The clinical trial process is separated into different phases, each with a specific objective.

• Initial human tests, called phase I studies, usually involve a small number (20 to 80) of healthy volunteers, and are conducted to determine dosing levels and assess the safety, tolerability, dose response and metabolic properties of the compound in humans.

   

• In phase II studies, the drug is administered to a larger number (50 to 500) of subjects. Unlike phase I trials which involve healthy volunteers, phase II studies confirm the drug's safety profile in patients diagnosed with the disease being studied. Phase II studies can be divided into two categories: phase IIa studies usually examine a variety of doses to identify the initial dosing regimen. Larger phase II studies, often referred to as phase IIb, confirm the safety in a larger patient population, and define the optimal dosing regimen. Because they are often double blinded, they may also provide preliminary data on the drug's efficacy.

   

• Phase III studies are much larger in scale, and gather additional information about the drug's safety and effectiveness in the intended patient population. Depending on the therapeutic area, thousands of patients may be enrolled in studies that compare the drug being tested to one or more currently available therapies. The objective is to show statistical superiority via either improved efficacy or safety over current treatments. This critical endpoint is needed to obtain regulatory approval to market the drug.

Listings of trials that are recruiting patients are available at several places on the Internet. The US government hosts a website called ClinicalTrials.gov This website provides regularly updated information about federally and privately supported clinical research in human volunteers. ClinicalTrials.gov gives you information about a trial's purpose, who may participate, locations, and phone numbers for more details. Before searching, you may want to learn more about clinical trials.

Resource Information

• An Introduction to Clinical Trials
• Participation in Clinical Trials
• Glossary of Clinical Trials Terms
• Links to General Information on Clinical Trials

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• Why participate in a clinical trial?
• Where do the ideas for trials come from?
• Who sponsors clinical trials?
• What is a protocol?
• What is a placebo?
• What is a control or control group?
• What are the different types of clinical trials?
• What are the phases of clinical trials?
• What is an "expanded access" protocol?

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• What happens during a clinical trial?
• What is informed consent?
• What kind of preparation should a potential participant make for the meeting with the research coordinator or doctor?
• What should people consider before participating in a trial?
• Does a participant continue to work with a primary health care provider while in a trial?
• What are side effects and adverse reactions?
• What are the benefits and risks of participating in a clinical trial?
• How is the safety of the participant protected?
• Can a participant leave a clinical trial after it has begun?

Diabetes trials that are listed at ClinicalTrials.gov are subdivided into several categories:

• Diabetes
• Diabetes, insulin dependent (type 1 diabetes)
• Diabetes, lipoatrophic
• Diabetes, experimental
• Diabetes, gestational
• Diabetes, non-insulin dependent (type 2 diabetes)
• Diabetic angiopathies (blood vessel disorders)
• Diabetic foot
• Diabetic nephropathies (kidney disease)
• Diabetic neuropathies (nerve disorders)
• Diabetic retinopathy (eye disease)