New Mexico
AIDS
InfoNet Fact
Sheet Number 105
- WHY DOES IT TAKE SO LONG TO APPROVE
NEW DRUGS?
- WHAT ARE THE “PHASES” OF
CLINICAL TRIALS?
- HOW DO WE KNOW IF A DRUG WORKS?
- USING UNAPPROVED DRUGS
- FOR MORE INFORMATION
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PrintSO LONG TO APPROVE NEW DRUGS?
Developing a new drug can take 7 years or more. First,
drug companies must find substances that are active against HIV.
Most HIV drugs are identified by testing existing drugs for anti-HIV
activity (screening). A newer method is rational drug
design. In this process, scientists “build” drug
molecules to fight HIV in specific ways.
When a promising drug is identified, it goes through pre-clinical
testing. This involves test-tube and animal studies. These
show whether the drug works against HIV and how it works. They
also show how it can be manufactured, and make sure it is not
too toxic (poisonous).
If pre-clinical results are good enough, the drug company files
an Investigational New Drug (IND) application. Then it
starts testing the drug in humans (clinical trials). When
enough clinical trials are completed, the manufacturer submits
an NDA, or New Drug Application. If the FDA approves
the NDA, the drug can be sold to treat specific medical conditions.
OF CLINICAL TRIALS?
There are four phases of human clinical trials. These apply to
all drugs, not just drugs for HIV/AIDS. If the results from any
phase of testing are not good enough, the company will stop developing
the drug.
Phase I trials test the safety of new drugs for humans.
These trials record the side effects that occur at different dosages
of the drug. Everyone in a Phase I trial receives the new drug,
but different participants may get different dosages. The trials
usually study less than 100 people, and take less than a year.
In Phase I trials, new drugs are given to humans for the first
time. People who participate in Phase I trials face the highest
risks compared to possible benefits.
Phase II trials can enroll several hundred people and
take 1 to 2 years. They study how well the drug works against
HIV disease. They also collect more information about side effects.
These trials are usually randomized. This means that trial
participants are divided into two groups that are similar in terms
of age, sex, and health. One group receives the study drug. The
other group is the reference or control group. People in
the control group get standard treatment (called “standard
of care.”) If there is no standard treatment, they may get
a dummy medication (called a placebo).
Trial participants and their doctors usually do not know who
is getting the study drug or the placebo. This is called a blinded
study. Studies are blinded so that the doctors will be totally
objective when they evaluate the health of patients in the study.
Phase III trials collect more data on a drug’s effectiveness
and side effects. These trials can study up to a few thousand
people and often last for a year or more.
Phase III trials are normally randomized and blinded. Participants
might not receive the study drug. With good results in Phase III
trials, a manufacturer can apply for FDA approval to sell the
new drug.
Phase IV trials are called “post-marketing studies”.
The regulations for Phase IV trials are not very clear, and they
are not conducted very often. Phase IV trials can monitor a new
drug’s long-term effectiveness and side effects, or how cost-effective
it is. They can also compare the new drug to other drugs approved
for the same condition.
IF A DRUG WORKS?
The FDA used to require trials that measured clinical endpoints
before approving a new HIV drug. These trials analyze how many
people get sicker, develop opportunistic infections, or die.
However, these trials take a long time and are very expensive.
A faster, cheaper way to test new drugs is by using indirect measures
of patient health. These surrogate markers are laboratory
values such as viral load or T-cell counts. In 1997, the FDA approved
the use of surrogate markers for full approval of new HIV drugs.
DRUGS
There are three legal ways to use drugs that the FDA has not approved
to treat your specific health problem:
1. Expanded Access is a program where manufacturersto
provide unapproved drugs to people who cannot take part in a clinical
trial. Patients must , and who meet conditions set by the drug
manufacturer. The drugs are usually offered at no charge, but
your doctor will have to collect information on how you respond
to the drug.
2. Drug companies sometimes provide new drugs to people who
are very ill and who have no other treatment options. This is
called through Compassionate Use, also called a “Treatment
IND Protocol”.
3. Your doctor can write a prescription for any FDA-approved drug,
even if you use it for some other medical condition. This is called
off-label use. There may be no information about how often
medications are used off-label, or how well they work.
The FDA Center for Drug Evaluation and Research has an informative
Internet web page: http://www.fda.gov/cder/handbook/dev_rev.htm
The AIDS Clinical Trials Information Service (telephone 1-800-TRIALS-A)
provides information on clinical trials in general, and on trials
that are currently enrolling participants.
Revised April 5, 2002
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