An adaptive design is provided for phase III clinical trials where the treatment responses are categorical. The proposed design extends the drop-the-loser rule (Ivanova ) which is proposed for binary treatment responses only. It is illustrated that the proposed design is an improvement over the existing design of Bandyopadhyay and Biswas  for such categorical responses in terms of low variability. Some probability generating functions of the proposed design are obtained. The applicability of the proposed design is illustrated by using some real data from an trial of patients of rheumatoid arthritis.
International Journal of Information and Management Sciences 18(1), pp.1-16