[Current status of research and development for anti-influenza virus drugs--chemotherapy for influenza]

Antiviral research for influenza viruses (FluV) is proceeding actively whereas few compounds are available for clinical use. Amantadine, an inhibitor of M2 ion-channel of FluV-A has been a key compound which disclosed important function of M2 protein, however, its clinical efficacy is restricted only in chemoprophylaxis of infection. Recently several compounds which showed novel antiviral mechanism for FluV replication emerged. They are inhibitors of conformation change of HA, of fusion of envelope and cellular membrane, of endonuclease on mRNA, of viral RNA replication, and of NA activity. Although most of these inhibitors are under investigations some of them are in clinical trial of phase II or phase III. It is obvious that most important problem in clinical use of anti-FluV drugs should be its side effects, bioavailability and stability in human bodies.