Drug resistance and antiretroviral drug development

As more drugs for treating HIV have become available, drug resistance profiles within antiretroviral drug classes have become increasingly important for researchers developing new drugs and for clini-cians integrating new drugs into their clinical practice. In vitro passage experiments and comprehen-sive phenotypic susceptibility testing are used for the pre-clinical evaluation of drug resistance. Clinical studies are required, however, to delineate the full spectrum of mutations responsible for resistance to a new drug and to identify the settings in which a new drug is likely to be most useful for salvage therapy