Clinical Trials – An Overview

by Brie Darcy, PT, DPT

With the recent development of a COVID-19 vaccine, there has been a lot of discussion around clinical trials.

Clinical trials are an essential and impactful part of healthcare. Broadly speaking, clinical trials are research studies performed in people for the purpose of evaluating a medical, surgical, or behavioral intervention. Clinical trials can be used to test the safety and efficacy of various products and therapeutics such as medications, medical devices, health behaviors, and, of course, vaccines.

In this blog, we provide a general overview of the clinical trial process and review some of the basic fundamentals of clinical trials.

Clinical Trials – The Basics

Clinical trials are used to add medical knowledge. When a researcher or team of researchers desires to investigate an experimental product (think – a new drug, vaccine, medical device, etc.) a clinical trial can be proposed. Each clinical trial is led by an individual (called the ‘principal investigator’), supported by additional study staff, and guided by a documented and approved protocol. Additionally, clinical trials that are federally supported (or investigating a product which would be regulated by the FDA) must be reviewed, approved, and monitored by an institutional review board (or IRB). The IRB’s role is to make sure the trial meets ethical standards, that risks are minimized, and that the welfare of participants are protected.


You likely have heard clinical trials referred to in Phases. Clinical trials pass through a series of phases which are designed to maximize participant safety and follow a logical progression of testing.

Phase 1

The first phase of a clinical trial is Phase 1. A Phase 1 clinical trial is typically utilized to determine if the investigational product (such as a novel treatment) is safe for people. For clinical trials investigating medications, medical devices, or vaccines, researchers will be paying careful attention to side effects or adverse events. Phase 1 clinical trials typically have a smaller number of volunteers. With reasonably demonstrated safety, an investigational treatment would progress to the next stage of clinical trial.

Phase 2

While Phase 1 studies focus on safety, Phase 2 studies emphasize efficacy, or, in other words, how well the treatment works and provides the desired effect. During a Phase 2 study, safety is continually monitored while the treatment is tested in a larger population of study participants. In this phase, participants may be “randomized” (or selected at random) into different treatment groups. One group may receive the treatment that is being investigated while another might receive a placebo treatment or a treatment that is considered to be the standard form of care for the condition. When possible, study group assignment may be concealed from study staff or even the study participants to reduce the likelihood of bias influencing the study results. Comparing data from the various study groups will facilitate determining the relative efficacy of the treatment. If a Phase 2 study demonstrates promising safety and efficacy, the treatment may progress to a Phase 3 study.

Phase 3

Treatments that exhibit promising results in Phase 2 may progress to a Phase 3 clinical trial. In Phase 3, an even larger population of individuals is studied with a goal of confirming effectiveness, monitoring side effects, and comparing results with similar or standard treatments. Phase 3 studies are the longest in duration and thus more likely to capture rare or long-term effects. Also in this phase, the Food and Drug Administration (FDA) may make a determination of approval based on the risks versus benefits of the treatment being studied.

Phase 4

After FDA approval, Phase 4 studies continue to monitor the safety and efficacy of the treatment in the general population.

Clinical research and clinical trials are vital components of nearly every advancement in modern medicine. While the processes for specific clinical trials can have some variation, this general framework guides much of the important innovations in our healthcare system.

Feel free to visit Moterum’s clinical trials page for information on how our clinical trials have guided our rehabilitation efforts!

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