Entry and fusion inhibitors of HIV

Considerable advances have been made towards finding compounds that are active as inhibitors of the entry and fusion of HIV. The discovery of chemokines a few years ago focused the attention on coreceptor inhibitors, in addition to fusion and attachment blockers. During the past 5 years there has been intense research activity, both from private companies and academic institutions, in order to find effective compounds that are able to inhibit the initial steps in the HIV lifecycle. Some of the presented compounds demonstrated in vitro synergism, thus there is rationale for their combined use in HIV-infected individuals. Many entry and fusion inhibitors of HIV are currently under investigation in controlled clinical trials and a number of them are bioavailable as oral formulations. This is an essential feature for the extended use of these compounds with the purpose of ameliorating patients adherence to medications, thus preventing the development of drug resistance. The focus of this review will be on the most recent developments in this field, with particular attention focused on promising compounds in preclinical and clinical trials.