Pop Quiz: Can You Answer These 5 Questions on Clinical Trials?
May 20, 2024
Karin Fleming
A female doctor in a white coat interacting with a patient


The world’s first clinical trial was “born” in the mid-1700s, when Scottish physician-researcher Dr. James Lind encouraged a group of sailors to join an experiment in which they ate oranges and lemons. Turns out the vitamin C-rich fruit helped prevent the onset of scurvy—an illness caused by severe vitamin C deficiency.

Centuries later, the clinical trial continues to advance medical knowledge for the treatment and prevention a range of health concerns. In recognition of International Clinical Trials Day May 20, Vitals brings you this “101” on these invaluable research studies.

  1. What is a clinical trial?

Clinical trials involve groups of people in studies of novel or existing drugs, surgical procedures, devices and new ways to improve quality of life. They help researchers and doctors understand the safety and effectiveness of various treatments and how drugs or other interventions impact people differently based on age, gender, and race/ethnicity. They can also help create new solutions to prevent, detect and treat complex, common or rare illnesses.

  1. Why do clinical trials matter?

Findings from clinical trials may lead to medical breakthroughs. These studies offer hope to people who participate, and to those yet to be diagnosed with illnesses like cancer, heart disease, stroke, diabetes and more.

  1. What are the types and phases of clinical trials?

Clinical trials are most commonly conducted in several phases:

Preclinical tests: Before clinical trials involving humans are conducted, potential treatments are first assessed in preclinical research. For example, the research may aim to learn if a drug or device is safe or harmful to humans. In preclinical studies of vaccines, researchers give the vaccine to animals to see if it produces an immune response.*

Phase 0: These studies are the first clinical trials conducted in humans. They aim to learn how a drug is processed in the body and how it affects humans. In these trials, a very small dose of a drug is given to about 10 to 15 people.

Phase 1: These studies assess the safety and the effects of a drug or device in humans. This phase of testing, which can take several months to complete, usually includes a small number of healthy study participants (20 to 100 people).  For drug studies, this may include how the drug is absorbed, metabolized, or excreted in humans, and what side effects may occur as dosing increases.

Phase 2:
These test the effectiveness of a drug or device over several months to two years and involve up to several hundred patients. Most Phase 2 drug studies are randomized trials where one group of patients receives an experimental drug, while a second “control” group receives a standard treatment or placebo. Often these studies are “blinded,” meaning neither the study participants nor the researchers know who has received the experimental drug or other intervention.

Phase 3:
These studies involve randomized and blind testing in several hundred to several thousand study participants. This large-scale testing, which can last several years, seeks to provide the manufacturer of a proposed treatment with a thorough understanding of the effectiveness of the drug or device, as well as the benefits and the possible adverse reactions or side effects.

Phase 4: These studies, often called Post Marketing Surveillance Trials, are conducted after a drug or device has been approved for consumer use.

*Clinical trials of vaccines are typically conducted in larger groups of people. They seek to further test the proposed vaccine’s safety and its ability to stimulate the immune system.

  1. What factors are important to consider before joining a clinical trial?

First and foremost, you should consult with your doctor about whether participation is right for you and ask about the risks and benefits. When you’ve done that, a few additional things to consider are:

  • Are you excited about the possibilities offered by new treatment?
  • Do you understand the types and phases of clinical trials?
  • Are you comfortable with the amount of care and attention you’ll receive as part of the trial, and with the possibility of additional tests or procedures?
  • Are you interested in potentially being involved in a breakthrough in treatment?

Talk to your doctor about any questions or concerns you might have, and about the type and level of treatment you’ll receive as part of the trial. It’s always important to be as informed as possible on every aspect of the treatment.  

  1. If I’m interested in participating in a clinical trial, where can I find more information?

Ask your doctor if a clinical trial is right for you. Sutter offers clinical trials potentially suitable for individuals with a wide range of health concerns. Find a list of enrolling studies available at Sutter Health.

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