Understanding Clinical Trials - 4 stages

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How Clinical Trials Work

http://clinicalresearch.nih.gov/how.html

Clinical research is medical research that involves people. Individuals

volunteer to participate in carefully conducted investigations that ultimately

uncover better ways to treat, prevent, diagnose and understand human disease.

Clinical research includes trials that test new treatments and therapies as well

as long–term natural history studies, which provide valuable information about

how disease and health progress.

The idea. Ideas for clinical research—also known as clinical trials or clinical

studies—often originate in the laboratory or patient-care settings. After

researchers test new therapies or procedures in the laboratory and in animal

studies, the most promising experimental treatments are moved into clinical

trials, which are conducted in phases. During a trial, more information is

gained about an experimental treatment, its risks, and its effectiveness.

The protocol. Clinical research is conducted according to a plan known as a

protocol. The protocol is carefully designed to safeguard the participants'

health and answer specific research questions. A protocol describes the

following:

Who is eligible to participate in the trial

Details about tests, procedures, medications, and dosages

The length of the study and what information will be gathered

A clinical study is led by a principal investigator, who is often a doctor.

Members of the research team regularly monitor the participants' health to

determine the study's safety and effectiveness.

Protocol review. Each clinical trial in the United States must be approved and

monitored by an Institutional Review Board (IRB) to ensure that the risks are

minimal and are worth any potential benefits. An IRB is an independent committee

that consists of physicians, statisticians, and members of the community who

ensure that clinical trials are ethical and that the rights of participants are

protected. Federal regulation requires all institutions in the United States

that conduct or support biomedical research involving people to have an IRB

initially approve and periodically review the research.

Sponsors. Clinical trials are sponsored or funded by various organizations or

individuals, including physicians, foundations, medical institutions, voluntary

groups, and pharmaceutical companies, as well as federal agencies such as the

National Institutes of Health, the Department of Defense, and the Department of

Veterans Affairs. Trials can occur at sites as varied as hospitals,

universities, doctors' offices, or community clinics.

Informed consent. Informed consent is the process of providing potential

participants with the key facts about a clinical trial before they decide

whether to participate. The process of informed consent (providing additional

information) continues throughout the study. To help someone decide whether or

not to participate, members of the research team explain the details of the

study. Translation or interpretive assistance can be provided for participants

with limited English proficiency. The research team provides an informed consent

document that includes details about the study, such as its purpose, duration,

required procedures, and who to contact for further information. The informed

consent document also explains risks and potential benefits. The participant

then decides whether to sign the document. Informed consent is not a contract.

Volunteers are free to withdraw from the study completely or to refuse

particular treatments or tests at any time. Sometimes, however, this will make

them ineligible to continue the study.

Types of clinical trials. The types of clinical trials include the following:

Treatment trials test new treatments, new combinations of drugs, or new

approaches to surgery or radiation therapy.

Prevention trials look for better ways to prevent a disease in people who have

never had the disease or to prevent the disease from returning. Better

approaches may include medicines, vaccines, or lifestyle changes, among other

things.

Diagnostic trials determine better tests or procedures for diagnosing a

particular disease or condition.

Screening trials test the best way to detect certain diseases or health

conditions.

Quality of life trials (or supportive care trials) explore and measure ways to

improve the comfort and quality of life of people with a chronic illness.

Phases of clinical trials. Clinical trials are conducted in " phases. " The trials

at each phase have a different purpose and help researchers answer different

questions.

Phase I trials—Researchers test an experimental drug or treatment in a small

group of people (20–80) for the first time. The purpose is to evaluate its

safety and identify side effects.

Phase II trials—The experimental drug or treatment is administered to a larger

group of people (100–300) to determine its effectiveness and to further evaluate

its safety.

Phase III trials—The experimental drug or treatment is administered to large

groups of people (1,000–3,000) to confirm its effectiveness, monitor side

effects, compare it with standard or equivalent treatments, and collect

information that will allow the experimental drug or treatment to be used

safely.

Phase IV trials—After a drug is licensed (approved by the FDA) or treatment is

launched, researchers track its safety, seeking more information about a drug or

treatment's risks, benefits, and optimal use. These long–term studies involving

large groups of participants continue to see if any unexpected side effects

occur in a small percentage of individuals.

Some concepts to understand. Typically, clinical trials compare a new product or

therapy with another that already exists to determine if the new one is as

successful as, or better than, the existing one. In some studies, participants

may be assigned to receive a placebo (an inactive product that resembles the

test product, but without its treatment value).

Comparing a new product with a placebo can be the fastest and most reliable way

to demonstrate the new product's therapeutic effectiveness. However, placebos

are not used if a patient would be put at risk—particularly in the study of

treatments for serious illnesses—by not having effective therapy. Most of these

studies compare new products with an approved therapy. Potential participants

are told if placebos will be used in the study before they enter a trial.

Randomization is the process by which two or more alternative treatments are

assigned to volunteers by chance rather than by choice. The assigned treatment

is administered with the highest level of professional care and expertise. The

results of each treatment are compared at specific points during a trial, which

may last for years. When one treatment is found superior, the trial is stopped

so that the fewest patients possible receive the less beneficial treatment.

In single- or double-blind studies, also called single- or double-masked

studies, the participants do not know which medicine is being used, so they can

describe what happens without bias. " Blind " (or " masked " ) studies are designed

to prevent members of the research team or study participants from influencing

the results. This allows scientifically accurate conclusions. In single-blind

( " single-masked " ) studies, only the patient is not told what is being

administered. In a double-blind study, only the pharmacist knows; members of the

research team are not told which patients are getting which medication, so that

their observations will not be biased. If medically necessary, however, it is

always possible to find out what the patient is taking.