First-in-human clinical trial of the autologous CD7-CART for relapsed/refractory ACUTE lymphoblastic leukemia/lymphoma.

Abstract

3026 Background: CD7 represents a potential target for T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/T-LBL). We developed CD7 nanobody derived chimeric antigen receptor T-cells (CD7-CART), and established a non-gene editing strategy by anchoring CD7 in the ER and/or Golgi to overcome the CART fratricide. Methods: This single-arm, open-label, phase I study is to investigate CD7-CART cell manufacturing feasibility without contamination of malignant T cells, and the safety and efficacy of the CART on patients with CD7 positive relapsed/refractory T-ALL/T-LBL. 3 subjects, identified as both CD4 and CD8 negative T-ALL or T-LBL were enrolled. CART cells were manufactured by using CD4+/CD8+ sorted T cells from leukapheresis. All patients (Pts) were pretreated with Flu/Cy prior to CART infusion. 1x106/kg CART cells were given to case 2 and 3, while 1.5x106/kg to case 1. Results: Case 1 was diagnosed as refractory ALL with myeloid differentiation, who had received intensive chemotherapy and allogeneic hematopoietic stem cell microtransplantation. Case 2 was diagnosed as ALL (T/B mixed type) but relapsed with CNS involvement, and received radiotherapy in addition to intensive chemotherapy. Prior to CART infusion, case 2 had no abnormal B cells but 17.69% of abnormal early T cellsfrom BM. Case 3 had stage VI of T-LBL, which recurred after multi-cycle chemotherapy of BFM-90 regimen and autologous SCT. After CART treatment, no neurotoxicity was observed in all pts. Case 1 had grade 3 CRSwhile case 2 and 3 had grade 1, although increased IL-6 was detected in all pts. Significant CART expansion and persistence were observed in case 2 and 3, and MRD negative CR was confirmed on day 28 in both pts. The number of generalized lymphadenopathy, lymph node size, and the degree of metabolism were all significantly reduced in case 3. Case 1 had only moderate CART expansion, but abnormal early T cells from BM decreased from 70.03% to 19.57% on day 30. After CART infusion, the number of peripheral abnormal T cells became either undetectable in case 2 and 3, or significantly decreased in case 1. Interestingly, CART had unsustained effect on normal T cells in all pts. As of Feb-10-2020, case 1 has 5 months of OS, including 3 months of PFS. Case 2 and 3 has reached 2 and 1 months of PFS and is still in remission. Conclusions: CD7-CART cells can be manufactured without contamination of malignant T cells. CD7-CART therapy is well-tolerated and has great therapeutic potential for relapsed/refractory CD7 positive T cell malignancies. Clinical trial information: NCT04004637 .