Guidance on clinical evidence requirements for medical devices: Comparator devices

Date published: November 15, 2022

On this page

• About comparator devices
• Criteria for comparing medical devices

About comparator devices

Certain devices require adequate device-specific clinical data. However, Health Canada understands that many medical devices are developed by making rapid and incremental changes to the design. In some cases, the proposed device may be so similar to an existing device that device-specific clinical data are not required.

Where pre-clinical bench testing and side-by-side comparisons can objectively demonstrate that the clinical performance of 2 devices is equivalent, then there is less likely a need for device-specific clinical data.

In addition, Health Canada may have already assessed a comparator device to be safe and effective for the same indications for use. This fact alone may be enough evidence of acceptable performance for the subject device, which means that device-specific clinical data may not be required.

If no similar licensed device can be used as a comparator (does not exist), a manufacturer may use publicly available data sources of comparable devices to assess clinical performance of the subject device. This would avoid the need to generate new clinical data for the device. To do so, manufacturers must:

• provide a detailed side-by-side comparison of the subject device with the unlicensed comparator and
• demonstrate sufficient similarity in order to make use of the published data

A selected comparator device should have device-specific clinical data for its intended purpose. Health Canada may or may not accept the comparator device clinical data as stand-alone evidence of the subject device's safety and effectiveness. This will depend on how robust and applicable the clinical evidence is and what uncertainties associated with differences, if any, there are in the clinical performance of the 2 devices.

Manufacturers who rely on comparator device information to support the safety and/or effectiveness of their subject device should provide a thorough comparison between the devices. To demonstrate equivalence and relevance, the following characteristics should be compared:

• design
• materials
• specifications
• indications for use
• physical properties
• diagnostic algorithms
• chemical formulations
• performance capabilities
• any other equivalent or relevant features

The manufacturer should demonstrate that the clinical performance of the subject device is well understood and explainable based on the device technology from the comparator. The need for a device-specific clinical investigation may depend on the ability of the existing evidence to:

• address the device's benefit/risk profile and
• demonstrate its safety and effectiveness

Some device types will continue to require device-specific clinical data due to their nature or risk profile. These include:

• dermal fillers
• breast implants
• drug-eluting stents
• metal-on-metal hip implants
• synovial visco-supplement injections

Selecting a device for comparison

It's important to select a relevant device for comparison. Manufacturers should not compare devices that:

• do not have the same intended uses
• do not have objective evidence for safety and effectiveness
• cannot be demonstrated to be technically similar to the subject device

Manufacturers should choose a device for comparison that's used as the standard of care for a specific indication. Information in the application of the subject device should demonstrate that the approved comparator device is performing as labelled and that risks are both well characterized and appropriately mitigated. The evidence should be current and relative to current best medical practices. It may also include post-market performance data that demonstrate real-world effectiveness and safety.

Multiple devices may be used for comparison if the subject device shares technological characteristics with more than 1 previously licensed or similar medical device.

Criteria for comparing medical devices

To assess performance adequately, the manufacturer should ensure that the comparator is used in a similar context for a sufficient time in a sufficient number of patients. Health Canada will consider if the experience with the comparator is sufficient in order to determine whether the comparable device is suitable.

Other criteria for ensuring that a comparable device is suitable include:

• indications for use and/or intended use, which includes looking at the:
  • clinical condition being treated
  • site of application to/in the body
  • population to be treated
  • severity and stage of the disease
    • indications for use and/or intended use should be compared to the indications for use/intended use stated in the Canadian version of the instructions for use/labelling for the comparator device
• technological characteristics, which include the device's technical characteristics, such as:
  • design and performance specifications
  • biological and chemical physical properties
• performance of the device (or biological safety if applicable), which includes the:
  • principles of operation and performance requirements
  • deployment methods
  • degradation profile
  • duration of treatment effect
  • conditions of use
    • biological characteristics related to the biocompatibility and biostability of materials in contact with body fluids/tissues

The manufacturer should also demonstrate that the associated data are applicable by demonstrating that the comparator device has been:

• studied in the same demographic groups
• peer reviewed in reputable journals
• studied for use in a way that's relevant to the Canadian health care system

The manufacturer should include the supporting non-clinical information within the technical documentation for the subject device.

Differences between the comparator device and the subject device should not influence the clinical safety and effectiveness of the subject device. The manufacturer should address any differences between the comparator device and the subject device that may affect the ability to extrapolate the clinical evidence to the subject device. An example would be a difference in technical characteristics. In this case, the manufacturer should explain why this difference would not result in different clinical outcomes.

Presentation of device comparisons

A table may be used to present similarities and differences between the subject device and the comparator device. Any clinical evidence related to the previously licensed or similar device that supports the safety and effectiveness of the subject device should be referenced.

We have provided an example summary table:

Characteristics of subject device X	Characteristics in comparator device Y	Related clinical evidence
Indications for use/intended use for subject device X	Indications for use/intended use for comparator device Y	Summary of how the clinical evidence supports the subject device given the indications for use/intended use
Clinical characteristics for subject device X	Clinical characteristics for comparator device Y	Summary of how the clinical evidence supports the subject device given the clinical characteristics
Physical and performance characteristics for subject device X	Performance characteristics for comparator device Y	Summary of how the clinical evidence supports the subject device given the identified performance characteristics
Biological characteristics for subject device X	Biological characteristics for comparator device Y	Summary of how the clinical evidence supports the subject device given the biological characteristics

Manufacturers should:

• identify and discuss any differences between the subject device and the comparator device characteristics
• provide a rationale on how differences between the comparator device and the subject device do or do not significantly impact the safety and effectiveness of the subject device for the proposed intended use and where applicable, for different populations, including males and females