&NA;Benzimidavir (BW 1263W94, 1263W94, GW 1263) is a novel, orally bioavailable benzimidazole compound selected for development by Glaxo Wellcome for the treatment of cytomegalovirus (CMV) infection. Glaxo Wellcome investigated benzimidavir in the early stages of development in collaboration with the University of Michigan (Department of Medicinal Chemistry). Phase I/II clinical studies are underway in the EU and the US.Although its mechanism of action is not fully understood, benzimidavir appears to interfere with CMV DNAsynthesis by blocking a virus-specific process that is a novel antiviral target.This possibly novel mechanism of action against CMV indicates that benzimidavir may be active against strains resistant to current therapies. Studies in volunteers have indicated good oral bioavailability and acceptable tolerance and it appears not to interfere with anti-HIV activity of antiretroviral drugs. Clinical trials will assess further the efficacy of benzimidavir for treatment of CMV infections.