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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] [What about the content of this article? (0)] [Affiliation(s)] [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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