Interferon γ-Primed Mesenchymal Stromal Cells as Prophylaxis for Acute Graft v Host Disease

Hematopoietic cell transplantation (HCT) is an established therapeutic modality for high risk hematological malignancies in adults and children. The primary cause of morbidity and mortality after HCT is graft versus host disease (GVHD), affecting up to 70% of patients even with current prophylaxis and directly accounting for approximately a third of regimen-related death. Currently, pharmacologic prophylaxis consists of a calcineurin inhibitor and methotrexate, a drug combination introduced around 40 years ago. Despite this regimen being recognized as the standard of care, it is only partially effective, increases the risk of infection and disease relapse and imparts drug-related, short- and long-term adverse effects. Mesenchymal stromal cells (MSCs) have potent immune modulatory activity which is markedly enhanced by exposure to interferon γ. In murine models, interferon γ (IFNγ) primed MSCs (γMSCs) potently suppress GVHD without untoward adverse effects suggesting this cell therapy may markedly reduce the regimen related toxicity of HCT; however γMSCs have never been infused into patients. This protocol is designed to test the hypothesis that freshly expanded γMSCs can be reliably produced and safely infused into patients undergoing HCT as GVHD prophylaxis. This is an investigator-initiated Phase I study using a rolling 6, dose escalation design with two independently accruing expansion cohorts: adults and pediatrics. Accrual to the pediatric tier will commence after the maximum tolerated dose (MTD) has been determined in adults. A successful outcome of this study will lay the foundation for a future Phase II study to demonstrate efficacy and support a Phase III randomized trial. The researchers plan to enroll a minimum of 4 and maximum of 45 subjects who are greater than 1 year old. Participants will be followed for up to 2 years after the HCT. The study will be conducted at Emory University and will recruit participants from the Winship Cancer Institute and Children's Hospital in Atlanta at Egleston.