What are the phases of a clinical trial of a drug for FDA approval?
Phase One clinical trials study the safety of the drug. Small amounts of the drug are administered to small numbers of healthy volunteers (persons who do not have
the condition for which the drug was created) to find out what happens in the human body to those taking the drug. A full range of doses is tested so volunteers will take both low doses and very high dose so the testers can determine what does is 'safe' and what is toxic.
Phase One trials also record 'side effects' - those effects of a drug, usually negative or unpleasant, that happen when people take the drug. eg. nausea, depression, dry mouth etc.
If a drug 'passes' phase one clinical trials, it then moves on to Phase Two.
Phase Two: A phase two study provides information about the drug's effectiveness and safety. If a drug has been shown safe at phase one, it will likely go into phase two testing, which may involve small numbers of patients who have the disease for which the drug is being tested. To participate in the trial at this point, patients may have to meet strict criteria. Those participating in Phase Two trials often need to meet special criteria eg. have been diagnosed with
the disease or condition within a certain time frame, not having taken drugs for the condition for a certain period of time, not have other conditions for which they are being treated etc.
Most phase two studies are randomized trials, meaning patients will be randomly chosen to receive either the experimental drug or an inactive substance, or placebo.
These tests are usually double blind that is, neither the participants not the persons doing the testing know which participants are receiving the drug and which are receiving the placebo. This cloaking is done to prevent subtle cues from those doing the testing influencing the participants response to whatever substance they are getting. (It has been shown the
a doctors expectation of cure or lack thereof...or even of likely side effects can be communicated to a participant and subtle affect his or her response to treatment. Randomization is used to prevent this from happening during a drug trial.
A drug which 'passes' Phase Two trials may go on to Phase Three trials.
Phase Three clinical trials use the largest number of subjects and usually take the longest period of time. The drug is tested on more people with the condition that it is supposed to treat. Many of these people may have other conditions and they may be taking other drugs for these. In other words, Phase Three volunteers are more like the general population than volunteers in either of the earlier phases. Again the tests will be randomized and double blind.
The aim of Phase Three trials is to gather additional information about a drugs value, its side effects, how it compares to treatments already in use etc.
If a drug proves useful and its side effects
are within limits, the manufacturer will ask the governing body eg. the FDA in the United States to "approve the drug for treating such and such a condition".
The governing body reviews all the testing and issues its decision. The FDA will review all the tests and results. Sometimes they will ask the opinion of other experts at advisory
committee hearings which are often open to the public. If the FDA finds
that the drug is both effective and safe it will approve the drug for use in specific condition(s).
Sometimes the FDA orders a company to continue with Phase Four trials.
Often companies conduct Phase Four trials on their own, even if the FDA does not
require it.
Phase Four clinical trials. If a drug is approved for use in relation to some specific condition(s), testing continues. The aim is to find out the long-term effects of the drugs, possible additional side effects and its impact on the quality of life of those using it. Recently in the United States, for example, the FDA manufacturers removed some drugs that had been approved after Phase Three clinical trials because the Phase Four studies showed that the drugs had
severe negative effects in their long term usage.
Osteopenia or Osteoporosis Studies seeking participants
If you choose to participate in any medical studies, you need to remember that researchers try to screen out the 'placebo effect'. Some participants will not receive the substance being studied; they will receive a dummy or 'placebo'.
To prevent subtle cues that might influence participants, neither participants nor those conducting the study will know who is receiving the drug under study or who is being receiving a placebo.
If you are thinking of participating in any drug treament study, you need to ask questions about the purpose of this stage of the study, potential risks etc.
- Center Watch lists many Clinical Trials in the United States. Information is categorized by State.
For Canadians and other international persons, they list trials by country. Any relevant trials would be listed under Musculoskeletal Trials.
- Novartis is currently seeking post menopausal women to participate in a study of a new treatment. You can access information and applications at their
Clinical Trials: Osteopenia
- The United States National Institute of Health lists a number of studies seeking
participants:
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Current research studies - Set # 1
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Current research studies - Set # 2
Go to
Osteopenia Treatments .
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