Understanding types of medical device clinical trials and their importance

Medical device clinical trial [phases]

medical device clinical trials

Clinical trials are carried out to gather data on the safety and efficacy of new drugs. However, many medical treatments involve medical devices, either instead of or in addition to chemical compounds (drugs). Whereas drug trials follow a specific series of clinical trial phases, medical devices are tested in a distinct series of studies, known as medical device clinical trials, or MDCTs. In this article, we provide an overview of medical device trials, including the stages involved and how they differ from clinical trials for drugs.

What are medical devices?

The term medical device covers a range of medical instruments designed to perform or assist in diagnostic testing and/or disease monitoring or treatment. Medical devices include tools such as:

Surgical implants (i.e., pacemakers)
Wearable devices (i.e., continuous glucose monitors for patients with diabetes)
Imaging instruments (i.e., magnetic resonance imaging [MRI] or computed tomography [CT] scanners)
General tools used by physicians or therapists to treat a condition, assist in diagnosis, or even perform regular check-ups (i.e., blood pressure monitors, stethoscopes, thermometers)

In the USA alone, approximately 1700 different generic types of medical devices have been registered, which are classified into 16 “panels” describing the medical field/specialty they pertain to. Medical devices are also grouped into three “classes” according to the level of control thought to be necessary to ensure the effectiveness and safety of the device (see the next section on medical device classes). For further detail on medical device classes and classification, see the official FDA documentation: Classify Your Medical Device | FDA

Medical device classes: What are class I, II and III medical devices?

The FDA classifies medical devices into class I, II, and III, according to the level of supervision required to ensure that the device is used in a reliable, safe, and effective manner. By extension, this classification is related to the potential risk posed to patients.

Class I Medical Devices: Non-invasive medical devices, which carry a lower degree of risk and are typically simpler in design than Class II and Class III medical devices. Such devices pose minimal to no risk to patients or healthcare professionals, even if they were to be used incorrectly.

Examples of class I medical devices: Bandages, wheelchairs, walkers, crutches, enema kits, latex gloves, and other common supplies and medical equipment that can be encountered in healthcare facilities and clinical trial sites alike.

Class II Medical Devices: Invasive medical devices which pose moderate to intermediate risk to the patient and/or healthcare practitioner. Class II medical devices include devices that are placed inside or left on the outside of the body. These medical devices thus have particular regulations and require FDA approval before being used in clinical trials because they present a certain degree of potential risk to patients.

Examples of class II medical devices: Pregnancy testing kits, single-use surgical tools such as scalpels, electrically powered wheelchairs, needles and syringes, dental sealants, respiratory equipment, bone-fixation plates.

Class III Medical Devices: Medical devices considered to pose significant risk to the patient and/or the medical professional, either in the malfunctioning of the device or even under correct usage. Approximately 10% of medical devices in use are classified as Class III devices. Such medical devices are often implanted or transplanted into the patient's body, and could be directly implicated in sustaining or supporting the patient's life. Class III medical devices must acquire FDA pre-marketing clearance based on substantial clinical findings and research evidence, and are governed by strict regulations.

Examples of class III medical devices: Artificial heart valves, pacemakers, breast implants, etc.

What are medical device clinical trials?

Medical device clinical trials (MDCTs) are clinical studies carried out with the aim of evaluating the efficacy, reliability, and safety of a medical device concerning its use in the diagnosis or treatment of an illness in human patients.

Medical device trials differ from clinical trials for drugs in that they follow an entirely different structure of trial phases.

Why are medical device clinical trials important?

Medical devices are ubiquitous in healthcare, serving as fundamental tools for diagnostic methods and disease monitoring and treatment. Medical device trials are essential for testing their safety before they are brought to market, and also serve to ensure that devices comply with regulations on product quality and safety.

How are medical devices approved for testing in medical device trials?

Before a new medical device is tested in human patients in medical device trials, it must pass through intensive preclinical testing and device screening to guarantee that the device is reliable, safe, and effective. Classification of the device according to the distinctions described in the sections above is also part of the preclinical testing stage (also known as the development stage).

Preclinical testing for medical devices can involve:

Bench testing: The medical device is tested in a lab or workshop to determine its functionality, reliability, and ability to perform as intended.
Technical testing: Designed to test the precision and dependability of the medical device. The electronic/mechanical components of the device will usually be subjected to quality control procedures.
Computer simulations: Computer simulations might be used to predict how well the medical device would operate under real-world use conditions. Simulations may be able to predict or foresee potential hazards or failure points, allowing the device to be modified before it is put into use.
Animal testing: A medical device may be clinically tested on animals, if necessary, particularly to evaluate its biocompatibility. Animal testing requires ethics approval, and would only be relevant for certain medical devices.

If results from preclinical testing look promising, the device can move on to be investigated in medical device clinical trials. Clinical trials for drugs follow a specific outline (i.e., Phase I through Phase IV trials), whereas medical device clinical trials involve through distinct stages, which we discuss next.

Medical device clinical trial phases

Early Feasibility Study (a.k.a. Pilot / Exploratory Study): This is an optional first step before conducting a feasibility study. These studies build upon the technical data obtained during preclinical testing with real-world tests, and often before the design of the device is finalized. This allows for practical experience and data to be gained and then leveraged to make any necessary improvements for the final design.
Feasibility Study: A feasibility study is typically the first study of the device in humans, but they are not always necessary (depending on the regulatory pathway being followed). The aim is to evaluate clinical safety and the functionality and performance of the device. In these studies, the device is tested directly in its intended use or therapeutic application, but in a small number of participants.
Pivotal Study: A pivotal study is the device equivalent of a phase III (pivotal) clinical trial. Pivotal studies aim to gather decisive evidence of the safety and effectiveness of the medical device toward its specific intended use, in a larger number of participants in order to obtain statistically significant results. Pivotal studies are the decisive trials for medical devices, as the results determine whether or not the device will be submitted for marketing approval.
Post-Marketing Study: After a medical device has been approved for use, the manufacturer may decide to conduct post-marketing studies (or post-marketing surveillance) to monitor and collect data on its use, effectiveness, and long-term safety. Data collected from such studies can help identify functional problems and longer-term effects or safety issues, and can be used to improve the product for its future iterations. This real-word data can be used in real-world evidence studies and to inform healthcare policy and standards of care.

Data from medical device clinical trials can also be used in Health Technology Assessments (HTA), which aim to measure the value of health technologies and inform guidance on their usage. HTA is a multidisciplinary, systematic, and transparent assessment of both the direct and indirect consequences of health technologies and interventions. One of the main purposes of HTA is to facilitate and promote collaboration between the worlds of clinical/healthcare research and policy-making in order to ensure coherence and oversight regarding the use of the many medical devices and healthcare technologies available.

Conclusions

Medical device trials are the equivalent of clinical drug trials, but for medical devices. They are a necessary regulatory step and serve to assess the dependability, effectiveness, and safety of the device when it’s used in or on humans. There are many types of medical devices, which the FDA classifies into three classes and 16 ‘panels’ (medical specialties). Medical devices are widely used to assist with diagnosis, monitoring, and treatment of diseases, and span from basic medical supplies as simple as bandages to complex instruments like MRI scanners. Although the regulatory pathway for medical devices differs from that of drugs, medical devices are also subjected to stringent tests before they can be approved and marketed. Medical device trials are crucial for ensuring that newly approved devices are safe and reliable.