Clinical trials are formalized research studies for determining the safety and effectiveness of new treatments. Generally they are prospective, meaning that rules for who can participate, how the research is conducted, what data are collected and how the results are to be interpreted are specified in advance. The rules are designed to minimize predictable sources of bias and noise in the data so that the main experimental question can be answered with a minimal number of participants. Clinical trials are approved and monitored by a local Institutional Review Board (IRB) and sometimes also by the FDA, study sponsor and/or other groups.
Clinical trials are very important for conducting research on diseases like mesothelioma. Because there is no established standard way of treating mesothelioma, many different treatment strategies are tested using clinical trials so that they may be compared to one another. Because it is a rare disease, there are relatively few potential participants so keeping the study size small is important. For the same reason, patients with mesothelioma may be invited to participate in more than one clinical trial at the same time.