Contract analysis

I. Purpose and Executive Summary This memorandum analyzes the likely positions of the U.S. Food and Drug Administration, Center for Devices and Radiological Health ("FDA" or "CDRH"), on each of the seven Pre-Submission ("Q-Sub" or "Pre-Sub") questions that Solstice Biomedical Inc. ("Solstice" or "SBI") intends to pose in its Pre-Sub meeting package. The Pre-Sub meeting package is targeted for submission by June 16, 2

II.A. Device Overview The Solstice Lumina™ CGM System (the "Lumina System" or the "Device") is a two-component integrated continuous glucose monitoring system designed for real-time glucose monitoring in adults with diabetes mellitus. The system comprises the following components: Lumina C14 Sensor. The Lumina C14 is a subcutaneously implantable continuous glucose monitoring sensor designed for a 14-day wear duration

II.B. Predicate Device Framework Solstice's proposed predicate device framework for the 510(k) submission employs a split-predicate approach utilizing one primary predicate and one secondary (reference) predicate, supplemented by an additional reference device cited solely for purposes of establishing corporate pedigree and prior FDA interaction history. The predicate framework is as follows: Primary Predicate: NovaS

1. Sensor Wear Duration: 14 days (Lumina C14) versus 10 days (NX-500). This difference is bridged by the secondary predicate K230489 (NX-700), which has an identical 14-day wear duration.

2. Electrode Material: Platinum-iridium alloy with proprietary PtIr-4G coating (Lumina C14) versus conventional platinum electrode (NX-500). This is the most significant technological difference and the one most likely to attract FDA scrutiny.

3. BLE Version: BLE 5.2 (Lumina System) versus BLE 5.0 (NX-500). This is an incremental wireless communication upgrade that is unlikely to raise substantial equivalence concerns but may trigger additional cybersecurity documentation expectations.

4. Reader Form Factor: Arm-worn integrated reader/transmitter (Lumina R7) versus handheld receiver (NX-500 reader). This represents a user-interface design change rather than a change in fundamental scientific technology.

5. Proprietary Algorithm: LuminaPredict v2.1 (Lumina System) versus the NovaSense proprietary algorithm (NX-500). Different algorithms for glucose calibration and prediction are a common feature of CGM 510(k) submissions and are typically addressed through performance data (MARD, error grid analysis) rather than as predicate-breaking differences.

II.C. Pre-Sub Questions Overview The Pre-Sub meeting package will present seven categories of questions to FDA, each addressing a critical regulatory element of the planned 510(k) submission. These seven question categories, which are analyzed in detail in Section III below, are:

1. Predicate Acceptance and Substantial Equivalence Framework — seeking FDA's concurrence on the appropriateness of K211034 as the primary predicate and K230489 as the secondary predicate, and the adequacy of the proposed approach to addressing the five identified technological differences.

2. Clinical Study Design and Endpoints — seeking FDA's feedback on the proposed LUMINA-US clinical study design, including the study population, sample size, primary and secondary endpoints, and the acceptability of the MARD and consensus error grid performance targets.

3. IDE Exemption Applicability (NSR Determination) — seeking FDA's input on whether the LUMINA-US study qualifies for the IDE exemption as a non-significant risk study under 21 C.F.R. § 812.2(c)(3).

4. Software Documentation Requirements and Level of Concern Designation — seeking FDA's guidance on the appropriate software safety classification and the scope of software documentation expected for the four software components of the Lumina System.

5. Cybersecurity Premarket Submission Expectations — seeking FDA's confirmation that the planned cybersecurity documentation approach aligns with the September 2023 cybersecurity guidance and identifying any additional expectations specific to BLE 5.2 communication.

6. Biocompatibility Testing Scope Adequacy — seeking FDA's concurrence on the proposed biocompatibility testing battery for the C14 sensor (subcutaneous implant) and the R7 reader (skin-contacting external device), with particular attention to the PtIr-4G electrode material. 7. iCGM Classification Pathway Considerations — seeking FDA's input on whether the Lumina System may pursue iCGM classification through the 510(

III. Analysis of Anticipated FDA Positions — Question by Question

III.A. Question 1: Predicate Acceptance and Substantial Equivalence Framework

III.A.1. Most Likely FDA Position Based on our review of CDRH precedent in the CGM space, the current regulatory framework for product code QKQ devices, and the specific characteristics of the proposed predicate devices, we assess that FDA will likely accept K211034 (NovaSense GlucoTrack NX-500) as the primary predicate device for the Lumina CGM System. This assessment is grounded in several factors. First, K211034 a

III.A.2. Risk Assessment Risk of predicate rejection: LOW. Both K211034 and K230489 are well-established CGM predicates within the QKQ product code space. Both were cleared through the 510(k) pathway, both are Class II devices under the same regulatory classification, and both share the same fundamental technological characteristics as the Lumina System. The split-predicate approach is a recognized and accepted CDRH

III.A.3. Contingency Strategy — If FDA Rejects Primary Predicate In the event that FDA determines K211034 (NovaSense GlucoTrack NX-500) is not an appropriate primary predicate — for example, due to a determination that the combined weight of the five identified technological differences, considered together rather than individually, raises different questions of safety or effectiveness — the first contingency is to r

III.B. Contingency: PMA vs. 510(k) Pathway

III.B.1. Likelihood of FDA Requiring PMA We assess the probability that FDA will require Solstice to pursue a PMA submission for the Lumina CGM System as low. This assessment is based on the following considerations: First, the Lumina CGM System falls within a well-established Class II product code (QKQ) with multiple cleared predicate devices. The 510(k) pathway has been the standard regulatory route for CGM devices

III.B.2. Contingency if PMA is Required Should FDA nonetheless determine that a PMA is required, the implications for Solstice would be substantial: Cost. A PMA pathway would entail estimated additional costs of $2,000,000 to $5,000,000 in additional clinical data generation (including an expanded clinical study with a larger sample size, longer follow-up duration, and potentially a randomized controlled design), reg

III.C. Question 2: Clinical Study Design and Endpoints

III.C.1. Most Likely FDA Position Based on our review of the September 2023 iCGM guidance, recent 510(k) clearances for CGM devices, and established CDRH expectations for clinical studies supporting CGM 510(k) submissions, we anticipate that FDA will find the overall LUMINA-US clinical study design to be generally appropriate for a 510(k) CGM submission. Specifically: Study Design. The proposed prospective, single-ar

III.C.2. Risk of Additional Endpoint Demands Pediatric Labeling Requirement: MODERATE RISK. There is a moderate risk that FDA will request a specific pediatric labeling plan or require Solstice to provide a detailed justification for the 18+ age restriction on the intended use population. The CGM market has seen a significant trend toward adolescent and pediatric use in recent years, with several CGM systems now clea

III.C.3. Contingency — If FDA Demands Additional Endpoints If FDA requires additional endpoints beyond those currently specified in the LUMINA-US study protocol, Solstice should evaluate whether these additional endpoints can be incorporated into the existing Protocol SBD-LUM-CL-001 without increasing enrollment beyond the planned 350 subjects. Many of the sub-analyses that FDA is likely to request (glucose range-spe

III.D. Question 3: IDE Exemption Applicability (NSR Determination)

III.D.1. Most Likely FDA Position We anticipate that FDA will likely concur that the LUMINA-US clinical study qualifies for the Investigational Device Exemption ("IDE") exemption under 21 C.F.R. § 812.2(c)(3), which exempts diagnostic devices from the full IDE requirements, provided that the study meets the criteria for a non-significant risk ("NSR") investigation. Our assessment is based on the following analysis: T

III.D.2. Contingency — If IDE Is Required If FDA indicates during the Pre-Sub meeting that the LUMINA-US study is likely to be classified as significant risk, or if Clearwater IRB independently makes an SR determination, Solstice should be prepared to submit an IDE application (Form FDA 3514) to FDA. The key implications of this contingency are as follows: Review Timeline. FDA review of an IDE application is 30 calen

III.E. Question 4: Software Documentation Requirements and Level of Concern

III.E.1. Most Likely FDA Position The software documentation question is an area where FDA's expectations have evolved significantly in recent years, and Solstice must ensure that its approach reflects the current regulatory framework rather than historical practices. Our assessment of FDA's likely position is as follows: Software Safety Classification. FDA will likely agree that the software components of the Lumina

III.E.2. Identified Gaps Sean Morrissey prepared a Software Documentation Checklist and Gap Analysis (dated April 28, 2025) based on a preliminary review of the software documentation packages provided by Solstice's engineering team. That analysis identified the following potential gaps that must be addressed before the 510(k) submission: (a) The software architecture documentation for the Lumina Mobile App v1.0.3 is

III.F. Question 5: Cybersecurity Premarket Submission Expectations

III.F.1. Most Likely FDA Position Cybersecurity is an area of intensifying FDA focus, and the Lumina System's BLE-connected architecture places it squarely within the scope of CDRH's cybersecurity expectations. We anticipate that FDA will expect full compliance with the September 2023 final guidance "Cybersecurity in Medical Devices: Quality System Considerations and Content of Premarket Submissions," which supersede

III.F.2. Risk Assessment Risk of cybersecurity-related deficiency finding: MODERATE. Cybersecurity has been one of the most frequent areas of FDA 510(k) "Refuse to Accept" ("RTA") decisions in 2024 and 2025. CDRH has publicly stated that incomplete cybersecurity documentation is a leading cause of RTA decisions for connected medical device submissions, and multiple CGM and connected device 510(k) submissions have bee