Dual CD19 and CD123 targeting prevents antigen-loss relapses after CD19-directed immunotherapies
Marco Ruella, … , Stephan A. Grupp, Saar Gill
Marco Ruella, … , Stephan A. Grupp, Saar Gill
Published August 29, 2016
Citation Information: J Clin Invest. 2016;126(10):3814-3826. https://doi.org/10.1172/JCI87366.
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Research Article Hematology Immunology

Dual CD19 and CD123 targeting prevents antigen-loss relapses after CD19-directed immunotherapies

Abstract

Potent CD19-directed immunotherapies, such as chimeric antigen receptor T cells (CART) and blinatumomab, have drastically changed the outcome of patients with relapsed/refractory B cell acute lymphoblastic leukemia (B-ALL). However, CD19-negative relapses have emerged as a major problem that is observed in approximately 30% of treated patients. Developing approaches to preventing and treating antigen-loss escapes would therefore represent a vertical advance in the field. Here, we found that in primary patient samples, the IL-3 receptor α chain CD123 was highly expressed on leukemia-initiating cells and CD19-negative blasts in bulk B-ALL at baseline and at relapse after CART19 administration. Using intravital imaging in an antigen-loss CD19-negative relapse xenograft model, we determined that CART123, but not CART19, recognized leukemic blasts, established protracted synapses, and eradicated CD19-negative leukemia, leading to prolonged survival. Furthermore, combining CART19 and CART123 prevented antigen-loss relapses in xenograft models. Finally, we devised a dual CAR-expressing construct that combined CD19- and CD123-mediated T cell activation and demonstrated that it provides superior in vivo activity against B-ALL compared with single-expressing CART or pooled combination CART. In conclusion, these findings indicate that targeting CD19 and CD123 on leukemic blasts represents an effective strategy for treating and preventing antigen-loss relapses occurring after CD19-directed therapies

Authors

Marco Ruella, David M. Barrett, Saad S. Kenderian, Olga Shestova, Ted J. Hofmann, Jessica Perazzelli, Michael Klichinsky, Vania Aikawa, Farzana Nazimuddin, Miroslaw Kozlowski, John Scholler, Simon F. Lacey, Jan J. Melenhorst, Jennifer J.D. Morrissette, David A. Christian, Christopher A. Hunter, Michael Kalos, David L. Porter, Carl H. June, Stephan A. Grupp, Saar Gill

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Figure 3

CART123, but not CART19, can successfully target CD19-negative B-ALL relapses.

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CART123, but not CART19, can successfully target CD19-negative B-ALL rel...
(A) A human xenograft model of CD19-negative relapse; experiment schematic. Two groups of NSG mice were respectively engrafted with B-ALL blasts (luciferase positive) originally obtained from the same patient (patient UPN#09) at baseline and when the patient relapsed with a CD19-negative disease after CART19. At day 17, mice in each group were randomized to receive CART19 or control T cells (UTD). Leukemia burden was followed using bioluminescence (BLI). (B) In both groups (baseline and relapse), mice treated with UTD showed disease progression (top graph). CART19 are only capable of inducing responses in the group of mice engrafted with baseline disease, while no antileukemia effect is observed in the group engrafted with CD19-negative relapse disease (bottom graph). (C) In another in vivo model, baseline (CD19+, CBG luciferase+) and relapsed (CD19–, CBR luciferase+) blasts from the same patient were mixed 1:1 and injected in the same NSG mice. Mice were then treated with CART19 or UTD, and the 2 B-ALL populations (baseline vs. relapse) were followed by bioluminescence. In mice treated with UTD, both populations showed progression (CBG and CBR bioluminescence), while in CART19-treated mice, only the relapsed clone (CD19-negative) showed frank progression (CBR). (D) CART123 successfully eliminated CD19-negative B-ALL relapses in vivo. Experiment schematic: luciferase-positive primary CD19-negative relapsed B-ALL blasts were injected in NSG mice, and after 17 days, mice were randomized based on tumor burden to receive either CART123, CART19, control T cells (UTD), or no treatment. (E) Mice receiving CART123 but not CART19 or UTD showed quick leukemia remission that was maintained in the long term (>120 days), leading to a significant advantage in overall survival (F). All graphs arerepresentative of 2 independent experiments (6-8 mice per group). Student’s t test or ANOVA for each time point/ratio was used. Survival curves were compared using the log-rank test. ***P < 0.001; ****P < 0.0001.