Clinical Testing Information
The clinical testing of experimental drugs is normally done in three phases, each successive phase involving a larger number of people. Once the FDA has granted a New Drug Approval (NDA), pharmaceutical companies also conduct post marketing or late phase three/phase four studies.
A Phase One Study:
Phase I studies are primarily concerned with assessing the drug’s safety. This initial phase of testing in humans is done in a small number of healthy volunteers (20 to 100), who are usually paid for participating in the study. The study is designed to determine what happens to the drug in the human
body — how it is absorbed, metabolized, and excreted. A phase I study will investigate side effects that occur as dosage levels are increased. This initial phase of testing typically takes several months. About 70 percent of experimental drugs pass this initial phase of testing.
A Phase Two Study:
Once a drug has been shown to be safe, it must be tested for efficacy. This second phase of testing may last from several months to two years, and involve up to several hundred patients. Most phase II studies are randomized trials. One group of patients will receive the experimental drug, while a second
“control†group will receive a standard treatment or placebo. Often these studies are “blinded” — neither the patients nor the researchers know who is getting the experimental drug. In this manner, the study can provide the pharmaceutical company and the FDA comparative information about the relative safety of the new drug, and its effectiveness. Only about one-third of experimental drugs successfully complete both phase I and phase II studies.
3 Phases to a Clinical Trial: Phase 1, Phase 2, Phase 3
Currently there are about 23 clinical research trials associated with dystonia — use of MyoBloc, deep brain stimulation, focal hand dystonia, EMG use in dystonia, diagnosis and history of neurological disorders. You can find more info about participating in any of these studies by visiting these websites:
Centerwatch.com
ClinicalTrials.gov (Dystonias Search)
CC.NIH.GOV
Dystonia Studies
Your participation is valuable in these studies. We do recommend that you learn about clinical trials before entering a research trial. You should ask yourself these questions before entering a trial:
- How long will the trial last?
- Where is the trial being conducted?
- What treatments will be used and how?
- What is the main purpose of the trial?
- How will patient safety be monitored?
- Are there any risks involved?
- What are the possible benefits?
- What are the alternative treatments besides the one being tested in the trial?
- Who is sponsoring the trial?
A Phase Three Study:
In a phase III study, a drug is tested in several hundred to several thousand patients. This large-scale testing provides the pharmaceutical company and the FDA with a more thorough understanding of the drug’s effectiveness, benefits, and the range of possible adverse reactions. Most phase III studies are
randomized and blinded trials.
Phase III studies typically last several years. Seventy to 90 percent of drugs that enter phase III studies successfully complete this phase of testing. Once a phase III study is successfully completed, a pharmaceutical company can request FDA approval for marketing the drug.
Post-Marketing — Late Phase Three/Phase Four Studies
In late phase III/phase IV studies, pharmaceutical companies have several objectives: (1) Studies often compare a drug with other drugs already in the market; (2) studies are often designed to monitor a drug’s long-term effectiveness and impact on a patient’s quality of life; and (3) many studies are designed to determine the cost-effectiveness of a drug therapy relative to other traditional and new therapies.
Leave a Reply