Designs for Partially Ordered Phase I Trials

• Activity Number: 1
• Type: Invited
• Date/Time: Sunday, July 29, 2012 : 2:00 PM to 3:50 PM
• Sponsor: Biometrics Section
• Author(s): Mark Conaway*+ and John O'Quigley and Nolan Wages
• Companies: University of Virginia and Universite Paris VI and University of Virginia
• Keywords: dose finding ; continual reassessment ; order restricted inference

Abstract

Most methods for the design of Phase I trials in oncology are intended for studies involving a single cytotoxic agent. The goal of these studies is to estimate the maximally tolerated dose, the highest dose that can be administered with an acceptable level of toxicity. A key assumption of these methods is the monotonicity of the dose-toxicity curve; administration of greater doses of the agent can be expected to produce toxicities in increasing proportions of patients. In this case, the dose-toxicity curve is said to follow a 'simple order' because the ordering of the probabilities of a 'dose-limiting toxicity' (DLT) for any pair of doses is known.

It is becoming increasingly common for combinations of agents to be tested in phase I trials. In these studies, the probabilities of a DLT associated with the dose combinations often follow a 'partial order' in that there are pairs of dose combinations for which the ordering of the probabilities is not known. This talk will review existing methods and outline new methods that combine features of the continual reassessment method and order restricted inference to develop designs for partially ordered phase I trials.