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

Round 1

Reviewer 1 Report

Chronic hepatitis B virus (HBV) infection poses a significant global public health threat, leading to substantial morbidity and mortality. Nucleotide or nucleoside analogs have dramatically improved the quality of life for chronic hepatitis B patients (CHB). However, a functional cure remains elusive due to the persistence of cccDNA in infected hepatocytes. In this review article, Nayak et al. provide a comprehensive overview of the historical progression up to the present and discuss the effects of HBV capsid assembly modulators (CAMs) on capsid assembly. These CAMs have the potential to suppress HBV replication and disrupt the cccDNA pool. Overall, this manuscript offers a valuable summary, identifies current challenges, and presents future perspectives for CAMs. It provides invaluable insights for researchers and clinicians involved in the field of HBV. This paper is well-written and suitable for publication.

Author Response

Dear Reviewer,

I hope this email finds you well. I wanted to express my sincere gratitude for taking the time to review our manuscript on the topic of Chronic Hepatitis B virus (HBV) infection. Your insightful comments and positive feedback have been truly valuable.

We appreciate your recognition of the significance of the global public health threat posed by chronic HBV infection and your acknowledgment of the improvements brought about by nucleotide or nucleoside analogs. Your mention of the challenges in achieving a functional cure and the potential of HBV capsid assembly modulators (CAMs) to address these challenges is particularly insightful.

Your positive assessment of our manuscript, highlighting its comprehensive overview, identification of current challenges, and presentation of future perspectives for CAMs, is encouraging. We are pleased to hear that you found the paper well-written and suitable for publication.

Thank you once again for your thoughtful review. Your expertise and feedback have contributed immensely to the quality of our work. We look forward to the possibility of incorporating your suggestions to enhance the manuscript further.

If you have any additional comments or suggestions, please feel free to share them. We highly value your input and are committed to addressing any concerns you may have.

Thank you for your time and consideration.

Best regards,

Soo Bong Han

Reviewer 2 Report

General comment

This paper is very long: 28 pages with 17 figures showing 121 formulas of core assembly modulators (CAM). The search for drug candidates suppressing the replication of hepatitis B virus (HBV) is highly relevant. However, this review has a very narrow scope. It focusses on one class of chemically related substances which efficiently modulate the assembly the HBV cores, but neglects to a large part CAMs other than sulfamoyl-based substances. The strength of this approach is that the authors extensively describe the discovery and optimization of this class of substances and provide deep insights into the chemistry of modern drug development.

The authors emphasize repeatedly that the therapy of chronic HBV infection requires approaches which reduce the pool the viral cccDNA. But they fail to present data or mechanisms by which the sulfamoyl-based CAMs would actively reduce this cccDNA pool. The only mechanism by which the CAMs reduce the pool is suppression of HBV DNA replication, i.e., by the same way how the NUCs act. CAMs do not “disrupt the cccDNA pool”.  The brief survey of the few clinical studies with CAMs does not document a significant improvement of HBV therapy compared to established NUCs. At least, a discussion of the cccDNA half life in CHB patients would be useful.

Specific points (points 8, 16-18 are major)

1.      Title. Spell out HBV in title.

2.      L20. Can the CAM really “disrupt” the cccDNA pool? I suggest to write: …  disrupt the production of new cccDNA.

3.      L40. Delete “Ag” from anti-HBcAg

4.      L43. Before mentioning NUCs it should be mentioned that the HBV genome replicates via reverse transcription of its pregenomic RNA and that NUCs are inhibitors of the HBV RT.

5.      L54. Replace “their poor effectiveness in targeting” by “that they do not target “. This is not poor but completely absent effectivity. Furthermore, another weakness of the NUCs is that they do not inhibit viral transcription or protein synthesis.

6.      Ref. 18 is incomplete. Many authors are missing.

7.      L97. Delete “nonspecific”. The binding of small HBsAg to glypican 5 is liver-specific and can be inhibited by anti-HBs antibodies.

8.      Fig. 2 should be corrected.

a.      The translation occurs in the cytoplasm.

b.      The pg mRMA is first translated to HBc protein and at lower frequency to the DNA pol.

c.      Thereafter, these three components assemble together with host factors to the replication-competent core particles.

d.      The addition of the HBsAg to the core particles should not be designated as encapsidation but as envelopment.

9.      L234. Correct to: … the Blumberg Institute collaborated with … Baruch Blumberg died in 2011. The text suggests that the collaboration occurred at 2018.

10.   Fig. 6 should be a bit larger with same size of the formula as in fig. 5. What is a “Markush structure”. Not all virologists may know this. The journal name is “viruses”.

11.   L277 and 527 Correct to: Ospedale San Raffaele here and in fig. 7.

12.   L387. Is Wang at the Shanghai Langwood pharmaceuticals?

13.   L443. Bound, not binded.

14.   L524. Which compound showed the highest activity in fig. 15?

15.   L593, 594. The CAMs do not suppress transcription or translation of the HBV genes. Thus, a reduction of HBsAg cannot be expected.

16.   L638. The reduction of the serum HBV RNA is indeed remarkable because it may be completely attributed to the CAM while reduction of serum HBV DNA may be completely be caused by the NUC.

17.   One point which should be discussed in more detail is the use of cell culture models. Unfortunately, there is no standard model for stably transfected HBV-producing cell lines. The differences between the various cited cell lines and the use of more natural systems should be more intensely discussed.

18.   References covering the taxonomy and molecular biology of HBV should be updated. The assembly of cores and the encapsidation of the HBV pregenome should be described in more detail, e.g., papers from Michael Nassal and/or Jianming Hu should be cited and discussed.

The English is well readable and contains very few mistakes.

Author Response

Please see the attachment

Author Response File: Author Response.pdf