(±)-(1α,2β,3α)-9-[2,3-bis(hydroxymethyl)cyclobutyl]guanine [(±)-BHCG or SQ 33 054]: A potent and selective inhibitor of herpesviruses

Abstract (±)-(1α,2β,3α)-9-[2,3- bis (hydroxymethyl)cyclobutyl]guanine [(±)-BHCG or SQ 33 054] is a newly synthesized nucleoside analog with potent and selective antiviral activity against members of the herpesvirus group, including human cytomegalovirus. The activity against a thymidine kinase deficient HSV-2 mutant was 25-fold poorer than against the parent virus, suggesting that phosphorylation is an important prerequisite for antiviral activity against HSV-2. (±)-BHCG is readily phosphorylated by purified HSV-1 thymidine kinase, and BHCG triphosphate synthesized enzymatically is a selective inhibitor of HSV-1 DNA polymerase. (±)-BHCG did not inhibit host cell growth at concentrations at least 1000-fold higher than HSV-2 inhibitory concentrations. Subcutaneous administration of (±)-BHCG was protective against HSV-1 systemic infections in mice. BHCG is an exciting antiviral agent and represents a new class of nucleoside analogs.