1. Characterization and root cause analysis of immunogenicity to pasotuxizumab (AMG 212), a prostate-specific membrane antigen-targeting bispecific T-cell engager therapy.
- Author
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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, and Mytych DT
- Subjects
- Male, Humans, Root Cause Analysis, Prostate-Specific Antigen metabolism, Antibodies metabolism, Antigens, Surface metabolism, T-Lymphocytes, Prostate, Biological Products
- 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., Competing Interests: All authors, except for NT, SW-R, GK, RB, H-DH, WL, CG, and BT, were/are employees of Amgen during the time this study and associated analyses were being conducted. SW-R and GK are employees of Bayer AG. Author WL was employed by Ordensklinikum Linz GmbH. RB is a patent holder for blinatumomab, from which he receives royalty payments, and has consulted for and received honoraria from Amgen, Cellex and Gemoab. H-DH has received travel, accommodations or other expenses from Johnson & Johnson, Boehringer Ingelheim, Amgen Inc. and Bristol Myers Squibb. WL has received honoraria from Accord and Novartis. BT has received a grant, consulting fees, and honoraria from Amgen Inc. NT was an employee of Labcorp Translational Biomarker Solutions at the time of this study and has no conflicts to disclose. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this study received funding from Bayer and Amgen. The funders were involved in the study design, collection, analysis, interpretation of results, the writing of this article and the decision to submit it for publication., (Copyright © 2023 Penny, Hainline, Theoharis, Wu, Brandl, Webhofer, McComb, Wittemer-Rump, Koca, Stienen, Bargou, Hummel, Loidl, Grüllich, Eggert, Tran and Mytych.)
- Published
- 2023
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