Dengue virus (DENV) causes ~96 million symptomatic infections annually, manifesting as dengue fever or occasionally as severe dengue 1,2 . There are no antivirals available to prevent or treat dengue. We describe a highly potent DENV inhibitor (JNJ-A07) that exerts nano-to picomolar activity against a panel of 21 clinical isolates, representing the natural genetic diversity of known geno-and serotypes. The molecule has a high barrier to resistance and prevents the formation of the viral replication complex by blocking the interaction between two viral proteins (NS3 and NS4B), thus unveiling an entirely novel mechanism of antiviral action. JNJ-A07 has an excellent pharmacokinetic profile that results in outstanding efficacy against DENV infection in mouse infection models. Delaying start of treatment until peak viremia results in a rapid and significant reduction in viral load. An analogue is currently in further development. MAIN TEXTDengue is currently considered one of the top10 global health threats 1 . Annually, an estimated 96 million develop dengue disease 2 , which is likely an underestimation [3][4][5] . The incidence has increased ~30-fold over the past 50 years. The virus is endemic in 128 countries in (sub-)tropical regions, with an estimated 3.9 billion people at risk of infection. A recent study predicts an increase to 6.1 billion people at risk by 2080 6 . The upsurge is driven by factors such as rapid urbanization and the sustained spread of the mosquito vectors [6][7][8] . DENV has four serotypes (further classified into genotypes), which are increasingly co-circulating in endemic regions. A second infection with a different serotype increases the risk of severe dengue 9,10 . The vaccine Dengvaxia ® , which is approved in a number of countries for those aged ≥9 years, is only recommended for those with previous dengue exposure 11,12,13 . There are no antivirals for the prevention or treatment of dengue; the development of pan-serotype DENV inhibitors has proven challenging 14,15 .

Integration of viral DNA into the host chromosome is an essential step in the life cycle of retroviruses and is facilitated by the viral integrase enzyme. The first generation of integrase inhibitors recently approved or currently in late-stage clinical trials shows great promise for the treatment of human immunodeficiency virus (HIV) infection, but virus is expected to develop resistance to these drugs. Therefore, we used a novel resistance selection protocol to follow the emergence of resistant HIV in the presence of the integrase inhibitor elvitegravir (GS-9137). We find the primary resistance-conferring mutations to be Q148R, E92Q, and T66I and demonstrate that they confer a reduction in susceptibility not only to elvitegravir but also to raltegravir (MK-0518) and other integrase inhibitors. The locations of the mutations are highlighted in the catalytic sites of integrase, and we correlate the mutations with expected drug-protein contacts. In addition, mutations that do not confer reduced susceptibility when present alone (H114Y, L74M, R20K, A128T, E138K, and S230R) are also discussed in relation to their position in the catalytic core domain and their proximity to known structural features of integrase. These data broaden the understanding of antiviral resistance against integrase inhibitors and may give insight facilitating the discovery of second-generation compounds.Integration of retroviral DNA is an essential step in the life cycle of human immunodeficiency virus (HIV) (29). The integration process is facilitated by the viral integrase (IN) enzyme which catalyzes the insertion of the viral DNA into the host genome in a multistep process involving viral and host proteins. HIV IN recognizes and binds specific sequences in the long terminal repeats (LTRs) of the viral retrotranscribed DNA in the cytoplasm. After DNA binding, IN cleaves GT dinucleotides from the 3Ј termini of the linear cDNA in a process called 3Ј processing (2). The processed viral DNA, as part of the preintegration complex, is then translocated into the nucleus, where IN inserts the viral DNA into the host chromosome by a process called strand transfer (2,12,13). There are few cellular enzymes with comparable function to HIV integrase (24), apart from the V(D)J polynucleotide recombinase RAG1 (34). Therefore, the IN enzyme has been considered an attractive target for antiretroviral therapy for the last decade (27, 36). Recent progress has resulted in two IN inhibitors (5, 30), with one drug in late-stage clinical trials and one currently approved for use in treatment-experienced patients (18). For all currently targeted retroviral proteins, inhibition with antiretroviral drugs has led to emergence of resistance in treated patients, often leading to treatment failure and requiring changes in the composition of the highly active antiretroviral therapy (HAART) drug regimen (6). Nevertheless, the emergence of new classes of drugs will enable new combinations of inhibitors to be used and will offer more treatment options to HIV-infected pati...

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Emergence of resistance to raltegravir reduces its treatment efficacy in HIV-1-infected patients. To delineate the effect of resistance mutations on viral susceptibility to integrase inhibitors, in vitro resistance selections with raltegravir and with MK-2048, an integrase inhibitor with a second-generation-like resistance profile, were performed. Mutation Q148R arose in four out of six raltegravir-selected resistant viruses. In addition, mutations Q148K and N155H were selected. In the same time frame, no mutations were selected with MK-2048. Q148H/K/R and N155H conferred resistance to raltegravir, but only minor changes in susceptibility to MK-2048. V54I, a previously unreported mutation, selected with raltegravir, was identified as a possible compensation mutation. Mechanisms by which N155H, Q148H/K/R, Y143R and E92Q confer resistance are proposed based on a structural model of integrase. These data improve the understanding of resistance against raltegravir and cross-resistance to MK-2048 and other integrase inhibitors, which will aid in the discovery of second-generation integrase inhibitors.

Dengue is a major health threat and the number of symptomatic infections caused by the four dengue serotypes is estimated to be 96 million1 with annually around 10,000 deaths2. However, no antiviral drugs are available for the treatment or prophylaxis of dengue. We recently described the interaction between non-structural proteins NS3 and NS4B as a promising target for the development of pan-serotype dengue virus (DENV) inhibitors3. Here we present JNJ-1802—a highly potent DENV inhibitor that blocks the NS3–NS4B interaction within the viral replication complex. JNJ-1802 exerts picomolar to low nanomolar in vitro antiviral activity, a high barrier to resistance and potent in vivo efficacy in mice against infection with any of the four DENV serotypes. Finally, we demonstrate that the small-molecule inhibitor JNJ-1802 is highly effective against viral infection with DENV-1 or DENV-2 in non-human primates. JNJ-1802 has successfully completed a phase I first-in-human clinical study in healthy volunteers and was found to be safe and well tolerated4. These findings support the further clinical development of JNJ-1802, a first-in-class antiviral agent against dengue, which is now progressing in clinical studies for the prevention and treatment of dengue.