Vapendavir is an investigational antiviral agent primarily studied for its potential in treating respiratory viral infections, particularly those caused by enteroviruses such as rhinovirus. It has been evaluated in clinical trials for the treatment of acute rhinovirus infection, especially in vulnerable populations like asthmatic patients and transplant recipients, where such infections can lead to severe respiratory complications.

The compound works by inhibiting viral capsid function, preventing the virus from uncoating and releasing its genetic material into host cells, thereby stopping replication. This mechanism makes it a promising candidate for broad-spectrum antiviral therapy against multiple picornaviruses.

Clinical development has focused on reducing viral load, symptom duration, and the risk of exacerbations in chronic respiratory conditions triggered by viral infections. While results have shown mixed efficacy, research continues into its potential use in high-risk patients and combination antiviral strategies.