These mutations can be analyzed according to several genotyping resistance interpretation

algorithms. The issue of whether various integrase inhibitors may be used sequentially, i.e., in a sequential strategy, is a subject of great potential importance. Indeed, this concept has been studied from the beginnings of the field of antiretroviral therapy to develop strategies that might enable patients to benefit from newer classes of drugs, even if they had previously failed therapy while on older compounds against which resistance had developed [3]. In some cases, newer compounds could AZD6738 price be used even within single drug classes to provide patient benefit in the event of resistance. A good example of this has been the use of AZD4547 purchase ritonavir-boosted darunavir (DRV) that has a high genetic barrier for resistance for use in the place of earlier protease inhibitors such as nelfinavir (NFV) and ritonavir-boosted lopinavir (LPV) that have lower genetic barriers to resistance [9–12]. Due to the fact that ritonavir helps to maintain higher levels

of PIs in the blood and tissues of treated individuals, the action of these compounds is prolonged and their genetic barrier for resistance is increased. check details It has also long been established that members of different drug families may be used even if resistance has developed against members of other drug classes. As an example, the development of drug resistance to the NNRTI family of compounds can often be confronted through the use of protease inhibitors, since no cross-resistance exists between these two drug classes. More recently, newer NNRTI compounds that have somewhat distinct resistance profiles have also been developed to provide benefits to patients when these compounds are used as a part of a second-line regimen [13]. In this context, the discovery of integrase strand transfer inhibitors (INSTIs) is important as a means of extending therapeutic options for individuals living with HIV. The integrase gene and enzyme of HIV were recognized early to be a potential therapeutic target and were Baf-A1 cost shown to be susceptible to inhibition by oligonucleotides

and synthetic peptides as early as 1995 [14, 15]. However, a seminal study only described the first promising small compound targeting integrase in 2000 [16]. This, in turn, has led to the development of all currently approved integrase inhibitors. In the USA, INSTIs currently available for HIV treatment include raltegravir (RAL), elvitegravir (EVG), and dolutegravir (DTG). Integration is a two-step reaction catalyzed by the HIV integrase protein (reviewed in [17, 18]). The first step consists of the processing of the 3′ end of the newly retrotranscribed double-stranded viral DNA and is followed by the strand transfer reaction that results in the irreversible insertion of the viral genome into the host DNA.