Abstract 940: The combinatorial activity of Eftozanermin ABBV621, a novel and potent TRAIL receptor agonist fusion protein, in pre-clinical models of hematologic malignancies
Authors: Smith Morey , Jin Sha , Cheng Dong , Zhang Haichao , Huska Jason , Widomski Deborah , Bontcheva Vicky , Buchanan Greg , Morgan-Lappe Susan , Phillips Darren , Tahir Stephen 
Published: July 2021

Abstract
The Combinatorial Activity of Eftozanermin (ABBV-621), a Novel and Potent TRAIL Receptor Agonist Fusion Protein, in Pre-clinical Models of Hematologic Malignancies Cell death can be initiated through activation of the extrinsic and intrinsic apoptotic signaling pathways. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily of cytokines, preferentially triggers the extrinsic apoptotic pathway by binding as a trimer to two closely related cell surface death receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5). Receptor trimerization leads to the formation of the death-inducing signaling complex (DISC) to recruit and activate downstream caspases that ultimately leads to apoptotic cell death. Because TRAIL signaling induces apoptosis, several TRAIL receptor agonists have been developed for the treatment of cancer. ABBV-621 is a novel, second generation TRAIL receptor agonist that is an engineered fusion protein consisting of an IgG1-Fc linked to a single chain trimer of TRAIL subunits resulting in a total of six death receptor binding sites per molecule to maximize receptor clustering that is currently being tested in Phase I clinical trials (NCT03082209).To expand upon the potential therapeutic utility of ABBV-621, we tested the combinatorial activity of ABBV-621 with numerous standard-of-care (SoC) therapeutics and targeted agents in diffuse large B-cell lymphoma (DLBCL), acute myeloid leukemia (AML) and multiple myeloma (MM) cell lines. The in vitro results led to selection of agents to combine with ABBV-621 for in vivo studies. In DLBCL cell line-derived xenograft (CDX) preclinical models, we observed combination activity of ABBV-621 with pevonedistat (PEV) a selective NEDD8 inhibitor. Additionally, synergistic activity was observed with ABBV-621 with either bendamustine (BED) or rituximab (RTX) alone, or BED/RTX together. In AML, we observed compelling combination activity of ABBV-621 with PEV in cell line-derived xenograft (CDX) models. In MM, combination of ABBV-621 plus bortezomib (BTZ) resulted in deeper anti-tumorigenic activity than either agent alone in several CDX models. The pre-clinical data presented here support expanding the indications and settings where ABBV-621 may have utility. A clinical trial assessing the activity of ABBV-621 in combination with bortezomib and dexamethasone in R/R MM patients is planned. Disclosures:All authors are employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the publication.
Citation Format: Morey Smith, Sha Jin, Dong Cheng, Haichao Zhang, Jason Huska, Deborah Widomski, Vicky Bontcheva, Greg Buchanan, Susan Morgan-Lappe, Darren Phillips, Stephen Tahir. The combinatorial activity of Eftozanermin ABBV621, a novel and potent TRAIL receptor agonist fusion protein, in pre-clinical models of hematologic malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 940.