Phase II clinical trials are generally the first conducted in patients (as opposed to healthy volunteers) and are small-scale trials that give an indication that the drug works effectively and is tolerated. Phase III trials are larger scale, involving hundreds or even thousands of patients and are required to confirm the clinical efficacy and relative safety of a medicine. Due to the patient numbers required and the international nature of many pharmaceutical companies, phase III trials are often carried out globally. Pharmaceutical physicians choose suitable disease targets, and design trials using appropriate measures of clinical efficacy, pharmacodynamic endpoints and safety.
Due to the international nature of most phase III trials, they may be coupled with local programmes conducted to satisfy particular national regulatory requirements, or to test particular formulations or routes of administration of medicines which are relevant to the clinical situation and/or the preferences of the healthcare system or medical culture concerned. The success of phase III trials may have significant consequences for business decisions made in pharmaceutical companies, perhaps involving the building of new factories or the installation of a new plant, the preparation of marketing plans, including reimbursement discussions/planning, the production of medical literature and the training of personnel.
Running safe and efficient clinical trials requires close collaboration between:
- the trial sponsor
- the hospital or clinic where the patients are located
- the consultant or GP responsible for them
- the chief investigator
- other healthcare professionals in the research team or supporting it
- the ethics committee responsible.
In order to ensure a high-quality service, pharmaceutical physicians or others from the sponsoring body can undertake training of the clinical investigators and their teams in clinical research principles and practices.