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The gammaCore Sapphire Non-invasive Vagus Nerve Stimulator is intended to provide non-invasive vagus nerve stimulation (nVNS) on the side of the neck. The gammaCore Sapphire device is indicated for:

• · Adjunctive use for the preventive treatment of cluster headache in adult patients.
• · The acute treatment of pain associated with episodic cluster headache in adult patients.
• · The acute treatment of pain associated with migraine headache in adult patients.
• · The preventive treatment of migraine headache in adult patients.

The gammaCore Sapphire (gammaCore) is a multiuse, handheld, rechargeable, portable device consisting of a rechargeable battery and signal-generating and amplifying electronics, with a slide control switch for user/operator control of the signal amplitude (relative range, 0-40 continuous).

The gammaCore Sapphire:

• . Includes a charging station incorporated into the "clam shell" storage case connected to a power adapter for charging of the device as necessary by the end user.
• Provides visible (light and display) and audible (beep) feedback regarding device and . stimulation status.
• Allows for multiple stimulations or doses; each stimulation or dose lasts 120 seconds, . after which the device automatically turns off unless turned off earlier by the user/operator.
• Delivers up to a fixed number of doses within a 24-hour period; once the maximum daily . number of doses has been reached, the device will not deliver any more doses until the following 24-hour period.
• Indicates on the display the number of remaining doses available in a 24-hour period. .

This document is a 510(k) summary for the gammaCore Sapphire device and doesn't explicitly state "acceptance criteria" in a quantitative table. Instead, it demonstrates substantial equivalence to a predicate device by proving that the expansion of indications for use (specifically, for the preventive treatment of migraine headache) does not raise new questions of safety or effectiveness.

The "acceptance criteria" effectively are that the new indication performs similarly in terms of safety and efficacy to the existing cleared indications and comparable to the predicate device, as demonstrated through clinical studies.

Here's a breakdown of the requested information based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

As noted, the document doesn't provide a formal table of "acceptance criteria" and "reported device performance" in the typical sense of a pass/fail metric for a specific algorithm. Instead, it presents clinical study results to demonstrate that the expanded indication for the gammaCore Sapphire device (preventive treatment of migraine headache) is safe and effective and does not raise new questions of safety or effectiveness compared to the predicate device and previously cleared indications.

The key "performance" is the therapeutic gain and P-value for migraine reduction and the safety profile demonstrated in the clinical trials.

• Therapeutic gain in mean reduction of migraine days per month: -0.74 (P=0.043)
• Therapeutic gain in mean reduction of headache days per month: -0.86 (P=0.045)
• Therapeutic gain in mean reduction of acute medication days per month: -0.80 (P=0.039)

EVENT Study (for preventive chronic migraine):

• Change in mean headache days from baseline to month 2: -1.4 (nVNS) vs. -0.2 (sham)
• Continued nVNS use led to significant reductions over time. |
  | Technological characteristics, intended use, and other device specifications remain unchanged or demonstrably equivalent. | "There have been no changes in the technological characteristics or intended use of the gammaCore Sapphire in the proposed Indications for Use statement."
  (Detailed comparison in Table 5 showing no changes in patient-contacting materials, electrical classification, waveform/frequency, maximum output, load impedance, power supply, service life, controls, output regulation, display, charger, RFID, Bluetooth, and alarm signals). |

2. Sample Size Used for the Test Set and Data Provenance

The "test set" in this context refers to the clinical study populations used to support the expanded indication.

• PREMIUM Study:

  • ITT (Intent-to-treat) Population: 332 subjects (ITT nVNS: 165, ITT Sham: 167)
  • mITT (modified Intent-to-treat) Population: 278 subjects (mITT nVNS: 138, mITT Sham: 140)
  • Data Provenance: Prospective, randomized, double-blind, sham-controlled, multicenter study conducted at 22 European sites from June 1, 2015, to November 21, 2017.

• EVENT Study:

  • ITT (Intent-to-treat) Population: 59 subjects (ITT nVNS: 30, ITT Sham: 29)
  • PP (Per-protocol) Population: 49 subjects (PP nVNS: 26, PP Sham: 23)
  • Data Provenance: Prospective, randomized, sham-controlled, multicenter pilot study for the prevention of chronic migraine, conducted at 6 sites in the United States from October 2012 to April 2014.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

Clinical trials for medical devices like this typically rely on patient-reported outcomes validated by medical professionals and objective measures (like headache day diaries). The "ground truth" here is less about image interpretation by experts and more about the clinical definition of migraine, headache days, and adverse events, as assessed by the investigators and patients themselves.

The document does not specify a separate panel of experts establishing ground truth in the way it might for an AI-powered diagnostic device. Instead, the "ground truth" for efficacy (e.g., reduction in migraine days) is derived from the comprehensive data collected during the trials, including patient diaries and clinical assessments by the investigators at the study sites. The inclusion criteria for patients required a diagnosis of migraine with or without aura in accordance with international classification criteria (ICHD-3 Beta for PREMIUM, ICHD-2 for EVENT), implying that the diagnosing clinicians (experts) established the baseline condition.

4. Adjudication Method for the Test Set

This type of information (e.g., 2+1, 3+1 adjudication) is typically relevant for studies where subjective assessments (like imaging reads) require a consensus for ground truth. For a clinical trial involving patient symptoms and objective measurements, this type of adjudication method is generally not applicable. The studies were randomized, sham-controlled, and double-blind, which are methods designed to reduce bias in treatment efficacy evaluation.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance

No, an MRMC comparative effectiveness study was not done. This device is a therapeutic stimulation device, not an AI-powered diagnostic tool requiring human reader assistance.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

This question is not applicable. The gammaCore Sapphire is a non-invasive vagus nerve stimulator, a physical device used by patients under a prescription, not an algorithm. The "performance" is the physiological effect of the stimulation.

7. The Type of Ground Truth Used

The "ground truth" for the efficacy endpoints was based on:

• Patient-reported outcomes: Primarily the number of migraine days per month, headache days per month, and acute medication days per month, typically recorded in diaries.
• Clinical assessment: Diagnosis of migraine based on established International Classification of Headache Disorders (ICHD) criteria by trained clinicians at the study sites.
• Safety monitoring: Assessment of adverse events by investigators.

8. The Sample Size for the Training Set

There isn't a "training set" in the context of an algorithm or AI. The device itself is a physical medical device. The "training" that occurs is the patient's and clinician's understanding of how to use the device, not an algorithmic learning process. The clinical studies described (PREMIUM and EVENT) serve as the validation datasets for safety and efficacy for the expanded indication.

9. How the Ground Truth for the Training Set Was Established

Not applicable, as there is no algorithmic "training set" for this device.

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