Abstract LB-138: Autologous-collected anti-cd19 chimeric antigen receptor (CAR) T cells for acute lymphocytic leukemia (ALL) and Non-Hodgkin's lymphoma (NHL) in children who have previously undergone allogeneic hematopoietic stem cell transplantation (HSCT). (2013)

Abstract Introduction: Despite aggressive therapies such as HSCT, survival in relapsed and refractory pediatric ALL and NHL is poor. CAR modified T cells targeting CD19 have been effective in adult B-cell malignancies. These studies have employed T cells either collected directly from non-HSCT patients or donor-derived EBV-specific cytotoxic T lymphocytes cultured over a period of 6-12 weeks. To treat children who have relapsed after HSCT with CAR T cells in a reasonable time frame, we developed an anti-CD19 CAR Phase I trial (NCT01593696) where T cells are collected directly from patients and manufactured in 11 days. Both HSCT-naïve and HSCT patients are eligible. Our CD19 CAR consists of a CD19-specific scFv and the CD28 and CD3ζ signaling domains. We report results with the first 4 patients (Pt), 3 of whom had undergone prior HSCT. Methods: Peripheral blood (PB) mononuclear cells were apheresed on Day -11. T cells were positively selected and activated using anti-CD3/anti-CD28 paramagnetic beads in IL-2 for 48 hours then transduced with the CD19-CAR gene via retroviral supernatant for an additional 48 hours. After an additional 7 days of expansion cells were harvested for infusion. Pts were treated with fludarabine (25 mg/m2/day on Days -4, -3, -2) and cyclophosphamide (900 mg/m2 on Day -2) prior to receiving 1x106 CAR transduced T cells/kg. Results: A 59- and 65-fold expansion of CAR T cells with 65% and 39% transduction efficiency was achieved in Pt 1 (ALL) and Pt 3 (NHL), respectively. Pt 1 achieved a complete response (CR) and experienced Gr 3 fever and Gr 2 hypotension correlating with mild elevation in IL-6, GM-CSF, INFγ and C-reactive protein (CRP) consistent with mild cytokine release syndrome (CRS). No other non-hematologic, CAR-related Gr 3 or 4 toxicities were observed. Pt 3 (ALL) only received 2.8% of the targeted CAR T cell dose due to lack of cell expansion, likely from recent prior therapy. Despite this, a transient CR with 0.01% MRD was observed at Day 19 with pronounced expansion of CAR T cells (15% of total T cells in PB, 5% in marrow, 6.2% in CSF). Pt 4 (primary refractory ALL, HSCT-naïve) has recently been infused after a 14-fold expansion with 33% transduction efficiency. To date, PB flow demonstrated: A) 9%, 0.01%, and 0% blasts B) 2.3%, 0.8%, and 0% B-cells and C) 0%, 11%, and 38% CAR+ T cells on Days -1, +4 and +6, respectively. Pt 4 also had mild CRS with Gr 3 fever and elevated CRP. Conclusions: Importantly, CAR T cell therapy was well tolerated without graft versus host disease in all three HSCT patients. These initial results indicate that autologous-collected anti-CD19 CAR T cell therapy is feasible and potentially effective for children with relapsed/refractory ALL including after HSCT. Citation Format: Daniel W. Lee, Nirali Shah, Maryalice Stetler-Stevenson, Marianna Sabatino, Kelly Richards, Cindy Delbrook, James N. Kochenderfer, Steven A. Rosenberg, David Stroncek, Crystal L. Mackall, Alan S. Wayne. Autologous-collected anti-cd19 chimeric antigen receptor (CAR) T cells for acute lymphocytic leukemia (ALL) and Non-Hodgkin's lymphoma (NHL) in children who have previously undergone allogeneic hematopoietic stem cell transplantation (HSCT). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-138. doi:10.1158/1538-7445.AM2013-LB-138