Understanding types of medical device clinical trials and their importance

medical device clinical trials

Clinical trials are a specific type of clinical research study designed to study and prove the safety and efficacy of new medical treatments. While there are many clinical trials conducted for new drugs, many treatments are administered via medical devices rather than chemical or biological compounds (drugs). These devices are tested in clinical trials known as medical device clinical trials, or MDCTs.

What are medical device clinical trials?

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

Medical devices include a range of medical instruments or tools designed to perform or assist in diagnostic testing, disease and/or symptom monitoring, or treatment. These can include such things as:

  • Surgical implants (i.e., pacemakers)
  • Wearable devices (i.e., real-time blood-sugar monitors for patients with diabetes)
  • Imaging instruments (i.e., magnetic resonance imaging [MRI] or computed tomography [CT or “cat” scan])
  • 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 kinds of medical devices have been registered, and are further classified into 16 “panels” describing the medical specialty (field) to which they pertain. Medical devices are also grouped into three “classes” according to the level of control believed to be necessary to ensure the effectiveness and safety of the device (further detail is given in the “Medical device classes” section of this article).

Why are medical device clinical trials important?

Medical devices are ubiquitous in the healthcare industry, providing the foundation for a significant portion of currently available diagnostic methods as well as monitoring and treatment programs. Clinical trials for medical devices are thus essential for proving their safety before they can be brought to market, and also for making sure they comply with global regulations on product quality and safety.

Data produced by medical device clinical trials can be used in Health Technology Assessments (HTA), which aim to guarantee the safety and efficiency of medical devices, whether they are to be used in physicians’ offices, pharmacies, clinical trial sites, or by patients themselves at home. 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.

What are the different medical device classes?

Medical devices are classified according to the level of supervision required to ensure that the device is used in a reliable, safe, and effective manner. It is, by extension, associated with the risk posed to the participants or patients in the use of the device.

Three regulatory classifications have been developed by the Food and Drug Administration (FDA) in the USA:

  • Class I Medical Devices: Non-invasive medical devices fall under the Class I category, which carry a lower degree of risk and are typically of a simpler design than those of Class II and Class III medical devices. Such devices pose minimal to no risk to patients or healthcare professionals even if they malfunction.

Examples: 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 risks to the patient or practitioner. This class can include devices that are left in/on the body. These medical devices require particular regulations and FDA approval before being used in clinical trials because they present some degree of potential risk to patients.

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

  • Class III Medical Devices: Medical devices considered to pose significant risk to the patient and/or the medical professional, either by the malfunctioning of said device or even inherently in its 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: Artificial heart valves, pacemakers, breast implants etc.

How are medical devices approved for testing in clinical trials?

Before any new medical device can be tested in human patients in clinical trials, it must pass through several cycles of intensive preclinical testing and device screening to guarantee that the device is optimally reliable, safe, and effective. Classification of the device according to the above distinctions is also part of the preclinical testing stage, also known as the development stage. Specialists assess medical devices during preclinical testing phases using laboratory tests, specialized technical screening, software simulations, and even animal testing, amongst other methods.

Preclinical testing for medical devices:

  • 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 also usually undergo engineering and quality testing procedures.
  • Computer simulations: Uses computer simulations to predict how well the medical device would operate under real-world usage conditions. Computer simulations may be able to reveal any potential hazards or unfavorable side effects, allowing the device to be modified before it is put into use.
  • Animal testing: A medical device may be clinically tested on live animals, if necessary, particularly to evaluate its biocompatibility and bio/pharmacodynamic profile. Animal testing requires ethics approval, and may not always be relevant considering anatomical and genetic differences between humans and most laboratory animals, especially when the medical device is designed to diagnose or treat complicated or uncommon human conditions.

After preclinical testing is complete and results look promising, the medical device can be investigated in clinical trials. Clinical trials for drugs tend to follow a specific outline (i.e., Phase I through Phase IV trials), whereas medical device clinical trials typically go through distinct stages. Let’s dive further into the various medical device clinical trial phases.

Medical device clinical trial stages

  1. Pilot / Early Feasibility / Exploratory / First-in-Human Studies: These studies, which can go by different names, typically represent the first use of a new device in human participants, and aim to evaluate clinical safety and the functionality/performance of the device. The device is tested directly in its intended use/therapeutic application, in a very small number of participants. These studies build upon the technical data obtained during preclinical testing with real-world tests. Importantly, these studies are usually conducted before the design of the device is finalized, allowing for practical experience and data to be employed in making any necessary improvements/changes for the final design.
  2. Traditional Feasibility Studies: These studies are similar to early feasibility studies, but are performed when the device is already in its final (or near-final) design. These may or may not be conducted after a prior early feasibility study, depending on whether modifications were required or how much data has been collected in preclinical testing. The results are utilized to design the next stage, a pivotal study.
  3. Pivotal Studies: Such studies are done to gather decisive evidence of the safety and effectiveness of the medical device toward its specific intended use, and in a larger number of participants in order to gain statistically significant results. These could be considered the “principal” trials for medical devices, as the results are used to determine whether or not the device will be submitted for marketing approval.
  4. Post-Marketing Studies: After the device has been approved for use, the manufacturer may decide to conduct post-marketing studies (or post-marketing surveillance) to collect data on and monitor its use, effectiveness, and long-term safety. Data collected from such studies may help identify any issues or to improve the product or its future iterations.


Medical device clinical trials (MDCTs) are conducted to assess a medical device's dependability, effectiveness, and safety in humans regarding its intended use in diagnosing, preventing, or treating conditions. Although the research stages differ from those which drugs/medicines go through, both prior to human testing and in clinical trials involving humans, medical devices must pass stringent testing before they can be approved and marketed. The high-quality data that is generated in MDCTs is crucial for ensuring that the clinical devices used in practice are safe, and for making new and improved devices available to patients and healthcare professionals.