Research updates
Phase III clinical trials   page 2
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1. Introduction (cont'd) Link to the Medical Research Council web site
What do trials trial?
The most common single purpose of a clinical trial is to test new drug treatments, but trials are also used to evaluate many other kinds of healthcare. Trials to test new drugs are usually run by the pharmaceutical industry (see Making new medicines in the People and medicine resource). However there are also many other trials undertaken by independent groups, such as the MRC and the medical research charities, that are aimed at addressing a much wider range of questions.
Trials may be used to explore the best way to use new or old drugs together or to test other treatment strategies, such as surgical operations or radiotherapy. More complicated "packages of care" may be tested. Rehabilitation, ante-natal care or cancer screening programmes are examples.The box below describes how a clinical trial showed that giving chemotherapy before surgery to patients with cancer of the oesophagus lengthens their lives. Approaches to disease prevention may also be evaluated by clinical trials; these include vaccinations, screening (for cancer or other diseases) and education campaigns (to stop smoking or prevent HIV infection, for example).
Box 1. A trial of treatments for oesophageal cancer
Over 800 patients took part in a clinical trial conducted by the Medical Research Council Oesophageal Cancer Working Party. All had cancer of the oesophagus considered by their surgeon to be surgically removable, and were randomly assigned to receive either immediate surgery or two courses, three weeks apart, of chemotherapy (with the anti-cancer drugs cisplatin and fluorouracil) followed by surgery.

A number of benefits were seen in the group receiving chemotherapy compared with the immediate surgery group. Patients’ ability to swallow was improved by the time their surgery was due, surgical removal of their cancer was more often complete, and their survival was prolonged. In the chemotherapy group, all the tumour was surgically removed in 60% of the patients compared with 54% of those in the immediate surgery group, and 43% of the patients in the chemotherapy group were alive two years after joining the study compared with 34% of those in the immediate surgery group.

(published in The Lancet, 18 May 2002)
Other phases of trials
The MRC Clinical Trials Unit undertakes mainly Phase III trials and sometimes Phase II trials. The phases are shown below.
Timeline graphic of phases with roll overs
Figure 2. Timeline for a drug trial. The length of phase III depends on the prognosis of the disease. This is typical of a trial of a drug for a disease with a shorter life expectancy. Roll over the phases to find out more information.
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Our next step is to examine the ethics of medical research in human participants.

Clinical trials are tests on people. Animal experiments are part of the pre-clinical development of a new drug. They belong to an earlier and separate part of the story told elsewhere. The rights and wrongs of the use of animals in biomedical research are discussed in MRC Update Ethics and the Gene Map.

 

 

Question 1
Clinical trials are used not only for new drugs but to test treatment strategies. Box 1 gives you an example.

a) What were the two treatment strategies being compared?

b) Which treatment strategy benefited the patients most? What were the benefits?

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