A RANDOMIZED LONGITUDINAL PLAY-THE-WINNER DESIGN FOR REPEATED BINARY DATA

Authors


  • Acknowledgments. The authors thank two referees, an associate editor, the Technical Editor, Dr Amita Pal, Ms Noelle Noble, Ms Kathy Nyland and Ms Sandy Walbrek for their valuable comments, which led to an improved presentation of the paper. The authors thank the Biometry Unit of the Indian Statistical Institute, Kolkata, for providing data from the PEMF experiment conducted therein. The authors also thank Mr Shyam Sundar Sahoo for some numerical computations, and Drs K.S. Ganguly and Tapas Samanta for their interest and encouragement in the present work.

Summary

In some clinical trials with two treatment arms, the patients enter the study at different times and are then allocated to one of two treatment groups. It is important for ethical reasons that there is greater probability of allocating a patient to the group that has displayed more favourable responses up to the patient's entry time. There are many adaptive designs in the literature to meet this ethical constraint, but most have a single binary response. Often the binary response is longitudinal in nature, being observed repeatedly over different monitoring times. This paper develops a randomized longitudinal play-the-winner design for such binary responses which meets the ethical constraint. Some performance characteristics of this design have been studied. It has been implemented in a trial of pulsed electro-magnetic field therapy with rheumatoid arthritis patients.

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