Question

Experimental studies can involve therapeutic or preventive trials. Provide an example for each type of trial.

Answer 1

vClinical trials are experiments or observations done in clinical research.Clinical trials in individuals can be classified as either therapeutic or preventive. These are done to learn whether they work well enough, called "efficacy" or "effectiveness"; and to learn whether they are safe enough, called "safety.

There are 5 phases

phase 0-

Phase 0 trials are the first clinical trials done among people. They aim to learn how a drug is processed in the body and how it affects the body. In these trials, a very small dose of a drug is given to about 10 to 15 people.

Phase I trials aim to find the best dose of a new drug with the fewest side effects. The drug will be tested in a small group of 15 to 30 patients.  

Phase II trials further assess safety as well as if a drug works. The drug is often tested among patients with a specific type of cancer. Phase II trials are done in larger groups of patients compared to Phase I trials.

Phase III trials compare a new drug to the standard-of-care drug. These trials assess the side effects of each drug and which drug works better. Phase III trials enroll 100 or more patients.There can be more than two treatment groups in phase III trials. The control group gets the standard-of-care treatment. The other groups get a new treatment.

Phase IV trials test new drugs approved by the FDA. The drug is tested in several hundreds or thousands of patients. This allows for better research on short-lived and long-lasting side effects and safety.  

Therapeutic trials are ones which enroll patients and provide a specific treatment to the patients to study its impact. Interventional trials (also called treatment trials) are clinical trials which set out to test treatments or combinations of treatments which have not yet been officially approved.New treatments are tested for the effectiveness in treating disease,

• A therapeutic trial is one in which the treatment under investigation is believed to be likely to benefit the participants in some way (at least those receiving the experimental drug - in the case of drug trials).

For example, a pharmaceutical company may have developed a new drug which it believes would be effective in the treatment of Alzheimer’s disease but must first test it on human volunteers in accordance with strict and rigorous guidelines in order to ensure that it is safe and effective. Some drugs might be aimed at curing a particular condition, whereas others might be aimed at better controlling symptoms of a particular condition.

Does treatment with Tamiflu shorten the duration and improve survival in patients with bird flu?

Prevention trials involve tests to find ways to prevent particular medical conditions or if people have them already, to prevent them from reoccurring. The emphasis of these studies might be on medicines, vitamins and minerals or lifestyle changes. Vaccination ,immunizations are examples.

Healthy or high-risk individuals are tested to find whether a treatment prevents disease, e.g.,

• Does the drug tamoxifen prevent development of breast cancer in women who have a high risk of developing breast cancer?
• How effective is this year's influenza vaccine in preventing the flu?
• Does a Mediterranean diet reduce the incidence of cardiovascular disease?