<p>Phase II clinical trials aim to determine whether an experimental treatment or drug is sufficiently promising to warrant further testing. The importance of stopping a clinical trial earlier stems from the fact that it is unethical to continue and to include new patients using an inefficient treatment. Many researchers have dealt with stopping rules for phase II clinical trials. Stallard et al. (<CitationRef CitationID="CR83">2001</CitationRef>) briefly described and compared different approaches for the statistical design of stopping rules for such trials. This paper offers an overview of the designs and stopping rules for phase II clinical trials proposed mainly in the last decade. The problem of early termination of clinical trials of phase II is important and remains an active area for further methodological development.</p>