Infection with human Cytomegalovirus (CMV) is near universal and seroprevalence rates reach 90% in individuals older than 80 years. Although usually asymptomatic in the normal host, CMV causes serious morbidity and mortality in transplant recipients and patients with AIDS. Congenital CMV is the leading infectious cause of mental retardation and deafness. There is no prophylactic vaccine for CMV. The available drugs suppress CMV replication and prevent hearing deterioration in congenitally-infected children. However, their use results in intolerable side effects and emergence of resistant viruses. Development of new therapies for CMV could reduce morbidity and mortality from this pathogen. Through screening of the LOPAC library we identified emetine as a CMV inhibitor at nM concentrations (EC50 ? 40 nM and selectivity index of 200). The anti-CMV activities of emetine occur earlier than those of ganciclovir (GCV), before initiation of DNA replication, and the combination of both compounds exhibits strong synergy. In a mouse CMV (MCMV) model emetine was well- tolerated, displayed long half-life, preferential distribution to tissues over plasma, and effectively suppressed MCMV. At doses of 1 mg/kg and 0.1 mg/kg administered orally every 3 days emetine effectively inhibited MCMV replication. These doses translate into 0.008 mg/kg human dose (0.1/12). Our data suggest that emetine can be repurposed for CMV therpeutics. Since its past use for amebiasis was at much higher doses (1 mg/kg/day for a total of 600 mg), pharmacokinetic characterization of low dose emetine is required before it can move into clinical trials in CMV-infected patients. In addition, there are no data on the biodistribution of emetine in human organs, an important factor for inhibition of CMV replication in tissues. The goals of this R34 are to plan a phase 0 PK study of subcutaneous emetine, validate the method for measurement of emetine levels in blood, prepare a F- 18- emetine for posistron emeission tomography studies for determination of emetine biodistribution in human tissues, and to obtain IND for the planned clinical trial. This R34 is a new collaboration between Johns Hopkins investigators that have the expertise for such studies: Dr. Craig Hendrix, leader of the Drug Development Unit, Dr. Dean Wong, nuclear medicine expert, and Dr. Michelle Rudek, director of the analytical pharmacology core.
Human Cytomegalovirus (CMV) is the most common congenital infection worldwide and one of the most serious infectious complications after solid organ and bone marrow transplantation. Treatment options for CMV are extremely limited, and all based on inhibition of the viral DNA polymerase. We recently identified emetine as a CMV inhibitor at very low doses; its repurposing for CMV therapeutics requires pharmacokinetic studies which will be planned in the R34.
