Phase I/II Trial of Early Infusion of Rapidly-generated Multivirus Specific T Cells (MVST) to Prevent Post Transplant Viral Infections

Allogeneic hematopoetic stem cell transplantation (SCT) is frequently complicated by life threatening viral reactivation. Conventional antiviral therapy is suboptimal for cytomegalovirus (CMV), adenovirus (AdV) and Epstein-Barr virus (EBV) and nonexistent for BK virus (BKV). An alternative approach to prevent viral reactivation is to infuse virus-specific cytotoxic T cells (CTL) prepared from the donor early after SCT. Such multivirus-specific CTL cells (MVST) have been successfully used in a number of centers to prevent or treat CMV, Ad and EBV. Activity of BKV-reactive cells has not been studied. Multi virus-specific T cells (MVST) are donor lymphocytes that are highly enriched for viral antigens and expanded in vitro before infusion into the transplant recipient. Viral reactivation is a particular problem inT cell depleted SCT. Median time to CMV reactivation is estimated as 28 days post T-depleted transplant, but infusion of MVST within the immediate post-SCT period has not been previously studied. This protocol will be the first of a planned series of cellular therapies to be layered on our existing T lymphocyte depleted transplant platform protocol 13-H-0144.

The aim of this study is to determine the safety and efficacy of very early infusion of MVST directed against the four most common viruses causing complications after T-depleted SCT. GMP-grade allogeneic MVST from the stem cell donor will be generated using monocyte-derived donor dendritic cells (DCs) pulsed with overlapping peptide libraries of immunodominant antigens from CMV, EBV, Ad, and BKV and expanded in IL-7 and IL-15 followed by IL-2 for 10-14 days. A fraction of the routine donor leukapheresis for lymphocytes obtained prior to stem cell mobilization will be used to generate the MVST cells. MVST passing release criteria will be cryopreserved ready for infusion post SCT.

Eligible subjects on NHLBI protocol 13-H-0144 will receive a single early infusion of MVST within 30 days (target day +14, range 0-30 days) post SCT. Phase I safety monitoring will continue for 6 weeks. Viral reactivation (CMV, EBV, Ad, BK) will be monitored by PCR by serial blood sampling. The only antiviral prophylaxis given will be acyclovir to prevent herpes simplex and varicella zoster reactivation. Subjects with rising PCR exceeding threshold for treatment, or those with clinically overt viral disease will receive conventional antiviral treatment. Patients developing acute GVHD will receive standard treatment with systemic steroids. These patients are eligible for reinfusion of MVST when steroids are tapered.

The clinical trial is designed as a single institution, open label, non-randomized Phase I/II trial of MVST in transplant recipients, designed as 3-cohort dose escalation Phase I followed by a 20 subject extension Phase II at the maximum tolerated dose of cells. Safety will be monitored continuously for a period of 6 weeks post T cell transfer. The primary safety endpoint will be the occurrence of dose limiting toxicity, defined as the occurrence of Grade IV GVHD or any other SAE that is deemed to be at least probably or definitely related to the investigational product. The primary efficacy endpoint for the phase II will be the proportion of CMV reactivation requiring treatment at day 100 post transplant. Secondary endpoints are technical feasibility of MSVT manufacture, patterns of virus reactivation by PCR, and clinical disease from EBV, Ad, BK, day 100 non-relapse mortality.