A Double-Blind Clinical Study in Patients with Herpes Zoster to Establish YN-72 (Brovavir) Dose

Abstract

YN-72 (bromovinyl araU, or BV-araU) is a new antiviral agent synthesized by Yamasa Shoyu Company. It is an arabinosyluracil derivative having a bromovinyl group at the 5 position. Its chemical structure is shown in figure 1. YN-72 had potent in vitro antiviral action against varicella-zoster virus (VZV) and herpes simplex virus type 1 (HSV-1). Its proliferation-depressing action on normal cells is very low, and therefore the antiviral agent is highly selective (1–6). The mechanism of action is as follows: YN-72 is phosphorylated only by viral thymidine kinase to become a monophosphate and diphosphate. It is converted to a triphosphate by cellular kinase, which antagonizes the action of DNA polymerase, inhibiting viral proliferation (7–10).