Effect of Subsequent Therapies After Discontinuation of Study Medication in Analyzing Overall Survival in Cancer Clinical Trials

• Activity Number: 192
• Type: Roundtables
• Date/Time: Monday, August 1, 2011 : 12:30 PM to 1:50 PM
• Sponsor: Biopharmaceutical Section
• Author(s): Julie Xiuyu Cong*+
• Companies: Boehringer Ingelheim
• Keywords: Subsequent treatment/therapy ; treatment discontinuation ; overall survival ; clinical trials ; cancer/oncology

Abstract

Typically in cancer trials, patients are discontinued from the randomized study medication (control or experimental treatment) if patients develop disease progression or intolerable adverse events. In many cancer settings, such patients continue living for a considerably long time and take other anti-cancer therapies available to them. These patients are typically followed up for vital status in the trial with the aim to evaluate overall survival. As a result of such subsequent therapies, the treatment effect of true interest (experimental vs. control) is not properly assessed using the standard Intent-to-Treat (ITT) approach. Various statistical methodologies have been proposed and investigated by statisticians worldwide, including but not limited to marginal structural model, nested structural model, propensity scores, etc. This roundtable session aims to discuss the pros and cons of available methodologies and stimulate new ideas.