Irvine, CA, December 11, 2017 – Today, PeproMene Bio, Inc. announced that Dr. Hong Qin, a member of its Scientific Advisory Board, posted a paper at 59th ASH annual meeting in regards to “CAR-T Cells Targeting BAFF-Receptor for B-Cell Malignancies: A Potential Alternative to CD19.” Dr. Larry Kwak, the chair of the Scientific Advisory Board, also endorsed his name on the paper. Followings are abstracts of the paper.
Background: Chimeric antigen receptor (CAR) T-cell adoptive therapies have the potential to revolutionize the treatment of cancers. Particularly in hematological malignancies, there are reports of promising clinical outcomes in advanced non-Hodgkin lymphomas (NHLs) with CD19-CAR T-cell therapy. However, disease relapse is problematic, and is thought to be caused by poor long-term persistence of the CAR T-cells, and loss of the CD19 target on tumors. Thus, there is an urgent need for improved novel CAR T-cell therapies directed at alternative targets. The CAR T-cell platform relies on antibody-derived single chain fragments (scFv), which are genetically engineered into chimeric T-cell receptors, and that recognize target cell surface proteins on tumors. One potential target is B-cell activating factor receptor (BAFF-R), a tumor necrosis factor receptor superfamily protein (TNFRSF13C) specifically involved in B lymphocyte development and mature B-cell survival, that is primarily expressed on B cells and various subtypes of B-cell NHLs and ALL. We have recently developed a humanized therapeutic BAFF-R antibody with strong anti B-cell tumor activity.
Method and Results: We adapted a scFv based on our humanized anti-BAFF-R antibody onto a second generation CAR platform containing CD3ζ and 4-1BB intracellular signaling domains. In response to BAFF-R-expressing malignant human B cells (NHLs, acute lymphoblastic leukemias, and chronic lymphocytic leukemias), our CAR T cells readily proliferated and secreted cytotoxic cytokines. We demonstrated both significant levels of BAFF-R CAR T-cell activation and malignant B-cell killing in vitro. Established human NHL tumors in xenogeneic models were eliminated following BAFF-R CAR T-cell treatments in vivo. Remarkable tumor-free survival was repeatedly observed in human lymphoma xenograft models including JeKo-1 (mantle cell lymphoma) and Raji (Burkitt lymphoma) in NSG mice. Moreover, upon tumor re-challenge and without any further treatment tumors failed to develop, due to persisting CAR T cells conferring continued anti-lymphoma activity. We pursued optimization of CAR T-cell persistence by comparing three subsets of early stage T cells (central memory, TCM; memory stem, TSCM; and naïve, TN) as potential starting material for CAR T cell generation. Our in vivo studies show CAR T cells from the TN population retained highest potency eradicating established tumors at a minimal therapeutic dose compared to other subtypes; 80% of TN CAR treated mice achieved long-term survival compared to 20% of TCM and 40% of TSCM CAR treated mice. We also observed the long term anti-tumor effects conferred by CD8+ CAR T cells required the addition of CD4+ CAR T cells. Finally, we performed a head-to-head comparison of BAFF-R CAR T cells with CD19 CAR T cells in the Raji model (Figure). Comparable expression levels of BAFF-R and CD19 were observed on the tumor cells (A), and both treatments elicited significant antitumor effects compared to T-cell and saline controls (B-C). However, the BAFF-R CAR T-cell treatment demonstrated long-term tumor free survival in all treated mice compared to the CD19 CAR T-cell treated cohort, which only showed delayed tumor growth.
Conclusion: BAFF-R CAR T cells demonstrate remarkable efficacy against B-cell malignancies. Unexpectedly, we found that naïve T cells were superior to TCM or TSCM subpopulations as starting material in vivo. Naïve T-cell starting products, after transduction and expansion, generated sufficient numbers of TCM and TSCM CAR T cells for activity. Targeting BAFF-R combined with our strategy to improve CAR T-cell persistence potentially addresses unmet clinical needs in B-cell NHLs and ALL, particularly in the setting of CD19 CAR-T-resistance or CD19-negative relapse.
To find the paper on the web: http://www.bloodjournal.org/content/130/Suppl_1/3180
About PeproMene Bio
PeproMene Bio, Inc. is a virtual, privately funded biotech company located Irvine, CA. We are developing novel immune-oncology therapies such as BAFF-R CAR-T therapy based on the novel antibodies. The BAFF-R CAR-T therapy program which was discovered and developed from Dr. Larry Kwak’s lab at MD Anderson and City of Hope was successfully licensed in from City of Hope, Duarte CA, in April 2017. Currently the further development is ongoing at City of Hope for its IND enabling study. We will continue to license-in and explore more of novel immuno-oncology programs via our network. For more information about the Company, please visit www.pepromenebio.com.
Contact
Steve Lee: 714-599-8077, steve@pepromenebio.com
