Clinical Trials Part 2, Who's Involved and How Are They Designed?

Clinical Trials Part 2, Who’s Involved and How Are They Designed?

This 4-part series explains what clinical trials are, how they’re run, what all the unfamiliar terminology means, and why people choose to participate in trials. We also include helpful resources to learn more.

In Part 1, Types of Clinical Trials, we covered the different types of clinical research trials. In this installment, we’ll take a look at the terms used to describe all of these studies. Let’s start with the people who are involved and the roles they play.

Every study is overseen by a principal investigator (PI) , who is typically a medical doctor. The PI has expertise in study design, regulatory compliance, data management, project management, and statistical analysis.

Sponsors prepare the protocol for the trial and oversee the study. They are often pharmaceutical companies developing the drug to be tested. They may also be physicians, hospitals, government agencies, institutions, advocacy groups, or other organizations.

A team of credentialed, qualified physicians, nurses, physician assistants, and pharmacists who monitor all participants per the study protocol and record the findings. Their number one priority is the safety of all participants.

These are the people who volunteer to be in the study. Sometimes they’re called patients or subjects. Note that sometimes participants are healthy people who choose to enroll as a way to help advance the research

The place where a clinical trial or study is conducted, which must meet criteria set forth by regulatory agencies.

Inpatient studies are conducted with participants who are admitted to a hospital or other facility where they get 24-hour care and observation. In outpatient studies, patients are not admitted but they are periodically examined by the study team to record/observe parameters outlined by the study protocol.

This group assures appropriate steps are taken (before and during the study) to protect the rights and welfare of all participants. They check to see the trial is well-designed, does not pose undue risks, and includes safeguards for patients. The IRB must approve the action plan for every clinical trial, and one is assigned to each study site.

What’s a Clinical Trial Protocol?

Every trial has a protocol – specific guidelines and procedures that detail what happens during the trial, when, and why. This helps ensure the results are reliable and helps reduce the risk to participants. Not every person with the disease or condition being studied will qualify for the trial. Wherever the clinical trial is conducted, the same protocol is strictly followed and includes things like:

  • Number of participants
  • Length of the study
  • Eligibility criteria (i.e., inclusion and exclusion criteria such as sex, age, type and stage of disease, current and/or previous treatment history, and the presence of other medical conditions. Not every person with the disease or condition being studied will qualify for the trial.)
  • Testing requirements
  • What data is to be collected

These terms describe different ways trials can be designed and conducted.

This means study participants are randomly assigned to different groups. The different groups can be separated using many different criteria, including variations in the study protocol.

Subjects and researchers are all aware of the intervention (drug, medical device, etc.) being given/tested.

Subjects do not know which group they are in (treatment group or placebo group).

Neither the researchers nor the subjects know which group the subjects are in until it’s revealed at the end of the study.

A substance that looks the same as the experimental drug, but doesn’t contain its active ingredients.

All subjects receive an existing medical therapy, but some then receive the additional experimental drug while others do not, or are given a placebo.

The study is carried out at one location.

The study is carried out in several locations. These can be different cities, or even different countries.

In the next installment, we’ll talk about the different phases of a clinical trial, what they’re designed to do, and what happens as the drug advances through the phases.

Clinical Trial Resources

If you’re thinking about participating in a clinical trial, PATHFNDR is now enrolling patients to evaluate the safety and efficacy of paltusotine, an investigational drug for the treatment of acromegaly.

CLICK HERE to learn more about the study and the eligibility requirements.

  • This database of privately and publicly funded clinical studies conducted around the world is one of the best resources available. You can search by disease, country, and other key filters to find a trial that may be right for you. The site includes a good list of questions to ask when considering participating in a clinical trial. See them here.

Deciding to participate in clinical trials

  • Animation and easy-to-understand language make this video from the Office for Human Research Protections (OHRP) a must-see for any potential trial participant.
  • Another OHRP video addresses randomization. Watch it here.

A participant’s first-hand account

  • Watch Juliana’s story about her experience participating in a trial for sickle cell anemia


National Institutes of Health (2015, August 20) Clinical Trials []. Retrieved May 2020.

U.S. Food and Drug Administration (2018, January 04) Step 3: Clinical Research []. Retrieved May 2020. (2019, March) Learn About Clinical Studies []. Retrieved May 2020.

National Health Service (2019, May 08) Clinical trials []. Retrieved May 2020.

UptoDate. Patient education: What are clinical trials? (The Basics). Topic 16168 Version 11.0