A clinical trial is the process through which new medications or therapies are tested to determine their ability to perform their stated task. They are also used to evaluate surgeries, radiation, and combinations of these treatments. Not all trials lead to success, but many do. There are four phases of clinical trials.
Phase I: This is the first way in which a new treatment is tested with humans. Before a phase I trial, the treatment is researched in the laboratory until it is believed to be safe and effective.
Phase I trials test the treatment on a small group of patients who have failed standard therapies. The goals of phase I are to determine the anticancer activity of the treatment, the effective dose, and identify any unexpected side effects. The dose is initially very low and then slowly increased if it appears safe.
Phase II: If a treatment passes phase I, it can be tested in a phase II trial. These trials are usually still limited to those patients who have failed conventional therapy. The goal of these trials is to identify the effectiveness of dosages, and they use a larger number of patients.
Phase III: In these trials, the new treatment is tested against standard therapy. Volunteers are randomized to receive either the new treatment or standard treatment, and neither the patients nor the doctors should know which treatment is given until after the study and whether it is feasible. Two separate, successful phase III trials must be completed before the treatment is eligible for Food and Drug Administration approval.
Phase IV: After a medication is approved by the Food and Drug Administration and made available to all patients, it continues to be monitored in a phase IV trial. Uncommon side effects may be identified as the number of patients increases and the types of diseases treated change.
A variety of clinical trials are being performed to assess different chemotherapy regimens for metastatic bladder cancer.