Design, synthesis, and biological evaluation of novel sulfamoylbenzamide derivatives as HBV capsid assembly modulators

Sophormodines A-C, three alkaloids with antiviral activities against the HBV from the seeds of the Tibetan medicine plant Sophora moorcroftiana

Three previously undescribed alkaloids sophormodines A-C (1-3), along with three known analogues (4-6), were isolated and fully elucidated from the seeds of the Tibetan medicine plant Sophora moorcroftiana. Compounds 1 and 2 possess unprecedented 6/5/6/6 and 5/6/6/6 ring systems, respectively, while 3 is a C15N2-alkaloid featuring a unique 5/6/6/6-tetracyclic carbon skeleton with an unusual pyrrole-2-carboxaldehyde unit. These previously undescribed structures were elucidated by means of spectroscopic data analysis (including NMR and MS), and the absolute configurations were determined using single-crystal X-ray diffraction and ECD data. Moreover, a biosynthetic pathway for the formation of 1-3 is also proposed. In addition, the isolated alkaloids were evaluated for their antiviral activity against hepatitis B virus (HBV). Overall, this study provides insights into the potential therapeutic uses of the compounds found in the seeds of S. moorcroftiana, particularly in the treatment of HBV infections.

Development of sulfamoylbenzamide-based capsid assembly modulators for hepatitis B virus capsid assembly

Hepatitis B virus (HBV) is a leading cause of chronic hepatitis and remains a significant global public health concern due to the lack of effective treatments. HBV replicates through reverse transcription within the viral capsid, making capsid assembly a promising antiviral target. However, no approved therapies currently target this process. In our previous study, we optimized the structure-activity relationship (SAR) of NVR 3-778 by modifying the A and B rings, leading to the identification of KR-26556 and Compound 3. In this study, we further synthesized derivatives to modify the C ring, resulting in the discovery of KR019 and KR026. These compounds exhibited over 170-fold higher selectivity than the reference compound while demonstrating potent antiviral activity in HBV-replicating cells. Mechanistic studies revealed that KR019 binds to the hydrophobic pocket at the core protein dimer-dimer interface, misdirecting capsid assembly into genome-free capsids and thereby inhibiting viral replication. Additionally, pharmacokinetic profiling confirmed favorable stability and safety. These findings highlight the strong antiviral potential of KR019 and KR026 and provide a foundation for further in vivo investigation.

A patent review of hepatitis B virus core protein allosteric modulators (2019-present)

INTRODUCTION

The hepatitis B virus (HBV) core protein is a significant therapeutic target due to its essential role in HBV replication. Over the past five years, numerous structurally unique CpAMs have been patented. However, no compounds have been approved due to various issues such as poor pharmacokinetics (PK) and hepatotoxicity. As a result, there is an urgent need to develop novel CpAMs without these limitations.

AREAS COVERED

This review provides a comprehensive analysis of patents related to CpAMs from 2019 to the present, with the aim of delineating the chemical evolution that has occurred in the pursuit of more promising CpAMs. The sources of patent information included databases of the European Patent Office, the China Patent Office and the U.S.A. Patent Office, while relevant research articles were accessed through PubMed.

EXPERT OPINION

During the optimization of CpAMs, striking a good balance between activity and druggability usually poses a certain challenge while the emergence of drug resistance issues further complicates the development process. A comprehensive analysis of the structural features of CpAMs and identification of essential patterns in chemical evolution can reveal common principles that improve pharmacodynamic (PD) and PK profiles, thereby facilitating the discovery of next-generation CpAMs.

Design, Synthesis, and Bioevaluation of Matrine Derivatives as Potential Anti-Hepatitis B Virus Agents

Hepatitis B virus (HBV) is a causative reagent that frequently causes progressive liver diseases, leading to the development of acute hepatitis, chronic hepatitis, cirrhosis, and eventually hepatocellular carcinoma. Despite several antiviral drugs, including interferon-α and nucleotide derivatives, being approved for clinical treatment of HBV, critical issues remain unresolved, e.g., their low-to-moderate efficacy and adverse side effects, as well as resistant strains. In this study, twenty-three matrine derivatives were synthesized, and their antiviral effects against HBV were evaluated. Of these, eleven compounds inhibited HBeAg secretion significantly more than the positive control, lamivudine (3TC). Among the compounds synthesized in this study, compounds 4a and 4d had the most potent inhibitory activity, with IC50 value of 41.78 and 33.68 μM, respectively. Compounds 1h, 4a, and 4d were also subjected to molecular docking studies. These compounds inhibited viral gene expression and viral propagation in a cell culture model. Thus, we believe our compounds could serve as resource for antiviral drug development.

Innovative medicinal chemistry strategies for enhancing drug solubility

Drug candidates with poor solubility have been recognized as the cause of many drug development failures, owing to the fact that low solubility is unfavorable for physicochemical, pharmacokinetic (PK) and pharmacodynamic (PD) properties. Given the imperative role of solubility during drug development, we herein summarize various strategies for solubility optimizations from a medicinal chemistry perspective, including introduction of polar group, salt formation, structural simplification, disruption of molecular planarity and symmetry, optimizations on the solvent exposed region as well as prodrug design. In addition, methods for solubility assessment and prediction are reviewed. Besides, we have deeply discussed the strategies for solubility improvement. This paper is expected to be beneficial for the development of drug-like molecules with good solubility.

Design, synthesis and anti-HBV activity study of novel HBV capsid assembly modulators

Capsid assembly modulators (CAMs) have the potential to cure chronic hepatitis B, as demonstrated in clinical trials. Lead compounds NVR3-778 and 5a were found to exist in normal and flipped conformations through induced fit docking. Therefore, we designed and synthesized series I and II compounds by interchanging the amide and sulfonamide bonds of 5a to modify both the tolerance region and solvent-opening region. Among them, compound 4a (EC50 = 0.24 ± 0.10 μM, CC50 > 100 μM) exhibited potent anti-HBV activity with low toxicity, surpassing the lead compounds NVR3-778 (EC50 = 0.29 ± 0.03 μM, CC50 = 20.78 ± 2.29 μM) and 5a (EC50 = 0.50 ± 0.07 μM, CC50 = 48.16 ± 9.15 μM) in HepAD38 cells. Additionally, compared with the lead compound, 4a displayed a stronger inhibitory effect on HBV capsid protein assembly. Molecular dynamics (MD) simulations confirmed that the normal conformation of 4a had relatively stable conformation at different frames of binding modes. Furthermore, 4a showed better metabolic stability in human plasma than positive control drugs. Therefore, compound 4a could be further structurally modified as a potent lead compound.

Recent Advances in the Development of Sulfamoyl-Based Hepatitis B Virus Nucleocapsid Assembly Modulators

Hepatitis B virus (HBV) is the primary contributor to severe liver ailments, encompassing conditions such as cirrhosis and hepatocellular carcinoma. Globally, 257 million people are affected by HBV annually and 887,000 deaths are attributed to it, representing a substantial health burden. Regrettably, none of the existing therapies for chronic hepatitis B (CHB) have achieved satisfactory clinical cure rates. This issue stems from the existence of covalently closed circular DNA (cccDNA), which is difficult to eliminate from the nucleus of infected hepatocytes. HBV genetic material is composed of partially double-stranded DNA that forms complexes with viral polymerase inside an icosahedral capsid composed of a dimeric core protein. The HBV core protein, consisting of 183 to 185 amino acids, plays integral roles in multiple essential functions within the HBV replication process. In this review, we describe the effects of sulfamoyl-based carboxamide capsid assembly modulators (CAMs) on capsid assembly, which can suppress HBV replication and disrupt the production of new cccDNA. We present research on classical, first-generation sulfamoyl benzocarboxamide CAMs, elucidating their structural composition and antiviral efficacy. Additionally, we explore newly identified sulfamoyl-based CAMs, including sulfamoyl bicyclic carboxamides, sulfamoyl aromatic heterocyclic carboxamides, sulfamoyl aliphatic heterocyclic carboxamides, cyclic sulfonamides, and non-carboxamide sulfomoyl-based CAMs. We believe that certain molecules derived from sulfamoyl groups have the potential to be developed into essential components of a well-suited combination therapy, ultimately yielding superior clinical efficacy outcomes in the future.