Читать книгу Clinical Pharmacology and Therapeutics - Группа авторов - Страница 128

These studies, often called ‘proof of concept’, look at whether a drug works in the patient population that might benefit from the treatment. They are usually conducted by specialists in the field, in a relatively controlled environment, and are designed to assess efficacy or markers of efficacy and the dose–response relationship. A key goal is to decide whether the odds are acceptably good that the compound is effective, may have an acceptable benefit/risk ratio and, if so, to define a single dose to be taken into the Phase III trials. However, some disease areas have very limited markers of efficacy which can be measured in a short, small trial; therefore, in these cases, dose selection is significantly more difficult and sometimes more than one dose will be taken into Phase III. In addition to looking at markers of efficacy, this stage of development allows the identification of side effects in the target patient population. Phase II would normally involve designing a double blind randomised control trial against placebo and possibly also a study against a standard reference drug therapy as control. If the exploratory type II studies suggest good efficacy and acceptable results concerning safety, tolerance and pharmacokinetics, then the larger Phase III clinical trials can be planned. This decision has potentially large cost implications as the costs rise exponentially once you start Phase III clinical trials.