Clinical trial

A clinical trial is one of the steps needed to introduce a new drug or therapy. Depending on the drug, either volunteers or patients suffering from a disease or condition are enrolled in a study. In general, a number of the people taking part will receive the real drug, or a good treatment, and the rest of the people will receive a treatment or drug that has no effect, called a placebo. These tests are statistical tests.

Examples of study designs:

• See if a certain drug is useful in treating a given disease.
• See if the disease or treatment improves with a different dose of medication.
• See if a drug that is already on the market can also help treat another disease (it was not designed for, at the start).
• See if a drug or treatment is better able to treat a patient's condition than the "standard" treatment already used.
• Compare two drugs or treatments to see which one is better able to treat a given condition.

History

Clinical trials were first introduced in Avicenna's The Canon of Medicine in 1025 AD, where he laid down rules for the experimental use and testing of drugs. He wrote a precise guide for practical experimentation in the process of discovering and proving the effectiveness of medical drugs and substances. He laid out the following rules and principles for testing the effectiveness of new drugs and medications, which still form the basis of modern clinical trials:

1. The drug must be free from any extraneous accidental quality.
2. It must be used on a simple, not a composite, disease.
3. The drug must be tested with two contrary types of diseases, because sometimes a drug cures one disease by its essential qualities and another by its accidental ones.
4. The quality of the drug must correspond to the strength of the disease. For example, there are some drugs whose heat is less than the coldness of certain diseases, so that they would have no effect on them.
5. The time of action must be observed, so that essence and accident are not confused.
6. The effect of the drug must be seen to occur constantly or in many cases, for if this did not happen, it was an accidental effect.
7. The experimentation must be done with the human body, for testing a drug on a lion or a horse might not prove anything about its effect on man.

One of the most famous clinical trials was James Lind's demonstration in 1747 that citrus fruits cure scurvy. He compared the effects of various different acidic substances, ranging from vinegar to cider, on groups of afflicted sailors, and found that the group who were given oranges and lemons had largely recovered from scurvy after 6 days.

Frederick Akbar Mahomed (d. 1884), who worked at Guy's Hospital in London, made substantial contributions to the process of clinical trials during his detailed clinical studies, where "he separated chronic nephritis with secondary hypertension from what we now term essential hypertension." He also founded "the Collective Investigation Record for the British Medical Association; this organization collected data from physicians practicing outside the hospital setting and was the precursor of modern collaborative clinical trials."