A Randomized Study of Maternal Donor Derived CMV Cytotoxic T-Lymphocytes (CTLs) and Valganciclovir vs Valganciclovir in Neonates With Moderate/Severe Maternal Acquired CMV Infection - Project Summary Congenital cytomegalovirus (cCMV) infection that is acquired in-utero, although an orphan disease (20-80,000 cases/yr in U.S.) is the most common congenital infection in the U.S. and the leading cause of long-term neurodevelopmental disabilities. cCMV infection represents 41% of all CMV associated childhood deaths. This high degree of morbidity and mortality is in large part secondary to the large CMV genome whose genes are designed to facilitate evasion, blocking, impairing and modulation of host anti-viral immune responses and an immaturity and deficit in neonatal T-cell adaptive immunity at birth. This maladaptive T-cell immune response at birth results from temporal and developmental immune dysregulation in-utero with a resulting bias towards tolerance and preventing maternal immunological rejection, thereby suppressing normal T-cell maturation and development of memory T-cells to foreign microbial antigens. Importantly, a poor CMV specific T-cell adaptive immune response predisposes neonates with cCMV acquired in-utero to a significant increased risk of serious long-term morbidity and increased mortality. Restoring, at least temporarily, both CD4 and CD8 specific CMV T- cell mediated immunity in neonates with maternal acquired cCMV is therefore critical to eradicating persistent, refractory and/or resistant CMV infection and undesirable long-term sequelae and represents an unmet need. We have previously established a Viral Cytotoxic T-Cell Lymphocyte Consortium (VIRCTLC) funded under an FDA Orphan Grant to manufacture under GMP conditions and enrich for haploidentical (maternal) donor-derived CMV specific CTLs utilizing a CMV specific Peptivator® and the cytokine Capture System (CCS®) on the Miltenyi CliniMACS® device for treatment of infants and children with refractory/persistent CMV infection with primary or secondary T-cell deficiencies. We, therefore, hypothesize that manufacturing maternal donor-derived CMV CTLs and subsequent administration in neonates with maternal acquired cCMV will be feasible and safe and effective in combination with standard of care (SOC) (valganciclovir [valGCV]) compared to those treated with SOC alone. The three overarching aims of this FDA orphan grant proposal includes: 1) To determine feasibility, safety and compare the efficacy of maternal donor-derived CMV specific CTLs with SOC vs SOC alone; 2) To characterize the genomic and immunomic signatures and persistence of maternal donor-derived CMV CTLs and comparison of innate and adaptive immune landscape post CMV CTL administration; and 3) To quantify the severity and incidence of long-term neurological sequelae and developmental disabilities between the two treatment groups. CMV CTLs will be manufactured under GMP conditions utilizing the CCS® and administered every 2 weeks up to 5 doses with valGCV x 6 months or valGCV alone. Genomic and immunomic studies will be performed by ScRNAseq, mass cytometry, high dimensional flow cytometry and Nanostring immunoprofiling. Long-term neurological sequelae will be measured by audiograms, brain MRIs, developmental testing, among others.