High-throughput repurposing screen identifies a DHODH inhibitor as a potent antiviral candidate against chikungunya virus

Introduction Chikungunya fever remains a growing global health challenge, with a subset of infected individuals developing long-lasting and severe disease manifestations. Although significant progress has been made in chikungunya virus (CHIKV) antiviral research, no licensed therapeutic options are currently available. In this context, drug repurposing offers a strategic approach to accelerate the identification and development of effective CHIKV treatments. Methods In this study, we conducted a high-throughput phenotypic screening assay based on a reporter CHIKV to evaluate 1,600 clinically approved or well-characterized compounds from the Repurposing, Focused Rescue, and Accelerated Medchem (ReFRAME) library and initiated the characterization of the in vitro antiviral profile of the most promising candidate. Results The developed high-throughput screening platform effectively identified 13 candidate antivirals. Farudodstat, a human dihydroorotate dehydrogenase (DHODH) inhibitor, emerged as the most promising candidate. It demonstrated robust inhibitory activity against epidemic CHIKV strains and efficacy that varied across cell lines of distinct origins, consistent with a host-dependent mechanism of action. As expected from the role of DHODH in the de novo pyrimidine biosynthesis pathway, supplementation with exogenous uridine restored viral replication in the presence of Farudodstat, indicating that blockade of DHODH underlies its anti-CHIKV activity. Discussion The potency and outstanding selectivity of Farudodstat as a CHIKV inhibitor in vitro, together with its favorable safety and pharmacokinetic properties, support the potential of Farudodstat as a promising oral antiviral candidate for the treatment of CHIKV fever.