Dual-targeting triplebody 33-16-123 (SPM-2) mediates effective redirected lysis of primary blasts from patients with a broad range of AML subtypes in combination with natural killer cells

Todd A Braciak; Claudia C Roskopf; Sarah Wildenhain; Nadja C Fenn; Christian B Schiller; Ingo A Schubert; Uwe Jacob; Annemarie Honegger; Christina Krupka; Marion Subklewe; Karsten Spiekermann; Karl-Peter Hopfner; Georg H Fey; Michael Aigner; Stefan Krause; Andreas Mackensen; Fuat S Oduncu

doi:10.1080/2162402X.2018.1472195

Dual-targeting triplebody 33-16-123 (SPM-2) mediates effective redirected lysis of primary blasts from patients with a broad range of AML subtypes in combination with natural killer cells

Oncoimmunology. 2018 Jul 30;7(9):e1472195. doi: 10.1080/2162402X.2018.1472195. eCollection 2018.

Authors

Todd A Braciak¹, Claudia C Roskopf¹, Sarah Wildenhain², Nadja C Fenn², Christian B Schiller², Ingo A Schubert³, Uwe Jacob⁴, Annemarie Honegger⁵, Christina Krupka^{1

6}, Marion Subklewe^{1

6}, Karsten Spiekermann¹, Karl-Peter Hopfner², Georg H Fey³, Michael Aigner⁷, Stefan Krause⁷, Andreas Mackensen⁷, Fuat S Oduncu¹

Affiliations

¹ Department of Hematology and Oncology, Medizinische Klinik und Poliklinik III, Klinikum der Universität München, Munich, Germany.
² Department of Biochemistry and Gene Center, Ludwig-Maximilians-Universität, Munich, Germany.
³ Department of Biology, University of Erlangen-Nuremberg, Erlangen, Germany.
⁴ Westend Innovation, Munich, Germany.
⁵ Department of Biochemistry, University of Zurich, Zurich, Switzerland.
⁶ Laboratory of Translational Cancer Immunol ogy, Gene Center of the LMU Munich, Munich, Germany.
⁷ Department of Internal Medicine 5 - Hematology/Oncology, University of Erlangen-Nuremberg, Erlangen, Germany.

Abstract

A number of agents designed for immunotherapy of Acute Myeloid Leukemia (AML) are in preclinical and early clinical development. Most of them target a single antigen on the surface of AML cells. Here we describe the development and key biological properties of a tri-specific agent, the dual-targeting triplebody SPM-2, with binding sites for target antigens CD33 and CD123, and for CD16 to engage NK cells as cytolytic effectors. Primary blasts of nearly all AML patients carry at least one of these target antigens and the pair is particularly promising for the elimination of blasts and leukemia stem cells (LSCs) from a majority of AML patients by dual-targeting agents. The cytolytic activity of NK cells mediated by SPM-2 was analyzed in vitro for primary leukemic cells from 29 patients with a broad range of AML-subtypes. Blasts from all 29 patients, including patients with genomic alterations associated with an unfavorable genetic subtype, were lysed at nanomolar concentrations of SPM-2. Maximum susceptibility was observed for cells with a combined density of CD33 and CD123 above 10,000 copies/cell. Cell populations enriched for AML-LSCs (CD34pos and CD34pos CD38neg cells) from 2 AML patients carried an increased combined antigen density and were lysed at correspondingly lower concentrations of SPM-2 than unsorted blasts. These initial findings raise the expectation that SPM-2 may also be capable of eliminating AML-LSCs and thus of prolonging survival. In the future, patients with a broad range of AML subtypes may benefit from treatment with SPM-2.

Keywords: AML; CD33-CD16-CD123; NK cells; dual targeting; immunotherapy; redirected lysis; single-chain triplebodies; therapeutic antibodies.

Publication types

Research Support, Non-U.S. Gov't

Grants and funding

This research was supported by academic research grants from the DFG (Deutsche Forschungsgemeinschaft; German Research Community, SFB 643, project C3), grant No. 2007.049.1 from the Wilhelm Sander Foundation, Neustadt, Germany; grant No. 109 063 from the Stiftung Deutsche Krebshilfe (German Cancer Foundation), and the Association Kaminkehrer helfen krebskranken Kindern (Chimney Sweeps support children with cancer) to GHF; by a grant from the Bavarian State (Ministry for Commerce and Economy) awarded in the M4 excellence competition to KPH, GHF and FO; by funding from the DFG CRC 1243 to KPH and MS; and by a student research fellowship awarded to CCR by the German José Carreras-Leukemia Foundation (www.carreras-stiftung.de, Scholarship No. DJCLS F 13/05). The collection of cell samples from AML patients maintained at the Department of Internal Medicine 5 of the University of Erlangen received financial support from the University’s Comprehensive Cancer Center (CCC).