Absorption, Distribution, Metabolism, and Excretion of the Novel Helicase-Primase Inhibitor, Amenamevir (ASP2151), in Rodents

Disproportionality analysis of amenamevir-induced encephalopathy using the Japanese adverse drug event report database

INTRODUCTION

Anti-herpesvirus drug-induced encephalopathy can complicate herpes zoster treatment; however, the association between the recently developed anti-herpesvirus drug amenamevir and encephalopathy development remains unknown. Determining the characteristics of amenamevir-induced encephalopathy is essential for potentially improving patient outcomes in the treatment of herpes zoster. The aim of this study is to identify the association between amenamevir treatment and encephalopathy and to determine the risk factors for amenamevir-induced encephalopathy via disproportionality analysis using the Japanese Adverse Drug Event Report (JADER) database.

METHOD

We conducted a retrospective observational study using anonymized data from the JADER database. Encephalopathy was defined according to the Standardized Medical Dictionary for Regulatory Activities Queries specific to "Noninfectious encephalopathy/delirium." Disproportionality analysis was used to calculate the reporting odds ratios (RORs) and 95 % confidence intervals (CIs) to assess associations between amenamevir and encephalopathy. Multivariable logistic regression considered age, gender, chronic kidney disease, and cytochrome P450 3A inhibitor use as potential risk factors.

RESULTS

Out of 713,316 patients, 246 were prescribed amenamevir. The median onset of encephalopathy in these patients was 3 days. Disproportionality of encephalopathy was observed in patients treated with amenamevir (ROR, 3.44; 95 % CI, 2.48-4.78). Furthermore, multivariable logistic regression analysis suggested that an age of ≥70 years was associated with amenamevir-induced encephalopathy (ROR, 7.63; 95 % CI, 2.25-25.9).

CONCLUSION

These results suggest that amenamevir treatment may be associated with encephalopathy, particularly in patients aged ≥70 years. Healthcare providers should be aware of this potential risk, especially in elderly patients, to prevent severe central nervous system complications.

The Diversity of Neurological Complications Associated with Herpes Zoster: A Retrospective Case Series of 26 Patients

Objective This study clarified a variety of neurological phenotypes associated with varicella-zoster virus (VZV) reactivation. Methods This retrospective single-center study included consecutive patients with herpes zoster accompanied by neurological disturbances from April 2016 to September 2022. A comparative analysis was performed to examine whether or not the neurological phenotype and severity were associated with the distribution of herpes zoster, clinical and laboratory findings, and treatments. Results Twenty-six patients with a median age of 74 years old were enrolled. None of the patients had been vaccinated against herpes zoster. Of the 26 patients, 14 (54%) developed monoparesis, 5 (19%) developed meningitis, 5 (19%) developed encephalitis, 1 (4%) developed paraplegia, and 1 (4%) developed bladder and rectal problems. Monoparesis of the upper limb is associated with herpes zoster involving the cervical and thoracic dermatomes, whereas meningitis and encephalitis often occur in patients with herpes zoster in the trigeminal and thoracic dermatomes. Neurological disability was generally severe [modified Rankin Scale (mRS) score ≥3] on admission [17 of 26 (65%) patients]. Good recovery after admission was associated with a lower mRS value before the onset of neurological disability, clinical meningitis, and elevated cell counts and protein levels in the cerebrospinal fluid. Good recoveries were observed in patients with herpes zoster in the trigeminal or thoracic dermatomes more frequently than in other dermatomes. Conclusion This study revealed that VZV-related neurological complications are heterogeneous, commonly leading to severe disability and poor outcomes, and that neurological phenotypes and outcomes are related to the distribution of herpes zoster.

Varicella-Zoster Meningitis and Myelitis After Herpes Zoster Dermatitis Treatment With Amenamevir: A Case Series and Literature Review

Varicella-zoster virus (VZV), known for causing chickenpox, establishes latent infections in neural tissues. Reactivation of VZV can lead to herpes zoster (HZ) and various neurological complications. In this report, we present four cases of VZV meningitis and myelitis following amenamevir treatment for HZ dermatitis with positive VZV DNA in cerebrospinal fluid (CSF) revealed by polymerase chain reaction (PCR). Three of them were considered immunocompromised hosts given the fact that two of these patients were taking immunosuppressive drugs for rheumatoid arthritis, and one patient had a history of sigmoid colon cancer (four months after resection). After HZ onset, amenamevir, which has poor CSF transfer, was prescribed for all the patients, and all of them developed central nervous complications by VZV (meningitis in three cases and myelitis in one case) confirmed by PCR. All the patients were treated with acyclovir, which has a higher CSF transfer, and fully recovered. We speculate that amenamevir might have failed to prevent VZV infection in the central nervous system (CNS) and think that consideration should be given to administering acyclovir in preference to amenamevir for ΗΖ patients at high risk of CNS VZV infection, such as immunocompromised hosts.

Therapeutic advances in neuroinfectious diseases

There have been several major advances in therapeutic options for the treatment of neurological infections over the past two decades. These advances encompass both the development of new antimicrobial therapies and the repurposing of existing agents for new indications. In addition, advances in our understanding of the host immune response have allowed for the development of new immunomodulatory strategies in the treatment of neurological infections. This review focuses on the key advances in the treatment of neurological infections, including viral, bacterial, fungal, and prion diseases, with a particular focus on immunomodulatory treatment options. This review also highlights the process by which clinicians can request access to therapeutic agents on a compassionate or emergency basis when they may not be commercially available. While many therapeutic advances have been achieved in the past several years, there remains a pressing need for the continued development of additional therapeutic agents in the treatment of neurological infections.

Real-world safety and efficacy of amenamevir in patients with herpes zoster in Japan: A postmarketing observational study (REWARD)

The helicase-primase inhibitor amenamevir (AMNV) was approved for herpes zoster in Japan in 2017. The authors conducted a 1-month postmarketing observational study to evaluate the real-world safety and efficacy (cutaneous improvement and pain resolution) of AMNV in patients with herpes zoster. Of the 3453 patients registered between March 2018 and December 2020, 3110 were included in the safety analyses. The mean age (±standard deviation) was 63.7 ± 17.5 years, with 57.9% of patients aged ≥65 years. Most patients had mild (53.3%) or moderate (41.0%) cutaneous lesions. Regarding pain, 43.9%, 25.6%, and 12.5% of patients had pain at the levels of 1-3, 4-6, and 7-10 on the numerical rating scale. In total, 30.0%, 27.2%, and 16.1% of patients were concomitantly treated with analgesics: acetaminophen, nonsteroidal anti-inflammatory drugs, and Ca2+ channel α 2δ ligands, respectively, and 10.6% were treated with topical antiherpetic drugs. Adverse drug reactions occurred in 0.77% of patients, including four serious adverse drug reactions in four patients (hyponatremia, thrombocytopenia, rash, and rhabdomyolysis). Regarding important potential risks, renal disorder, cardiovascular events, and decreased platelets were observed in one, one, and two patients, respectively. Concerning efficacy, the cutaneous improvement rate (significantly improved or improved) was 95.5%, with significantly higher improvement rates in patients treated with AMNV for 7 days and in patients with less severe cutaneous lesions or less pain. Factors affecting the time to pain resolution were the severity of cutaneous lesions and pain at the start of AMNV treatment and older age. This study demonstrated that the AMNV is safe and effective in patients with herpes zoster in a real-world clinical setting.

Aseptic meningitis after amenamevir treatment for herpes zoster ophthalmicus with oculomotor nerve palsy in a patient taking immunosuppressant

A 79-year-old woman presented with vomiting after being prescribed amenamevir by her primary care physician. She had a medical history of rheumatoid arthritis and was administered prednisolone and methotrexate. She was finally diagnosed with herpes zoster ophthalmicus and aseptic meningitis, and intravenous antiviral therapy was initiated. However, the patient developed oculomotor nerve palsy on the 11th day of hospitalization. In this case, there was a time lag between the administration of antiviral drugs and clinical improvement. Our case suggests the necessity of selecting antivirals, especially in high-risk cases of CNS complications, to avoid the low intracerebral transferability of antiviral drugs, including amenamevir.

Orofacial Dyskinesia and Intractable Hiccups in a Patient with Varicella-zoster Virus Encephalomyelitis

A 73-year-old Japanese man with diabetic complications presented with involuntary lip movements and long-lasting hiccups after developing zoster rash. Magnetic resonance imaging revealed lesions involving the medial temporal lobe and C1 level of the spinal cord. Varicella-zoster virus (VZV) encephalomyelitis was diagnosed. We considered attributing the orofacial dyskinesia, a very rare symptom of VZV central nervous system (CNS) complications, to the temporal lobe lesion. Although the culprit lesion for the hiccups was unclear, further examinations may have clarified this issue. As immunocompromised patients with herpes zoster may develop CNS complications with a wide variety of symptoms, special care is needed.

Aseptic Meningitis after Amenamevir Treatment for Herpes Zoster in the First Branch of the Trigeminal Nerve

Amenamevir has been approved for the treatment of herpes zoster (HZ); however, its therapeutic efficacy against central nervous system (CNS) infection may be insufficient due to its low spinal fluid permeability. We herein report a case of aseptic meningitis in a 91-year-old Japanese man treated with amenamevir for HZ in the trigeminal nerve region. Several cases of CNS infection have been reported in patients receiving amenamevir treatment for HZ. Patients with CNS complications often have skin rashes near the trigeminal region. Thus, we should be alert for signs of CNS infection when administering amenamevir to patients with such rashes.

Identification of Potential Antiviral Inhibitors from Hydroxychloroquine and 1,2,4,5-Tetraoxanes Analogues and Investigation of the Mechanism of Action in SARS-CoV-2

This study aimed to identify potential inhibitors and investigate the mechanism of action on SARS-CoV-2 ACE2 receptors using a molecular modeling study and theoretical determination of biological activity. Hydroxychloroquine was used as a pivot structure and antimalarial analogues of 1,2,4,5 tetraoxanes were used for the construction and evaluation of pharmacophoric models. The pharmacophore-based virtual screening was performed on the Molport® database (~7.9 million compounds) and obtained 313 structures. Additionally, a pharmacokinetic study was developed, obtaining 174 structures with 99% confidence for human intestinal absorption and penetration into the blood-brain barrier (BBB); posteriorly, a study of toxicological properties was realized. Toxicological predictions showed that the selected molecules do not present a risk of hepatotoxicity, carcinogenicity, mutagenicity, and skin irritation. Only 54 structures were selected for molecular docking studies, and five structures showed binding affinity (ΔG) values satisfactory for ACE2 receptors (PDB 6M0J), in which the molecule MolPort-007-913-111 had the best ΔG value of -8.540 Kcal/mol, followed by MolPort-002-693-933 with ΔG = -8.440 Kcal/mol. Theoretical determination of biological activity was realized for 54 structures, and five molecules showed potential protease inhibitors. Additionally, we investigated the Mpro receptor (6M0K) for the five structures via molecular docking, and we confirmed the possible interaction with the target. In parallel, we selected the TopsHits 9 with antiviral potential that evaluated synthetic accessibility for future synthesis studies and in vivo and in vitro tests.

[Varicella-zoster meningoencephalitis and vasculitis after treatment with amenamevir to herpes zoster in the trigeminal nerve area]

A 78-year-old woman was diagnosed with herpes zoster in the first branch of the trigeminal nerve and was treated with amenamevir. Subsequently, she was hospitalized for postherpetic neuralgia. Fever and unconsciousness were observed, and a diagnosis of varicella-zoster virus meningoencephalitis and vasculitis was made. In addition to the antithrombotic therapy, she was treated with intravenous acyclovir and steroid pulse therapy; however, her unconsciousness persisted. Amenamevir was not transferrable to the spinal fluid and resulted in an incomplete treatment of herpes zoster in the cerebral nerve region, suggesting that this case may be related to the severe course of the disease.

Tissue distribution, excretion, and metabolism of 2,6-di-tert-butyl-hydroxytoluene in mice

As one typical synthetic phenolic antioxidant, 2,6-di-tert-butyl-hydroxytoluene (BHT) has been widely adopted in food and other human products, and considered as an emerging contaminant due to its toxic effects. Understanding bioaccumulation and metabolism of BHT is crucial to evaluate its environmental fate and toxicity. In this study, the tissue distribution, excretion, and metabolism of BHT in mice were investigated. It was shown that BHT was prone to be accumulated in metabolism-related organs (i.e., liver and kidney) with AUC_{0-120 h} (area under the concentration-time curve from 0 to 120 h) values of 206 h·μg/g in liver and 162 h·μg/g in kidney. For metabolites, 2,6-di-tert-butyl-4-hydroxy-4-methyl-2,5-cyclohexadione (BHT-quinol) was preferentially accumulated in liver, while 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH) was the major metabolite in excreta. The major excretion of BHT and metabolites was through feces with a value of 25.1 ± 0.16% of the initial dose compared with urine of 1.27 ± 0.05%. The possible metabolic pathways of BHT were elucidated as the oxidation of the para-methyl, tert-butyl groups, and aromatic ring based on the known and identified unknown metabolites by HPLC-Q-TOF-MS/MS. The preferred accumulation of BHT and metabolites in liver implies their potential hepatotoxicity. Results here also suggested that considering the distribution and excretion of metabolites can better assess BHT's fate and risk in mammals.

Pharmacokinetics and Dialyzability of a Single Oral Dose of Amenamevir, an Anti-Herpes Drug, in Hemodialysis Patients

Introduction

Amenamevir (ASP2151), a herpesvirus helicase-primase inhibitor, is currently used for the treatment of herpes zoster in Japan. Amenamevir is mainly metabolized in the liver, and urinary excretion of amenamevir is approximately 10% in healthy adults. The increase of systemic exposure in non-dialysis patients with severe renal impairment was much less than that associated with nucleoside antiviral agents. The aim of this study was to evaluate the pharmacokinetics and dialyzability of a single oral dose (400 mg) of amenamevir in hemodialysis patients.

Methods

This was a single-arm, open-label, multicenter clinical pharmacology study. Nine patients aged 20–80 years with end-stage kidney disease and undergoing maintenance hemodialysis three times weekly were enrolled. Pharmacokinetics and dialyzability were investigated by serial collection of blood samples until 48 h post-dose during the study.

Results

The maximum plasma concentration and time to reach maximum plasma concentration during 24 h post-dose were 1585 ng/mL and 6.2 h, respectively. The area under the plasma concentration–time curve (AUC) from time zero to 24 h was 23,890 ng h/mL. The median terminal elimination half-life within 24 h before, during, and after hemodialysis was 14.7, 15.2, and 12.4 h, respectively. The AUC in hemodialysis patients was approximately double that in healthy adults. This increase in AUC was much less than that reported in nucleoside antiviral agents. The hemodialysis clearance, elimination fraction percentage, and amount of amenamevir removed were 37.8 mL/min, 28.1%, and 132.0 μg, respectively. The amount of amenamevir removed by hemodialysis was minimal. None of the hemodialysis parameters were associated with serum albumin. This study revealed no clinically relevant safety concerns.

Conclusion

There were no clinically relevant safety concerns when 400 mg of amenamevir was administered as a single dose to hemodialysis patients without dose adjustment and/or modification of the dosing schedule.

Trial Registration

JapicCTI-184242.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-020-01375-1) contains supplementary material, which is available to authorized users.