Article
Author: Perry, Elizabeth ; Shen, Yue ; Diaz-Rohena, Daisy Y ; Ravikrishnan, Janani ; Bhat, Seema A ; Anthony, Stephen P ; Chen, Yi ; Chen, Yu ; Wierda, William G ; Satpati, Suresh ; Lapalombella, Rosa ; Misra, Shrilekha ; Mitchell, Andrew ; Woyach, Jennifer A ; Davids, Matthew S ; Sampath, Deepa ; Mo, Xiaokui ; Lozanski, Arletta ; Sanchez, John ; Rogers, KerryA ; Lai, Tzung-Huei ; Kittai, Adam S ; Kaufman, Tierney ; Lozanski, Gerard ; Williams, Charmelle D ; Collins, Mary C ; Jain, Nitin ; Byrd, John C ; Liu, Chaomei ; Muhowski, Elizabeth ; Tan, Fenlai
Patients with chronic lymphocytic leukemia (CLL) respond well to initial treatment with the Bcell lymphoma 2 (BCL2) inhibitor venetoclax. Upon relapse, they often retain sensitivity to BCL2 targeting, but durability of response remains a concern. We hypothesize that targeting both BCL2 and B-cell lymphoma-extra large (BCLXL) will be a successful strategy to treat CLL, including for patients who relapse on venetoclax. To test this hypothesis, we conducted a pre-clinical investigation of LP-118, a highly potent inhibitor of BCL2 with moderate BCLXL inhibition to minimize platelet toxicity. This study demonstrated that LP-118 induces efficient BAK activation, cytochrome C release, and apoptosis in both venetoclax naïve and resistant CLL cells. Significantly, LP-118 is effective in cell lines expressing the BCL2 G101V mutation and in cells expressing BCLXL but lacking BCL2 dependence. Using an immunocompetent mouse model, Eμ-TCL1, LP-118 demonstrates low platelet toxicity, which hampered earlier BCLXL inhibitors. Finally, LP-118 in the RS4;11 and OSU-CLL xenograft models results in decreases in tumor burden and survival advantage, respectively. These results provide a mechanistic rationale for the evaluation of LP-118 for the treatment of venetoclax responsive and relapsed CLL.