Abstract 3085: The BET family bromodomain inhibitor ABBV-075 targets multiple pathogenesis factors in multiple myeloma and exhibits robust in vivo efficacies as a single agent and in combination with bortezomib

Abstract

Abstract Small molecule inhibitors of the bromodomain and extraterminal domain (BET) proteins represent a potential new class of cancer therapeutic agents. ABBV-075 is a potent and selective BET family bromodomain inhibitor that was recently advanced to Phase 1 studies. Here we report the in vitro and in vivo characterization of ABBV-075 in preclinical models of multiple myeloma. ABBV-075 exhibited significant anti-proliferative activities and triggered robust apoptosis across many multiple myeloma cell lines, including cell lines that were engineered to become resistant to bortezomib. As reported for other BET inhibitors, ABBV-075 potently inhibited super-enhancer regulated potential cancer drivers such as Myc, IRF8 etc. In addition to directly impacting multiple myeloma cell growth and survival, ABBV-075 also diminished stroma cell derived IL-6 secretion and prevented HUVEC cell proliferation in vitro. Given the importance of angiogenesis and the survival factor IL-6 for multiple myeloma pathogenesis, ABBV-075 could potentially produce significant therapeutic benefits in myeloma by simultaneously targeting multiple critical pathogenesis mechanisms for this disease. ABBV-075 caused significant tumor growth delay in the OPM2 flank tumor model as a monotherapy. Combining ABBV-075 with Bortezomib provided further therapeutic benefit compared with the treatment of either of the two agents individually. Taken together, our results suggest that ABBV-075 could be a promising option to explore for the treatment of multiple myeloma. Citation Format: Tamar Uziel, Xiaoyu Lin, Emily Faivre, Aparna Sarthy, Daniel H. Albert, Leiming Li, Denise Wilcox, Xiaoli Huang, Terry Magoc, Lloyd Lam, Steven W. Elmore, Keith McDaniel, Warren Kati, Yu Shen. The BET family bromodomain inhibitor ABBV-075 targets multiple pathogenesis factors in multiple myeloma and exhibits robust in vivo efficacies as a single agent and in combination with bortezomib. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3085.