Costimulated, Tumor-Derived Donor Lymphocyte (TDL) Infusion for B-Cell Tumor Relapse After Allogeneic Hematopoietic Stem Cell Transplantation
Authors: Hardy Nancy M. , Fellowes Vicki , Rose Jeremy , Fowler Daniel H. , Gress Ronald E. , Levine Bruce L. , June Carl H. , Hakim Frances T , Bishop Michael R. 
Published: October 2019

Abstract
Abstract 683

Donor lymphocyte infusion (DLI) is the primary treatment for relapse after allogeneic hematopoietic stem cell transplantation (allotransplant), but is effective in less than half of patients and is associated with significant graft-vs-host disease (GVHD). Furthermore, DLI is not available for cord-blood or many unrelated-donor recipients. We theorized that tumor from patients relapsing post-allotransplant would contain infiltrating donor T- lymphocytes with tumor-specificity. If such cells had been “primed”, but inadequately costimulated for tumor cell killing, costimulation ex-vivo could generate a donor lymphocyte product with increased graft-vs-tumor (GVT) potency. Preclinical feasibility was demonstrated in tumor biopsies from patients with tumor progression after allotransplant. Ex-vivo CD3/CD28 costimulation of tumor-infiltrating lymphocytes with antibody-coated magnetic beads yielded donor products, predominently consisting of effector T-cells; tumor specimens of greater than 1 cm reliably produced donor T cell expansions that would permit clinically relevant cell dosing. Based on these preclinical results, we conducted a Phase 1 study of tumor-derived donor lymphocyte (TDL) therapy in allotransplant recipients with B-lymphoid tumor progression despite full-donor T cell chimerism and DLI, or for which DLI was not available. The primary objectives of (1) feasibility of ex-vivo costimulation of lymphocytes from surgically harvested tumor to generate a TDL product and (2) safety of TDL infusion (TDLI) in patients with relapse after allotransplant were met within the first 7 of 15 planned subjects. All 7 patients had chemotherapy-refractory relapse after allotransplant (diffuse large-B cell lymphoma (DLBCL) = 2; Hodgkin's Lymphoma (HL) = 4; chronic lymphocytic leukemia (CLL) = 1). Tumor was surgically resected. Lymphocytes were released from tumor tissue through mechanical dispersion and cultured with CD3/CD28 antibody-coated magnetic beads in media supplemented with IL-2 (100 IU/ml) for a median of 12 days (range: 7– 42 days). T cells comprised from 0.5 – 63.4% of tumor cell suspensions (culture inocula) and 82 – 99% of expanded products (22- to 144-fold expansion). PCR-based chimerism assessment of products demonstrated that the TDL were of donor origin (median 99% donor). During TDL expansion, markers of activation and effector function increased (CD4: CD40L; CD8: CD137, perforin, NKG2D). Percentages of FoxP3+ Treg cells declined and TBet+ Th1/Tc1 effectors increased in the costimulated TDL product. Expression of CD27 and CD28 has been associated with long-term persistence of infused effector T cells; although these markers declined in culture, expression was retained in a significant proportion of cells from the 5 products that were cultured for less than 14 days. TDL products meeting release criteria for tumor contamination (<5%) and sterility were generated for all subjects. TDL were administered to all subjects, with a median of 2.63 × 107 cells/kg (range: 0.93 – 10 × 107 cells/kg) infused. No acute toxicities were seen during 24 hours of observation post-infusion, and there was no evidence of GVHD over a minimum follow-up of 4 weeks. Three subjects succumbed to their cancer prior to disease restaging (2 DLBCL and 1 HL). In 2 of 4 evaluable subjects, tumor-specific effects were observed following TDLI: in the first (HL), FDG-PET uptake by tumor declined at 4 and at 8 weeks after TDLI; in the second (HL), peri-tumoral pulmonary infiltrates developed 4 weeks after TDLI, with a subsequent tumor response upon initiation of systemic steroids. The remaining 2 subjects demonstrated mixed responses, with transient overall disease stabilization. We have demonstrated the feasibility and safety of TDL therapy, with suggestive evidence of tumor-directed biologic effects and potential GVT activity. Incorporating host immune depletion prior to TDLI, as has been required for efficacy in autologous adoptive cellular therapy, may permit more potent and sustainable GVT responses. TDL may provide a therapeutic option for patients without a source of DLI, e.g., cord-blood recipients, or for those whose tumors do not respond to standard DLI.

Disclosures:
June: N/A: Inventor, Government-held Patent.