicity testing demonstrated that the R7 reader materials are non-cytotoxic.
• Sensitization testing demonstrated that the R7 reader materials do not induce delayed-type hypersensitivity.
• Irritation testing demonstrated that the R7 reader materials do not cause skin irritation.
The biocompatibility evaluation specifically included the proprietary PtIr-4G electrode coating used in the Lumina C14 sensor. Extracts of the PtIr-4G electrode material were tested in all applicable biocompatibility assays, and the results confirmed that the PtIr-4G material meets all applicable biocompatibility requirements for a subcutaneously implanted device with up to 30 days of tissue contact.
Complete biocompatibility testing reports from Whitmore Laboratories Inc. are included in Appendix C of the full 510(k) submission.
Total Biocompatibility Testing Cost: The total cost of biocompatibility testing performed by Whitmore Laboratories Inc. for the Solstice Lumina™ CGM System was approximately $485,000.
8. Summary of Performance Data — Clinical
8.1 Clinical Study Overview
A prospective, single-arm, multicenter clinical study was conducted in the United States to evaluate the safety and performance of the Solstice Lumina™ CGM System in the intended use population.
IDE Status: The LUMINA-US clinical study was conducted under the investigational device exemption (IDE) provisions of 21 C.F.R. Part 812. Specifically, the study was determined to qualify for IDE exemption under 21 C.F.R. § 812.2(c)(3) as a non-significant risk (NSR) diagnostic device study. An Institutional Review Board (IRB) — Clearwater Institutional Review Board LLC — reviewed the study protocol, informed consent documents, and risk assessment and concurred with the non-significant risk determination. The study was conducted in accordance with the IRB-approved protocol, and all subjects provided written informed consent prior to enrollment.
The study enrolled 350 adult subjects (aged 18 years and older) with diagnosed Type 1 or Type 2 diabetes mellitus across six geographically diverse clinical sites in the United States. The study population was approximately equally divided between subjects with Type 1 diabetes (n = 175) and subjects with Type 2 diabetes (n = 175) to ensure representation of both primary patient populations within the intended use.
8.2 Primary Endpoints
The primary efficacy and performance endpoints of the LUMINA-US clinical study were:
(a) Sensor Accuracy — Mean Absolute Relative Difference (MARD): The primary accuracy endpoint was the overall MARD of the Lumina C14 sensor, calculated as the mean of the absolute values of the relative differences between paired sensor glucose readings and contemporaneous reference laboratory glucose measurements (YSI 2900D glucose analyzer). The performance target was an overall MARD of ≤ 9.0%, consistent with FDA expectations for iCGM-class devices per FDA guidance, "Integrated Continuous Glucose Monitoring Systems — Premarket Safety and Effectiveness Recommendations" (September 2023).
(b) Sensor Accuracy — Consensus Error Grid Analysis: The secondary accuracy endpoint was the distribution of paired sensor-reference glucose data points on the Clarke Error Grid (Consensus Error Grid Analysis). The performance target was that ≥ 99% of all paired data points fall within Zones A and B of the Clarke Error Grid.
(c) Sensor Wear Duration: Verification that the Lumina C14 sensor maintains acceptable accuracy and functional performance throughout the full 14-day (336-hour) wear period, including analysis of sensor accuracy metrics as a function of sensor wear day (Day 1 through Day 14).
8.3 Secondary Endpoints
The secondary endpoints of the LUMINA-US clinical study were:
(a) Safety: Assessment of the overall safety profile of the Solstice Lumina™ CGM System, including:
• Frequency, severity, and relatedness of adverse events (AEs) and serious adverse events (SAEs)
• Sensor insertion site reactions (erythema, edema, pain, infection, bleeding)
• Device-related complaints and malfunctions
• Premature sensor removal rates and reasons for premature removal
(b) User Labeling Comprehension: A labeling comprehension study was conducted as part of the LUMINA-US clinical study to evaluate the ability of intended users (patients with diabetes and healthcare professionals) to understand and correctly follow the instructions for use (IFU) of the Solstice Lumina™ CGM System. The labeling comprehension study assessed user understanding of sensor insertion procedures, device operation, glucose reading interpretation, alert management, and device removal and disposal.
8.4 Clinical Results Summary
[Clinical data to be inserted upon completion of the LUMINA-US study and final analysis of the clinical database. The following placeholder summary describes the anticipated format and content of the clinical results section.]
Upon completion of the LUMINA-US study and final data analysis, this section will include:
• Study Population Demographics: A summary of the demographic characteristics of the enrolled study population, including age, sex, race/ethnicity, diabetes type (T1D vs. T2D), duration of diabetes, HbA1c at enrollment, and insulin use status.
• MARD Results: The overall MARD and stratified MARD values (by glucose range, sensor wear day, diabetes type, and other relevant subgroups) will be reported. The target overall MARD is ≤ 9.0%.
• Consensus Error Grid Results: The distribution of paired sensor-reference data points on the Clarke Error Grid will be reported, including the percentage of data points in Zone A, Zone B, and Zones C/D/E. The target is ≥ 99% of data points in Zones A+B.
• Sensor Wear Duration Performance: Analysis of sensor accuracy and functional performance as a function of sensor wear day (Day 1 through Day 14) will be presented to demonstrate that the sensor maintains acceptable performance throughout the full 14-day wear period.
• Safety Findings: A summary of adverse events, serious adverse events, sensor insertion site reactions, device-related complaints, and premature sensor removal events will be provided.
• Labeling Comprehension Outcomes: A summary of the labeling comprehension study results, including the percentage of intended users who demonstrated correct understanding and ability to follow the instructions for use.
The complete clinical study report for Protocol SBD-LUM-CL-001 (LUMINA-US) is included in Appendix D of the full 510(k) submission.
Clinical Study Budget: The total cost of the LUMINA-US clinical study was approximately $4,200,000 (350 subjects × $12,000 per subject, inclusive of CRO management fees, clinical site fees, laboratory costs, data management, and statistical analysis).
9. Substantial Equivalence Determination
9.1 Same Intended Use
The Solstice Lumina™ CGM System has the same intended use as the primary predicate device, the NovaSense GlucoTrack NX-500 CGM System (K211034), and the secondary predicate device, the NovaSense GlucoTrack NX-700 CGM System (K230489). Specifically, all three devices are intended for the continuous monitoring of glucose levels in persons aged 18 years and older who have been diagnosed with Type 1 or Type 2 diabetes mellitus. All three devices are prescription-use continuous glucose monitoring systems intended to provide real-time glucose concentration values, trend information, and configurable alerts to support diabetes management.
The subject device and both predicate devices share the same product code (QKQ — Electrode, Glucose, Subcutaneous), the same device class (Class II), and the same regulation number (21 C.F.R. § 862.1355 — Glucose test system). All three devices are classified within the Chemistry and Toxicology Devices review panel and are reviewed by the CDRH Division of Chemistry and Toxicology Devices.
9.2 Same Technological Characteristics
The Solstice Lumina™ CGM System and both predicate devices employ the same fundamental technology: an enzymatic electrochemical biosensor for the measurement of glucose concentration in the interstitial fluid. In all three devices, glucose oxidase catalyzes the oxidation of glucose, and the resulting electrochemical signal is detected amperometrically at a noble metal working electrode. The electrochemical signal is processed by onboard firmware and software algorithms to generate a glucose concentration value that is displayed to the user.
Additionally, all three devices share the following common technological characteristics:
• Wireless communication between the sensor and the reader/receiver via Bluetooth Low Energy (BLE) protocol
• Real-time display of glucose concentration values, directional trend arrows, and trend graphs
• Configurable hypoglycemia and hyperglycemia alert functionality
• Measurement range of 40–400 mg/dL
• Warm-up time of ≤ 60 minutes following sensor in

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