Blocking NS3-NS4B interaction inhibits dengue virus in non-human primates.

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.

A pan-serotype dengue virus inhibitor targeting the NS3-NS4B interaction.

Dengue virus causes approximately 96 million symptomatic infections annually, manifesting as dengue fever or occasionally as severe dengue1,2. There are no antiviral agents available to prevent or treat dengue. Here, we describe a highly potent dengue virus inhibitor (JNJ-A07) that exerts nanomolar to picomolar activity against a panel of 21 clinical isolates that represent the natural genetic diversity of known genotypes 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 revealing a previously undescribed mechanism of antiviral action. JNJ-A07 has a favourable pharmacokinetic profile that results in outstanding efficacy against dengue virus infection in mouse infection models. Delaying start of treatment until peak viraemia results in a rapid and significant reduction in viral load. An analogue is currently in further development.

Di-fluoro azepane HBV capsid assembly modulators.

The protein that forms the inner shell of the HBV virus, known as the capsid core protein, plays a crucial role in allowing chronic HBV infections to persist. Studies have shown that disrupting the assembly of the capsid can effectively combat the virus, and small molecule drugs that target the HBV capsid assembly modulator (CAM) process have been successful in clinical trials. Herein is described a distinct series of di-fluoro azepane CAMs with exceptional potency, pharmacokinetic, and solubility properties.

Diazepinone HBV capsid assembly modulators.

The HBV capsid core protein serves a number of important functions in the viral life cycle enabling chronic HBV infection to persist, and therefore is a promising drug target. Interfering with capsid assembly has shown efficacy in clinical trials with small molecule capsid assembly modulators (CAMs). Herein is described the further optimization of a progressive series of diazepinone HBV CAMs.

Oxadiazepinone HBV capsid assembly modulators.

The HBV core protein serves multiple essential functions in the viral life cycle that enable chronic HBV infection to persist, and as such, represents a promising drug target. Modulation of the HBV capsid assembly has shown efficacy in early clinical trials through use of small molecule capsid assembly modulators (CAMs). Herein is described the evolution and SAR of a novel pyrazolo piperidine lead series into advanced oxadiazepinone HBV CAMs.

Identification of a new class of HBV capsid assembly modulator.

The HBV core protein is a druggable target of interest due to the multiple essential functions in the HBV life cycle to enable chronic HBV infection. The core protein oligomerizes to form the viral capsid, and modulation of the HBV capsid assembly has shown efficacy in clinical trials. Herein is described the identification and hit to lead SAR of a novel series of pyrazolo piperidine HBV capsid assembly modulators.

Design and synthesis of tetrahydropyridopyrimidine based Toll-Like Receptor (TLR) 7/8 dual agonists.

In a continuing effort to discover novel TLR agonists, herein we report on the discovery and structure-activity relationship of novel tetrahydropyridopyrimidine TLR 7/8 agonists. Optimization of this series towards dual agonist activity and a high clearance profile resulted in the identification of compound 52a1. Evaluation in vivo revealed an interferon stimulated response (ISG) in mice with limited systemic exposure and demonstrated the potential in antiviral treatment or as a vaccine adjuvant.

Discovery of selective 2,4-diaminoquinazoline toll-like receptor 7 (TLR 7) agonists.

The discovery of a novel series of highly potent quinazoline TLR 7/8 agonists is described. The synthesis and structure-activity relationship is presented. Structural requirements and optimization of this series toward TLR 7 selectivity afforded the potent agonist 48. Pharmacokinetic and pharmacodynamic studies highlighted 48 as an orally available endogenous interferon (IFN-α) inducer in mice.

Discovery of JNJ-1802, a First-in-Class Pan-Serotype Dengue Virus NS4B Inhibitor.

Dengue is a global public health threat, with about half of the world's population at risk of contracting this mosquito-borne viral disease. Climate change, urbanization, and global travel accelerate the spread of dengue virus (DENV) to new areas, including southern parts of Europe and the US. Currently, no dengue-specific small-molecule antiviral for prophylaxis or treatment is available. Here, we report the discovery of JNJ-1802 as a potent, pan-serotype DENV inhibitor (EC50's ranging from 0.057 to 11 nM against the four DENV serotypes). The observed oral bioavailability of JNJ-1802 across preclinical species, its low clearance in human hepatocytes, the absence of major in vitro pharmacology safety alerts, and a dose-proportional increase in efficacy against DENV-2 infection in mice were all supportive of its selection as a development candidate against dengue. JNJ-1802 is being progressed in clinical studies for the prevention or treatment of dengue.

Structure-Activity Relationship of Oxacyclo- and Triazolo-Containing Respiratory Syncytial Virus Polymerase Inhibitors.

Despite the availability of medicines preventing respiratory syncytial virus (RSV) infection, post-exposure treatment options are needed for addressing patient's needs. RSV non-nucleoside polymerase inhibitors (NNI) have emerged as a promising asset for which our group previously disclosed JNJ-8003 with potent in vitro antiviral activity and pronounced in vivo efficacy. In this work, a structural-guided design to modify the linker vector of JNJ-8003 resulted in the identification of 2-oxacyclo pyridine-containing derivatives whose various ring closing strategies are described. In addition, bioisosteric replacement of an amide bond with triazole retained potency, and cryo-electron microscopy (cryo-EM) confirmed binding in the capping domain. Subsequent NMR conformational analysis suggested a correlation between the potency and conformations. Our efforts have fulfilled the aim of identifying linker modifications with maintained biological activity while enriching structural diversity and allowing modulations of other parameters.

Discovery of gem-Dimethyl-hydroxymethylpyridine Derivatives as Potent Non-nucleoside RSV Polymerase Inhibitors.

Respiratory syncytial virus (RSV) is an RNA virus infecting the upper and lower respiratory tract and is recognized as a major respiratory health threat, particularly to older adults, immunocompromised individuals, and young children. Around 64 million children and adults are infected every year worldwide. Despite two vaccines and a new generation monoclonal antibody recently approved, no effective antiviral treatment is available. In this manuscript, we present the medicinal chemistry efforts resulting in the identification of compound 28 (JNJ-8003), a novel RSV non-nucleoside inhibitor displaying subnanomolar activity in vitro as well as prominent efficacy in mice and a neonatal lamb models.

Spiro-Azetidine Oxindoles as Long-Acting Injectables for Pre-Exposure Prophylaxis against Respiratory Syncytial Virus Infections.

Respiratory syncytial virus (RSV) is a major cause of hospitalization in infants, the elderly, and immune-compromised patients. While a half-life extended monoclonal antibody and 2 vaccines have recently been approved for infants and the elderly, respectively, options to prevent disease in immune-compromised patients are still needed. Here, we describe spiro-azetidine oxindoles as small molecule RSV entry inhibitors displaying favorable potency, developability attributes, and long-acting PK when injected as an aqueous suspension, suggesting their potential to prevent complications following RSV infection over a period of 3 to 6 months with 1 or 2 long-acting intramuscular (IM) or subcutaneous (SC) injections in these immune-compromised patients.

Design and synthesis of HIV-1 protease inhibitors for a long-acting injectable drug application.

The design and synthesis of novel HIV-1 protease inhibitors (PIs) (1-22), which display high potency against HIV-1 wild-type and multi-PI-resistant HIV-mutant clinical isolates, is described. Lead optimization was initiated from compound 1, a Phe-Phe hydroxyethylene peptidomimetic PI, and was directed towards the discovery of new PIs suitable for a long-acting (LA) injectable drug application. Introducing a heterocyclic 6-methoxy-3-pyridinyl or a 6-(dimethylamino)-3-pyridinyl moiety (R(3)) at the para-position of the P1' benzyl fragment generated compounds with antiviral potency in the low single digit nanomolar range. Halogenation or alkylation of the metabolic hot spots on the various aromatic rings resulted in PIs with high stability against degradation in human liver microsomes and low plasma clearance in rats. Replacing the chromanolamine moiety (R(1)) in the P2 protease binding site by a cyclopentanolamine or a cyclohexanolamine derivative provided a series of high clearance PIs (16-22) with EC(50)s on wild-type HIV-1 in the range of 0.8-1.8 nM. PIs 18 and 22, formulated as nanosuspensions, showed gradual but sustained and complete release from the injection site over two months in rats, and were therefore identified as interesting candidates for a LA injectable drug application for treating HIV/AIDS.

Discovery of Acyl-Indole Derivatives as Pan-Serotype Dengue Virus NS4B Inhibitors.

In the absence of any approved dengue-specific treatment, the discovery and development of a novel small-molecule antiviral for the prevention or treatment of dengue are critical. We previously reported the identification of a novel series of 3-acyl-indole derivatives as potent and pan-serotype dengue virus inhibitors. We herein describe our optimization efforts toward preclinical candidates 24a and 28a with improved pan-serotype coverage (EC50's against the four DENV serotypes ranging from 0.0011 to 0.24 µM for 24a and from 0.00060 to 0.084 µM for 28a), chiral stability, and oral bioavailability in preclinical species, as well as showing a dose-proportional increase in efficacy against DENV-2 infection in vivo in mice.

From Oxetane to Thietane: Extending the Antiviral Spectrum of 2'-Spirocyclic Uridines by Substituting Oxygen with Sulfur.

In continuation of our efforts of finding novel nucleoside inhibitors for the treatment of viral diseases, we initiated a discovery research program aimed at identifying novel nucleos(t)ide inhibitors for emerging diseases like Dengue and Chikungunya. Based on the previously reported 2'-spiro-oxetane uridine derivatives active against Hepatitis C Virus (HCV), we envisaged its sulfur analogue as an interesting congener both from a synthetic as well as biological point of view. Surprisingly, we found the 2'-spirothietane uridine derivatives not only to be active against HCV and Dengue virus (DENV), viruses belonging to the flavivirus family, but also to demonstrate activity against alphaviruses like Chikungunya virus (CHIKV) and Sindbis virus (SINV).

Design, Synthesis, and Biological Evaluation of Novel Indoles Targeting the Influenza PB2 Cap Binding Region.

In the search for novel influenza inhibitors we evaluated 7-fluoro-substituted indoles as bioisosteric replacements for the 7-azaindole scaffold of Pimodivir, a PB2 (polymerase basic protein 2) inhibitor currently in clinical development. Specifically, a 5,7-difluoroindole derivative 11a was identified as a potent and metabolically stable influenza inhibitor. 11a demonstrated a favorable oral pharmacokinetic profile and in vivo efficacy in mice. In addition, it was found that 11a was not at risk of metabolism via aldehyde oxidase, an advantage over previously described inhibitors of this class. The crystal structure of 11a bound to influenza A PB2 cap region is disclosed here and deposited to the PDB.

A small-molecule fusion inhibitor of influenza virus is orally active in mice.

Recent characterization of broadly neutralizing antibodies (bnAbs) against influenza virus identified the conserved hemagglutinin (HA) stem as a target for development of universal vaccines and therapeutics. Although several stem bnAbs are being evaluated in clinical trials, antibodies are generally unsuited for oral delivery. Guided by structural knowledge of the interactions and mechanism of anti-stem bnAb CR6261, we selected and optimized small molecules that mimic the bnAb functionality. Our lead compound neutralizes influenza A group 1 viruses by inhibiting HA-mediated fusion in vitro, protects mice against lethal and sublethal influenza challenge after oral administration, and effectively neutralizes virus infection in reconstituted three-dimensional cell culture of fully differentiated human bronchial epithelial cells. Cocrystal structures with H1 and H5 HAs reveal that the lead compound recapitulates the bnAb hotspot interactions.

Synthesis and Evaluation of N-Phenyl-3-sulfamoyl-benzamide Derivatives as Capsid Assembly Modulators Inhibiting Hepatitis B Virus (HBV).

Small molecule induced hepatitis B virus (HBV) capsid assembly modulation is considered an attractive approach for new antiviral therapies against HBV. Here we describe efforts toward the discovery of a HBV capsid assembly modulator in a hit-to-lead optimization, resulting in JNJ-632, a tool compound used to further profile the mode of action. Administration of JNJ-632 (54) in HBV genotype D infected chimeric mice resulted in a 2.77 log reduction of the HBV DNA viral load.

2,4-Diaminoquinazolines as Dual Toll-like Receptor (TLR) 7/8 Modulators for the Treatment of Hepatitis B Virus.

A novel series of 2,4-diaminoquinazolines was identified as potent dual Toll-like receptor (TLR) 7 and 8 agonists with reduced off-target activity. The stereochemistry of the amino alcohol was found to influence the TLR7/8 selectivity with the ( R) isomer resulting in selective TLR8 agonism. Lead optimization toward a dual agonist afforded ( S)-3-((2-amino-8-fluoroquinazolin-4-yl)amino)hexanol 31 as a potent analog, being structurally different from previously described dual agonists ( McGowan J. Med. Chem. 2016 , 59 , 7936 ). Pharmacokinetic and pharmacodynamic (PK/PD) studies revealed the desired high first pass profile aimed at limiting systemic cytokine activation. In vivo pharmacodynamic studies with lead compound 31 demonstrated production of cytokines consistent with TLR7/8 activation in mice and cynomolgus monkeys and ex vivo inhibition of hepatitis B virus (HBV).