The role of resistance testing in clinical trial design and product labelling: a regulatory perspective

Assays that attempt to characterize HIV susceptibility or resistance are among the latest technologies that are likely to impact HIV clinical trial design, antiretroviral drug development and patient management. However, at present the Food and Drug Administration (FDA) have yet to approve any phenotypic or genotypic HIV resistance assay and the role of resistance testing in clinical management of patients and in drug development is ill defined. In November 1999, the Division of Antiviral Drug Products at the FDA convened a meeting of its advisory committee to consider the available information about HIV resistance testing, and to generate some recommendations about how these assays could be utilized in antiretroviral drug development. In addition, the committee was presented with several hypothetical regulatory scenarios in order to illustrate how HIV resistance testing might be incorporated in antiretroviral drug development and drug labelling. In this article, we discuss the regulatory history of resistance testing in antimicrobial drug development, the current use of resistance testing for antiretrovirals, as well as a summary of the hypothetical scenarios that were presented to the committee and the discussion of the committee members regarding those scenarios.