Clinical Trials - Phase - III

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Written by Vanessa Jones, B.A  | Medically Reviewed by Dr. Sunil Shroff, MBBS, MS, FRCS (UK), D. Urol (Lond) on Aug 28, 2014
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Clinical Trials - Phase - III

A Placebo is usually used as the "treatment" for one arm of a randomized trial, typically a double blind randomized trial.

However in cases where the treatment causes obvious side effects, a placebo cannot sensibly be used. If there is no effective standard treatment, the control group may simply get no treatment. In such cases, members of the control group will know that they are in the control group.

Open Trial ( Unblinded )

  • Randomized trials
  • Open trials
  • Factorial trials
  • Crossover trials
  • Orphan drug trials

In this type of a trial the researcher as well as the patient knows the full details of the treatment or experimental drug. An Open Label Trial can be Randomized, or non-randomized, as long as the patients and doctors know what treatment has been assigned. Trials of surgical procedures and comparisons of medical devices are often by nature open. One of the problems with an open drug trial is that many participants may not want to take placebos, because they presume the drug will be better.

Open trials are not very reliable .The main use of the this trial is to look for adverse effects of a drug / treatment.

Factorial trials

  • Randomized trials
  • Open trials
  • Factorial trials
  • Crossover trials
  • Orphan drug trials

In a factorial trial, patients are treated with a combination of drugs, in such trials a new drug may be evaluated by testing it in combination with other drugs rather than by itself. A simple factorial trial would have one group testing therapy A, another testing therapy B, a third group testing A and B combined, and a control group testing neither A nor B. Factorial designs are considered an efficient way to test medicines in combination, but their results are not always easy to interpret.

Crossover trials

  • Randomized trials
  • Open trials
  • Factorial trials
  • Crossover trials
  • Orphan drug trials

In a crossover trial a comparison is made between two or more treatments or interventions and each participant gets both treatments being tested. Some participants are assigned at random to receive drug A, and later, drug B. Others receive B, then A. The principal drawback of a crossover trial is that the effects of one treatment may "carry over" and alter the response to subsequent treatments, for this reason crossover trials are not often used.

Orphan Drug Trials

  • Randomized trials
  • Open trials
  • Factorial trials
  • Crossover trials
  • Orphan drug trials

Orphan drug trials test drugs for rare genetic diseases that may affect only a few thousand individuals in a population. Because the affected individuals are so few, an orphan drug may be tested only on a small number of participants, who generally are so sick that if the drug works, their improved health is readily apparent.

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can any one give me different names given to different phases in clinical studies?

My colleagues and I have just concluded one of India's most in-depth studies on "Clinical Trials in India". We have looked at various areas such as:
- Market Trends
- Growth Drivers
- Regulatory Bodies and Framework
- Major Players.
-Etc.
We interviewed over 200 individuals and firms to collect the data in what we believe is one of the most detailed study on the subject in India.

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