Allogenic and autologous anti-CD7 CAR-T cell therapies in relapsed or refractory T-cell malignancies

Abstract

Chimeric antigen receptor-T (CAR-T) therapy remains to be investigated in T-cell malignancies. CD7 is an ideal target for T-cell malignancies but is also expressed on normal T cells, which may cause CAR-T cell fratricide. Donor-derived anti-CD7 CAR-T cells using endoplasmic reticulum retention have shown efficacy in patients with T-cell acute lymphoblastic leukemia (ALL). Here we launched a phase I trial to explore differences between autologous and allogeneic anti-CD7 CAR-T therapies in T-cell ALL and lymphoma. Ten patients were treated and 5 received autologous CAR-T therapies. No dose-limiting toxicity or neurotoxicity was observed. Grade 1-2 cytokine release syndrome occurred in 7 patients, and grade 3 in 1 patient. Grade 1-2 graft-versus-host diseases were observed in 2 patients. Seven patients had bone marrow infiltration, and 100% of them achieved complete remission with negative minimal residual disease within one month. Two-fifths of patients achieved extramedullary or extranodular remission. The median follow-up was 6 (range, 2.7-14) months and bridging transplantation was not administrated. Patients treated with allogeneic CAR-T cells had higher remission rate, less recurrence and more durable CAR-T survival than those receiving autologous products. Allogeneic CAR-T cells appeared to be a better option for patients with T-cell malignancies.

Fig. 1. Consort diagram of patient flow.

Ten patients were enrolled in the study and underwent leukapheresis. Anti-CD7 CAR-T cells were derived from patients or their donors and infused into all patients at a low dose (1 × 10⁶/kg, n = 5) or a high dose (2 × 10⁶/kg, n = 5).

Fig. 2. Clinical response to anti-CD7 CAR-T cells.

A The clinical responses of patients’ BM and EMD post anti-CD7 CAR-T infusion are shown by swimmer plots. For patients without BM infiltration or EMD, striped bars are presented. PT patient, BM bone marrow, EMD extramedullary disease, CR complete remission, PR partial response, SD stable disease, PD progressive disease. * EMD did not existed during screening in patient 2 and she achieved MRD- CR after infusion. On the 140th post infusion, extramedullary recurrence occurred in the gastric wall, pelvic peritoneum and multiple lymph nodes detected by PET-CT. B Representative PET-CT images of patient 6 before and after anti-CD7 CAR-T cells infusion. As is shown in PET-CT, patient 6 had lesions in nasopharynx and left clavicle. The patient achieved extramedullary complete remission at day 30 post infusion. C Images of patient 1 before and after anti-CD7 CAR-T cells infusion. Patient 1 had diffuse lesions over the body, especially on his elbows and right knee (left), and achieved remarkable remission with a small phyma on the right knee on Day 65.

Fig. 3. CAR-T cell expansion and persistence.

A Kinetics of CAR vector transgene copies per microgram of genomic DNA of peripheral blood mononuclear cells in individual patients measured by ddPCR. The dotted line indicated the threshold determined by quantitation of normal samples. B Kinetics of CD7- CAR-T cells in peripheral blood detected by FCM. C Correlation of the peak CAR copies in the peripheral blood with sources and efficacy. D The percentages of CD7⁺ T cells were determined by FCM. Due to the lack of specimens, the condition of patients 1 and 2 could not be detected.

Fig. 4. Serum biomarkers in peripheral blood after CAR-T cell infusions.

A A heatmap of biomarkers. Each row is a biomarker, and each column is a time point. At each time point, the color patches from left to right represent patient 1–10, respectively. B Kinetics of IL-6, IL-10 and IFN -γ in peripheral in individual patients measured by cytometric bead array. Pronounced increases of these cytokines were detected in patients 2, 5, 7, 8 and 9, which were overlapped with grade 1 or 2 cytokine release syndrome and precede the peak of CAR-T cell expansion.

Fig. 5. Single-cell RNA sequencing of patients 1 and 5.

A Proportion of various types of cells in peripheral blood mononuclear cells (PBMCs) from patient 1 and patient 5. B Visualize the expression of CD7 in peripheral blood cells by UMAP plots. C Proportion of various types of cells in T cells (PBMCs) from patient 1 and patient 5. D Visualize the expression of TIGHT and GZMA in T cells by UMAP plots. Patient 1 (left), patient 5 (right).