In recent years randomized trials designed to establish non-inferiority of a new treatment as compared to a standard one have been more widely used. Two-sample statistics have been proposed for this equivalence testing problem. However, they are not suited to situations where a long-term survivor fraction is expected. In this paper we propose a score test designed for establishing non-inferiority for the new treatment as compared to the standard one while assuming identical long-term survivor rates. Simulations results show that the proposed statistic has satisfactory size and power as long as certain restricting conditions are verified. A breast cancer trial is analysed as an example.
Copyright 2003 John Wiley & Sons, Ltd.