Repurposing of FDA-Approved Antiviral Drugs Against Monkeypox Virus: Comparative In Vitro Screening and Structure Based In Silico Studies

<b>Background/Objectives</b>: Monkeypox is endemic to the African continent and has recently garnered global attention due to reported outbreaks in non-endemic nations. No approved drug is available for non-severe cases, and some isolates gained resistance to approved antivirals. In this study, we employed a drug repositioning strategy to evaluate the efficacy of existing FDA-approved antiviral drugs if repurposed for use against emerging Monkeypox, representing a cost-effective method for identifying novel therapeutic interventions. <b>Methods</b>: Methodology including Egyptian virus strain isolation, propagation and titration followed by in vitro studies, molecular docking and molecular dynamics simulations combined with binding free energy were carried out. Twenty-three FDA-approved drugs, including Abacavir, Acyclovir, Amantadine, Chloroquine, Daclatasvir, Dolutegravir, Entecavir, Favipiravir, Hydroxychloroquine, Lamivudine, Molnupiravir, Nevirapine, Oseltamivir, Penciclovir, Remdesivir, Ribavirin, Sofosbuvir, Tenofovir, Valaciclovir, Valganciclovir, Velpatasvir, Zanamivir, and Zidovudine, were screened for potential anti-monkeypox activity in vitro. In silico studies were carried out against three monkeypox proteins, Thymidylate Kinase, A42R Profilin-Like Protein, and VACV D13, to identify their potential targets. <b>Results</b>: In vitro testing showed that two antiviral drugs are positive. The employed computational methods indicate that remdesivir demonstrated superior binding patterns with elevated scores and stable complexes throughout the simulation. <b>Conclusions</b>: Our findings showed that Remdesivir therapeutic compound is potent against the tested strain of MPXV, and exhibited a robust binding affinity for Thymidylate Kinase, A42R Profilin-Like Protein, and VACV D13 enzymes, and thus may potentially be utilized as antiviral for the treatment of monkeypox virus.