7/25/2017
Submission Completed
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AntiCD123 CAR TCell Therapy for the Treatment of Myelodysplastic Syndrome Wei Zhang, MS1*, Brett M. Stevens, Ph.D.1*, Elizabeth Elizabeth Budde, MD, PhD2, Stephen J. Forman, MD2, Craig T. Jordan, Ph.D.1* and Enkhtsetseg Purev, M.D., Ph.D.1 1Division of Hematology, Department of Medicine, University of Colorado, Aurora, CO; 2Hematology & Hematopoietic Cell
Transplantation, City of Hope National Medical Center, Duarte, CA INTRODUCTION: Myelodysplastic syndrome (MDS) is a group of heterogeneous disorders caused by ineffective hematopoiesis characterized by bone marrow dysplasia resulting in cytopenias. Currently, treatment options for MDS are limited to supportive care and hypomethylating agents with most patients eventually succumbing to the disease (anemia, infection or hemorrhage) or progressing to leukemia. Previously it have been demonstrated that CD123 is an important target for the treatment of MDS due to its aberrantly high expression in highrisk MDS cells compared to lowrisk MDS cells and normal cells. As such, CD123directed therapy may be useful in treating patients with highrisk MDS. METHODS: Chimeric antigen receptor (CAR) vector containing a CD123specific singlechain variable fragment in combination with a CD28 costimulatory domain, CD3ζ signaling domain and tEGFR was expressed on healthy donor and patient derived T lymphocytes utilizing lentiviral vector delivery to target highrisk MDS cells. An antiCD19 CAR was used as a negative control. CAR expressing or control Tcells were cocultured with MDS cell line (MDSL) or primary MDS cells from patient bone marrow to examine in vitro antitumor function. Eradication of MDS cells was analyzed by flow cytometry 48hr after coculture. Intracellular TNFα and cell surface CD107A were examined in effector cells 5 hours after cocultured with MDS cells. For in vivo analysis of CD123 CAR T cells, NSGS mice were engrafted with 1.5x106 primary highrisk MDS cells for eight weeks, and were infused with autologous antiCD123 CAR Tcells or control. Tumor burden was then analyzed on day 28. RESULTS: Healthy donor derived antiCD123 CAR Tcells effectively eliminated MDS cell line (MDSL) (>99%), and primary bone marrow derived MDS cells (>70%) in vitro. The killing was associated with increased cytokine release and degranulation by antiCD123 CAR Tcells, which did not occur with control antiCD19 CAR Tcells. In addition, antiCD123 CAR Tcells generated from patients with highrisk MDS showed 50~70% transduction efficiency. These cells successfully eradicated autologous CD123+ MDS cells at >99.9% in vitro compared to untransduced control Tcells (Figure 1A). The killing was also confirmed by increased intracellular TNFα expression (Figure 1B). Furthermore, a patient derived xenograft system (PDX) was utilized to examine the killing ability of autologous antiCD123 CAR Tcells in vivo. Highrisk MDS bone marrow cells were engrafted in NSGS mice. Eight weeks following engraftment, 7x104 autologous EGFRt+ antiCD123 CAR Tcells or mock T cells were infused via tail vein. On day 28 after autologous antiCD123 CAR Tcell infusion, we observed significant decreases in both CD34+/CD38/CD123+ MDS cells and MDS bulk (hCD45+/EGFRt) while mice infused with mock CAR Tcells were unable to reduce tumor burden (Figure 1C and 1D). To extend the utility of our approach, we performed drug screening to identify the agents that increase expression of CD123 on MDS cells. We hypothesize that drugs inducing increased expression of CD123 will increase efficacy of antiCD123 CAR T cell and avoid resistance arising from CD123 low/dim MDS progenitor cells. 134 various oncologic drugs were dosed at multiple concentrations (1nM, 100nM, 1uM, 0uM) and incubated with MDSL cell line for 6hr, 16hr or 48hr. MDSL cells were then analyzed for CD123 expression (Mean fluorescence) and cell viability (%live out of total) by flow cytometry. Eight drugs with low cytotoxicity significantly increased CD123 expression, including trifluridine (1uM), sunitinib (100nM), metoxantrone (1nM), dasatinib (10uM), imatinib (1uM), regorafenib (10uM), dabrafenib (100nM) and DEAB (100nM). These drug candidates will be examined further in primary MDS bone marrow samples and in combination with antiCD123 CAR Tcells. CONCLUSION: These results demonstrate that antiCD123 CAR Tcells exhibit activity against highrisk MDS, and represent an effective therapeutic option for patients with highrisk MDS.
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7/25/2017
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Abstract ID#: 101326 Password: 315905 Title: AntiCD123 CAR TCell Therapy for the Treatment of Myelodysplastic Syndrome Review Category Selection: 703. 703. Adoptive Immunotherapy Preferred Presentation Format: Oral Submitter's Email Address:
[email protected] Publish only on the Blood Abstracts site: Yes First submission to an ASH Annual Meeting: Yes Compliance with the Declaration of Helsinki for Studies Involving Human Subjects: Agree Is the first author/presenter of this abstract a hematologist in training?: No Interim Analysis of Clinical Trial: No Special Consideration: No Hematologist in training: No Keywords: Immune Therapy, Myelodysplasia, T Cell Reconstitution First Author Presenter Wei Zhang, MS University of Colorado 12801 E 19th Ave, RC210430D Division of Hematology, Department of Medicine Aurora, CO 80045 Email:
[email protected] Will not be published I have relevant financial relationship(s) to disclose. No Signed on 07/24/2017 by Wei Zhang, MS Second Author Brett M. Stevens, Ph.D. University of Colorado Division of Hematology, Department of Medicine Aurora, CO 80045 Email:
[email protected] Will not be published I have relevant financial relationship(s) to disclose. No Signed on 07/24/2017 by Brett M. Stevens, Ph.D. Third Author Elizabeth Elizabeth Budde, MD, PhD City of Hope National Medical Center 1100 Fairview Ave. N Hematology & Hematopoietic Cell Transplantation Duarte, CA 91010 Fax Number: (206) 6675454 Email:
[email protected] Will not be published I have relevant financial relationship(s) to disclose. No Signed on 07/24/2017 by Elizabeth Elizabeth Budde, MD, PhD Fourth Author Stephen J. Forman, MD City of Hope National Medical Center 1500 East Duarte Road Hematology & Hematopoietic Cell Transplantation Duarte, CA 91010 Email:
[email protected] Will not be published I have relevant financial relationship(s) to disclose. No Signed on 07/24/2017 by Stephen J. Forman, MD https://ash.confex.com/ash/2017/cop/papers/index.cgi?username=101326&password=315905
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7/25/2017
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Fifth Author Craig T. Jordan, Ph.D. University of Colorado Division of Hematology, Department of Medicine Aurora, CO 80045 Email:
[email protected] I have relevant financial relationship(s) to disclose. No Signed on 07/24/2017 by Craig T. Jordan, Ph.D. Sixth Author Corresponding Enkhtsetseg Purev, M.D., Ph.D. University of Colorado Division of Hematology, Department of Medicine Aurora, CO Email:
[email protected] I have relevant financial relationship(s) to disclose. No Signed on 07/24/2017 by Enkhtsetseg Purev If necessary, you can make changes to your abstract between now and the deadline of Wednesday, August 2, 2017 To access your submission in the future, use the direct link to your abstract submission from one of the automatic confirmation emails that were sent to you during the submission. Or point your browser to /ash/reminder.cgi to have that URL mailed to you again. Your username/password are 101326/315905. Any changes that you make will be reflected instantly in what is seen by the reviewers. You DO NOT need to go through all of the submission steps in order to change one thing. If you want to change the title, for example, just click "Title" in the abstract control panel and submit the new title. When you have completed your submission, you may close this browser window. Tell us what you think of the abstract submittal Home Page
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