Researchers reassure as drugs trial patients treated in hospital
15 March 2006
Inspectors are trying to find out why six men fell ill while taking part in a clinical trial for a private company at a hospital in north-west London. The men were part of a Phase I clinical trial of a drug to treat chronic inflammatory conditions and leukaemia.
Parexel, the company running the trial, said it had operated within regulatory guidelines. The UK medicines watchdog, the Medicines and Healthcare products Regulatory Agency (MHRA), has suspended the trial and has sent inspectors to the research unit to investigate.
Researchers have been keen to reassure the public and people considering taking part in trials of drugs that such reactions are extremely rare. Professor Janet Darbyshire, director of the MRC Clinical Trials Unit, said “This is a very unfortunate and extremely rare event. All drugs and vaccines undergo extensive laboratory and animal tests before they go into human trials. Researchers follow strict protocols and guidelines and the trials are carefully controlled so that in the unlikely event a situation like this occurs, it would be picked up and dealt with quickly and appropriately, as happened in this case.
“The UK is a world leader in the development of drugs and vaccines which have saved millions of lives. Trials have a vital role to play in the evaluation of the drugs but there is always an element of uncertainty when a new drug is tested in humans for the first time which is why every precaution is taken to ensure the welfare of volunteers. It is essential for new and better treatments to be developed that these studies are undertaken, and that participants, both healthy and patients, volunteer for these studies.”
All new treatments, including drugs, are tested through clinical trials before they receive a licence from the Regulatory Authorities for their use. Clinical trials are only undertaken in humans after prolonged studies in the laboratory and animals.
Clinical trials are usually classified into one of three phases:
Phase I trials: These first studies in people evaluate how a new drug should be given (by mouth, injected into the blood, or injected into the muscle), how often, and what dose is safe. These studies are essential to understand unanticipated and unexpected effects of new drugs that could not be known in advance. A phase I trial normally enrols only a small number of participants, usually healthy volunteers.
Phase II trials: A phase II trial continues to test the safety of the drug, and begins to evaluate whether the new drug works.
Phase III trials: These studies test a new drug or a new combination of drugs, in comparison to the current standard. A participant will usually be assigned to a standard treatment or the new treatment in an unbiased way (usually through a process called randomization). Phase III trials often enrol large numbers of people and may be conducted at many doctors' offices, clinics, and centres nationwide.
Professor Darbyshire added “The methods used by these studies are very closely scrutinised in advance of them starting, and researchers have to follow clear and detailed protocol and guidance. Throughout the studies, especially the Phase I and II trials, participants are very closely monitored, so that unanticipated effects are detected as soon as possible and appropriate action taken. Participation in these studies is entirely voluntary, and every participant signs a form indicating that they understand the nature of the study and agree to take part – the consent form. Participants are free to withdraw from a clinical trial at any stage, without any effect on the management of their illness.”
Further information
- Why clinical trials matter (this website)
- MRC clinical trials unit: http://www.ctu.mrc.ac.uk
- MRC/Cancer Research UK/BHF Clinical Trial Service Unit & Epidemiological Studies Unit: http://www.ctsu.ox.ac.uk/
