No abstract

Purpose T cells can be genetically modified to express an anti-CD19 chimeric antigen receptor (CAR). We assessed the safety and efficacy of administering autologous anti-CD19 CAR T cells to patients with advanced CD19+ B-cell malignancies. Patients and Methods We treated 15 patients with advanced B-cell malignancies. Nine patients had diffuse large B-cell lymphoma (DLBCL), two had indolent lymphomas, and four had chronic lymphocytic leukemia. Patients received a conditioning chemotherapy regimen of cyclophosphamide and fludarabine followed by a single infusion of anti-CD19 CAR T cells. Results Of 15 patients, eight achieved complete remissions (CRs), four achieved partial remissions, one had stable lymphoma, and two were not evaluable for response. CRs were obtained by four of seven evaluable patients with chemotherapy-refractory DLBCL; three of these four CRs are ongoing, with durations ranging from 9 to 22 months. Acute toxicities including fever, hypotension, delirium, and other neurologic toxicities occurred in some patients after infusion of anti-CD19 CAR T cells; these toxicities resolved within 3 weeks after cell infusion. One patient died suddenly as a result of an unknown cause 16 days after cell infusion. CAR T cells were detected in the blood of patients at peak levels, ranging from nine to 777 CAR-positive T cells/μL. Conclusion This is the first report to our knowledge of successful treatment of DLBCL with anti-CD19 CAR T cells. These results demonstrate the feasibility and effectiveness of treating chemotherapy-refractory B-cell malignancies with anti-CD19 CAR T cells. The numerous remissions obtained provide strong support for further development of this approach.

Purpose Multiple myeloma (MM) is a usually incurable malignancy of plasma cells. New therapies are urgently needed for MM. Adoptive transfer of chimeric antigen receptor (CAR)-expressing T cells is a promising new therapy for hematologic malignancies, but an ideal target antigen for CAR-expressing T cell therapies of MM has not been identified. B-cell maturation antigen (BCMA) is a protein that has been reported to be selectively expressed by B-lineage cells including MM cells. Our goal was to determine if BCMA is a suitable target for CAR-expressing T cells. Experimental Design We conducted an assessment of BCMA expression in normal human tissues and MM cells by flow cytometry, quantitative PCR, and immunohistochemistry. We designed and tested novel anti-BCMA CARs. Results BCMA had a restricted RNA expression pattern. Except for expression on plasma cells, BCMA protein was not detected in normal human tissues. BCMA was not detected on primary human CD34+ hematopoietic cells. We detected uniform BCMA cell-surface expression on primary MM cells from 5 of 5 patients. We designed the first anti-BCMA CARs to be reported, and we transduced T cells with lentiviral vectors encoding these CARs. The CARs gave T cells the ability to specifically recognize BCMA. The anti-BCMA-CAR-transduced T cells exhibited BCMA-specific functions including cytokine production, proliferation, cytotoxicity, and in vivo tumor eradication. Importantly, anti-BCMA-CAR-transduced T cells recognized and killed primary MM cells. Conclusions BCMA is a suitable target for CAR-expressing T cells, and adoptive transfer of anti-BCMA-CAR-expressing T cells is a promising new strategy for treating MM.

Key Points Donor-derived anti-CD19-CAR T cells cause regressions of refractory malignancies after allogeneic transplantation.