Bookmark this page or recommend it.

Phase I trials test a new drug on human beings after many laboratory investigations. This type of trial usually treats only a small number of patients. One important aim is to test for tolerance. Phase I trials often recruit patients in whom tumors, despite previous multiple treatments, continue to grow. For those patients, participation in a Phase I trial provides an excellent opportunity to receive a new drug under carefully monitored conditions.

Phase II trial test mainly the efficacy of a new therapy and trials usually comprise 30-80 participants, sometimes more. To better analyse the efficacy of a new drug on individual patients, many Phase II trials carry out additional biological investigations on blood or tumor tissue in parallel to the therapy.

Phase III trials compare new therapies with standard therapy. Not only can different drugs or combinations of drugs be compared with each other, but so can surgical and radiation treatment interventions, for example. The allocation to a specific treatment arm in a Phase III trial follows the principle of chance. This allocation method is called randomisation. Only through this ‘by chance’ allocation is it possible to avoid any influence on the study results by the doctor or patient, and to discover any real differences in results between the treatment arms. It is possible that in cases where there is no known standard therapy for a specific treatment indication, the control group is not being treated at all.

> Back