In clinical trials, monitoring accumulating data at regular intervals is essential for balancing ethical and financial considerations against scientific rigor. This comprehensive second edition reflects the remarkable evolution in adaptive clinical trial methodology over the past two decades. Since publication of the first edition, these approaches have transformed from theoretical concepts to widely accepted practices, now endorsed by regulatory authorities, including formal FDA guidance. FeaturesEleven entirely new chapters, including optimal design construction, delayed "pipeline" data accommodation, and multiple comparison proceduresEight dedicated chapters on adaptive methods including sample size re-assessment, seamless Phase II/III trials, multi-arm multi-stage trials, and enrichment designsExact methods for binary and Poisson data with applications to vaccine trialsExpanded discussion of binding versus non-binding futility boundaries for enhanced decision-makingA chapter with a thoroughly updated review of Bayesian approaches to sequential trial design and analysisIncorporates response-adaptive treatment assignment in group sequential designsPractical computational methods and software guidance for implementing the techniquesThis definitive resource serves statisticians, clinical researchers, pharmaceutical scientists, and regulatory professionals involved in clinical trial design and analysis. The text balances theoretical foundations with practical implementation guidance, making it invaluable for both experienced practitioners and those new to adaptive trial methodology. With twice the content of the first edition, Group Sequential and Adaptive Methods for Clinical Trials, Second Edition provides the comprehensive understanding needed to design more efficient, ethical, and scientifically rigorous clinical trials, ultimately accelerating the delivery of effective treatments to patients.