• • Define safety and tolerability. • Safety profile of ApoCell infusion. • Time to neutrophil and platelet recovery. • Proportions of subjects with graft failure. • Incidence of infections. [ Time Frame: 180 days ]
  

• • Proportions of subjects with overall survival • Proportions of subjects with acute GvHD-free survival at Day 100. • Rates and grade of acute GvHD following ApoCell infusion. [ Time Frame: 180 days ]
  

Allogeneic hematopoietic stem-cell transplantation (HSCT) has revolutionized the treatment of hematopoietic malignancies, inherited hematopoietic disorders, aplastic anemia, and other severe diseases. Unfortunately, graft versus host disease (GvHD) remains a major toxicity that greatly limits the application and efficacy of allogeneic HSCT, occurring commonly after the procedure and affecting 30 to 80% of patients. Acute GvHD occurs within 100 days in up to 50% of allogeneic HLA-matched HSCT recipients despite prophylactic immunosuppressive drugs.

The most efficient treatment for GvHD prevention is T cell depletion. However, most clinicians avoid that modality due to the crucial effect of T cells in prevention of tumor relapse. Current standard prophylaxis and therapy for acute GvHD include mainly the use of immunosuppressive drugs that help less than 50% of the patients and are associated with increased infection risk. New strategies of GvHD prophylaxis are examined and this study uses a physiological strategy of antigen presenting cell (APC) tolerance induction that will modulate effector cells either directly or via T regulatory cells.

ApoCell treatment is anticipated to be a prophylactic measure for acute GvHD by inducing tolerance in the donor effector cells, leading to a potentially significant decrease in the immune response of the donor cells against the recipient. The effects of apoptotic cells on preventing GvHD may involve the following mechanisms: inhibit pro-inflammatory cytokine production, promote anti-inflammatory cytokines production, induce tolarogenic APCs, decrease ability to stimulate T-cell responses, delete CD8 T-effector cells, induce regulatory T-cells, and inhibit response to inflammatory cytokines and LPS.

Tolarex Ltd. is proposing a novel cell-based approach of donor apoptotic cells treatment, ApoCell, for a Phase I-IIa study of patients undergoing sibling HSCT with high risk of developing acute GvHD. The ApoCell product is composed of HLA-matched donor mononuclear enriched leukocytes in the form of liquid suspension that will be injected intravenously to the patient 24 hours prior to HSCT. The ApoCell suspension contains at least 55% of early apoptotic cells. The cell suspension is prepared under cGMP conditions with PBS solution within 8 hours prior to intravenous injection and should be stored at 2-8oC until administered.