Phase I Experience with a Bi-Specific CAR Targeting CD19 and CD22 in Adults with B-Cell Malignancies

Autologous CD19 directed CAR T-cell therapy has response rates of >70% in adult acute lymphoblastic leukemia (ALL) and >40% in adult diffuse large B cell lymphoma (DLBCL). Large trials (ZUMA-1/JULIET/TRANSCEND) have highlighted that many patients fail to achieve durable responses. Several groups have reported on the phenomenon of CD19 immune escape as a cause (Grupp et al, NEJM 2013, Neelapu et al, NEJM 2017) and the NIH Pediatric Oncology Branch has shown CD22 as an alternative target (Fry et al, Nat Med. 2018). We developed a bi-specific CAR construct targeting CD19 & CD22 with intracellular signaling domains incorporating 4-1BB and CD3 (CD19/CD22.BB.z) to overcome CD19 immune escape. Here, we present our Phase I experience with this bi-specific CAR in adults.This is a single institution phase I dose escalation study enrolling patients Age ≥ 18 years with relapsed/refractory B-ALL or DLBCL after standard therapies. Primary aim is to determine feasibility of manufacturing the bi-specific CAR and safety at three dose levels (1 x 106 CAR T cells/kg, 3 x 106 CAR T cells/kg, 1 x 107 CAR T cells/kg). Clinical response was evaluated as a secondary endpoint utilizing standard response criteria for ALL and DLBCL. All patients underwent lymphodepletion with cyclophosphamide (500mg/m2 daily x3 doses) and fludarabine (30mg/m2 daily x 3 doses) followed by CAR infusion two days later. Patients were assessed at pre-defined time-points (Day 28, Month 3, 6, 9, 12 then every 6-1...

Source: Blood - November 21, 2018 Category: Hematology Authors: Hossain, N., Sahaf, B., Abramian, M., Spiegel, J. Y., Kong, K., Kim, S., Mavroukakis, S., Oak, J., Natkunam, Y., Meyer, E. H., Frank, M. J., Feldman, S. A., Long, S. R., Qin, H., Fry, T. J., Muffly, L. S., Mackall, C. L., Miklos, D. B. Tags: 801. Gene Therapy and Transfer: Clinical Trials for Hemophilia and Using CAR T Cells Source Type: research