Transcript What is a Clinical Trial

Designing and Managing
Drug and Substance Abuse
Clinical Trials
Chapter 1:
What Is a Clinical Trial?
(Beta Version)
Learning Objectives
• Recognize when research projects are
considered clinical trials under US laws
and regulations
• Use appropriate research terminology to
describe a clinical trial
The First Recorded Clinical Trial
• In 1747 an English physician, James Lind thought that acidic
foods might cure scurvy. He assigned 12 sailors with scurvy
into one of six groups. All men then received the same daily
diet plus:
1.
2.
3.
4.
5.
6.
Group one - A quart of cider daily
Group two – Twenty-five drops of elixir of vitriol (sulfuric acid)
Group three - Six spoonfuls of vinegar
Group four - Half a pint of seawater
Group five - Two oranges and one lemon
Group six - A spicy paste plus a drink of barley water
• At the end of 6 days, one sailor from group five was fit for duty
and the second had almost recovered. Other than these two
men, only the sailors from group one showed some effect of
their treatment
The US Government’s
Definition of a Clinical Trial
US Government’s Definition
• Clarifies the difference between clinical
trials and other types of human research
• Clinical trials funded or regulated by the
US government must meet specific:
– Legal requirements
– Regulatory requirements
Clinical Trial Components
•
Key Components of a Clinical Trial
– It is a prospective study
– It is in humans
– It is designed to answer questions about a
biomedical intervention or a behavioral
intervention
US Government’s Definition of a
Clinical Trial
• A clinical trial is a prospective
biomedical or behavioral research
study of human subjects, that is
designed to answer specific questions
about biomedical or behavioral
interventions
Drug Abuse Research Projects
That Are NOT Clinical Trials
• Primate testing of a new HIV therapy intended
for humans
• Ethnographic research to understand patterns of
IV drug users
• Program evaluation of a government initiative to
reduce cocaine use by unwed mothers
• An epidemiologic study of drug abuse patterns
among persons receiving naltrexone for alcohol
dependency
Important Terms That
Describe Clinical Trials
Four Major Features of
Clinical Trials
Stage (phase) of the study
intervention
Controls
Randomization
Blinding
Key terms to describe the four
basic features of a clinical trial
FEATURE
TERMS USED
Study Stage
Phase I
Phase II
Phase III
Phase IV
Controls
Uncontrolled
Placebo
Active Control(s)
Randomization
Non-randomized
Randomized
Blinding
Unblinded
Single-blind
Double-blind
Triple-blind
Study Stage: The Four
Phases of Clinical Trials
The Four Phases of
Clinical Trials
• Phase I – The intervention is new and is being tested in
a small group of people for safety
• Phase II – The intervention looks promising and is being
evaluated in a larger group of people for safety and
efficacy
• Phase III – The intervention appears safe and effective
and is being evaluated in a real-world study
• Phase IV – The intervention is now in use and is being
monitored for safety
Controls in Clinical Trials
Controls In Clinical Trials
• An intervention is compared to something
else, a “control”
• Compared to…
– What has been done in the past
– No treatment
– Current treatment (standard treatment)
– Similar-looking but ineffective treatment
(placebo)
Historical Controls
• All that is necessary when the intervention
has a dramatic effect
No Treatment
• Common in evaluating surgical procedures
Placebo
• Duplicate the experience of the
intervention without the active component
• Can provide clear improvement in
symptoms (“placebo effect”)
• Determine the extent to which intervention
alone affects treatment
Current Treatment
• Contains an active component
• Frequently used in Phase III trials
– Understand the benefits of a new treatment in
a real-world setting
Randomization in
Clinical Trials
What Is Randomization?
• Assigning of persons to the control group
or the intervention group based on chance
• An essential feature of a good clinical trial
• Must be unrelated to the variables of
interest
Why Is Randomization Necessary?
• Results can differ because of some
factor unrelated to the treatment
• Bias
• Confounding
Common Randomization Schemes
• Complete randomization
• Block randomization
• Urn randomization
• Stratified randomization
• Cluster randomization
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Blinding in Clinical Trials
Purpose of Blinding
• Many clinical trials lack well-defined,
objective endpoints
• Measures are subject to:
– Intentional manipulation
– Unintentional bias
• Disguise whether subjects are receiving
intervention or the control treatment
Types of Blinding
•
•
•
•
Unblinded or Open Label
Single blind
Double blind
Triple blind
Summary
• A clinical trial is a prospective
biomedical or behavioral research
study of human subjects that is
designed to answers specific
questions about biomedical or
behavioral interventions
Summary
FEATURE
TERMS USED
Study Stage
Phase I
Phase II
Phase III
Phase IV
Controls
Uncontrolled
Placebo
Active Control(s)
Randomization
Non-randomized
Randomized
Blinding
Unblinded
Single-blind
Double-blind
Triple-blind
Credits
Content Developer/Author
John M. Harris Jr., MD, MBA
Medical Directions, Inc.
Content Editor/Spanish Translation
Jorge G. Ruiz, MD, FACP
University of Miami Miller School of Medicine
Instructional Designer
Rudy W. Picardo
Stein Gerontological Institute