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NMPA RFA & MWA Equipment Clinical Guideline Asks Feedback

NMPA issued the “Clinical Evaluation Guideline with Predicate Comparison of Radiofrequency Ablation (RFA) and Microwave Ablation (MWA) Equipment (Draft)” for feedback on February 18, 2024. Feedback needs to be submitted by March 8, 2024.

For an English copy of the draft guideline, please email info@ChinaMeDevice.com. We charge nominal fees for the translation.

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Application Scope

RFA and MWA equipment in the proposed guideline is intended to treat liver cancer or thyroid nodules. Cardiac ablation is excluded. Devices used for vein ablation can be referenced in the applicable sections.

RFA uses radio waves with a frequency greater than 100 kHz but not exceeding 5 MHz. MWA uses microwaves with a frequency greater than 300 MHz but not exceeding 30 GHz.

If the product or a key component have new technological characteristics (such as adopting a new working principle or design), or new intended use, without clinical data demonstrating the safety and effectiveness, consideration should be given to start the clinical trials.

Predicate Comparison

The proposed guideline recommends selecting predicate devices for clinical evaluation. When comparing, prioritize products with similar scopes and technical features. Analyze similarities and differences in applicable scopes and clinical information. Standardize applicable scopes, considering instrument compatibility and indications. For instance, a liver RFA may specify usage with internally cooled electrodes for liver tumor ablation. The instructions should detail applicable tissue size, location, and provide information on lesions, such as liver tumors with diameters ≤3cm. Emphasize key points like indications, application sites, usage methods, and precautions, focusing on disease types, severity, and clear specifications for each indication and corresponding ablation needle model.

Technical Features

The guideline emphasizes a detailed comparison of technical features between the declared product and the predicate, with a focus on structure, performance, and key technological aspects.

Structural Composition:

  • For radiofrequency ablation devices, components include the main unit, electrodes, infusion pump, cables, connectors, channels, and footswitch.
  • Microwave ablation devices consist of the main unit (with microwave source), ablation needles (with radiation zone), output cables, temperature probes, and footswitch.
  • Detailed structural illustrations, such as cross-sectional or 3D diagrams, are recommended for electrodes and needles.

Product Performance, Functions, and Key Technical Features:

  • Evaluate all output modes separately for safety and effectiveness.
  • Focus on main unit performance (frequency, output power, power curve, temperature control, etc.) and electrode/needle characteristics (size, conductivity, materials, etc.).
  • Consider factors like flow rate, pressure (if applicable), and software core functionalities, including energy adjustment and control.
  • Conduct in vitro tissue experiments for each output mode, comparing ablation quantities between the declared and comparable products. Representative tissues, like fresh animal liver, should be chosen for relevance.
  • Assess the equivalence of ablation treatment on representative tissues and target tissues for the product and the predicate.
  • Experiment parameters should simulate clinical use, and comparisons should address factors like temperature probe layout.
  • Record dimensions and shapes of ablation areas, assessing the correlation between ablation range and output energy, duration, and temperature (if applicable).
  • Pathological examination with size-measured images is recommended for results verification, considering factors like adhesion and needle breakage.
  • Analyze results thoroughly based on reasonable acceptance standards.

Safety and Efficacy Evidence for Discrepancies

If there are differences in the declared product and the predicate, the applicant should analyze the product’s intended use, existing similar products, clinical data (if available), clinical requirements, and may submit its own clinical data if necessary. Clinical data for predicates can be obtained from literature or clinical trials.

No Significant Differences in Key Design Structures:

  • If there are no significant differences in key design structures, software core functions, applicable scope, and usage methods between the declared and similar products:
  • For consistent energy output characteristics, no additional animal testing may be required.
  • For differing energy output characteristics, based on clear performance parameter settings, the applicant may need to conduct animal testing according to guidelines, providing necessary data.

Animal Testing Requirements:

  • Animal testing is recommended to provide evidence of safety and effectiveness based on performance and in vitro tissue comparisons.
  • Control groups, preferably using similar products, should be established in animal experiments, considering ablation points that do not interfere with each other.
  • Animal testing should address potential additional risks and typical output parameters under such conditions.
  • Consider representative and appropriate animal models, such as pigs or dogs, based on the applicable scope and target tissues.
  • Adequate animal numbers, adhering to the 3R principle, ensure reliable results. Multiple tissue sites in the same animal or different animals can be used, and multiple observation time points should be considered.
  • Set reasonable observation periods, considering immediate postoperative, 7 days postoperatively (if applicable), and other relevant time points, providing reasons for the selection.

IFU Writing

The user manual should specify indications and contraindications. It must disclose in vitro and, if applicable, animal trial results, details on multi-needle or repeated ablation procedures, including lesion repositioning and needle spacing. The manual should provide typical and maximum power for each accessory, expected device performance, and usage scenarios, methods, and precautions for different modes.