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Clinical trials

Like all innovative pharmaceutical companies, we carry out a series of clinical trials to test each investigational drug for the potential to become a new medicine.

The effect of the potential drug will often be compared to that of an inactive substance, a placebo, which is prepared to look like the drug so as to prevent bias during the trial. The investigational drug may also be compared against marketed medicines.

Phase I trials typically involve healthy volunteers. These trials study the safety of the drug and its interaction with the body, for example, its concentration and duration in the blood following various doses, and begin to answer such questions as whether the drug inhibits or amplifies the effects of other medicines that might be taken at the same time.

Phase II studies enrol patients with the illness an investigational drug is designed to treat. These trials evaluate whether the drug shows favourable effects in treating an illness and seek to determine the proper dose. They provide an opportunity to explore the therapeutic potential of the drug in what may be quite different illnesses. The evaluation of safety continues.

If Phase II results have been encouraging, Phase III trials, the largest part of a clinical-development program, go forward. Phase III trials are designed to provide the substantial evidence of efficacy and safety required, in addition to data from earlier-phase trials, before regulatory agencies will approve the investigational drug as a medicine and allow it to be marketed.

Trials of a medicine may continue even after it has been approved for marketing. Known as Phase IV trials, they may further evaluate the effect of the medicine for the approved use, assess other potential uses, or yield additional safety data. Regulatory agencies may require these trials to address specific questions.

Given the exploratory nature of clinical development, investigators often need to conduct trials of varying designs to determine the potential of an investigational drug and its best use. Rarely does any one trial enable a full understanding.

Therefore, a pharmaceutical company performs a comprehensive analysis of its studies for submission to regulatory agencies. The prescribing information ultimately approved by those agencies, following their own authoritative, cross-study analyses, directs the appropriate use of the medicine.

Although pharmaceutical companies design and take responsibility for the trials they sponsor, any clinical-development program ultimately depends on the commitment of physician-investigators and the patients they enrol in the settings of clinics and hospitals. A new medicine, or new use of a medicine, is the result of a collaborative, often international effort.

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