Emerging and recurrent issues in drug development.

This paper reviews several emerging and recurrent issues relating to the drug development process. These emerging issues include changes to the FDA regulatory environment, internationalization of drug development, advances in computer technology and visualization tools, and efforts to incorporate meta-analysis methodology. Recurrent issues include: renewed interest in statistical methods for handling subgroups in the design and analysis of clinical trials; renewed interest in alternatives to the 'intention-to-treat' analysis in the presence of non-compliance in randomized clinical trials; renewed interest in methodology to address the multiplicities resulting from a variety of sources inherent in the drug development process, and renewed interest in methods to assure data integrity. These emerging and recurrent issues provide a continuing challenge to the international community of statisticians involved in drug development. Moreover, the involvement of statisticians with different perspectives continues to enrich the field and contributes to improvement in the public health.