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VA National Clinical Public Health Programs — Hepatitis C
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URL: http://www.hepatitis.va.gov/vahep?page=treat-04-07
Clinical Trials
What are the different types of clinical trials?
There are four different types of clinical trials: Phase I, Phase II, Phase III, and Phase IV.
Phase I
is the first time they have tried the drug in people
tests for the drug's safety and helps find the right dose
may ask for frequent tests or a stay in the hospital to check for safety and effectiveness
lasts a fairly short time
has a small number of patient volunteers
Phase II
happens when early studies show that the drug may work well to fight hepatitis C
tests for safety and effective dose level
lasts longer than Phase I trials
tries to find out what kind of side effects you get with this medicine
has several hundred patients
Phase III
happens if the drug worked well in Phase I and II
compares standard treatments (
medicines that you can already get by prescription
) or sugar pills (
placebos
) with the new medicine
may last longer than Phases I and II
looks for ways to reduce the side effects and improve the quality of your life while you are taking the medicine
is the last phase of study before a drug is sent to the FDA
has many patients (
sometimes thousands
)
Phase IV
happens when the drug is already available by prescription
happens less often than other phases
checks other safety issues and long-term side effects
may be used to check higher or lower amounts (or
doses
) of the medicine
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Reviewed/Updated Date: February 8, 2007