Clinical Trials
From DrugPedia: A Wikipedia for Drug discovery
Clinical Trials are conducted to determine whether new drugs or treatments are both safe and effective.
Clinical trials help physicians discover the answers to the following questions:
1.Is the treatment safe and effective? 2.Is the treatment potentially better than the treatments alredy existing? 3.What are the side effects of the treatment? 4.Does the treatment have any possible risks? 5.How well does the treatment work?
Types of Clinical Trials
- Treatment trials : test experimental treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.
- Prevention trials : look for better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vaccines, vitamins, minerals, or lifestyle changes.
- Diagnostic trials : are conducted to find better tests or procedures for diagnosing a particular disease or condition.
- Screening trials : test the best way to detect certain diseases or health conditions.
- Quality of Life trials (or Supportive Care trials) : explore ways to improve comfort and the quality of life for individuals with a chronic illness.
Phases of Clinical Trials
Clinical trials are conducted in four different phases. The trials at each phase have a different purpose and help scientists answer different questions.
In Phase I trials, researchers test an experimental drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
In Phase II trials, the experimental study drug or treatment is given to a larger group of people (100-300) to see if it is effective and to further evaluate its safety.
In Phase III trials, the experimental study drug or treatment is given to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the experimental drug or treatment to be used safely.
In Phase IV trials, post marketing studies delineate additional information including the drug's risks, benefits, and optimal use.
| Phases | Number of Patients | Duration | Purpose | Percent of Drugs Successfully Tested |
|---|---|---|---|---|
| Phase I | 20-100 | Several Months | Safety | 70 % |
| Phase II | 100-500 | Several months to 2 years | Efficacy | 33 % |
| Phase III | 1000-8000 | 1-4 years | Safety, Efficacy and Dosage | 25-30 % |
| Phase IV (Post-Market Survelliance) | - | - | drug's risks, benefits, and optimal use | - |
