ABSTRACT
The primary objective of phase I trials of a new anticancer drug is to assess the toxic side effects of the drug and to recommend a dose for the subsequent phase II trials. This recommended dose is typically the maximum test dose that does not exceed an acceptable level of toxicity, the so-called maximum tolerated dose (MTD). Traditional chemotherapy takes the cytotoxic therapeutic mechanism under which toxicity may be viewed as a surrogate for anti-tumor activity. Toxicity, therefore, is in a sense a desirable endpoint, so the trial objective is to find a dose that is associated with a given level of toxicity probability. Also in this sense, this MTD is presumed optimal in the absence of information about efficacy and clinical response.
