Study to Evaluate Safety and Activity of TRL345 in Healthy Volunteers

Human cytomegalovirus (HCMV) is the most common medically significant infection in transplant patients. HCMV is usually a serious and even fatal infection in newborn SCID infants requiring hematopoietic stem cell transplant. HCMV is also the leading cause of congenital viral infection, with an incidence in the United States of 1-3% of live births. Primary HCMV infection during early pregnancy poses a 30-40% risk of intrauterine transmission. Approximately 10-15% of congenitally infected infants are symptomatic, presenting with intrauterine growth restriction and permanent birth defects, including neurological deficiencies, retinopathy, and sensori-neuronal deafness; of the infected but asymptomatic infants, 15-20% will later develop permanent sequelae. Trellis Bioscience is developing TRL345, a fully human monoclonal antibody that has specificity to the AD-2 site I in gB of HCMV, both for transplant patients and for the prevention of maternal HCMV infection during pregnancy. Antibody therapy provides an alternative to antiviral drugs with an expectation of qualitatively lower toxicity. The leading small molecule antiviral effective against HCMV, ganciclovir (and its oral prodrug formulation valganciclovir), has side effects (including neutropenia, nephrotoxicity, and potential mutagenicity) that make its use problematic for major indications, including congenital transmission or the early post-transplant period for HCT. Although the recently approved small molecule antiviral letermovir has reduced neutropenic activity and is therefore useful in hematopoietic cell transplantation (HCT), it has not eliminated CMV reactivation in adult HCT patients.