Statistical and methodological issues in microbicide trial design.

Microbicide trials aim to measure the effect of a microbicide in reducing the risk of acquiring human immunodeficiency virus. Such trials present a number of challenging issues from design and conduct through to analysis and reporting. This begins with the initial identification of the target trial population. Prevention trials need to identify those at risk of human immunodeficiency virus infection. This can be more difficult in the general population compared with treatment trials that can target specific patient groups who have a confirmed diagnosis of the disease of interest. Consequently, microbicide trial participants will inevitably be recruited who are never at risk of HIV infection. In this chapter we outline the main features of microbicide trial design, key issues during conduct and analysis, and discuss the challenges specific to these types of clinical trials. Crown