Tecovirimat Resistance in Mpox Patients, United States, 2022-2023

During the 2022 multinational outbreak of monkeypox virus (MPXV) infection, the antiviral drug tecovirimat (TPOXX; SIGA Technologies, Inc., https://www.siga.com) was deployed in the United States on a large scale for the first time. The MPXV F13L gene homologue encodes the target of tecovirimat, and single amino acid changes in F13 are known to cause resistance to tecovirimat. Genomic sequencing identified 11 mutations previously reported to cause resistance, along with 13 novel mutations. Resistant phenotype was determined using a viral cytopathic effect assay. We tested 124 isolates from 68 patients; 96 isolates from 46 patients were found to have a resistant phenotype. Most resistant isolates were associated with severely immunocompromised mpox patients on multiple courses of tecovirimat treatment, whereas most isolates identified by routine surveillance of patients not treated with tecovirimat remained sensitive. The frequency of resistant viruses remains relatively low (<1%) compared with the total number of patients treated with tecovirimat.

Surface enhanced Raman scattering investigation of tecovirimat on silver, gold and platinum loaded silica nanocomposites: Theoretical analysis (DFT) and molecular modeling

As of today, there have been 612 million confirmed cases of coronavirus disease (COVID-19) around the world, with over 6 million fatalities. Tecovirimat (TPOXX) is an anti-viral drug, and it was the first drug approved for the treatment of anti-pox virus in the US. However, the effectiveness of this drug against COVID-19 has not yet been explored. Since TPOXX is an anti-viral drug, an attempt has been made to determine its ability to act as a COVID inhibitor. Recent medical advances have resulted in the development of nano cage-based drug delivery. Drug delivery clusters based on nano cages have recently been used in the medical industry. As such, we used DFT coupled to the B3LYP/LANL2DZ basis set to study the adsorption behavior of the anti-viral drug TPOXX on Au/Ag/Pt⋯SiO2loaded silica nanocomposites. In order to identify the active site of the molecule, we have used the frontier molecular orbital (FMO) theory of molecular electrostatic potential (MEP). The compound and its complexes obey Lipinski's rule of five and have good drug-likeness properties based on the bioactivity evaluation. The biological properties of organic molecules and nano metal clusters were compared. The TPOXX with its nanocomposites was also studied in terms of Electron Localization Function (ELF) and Localized Orbital Locator (LOL). Molecular docking was performed for both pure molecule and its silica nanocomposites-doped derivatives with the chosen proteins to discuss the protein-ligand binding properties. These results could be more helpful in designing the drug and exploring its application for the inhibition of SARS-CoV-2.

Emerging pharmacological strategies for treating and preventing mpox

INTRODUCTION

Since May 2022, there have been nearly 87,000 documented cases of mpox worldwide, with 119 deaths. Pharmacological interventions for mpox include the MVA-BN smallpox vaccine, tecovirimat, cidofovir, its pro-drug brincidofovir, and vaccinia immune globulin intravenous (VIGIV).

AREAS COVERED

The literature search and information gathering for this review included the PubMed database focusing on mpox and monkeypox, in combination with tecovirimat, brincidofovir, cidofovir, VIGIV, and smallpox vaccine. WHO.int, CDC.gov, FDA.gov, and ClinicalTrials.gov websites were accessed for the most recent information on the mpox outbreak. Mechanisms for deployment and access to treatment including expanded access, emergency use, and clinical trials will be discussed. Treatment outcomes with safety data will be presented.

EXPERT OPINION

The vaccine as a preventive measure, along with numerous treatment options, largely controlled the outbreak, although deployment of each could be improved upon to hasten and broaden access. More widespread coverage by the vaccine is necessary to prevent future resurgence of mpox. Tecovirimat has emerged as a safe frontline treatment for mpox, while brincidofovir use has been limited by safety concerns. VIGIV and cidofovir should be reserved for the most severe cases in which other options are not fully effective.

New Perspectives on Antimicrobial Agents: Tecovirimat for Treatment of Human Monkeypox Virus

Tecovirimat is an antiviral drug initially developed against variola virus (VARV) to treat smallpox infection. Due to its mechanism of action, it has activity against the family of orthopoxviruses, including vaccinia and the human monkeypox virus (HMPXV). Efficacy studies have thus far been limited to animal models, with human safety trials showing no serious adverse events. Currently approved by the FDA only for the treatment of smallpox, tecovirimat shows promise for the treatment of HMPXV. Tecovirimat has been prescribed via an expanded access for an investigational new drug protocol during the 2022 outbreak. This review will examine the literature surrounding tecovirimat's mechanism of action, pharmacokinetics, safety, efficacy, and potential for resistance.