A pilot study is one in which a few patients are enrolled to determine how feasible it is to deliver the treatment (or how feasible it is to administer a diagnostic test. Pilot studies often precede Phase I-II studies.
A Phase I study is designed to assess the tolerability or safety of a drug or other treatment. Often the dose of the drug is progressively increased to determine the maximal tolerated dose in patients. Phase I studies also examine the pharmacokinetics of the drugs in humans, meaning determining the mechanism and rate in which a drug is absorbed, distributed, metabolized, and excreted. Phase I studies are often offered to patients when standard therapies have failed or are not expected to be effective. Phase I studies that enroll patients with mesothelioma may also enroll patients with other types of cancer.
Next, read about Phase II studies.