Why are clinical studies necessary?
Medical device clinical studies provide evidence for a PMA submission. Under 21 CFR 860.7, the FDA relies only on “valid scientific evidence” to determine whether there is reasonable assurance that a device is safe and effective. Valid scientific evidence can originate from a variety of sources, including well-controlled studies. Even though there are options other than clinical studies to serve as the evidence for a PMA, 21 CFR 860.7(e)(2) emphasizes the use of well-controlled studies more than any other type of evidence.
What are the stages of medical device clinical studies?
- Exploratory Stage – first-in-human and feasibility studies, iterative learning, & product development (this stage helps better understand how the device may perform, its intended use, and how to select an appropriate pivotal study design)
- Pivotal Stage – definitive study to support the safety and effectiveness evaluation of the medical device for its intended use
- Postmarket Stage – includes studies intended to better understand the long-term effectiveness and safety of the device, including rare adverse events
Designing a medical device clinical study:
To design a medical device clinical study, one must consider: types of device studies, bias and variance, study objectives, subject selection, stratification, site selection, and comparative study designs. Some points to keep in mind in the key areas:
- Types of Device Studies: clinical outcome studies are typically used for therapeutic and aesthetic devices (as well as some diagnostic devices), while diagnostic clinical performance studies are typically used for diagnostic devices
- Clinical Outcome Studies: it is preferred that these studies be double-masked, randomized, and controlled. If masking cannot occur, bias should be addressed through controls
- Diagnostic Clinical Performance Studies: It is preferred that these studies be masked to the third party evaluator but unmasked to the investigator.
- Bias and Variance: an objective of a clinical study is to eliminate or reduce the bias; and, variance can be reduced by either a more efficient design or by a larger sample size
See all of the FDA’s thoughts on “Design Considerations for Pivotal Clinical Investigations for Medical Devices” here: Pivotal Stakeholder Presentation. They ended this presentation by noting that device studies “allow for a broad range of designs,” and they encourage companies to meet with the FDA for a pre-sub or IDE meeting to ask questions about medical device clinical study design.
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