Clinical Trials

© 2010 Project Lead The Way, Inc.Medical Interventions

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

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

people)

Phase II Trial

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

participants)

Phase III Trial

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

participants)

Phase IV Trial

• Collect additional information after the drug enters the market, such as:– Drug’s risks– Drug’s 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

Single-Blind

• 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 studies

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

combined– 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 apparent

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 following:– 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

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.