A Pangenotypic Hepatitis E Virus Replication Inhibitor With High Potency in a Rat Infection Model.

Background & Aims: Hepatitis E virus (HEV) constitutes a substantial public health burden with ∼20 million human infections annually, including 3.3 million symptomatic cases. Appropriate treatment options for, in particular, immunocompromised patients with HEV infection and pregnant women are lacking, underscoring the urgent need for potent and safe antiviral drugs.

Discovery of -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.

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.

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.

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 and with improved pan-serotype coverage (EC's against the four DENV serotypes ranging from 0.

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 million with annually around 10,000 deaths. 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) inhibitors.

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).

Discovery of 3-({5-Chloro-1-[3-(methylsulfonyl)propyl]-1-indol-2-yl}methyl)-1-(2,2,2-trifluoroethyl)-1,3-dihydro-2-imidazo[4,5-]pyridin-2-one (JNJ-53718678), a Potent and Orally Bioavailable Fusion Inhibitor of Respiratory Syncytial Virus.

Respiratory syncytial virus (RSV) is a seasonal virus that infects the lungs and airways of 64 million children and adults every year. It is a major cause of acute lower respiratory tract infection and is associated with significant morbidity and mortality. Despite the large medical and economic burden, treatment options for RSV-associated bronchiolitis and pneumonia are limited and mainly consist of supportive care.

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 was identified as a potent and metabolically stable influenza inhibitor. demonstrated a favorable oral pharmacokinetic profile and in vivo efficacy in mice.

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.

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.

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.

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.

Identification and Optimization of Pyrrolo[3,2-d]pyrimidine Toll-like Receptor 7 (TLR7) Selective Agonists for the Treatment of Hepatitis B.

Pyrrolo[3,2-d]pyrimidines were identified as a new series of potent and selective TLR7 agonists. Compounds were optimized for their activity and selectivity over TLR8. This presents an advantage over recently described scaffolds that have residual TLR8 activity, which may be detrimental to the tolerability of the candidate drug.

Discovery of 1-((2R,4aR,6R,7R,7aR)-2-Isopropoxy-2-oxidodihydro-4H,6H-spiro[furo[3,2-d][1,3,2]dioxaphosphinine-7,2'-oxetan]-6-yl)pyrimidine-2,4(1H,3H)-dione (JNJ-54257099), a 3'-5'-Cyclic Phosphate Ester Prodrug of 2'-Deoxy-2'-Spirooxetane Uridine Triphosphate Useful for HCV Inhibition.

JNJ-54257099 (9) is a novel cyclic phosphate ester derivative that belongs to the class of 2'-deoxy-2'-spirooxetane uridine nucleotide prodrugs which are known as inhibitors of the HCV NS5B RNA-dependent RNA polymerase (RdRp). In the Huh-7 HCV genotype (GT) 1b replicon-containing cell line 9 is devoid of any anti-HCV activity, an observation attributable to inefficient prodrug metabolism which was found to be CYP3A4-dependent. In contrast, in vitro incubation of 9 in primary human hepatocytes as well as pharmacokinetic evaluation thereof in different preclinical species reveals the formation of substantial levels of 2'-deoxy-2'-spirooxetane uridine triphosphate (8), a potent inhibitor of the HCV NS5B polymerase.

Molecular mechanism of respiratory syncytial virus fusion inhibitors.

Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. Here we show that these inhibitors bind to a three-fold-symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F.

Nucleotide prodrugs of 2'-deoxy-2'-spirooxetane ribonucleosides as novel inhibitors of the HCV NS5B polymerase.

The limited efficacy, in particular against the genotype 1 virus, as well as the variety of side effects associated with the current therapy for hepatitis C virus (HCV) infection necessitates more efficacious drugs. We found that phosphoramidate prodrugs of 2'-deoxy-2'-spirooxetane ribonucleosides form a novel class of HCV NS5B RNA-dependent RNA polymerase inhibitors, displaying EC50 values ranging from 0.2 to >98 μM, measured in the Huh7-replicon cell line, with no apparent cytotoxicity (CC50 > 98.

Benzoxazole and benzothiazole amides as novel pharmacokinetic enhancers of HIV protease inhibitors.

A new class of benzoxazole and benzothiazole amide derivatives exhibiting potent CYP3A4 inhibiting properties was identified. Extensive lead optimization was aimed at improving the CYP3A4 inhibitory properties as well as overall ADME profile of these amide derivatives. This led to the identification of thiazol-5-ylmethyl (2S,3R)-4-(2-(ethyl(methyl)amino)-N-isobutylbenzo[d]oxazole-6-carboxamido)-3-hydroxy-1-phenylbutan-2-ylcarbamate (C1) as a lead candidate for this class.

Design, synthesis, and antiviral evaluation of purine-β-lactam and purine-aminopropanol hybrids.

Purine-β-lactam chimera were prepared as a novel class of hybrid systems through N-alkylation of 6-benzylamino- or 6-benzyloxypurine with (ω-haloalkyl)-β-lactams, followed by reductive ring opening of the β-lactam ring by LiEt(3)BH to provide an entry into the class of purine-aminopropanol hybrids. Both new types of hybrid systems were assessed for their antiviral activity and cytotoxicity, resulting in the identification of eight purine-β-lactam hybrids and two purine-aminopropanol hybrids as promising lead structures.

Discovery of 4'-azido-2'-deoxy-2'-C-methyl cytidine and prodrugs thereof: a potent inhibitor of Hepatitis C virus replication.

4'-Azido-2'-deoxy-2'-methylcytidine (14) is a potent nucleoside inhibitor of the HCV NS5B RNA-dependent RNA polymerase, displaying an EC(50) value of 1.2 μM and showing moderate in vivo bioavailability in rat (F=14%). Here we describe the synthesis and biological evaluation of 4'-azido-2'-deoxy-2'-methylcytidine and prodrug derivatives thereof.

TMC310911, a novel human immunodeficiency virus type 1 protease inhibitor, shows in vitro an improved resistance profile and higher genetic barrier to resistance compared with current protease inhibitors.

TMC310911 is a novel human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) structurally closely related to darunavir (DRV) but with improved virological characteristics. TMC310911 has potent activity against wild-type (WT) HIV-1 (median 50% effective concentration [EC(50)], 14 nM) and a wide spectrum of recombinant HIV-1 clinical isolates, including multiple-PI-resistant strains with decreased susceptibility to currently approved PIs (fold change [FC] in EC(50), >10). For a panel of 2,011 recombinant clinical isolates with decreased susceptibility to at least one of the currently approved PIs, the FC in TMC310911 EC(50) was ≤ 4 for 82% of isolates and ≤ 10 for 96% of isolates.