Multi-Virus-Specific T-Cell Therapy For Patients After Hematopoietic Stem Cell and Cord Blood Transplantation

Cytomegalovirus, EBV and adenovirus are particularly problematic in patients after hematopoietic stem cell (HSCT) and cord blood transplantation (CBT) and are associated with significant morbidity and mortality. Deficiencies in conventional therapeutics have increased interest in an immunotherapeutic approach to viral disorders. We have developed two strategies to grow multivirus-specific donor-derived T-cells from peripheral blood (PB) and naive cord blood (CB). Using an adenoviral-vector expressing CMVpp65 to modify monocytes, DC and EBV-LCL we generated a single culture of PB or CB mononuclear cells that gave rise to multivirus-specific cytotoxic T-cells (CTL)(n=76). We have infused 34 patients with PB-derived CTL and 8 patients with CB-derived CTL. Patients received CTL infusions from 35 to 164days (median 84d) post HSCT or CBT at a median of 5x10e7 cells/m2. None developed >grade II GvHD or other toxicities over 3 months of safety monitoring after infusion. We observed up to a 5-fold increase in CMV- and EBV-specific T-cells by 4weeks post-CTL as measured by IFN-g ELISPOT assay. 33 viral reactivations were observed in patients before or immediately after CTL infusion. In the absence of conventional therapy, 8 of the 11 patients with CMV infection became negative for CMV in the blood within 7d of CTL infusion, with a corresponding rise in CMV-specific CTL in PB. Each of 10 patients with high EBV loads cleared their virus, as did 11 of 12 patients with adenoviral infections/disease. This study demonstrates that multivirus-specific CTL derived from the PB of seropositive donors as well as the CB of virus naive donors expand in vivo and are active against multiple viruses. Furthermore, by restoring immunity to multiple viruses simultaneously, the need for continued prophylaxis with pharmacotherapy is eliminated, thus, improving the efficiency and cost effectiveness of protecting HSCT and CBT recipients from these potentially lethal viruses.