Pleconaril

Pleconaril is an antiviral drug being developed by Schering-Plough for prevention of asthma exacerbations and common cold symptoms in asthmatic subjects exposed to picornavirus respiratory infections. Although the formulation used by Schering-Plough is a nasal spray, pleconaril is orally bioavailable, and is active against viruses in the Picornaviridae family, including Enterovirus and Rhinovirus.

History
Pleconaril was originally developed by Sanofi-Aventis, and licensed to ViroPharma in 1997. ViroPharma developed it further, and submitted a New Drug Application to the United States Food and Drug Administration (FDA) in 2001. The application was rejected, and ViroPharma re-licensed it to Schering-Plough in 2003. As of 2007, it is in Phase II clinical trials.

Mechanism of action
Pleconaril binds to a hydrophobic pocket in VP1, the major protein which comprises the capsid (the outer "shell") of picornaviruses. In enteroviruses, this prevents the virus from exposing its RNA, and in rhinoviruses it also prevents the virus from attaching itself to the host cell.