I trial is to evaluate the safety of a new treatment, including excess toxicity and side effects. The objective of a Phase II trial is to determine whether a specific treatment is effective enough to warrant further study, usually if the new treatment appears potentially better than the existing best treatment. Phase I and II trials are relatively small, involving approximately 20-50 patients, and usually all patients are given the new treatment intervention. Such a trial can be quite large, including 100 to several thousand patients and could take place at several different centers. The Phase III trial is much more definitive due to the larger number of patients, the randomization process, and the multiple centers participating.
Statistical considerations are vital to any clinical trial.
The biostatistician ensures that the design of the study is appropriate to meet the objectives of the study. The statistician also ensures that a sufficient number of patients are included in the clinical trial to answer its primary objective, but not so many that patients might be subjected unnecessarily to an ineffective or unsafe treatment or that the study would be conducted over an unnecessarily long period of time. The statistician will describe in advance the statistical methods to be used to analyze the data, such as a binomial comparison of the proportion of responses, a t test for comparisons of means of continuous data, or a survival analysis to compare differences in survival. When the study is completed, the statistician will analyze the data and write a report on the results that were found. Information about the results of clinical trials is quite commonly reported in the news, including television, newspapers and magazines.