Clinical Trials Mrs. Stewart Medical Interventions Central Magnet School - PowerPoint PPT Presentation


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Clinical Trials Mrs. Stewart Medical Interventions Central Magnet School


Title: Clinical Trials Subject: MI - Unit 3 - Cancer Author: Rachel Allard & Stephanie Poll Last modified by: stewartp Created Date: 2/18/2009 7:42:31 PM – PowerPoint PPT presentation

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Title: Clinical Trials Mrs. Stewart Medical Interventions Central Magnet School

Clinical Trials Mrs. Stewart Medical
Interventions Central Magnet School
Purpose of Clinical Trials
  • Assess safety and efficacy of
  • Experimental treatments
  • New combinations of drugs
  • New approaches to surgery or radiation therapies
  • Better disease prevention approaches
  • Better diagnostic approaches

Clinical Trial Phases
  • Phase I trials
  • Phase II trials
  • Phase III trials
  • Phase IV trials

Phase I Trial
  • Test small group of people (fewer than 100
  • Evaluate safety of drug
  • Determine safe dosage range
  • Identify side effects

Phase II Trial
  • Test larger group of people (up to 200
  • Learn more about safety and side effects
  • Sharpen estimates of proper dosage
  • Determine effectiveness

Phase III Trial
  • Test large groups of people (1,000-3,000
  • Determine effectiveness
  • Determine side effects

Phase IV Trial
  • Collect additional information after the drug
    enters the market, such as
  • Drugs risks
  • Drugs benefits
  • Optimal use

Types of Clinical Trials
  • Randomized, double-blind trials
  • Open trials
  • Factorial trials
  • Crossover trials
  • Orphan drug trials

Controlled, Randomized, Double-Blind Trials
  • Controlled One group receives the treatment and
    another group does not.
  • Randomized control group and treatment group are
    chosen at random.
  • Double-blind Neither subjects nor scientists
    know who is assigned to which group until after
    the data are collected.

Treatment Group vs. Control Group
  • Treatment Group
  • Given experimental drug
  • Control Group
  • Given standard treatment or a placebo
  • Placebo an inactive pill, liquid, or powder that
    has no treatment value

Why Double-Blind?
  • Prevents subjects in different groups from
    behaving in different ways
  • Prevents scientists from introducing any
    unconscious bias into the data collection process

  • Subjects do not know which group they are
    assigned to.
  • Researchers know who is assigned to which group.
  • Prone to researcher bias.

Open Trials
  • Set-up where researchers and subjects know what
    treatment is being given
  • Often used to test surgical procedures and
    medical devices, that by nature, cannot be done
    without subject or researcher knowing who is
    receiving the treatment
  • More prone to error and bias than double-blind

Factorial Trials
  • Used to test medicines in combination
  • Set-up in the following manner
  • First group tests therapy A
  • Second group tests therapy B
  • Third group tests therapy A and therapy B
  • Fourth group, the control group, tests neither
    therapy A nor therapy B
  • Difficult to interpret results

Crossover Trials
  • Used to test two treatments
  • Set-up where each participant gets both
    treatments being tested
  • Some participants are assigned at random to
    receive drug A and when done, receive drug B
  • Other participants receive drug B and when done,
    receive drug A

Orphan Drug Trials
  • Used to test drugs designed to treat rare
    diseases (affecting fewer than 200,000 Americans)
  • Tested on small number of participants who are
    very sick
  • If drug works, improved health is usually readily

Safety and Ethical Regulations
  • Clinical trials are designed to safeguard the
    health of the participants.
  • Clinical trials done in the United States must be
    approved and monitored by an Institutional Review
    Board (abbreviated IRB)

Institutional Review Boards
  • IRBs are independent committees comprised of
    physicians, statisticians, community advocates,
    and others. The role of the IRB is to do the
  • Ascertain that clinical trials are scientifically
    worthy and that ethical guidelines are met
  • Potential benefits for participants should
    outweigh risks
  • Participants must be informed of all potential
    risks and agree to willingly participate and can
    drop-out at any time (called informed consent)
  • Monitor the trial during its run and may even
    halt the trial if serious problems are reported

Examples of Unethical Clinical Trials
  • Prisoners in Nazi concentration camps during WWII
    were experimented on.
  • conducted high-altitude experiments, using a
    low-pressure chamber, to determine the maximum
    altitude from which crews of damaged aircraft
    could parachute to safety
  • freezing experiments using prisoners to find an
    effective treatment for hypothermia
  • scientists tested immunization compounds and sera
    for the prevention and treatment of contagious
    diseases, including malaria, typhus,
    tuberculosis, typhoid fever, yellow fever, and
    infectious hepatitis.
  • sterilization experiments
  • determine how different "races" withstood various
    contagious diseases.

Examples in the U.S.
  • Tuskegee airmen 400 African-American men left
    untreated from syphillis despite cure available
    so that scientists could study the natural
    course of the disease
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What Happens After Clinical Trial
  • When the trial ends, the drug company submits all
    data to the Food and Drug Administration (FDA)
    for approval to market the drug.
  • If FDA agrees that the drug is safe and
    effective, it grants approval and the drug is
    moved into everyday medical practice.
  • Once on the market, the FDA continues to survey
    the side effects experienced by patients within
    the general population.