Donor-Derived CD7 Chimeric Antigen Receptor T Cells for T-Cell Acute Lymphoblastic Leukemia: First-in-Human, Phase I Trial

Authors

Jing Pan

¹State Key Laboratory of Experimental Hematology, Boren Clinical Translational Center, Department of Hematology, Beijing Boren Hospital, Beijing, China

Jing Pan, Yue Tan, Guoling Wang, Biping Deng, Zhuojun Ling, Weiliang Song, Samuel Seery, Yanlei Zhang, Shuixiu Peng, Jinlong Xu, Jiajia Duan, Zelin Wang, Xinjian Yu, Qinlong Zheng, Xiuwen Xu, Ying Yuan, Fangrong Yan, Zhenglong Tian, Kaiting Tang, Jiecheng Zhang, Alex H. Chang, Xiaoming Feng

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PURPOSE

Patients with relapsed or refractory T-cell acute lymphoblastic leukemia (r/r T-ALL) have few options and poor prognosis. The aim was to assess donor-derived anti-CD7 chimeric antigen receptor (CAR) T-cell safety and efficacy in patients with r/r T-ALL.

In this single-center, phase I trial, we administered anti-CD7 CAR T cells, manufactured from either previous stem-cell transplantation donors or new donors, to patients with r/r T-ALL, in single infusions at doses of 5 × 10⁵ or 1 × 10⁶ (±30%) cells per kilogram of body weight. The primary end point was safety with efficacy secondary.

Twenty participants received infusions. Adverse events including cytokine release syndrome grade 1-2 occurred in 90% (n = 18) and grade 3-4 in 10% (n = 2), cytopenia grade 3-4 in 100% (n = 20), neurotoxicity grade 1-2 in 15% (n = 3), graft-versus-host disease grade 1-2 in 60% (n = 12), and viral activation grade 1-2 in 20% (n = 4). All adverse events were reversible, except in one patient who died through pulmonary hemorrhage related to fungal pneumonia, which occurred at 5.5 months, postinfusion. Ninety percent (n = 18) achieved complete remission with seven patients proceeding to stem-cell transplantation. At a median follow-up of 6.3 months (range, 4.0-9.2), 15 remained in remission. CAR T cells were still detectable in five of five patients assessed in month 6, postinfusion. Although patients' CD7-positive normal T cells were depleted, CD7-negative T cells expanded and likely alleviated treatment-related T-cell immunodeficiency.

Among 20 patients with r/r T-ALL enrolled in this trial, donor-derived CD7 CAR T cells exhibited efficient expansion and achieved a high complete remission rate with manageable safety profile. A multicenter, phase II trial of donor-derived CD7 CAR T cells is in progress (NCT04689659).