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Penny HL, Hainline K, Theoharis N, Wu B, Brandl C, Webhofer C, McComb M, Wittemer-Rump S, Koca G, Stienen S, Bargou RC, Hummel HD, Loidl W, Grüllich C, Eggert T, Tran B, Mytych DT. Characterization and root cause analysis of immunogenicity to pasotuxizumab (AMG 212), a prostate-specific membrane antigen-targeting bispecific T-cell engager therapy. Front Immunol 2023; 14:1261070. [PMID: 37942314 PMCID: PMC10628759 DOI: 10.3389/fimmu.2023.1261070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/02/2023] [Indexed: 11/10/2023] Open
Abstract
Introduction In oncology, anti-drug antibody (ADA) development that significantly curtails response durability has not historically risen to a level of concern. The relevance and attention ascribed to ADAs in oncology clinical studies have therefore been limited, and the extant literature on this subject scarce. In recent years, T cell engagers have gained preeminence within the prolific field of cancer immunotherapy. These drugs whose mode of action is expected to potently stimulate anti-tumor immunity, may potentially induce ADAs as an unintended corollary due to an overall augmentation of the immune response. ADA formation is therefore emerging as an important determinant in the successful clinical development of such biologics. Methods Here we describe the immunogenicity and its impact observed to pasotuxizumab (AMG 212), a prostate-specific membrane antigen (PSMA)-targeting bispecific T cell engager (BiTE®) molecule in NCT01723475, a first-in-human (FIH), multicenter, dose-escalation study in patients with metastatic castration-resistant prostate cancer (mCRPC). To explain the disparity in ADA incidence observed between the SC and CIV arms of the study, we interrogated other patient and product-specific factors that may have explained the difference beyond the route of administration. Results Treatment-emergent ADAs (TE-ADA) developed in all subjects treated with at least 1 cycle of AMG 212 in the subcutaneous (SC) arm. These ADAs were neutralizing and resulted in profound exposure loss that was associated with contemporaneous reversal of initial Prostate Surface Antigen (PSA) responses, curtailing durability of PSA response in patients. Pivoting from SC to a continuous intravenous (CIV) administration route remarkably yielded no subjects developing ADA to AMG 212. Through a series of stepwise functional assays, our investigation revealed that alongside a more historically immunogenic route of administration, non-tolerant T cell epitopes within the AMG 212 amino acid sequence were likely driving the high-titer, sustained ADA response observed in the SC arm. Discussion These mechanistic insights into the AMG 212 ADA response underscore the importance of performing preclinical immunogenicity risk evaluation as well as advocate for continuous iteration to better our biologics.
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Affiliation(s)
| | - Kelly Hainline
- Department of Clinical Immunology, Amgen, Thousand Oaks, CA, United States
| | | | - Bin Wu
- Department of Biologics, Amgen, Thousand Oaks, CA, United States
| | - Christian Brandl
- Department of Translational Safety & Bioanalytical Sciences, Amgen Research (Munich) GmbH, Munich, Germany
| | - Christian Webhofer
- Department of Process Development, Amgen Research (Munich) GmbH, Munich, Germany
| | - Mason McComb
- Department of Clinical Pharmacology, Modeling & Simulation, Amgen, Thousand Oaks, CA, United States
| | - Sabine Wittemer-Rump
- Bayer AG, Research and Development Oncology (RED Onc), Pharmaceuticals, Berlin, Germany
| | - Gökben Koca
- Bayer AG, Research and Development Oncology (RED Onc), Pharmaceuticals, Berlin, Germany
| | - Sabine Stienen
- Department of Early Development (Oncology), Amgen Research (Munich) GmbH, Munich, Germany
| | - Ralf C. Bargou
- Translational Oncology/Early Clinical Trial Unit (ECTU), Comprehensive Cancer Center Mainfranken, University Hospital Wurzburg, Wurzburg, Germany
| | - Horst-Dieter Hummel
- Translational Oncology/Early Clinical Trial Unit (ECTU), Comprehensive Cancer Center Mainfranken, University Hospital Wurzburg, Wurzburg, Germany
| | - Wolfgang Loidl
- Department of Urology, Ordensklinikum Linz GmbH, Linz, Austria
| | - Carsten Grüllich
- Department of Medical Oncology, National Center for Tumor Diseases, Heidelberg University Medical Center, Heidelberg, Germany
| | - Tobias Eggert
- Department of Early Development (Oncology), Amgen, Thousand Oaks, CA, United States
| | - Ben Tran
- Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Daniel T. Mytych
- Department of Clinical Immunology, Amgen, Thousand Oaks, CA, United States
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Laust AK, Sur BW, Wang K, Hubby B, Smith JF, Nelson EL. VRP immunotherapy targeting neu: treatment efficacy and evidence for immunoediting in a stringent rat mammary tumor model. Breast Cancer Res Treat 2007; 106:371-82. [PMID: 17351745 DOI: 10.1007/s10549-007-9517-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Accepted: 01/07/2007] [Indexed: 10/23/2022]
Abstract
The ability to overcome intrinsic tolerance to a strict "self" tumor-associated antigen (TAA) and successfully treat pre-existing tumor is the most stringent test for anti-tumor immunotherapeutic strategies. Although this capacity has been demonstrated in various models using complicated strategies that may not be readily translated into the clinical arena, straightforward antigen-specific immunotherapeutic strategies in the most stringent models of common epithelial cancers have largely failed to meet this standard. We employed an immunotherapeutic strategy using an alphavirus-based, virus-like replicon particle (VRP), which has in vivo tropism for dendritic cells, to elicit immune responses to the non-mutated TAA rat neu in an aggressive rat mammary tumor model. Using this VRP-based immunotherapeutic strategy targeting a single TAA, we generated effective anti-tumor immunity in the setting of pre-existing tumor resulting in the cure of 36% of rats over multiple experiments, P = 0.002. We also observed down-regulation of rat neu expression in tumors that showed initial responses followed by tumor escape with resumption of rapid tumor growth. These responses were accompanied by significant anti-tumor proliferative responses and CD8+ cellular tumor infiltrates, all of which were restricted to animals receiving the anti-neu immunotherapy. Together these data, obtained in a stringent "self" TAA model, indicate that the VRP-based antigen-specific immunotherapy elicits sufficiently potent immune responses to exert immunologic pressure, selection, and editing of the growing tumors, thus supporting the activity of this straightforward immunotherapy and suggesting that it is a promising platform upon which to build even more potent strategies.
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Affiliation(s)
- Amanda K Laust
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California, Irvine, CA 92697, USA
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