This book chapter discusses response-adaptive randomization procedures which are based on optimal allocation proportions, e.g. derived from theoretical optimization problems. We elucidate the objectives of these proportions, emphasizing their role in maximizing statistical power and/or enhancing patient benefit. Moreover, practical insights on estimation and targeting of these allocation proportions are provided. A clinical trial example, the CALISTO trial, illustrates the application of these procedures. We aim to provide an overview that serves as a basis for discussions about optimal allocation proportions, assists in their implementation in practice and highlights future research areas.