CC-91516 (also called CC0776314), a selective and potent inhibitor of ERK1/2 and NLK, was discovered via a phenotypic screen of a kinase-focused library for compounds that synergize with mTOR kinase inhibitor CC-223 to induce apoptosis in combination with CC-223. Broad kinase selectivity profiling identified ERK1/2 and NLK as targets of CC-91516. Crystal structure of CC-91516 in complex with ERK2 reveals that its 2, 4, 6-trichlorophenyl moiety binds to a unique back pocket of the adenosine-5′-triphosphate (ATP) binding site of ERK2, which is not accessible to other ERK inhibitors such as BVD-523 and GDC-0994. This unique binding mode of CC-91516 leads to a slow off-rate for its ERK binding with long residence time disrupting both the active and inactive ERK forms. Consequentially, CC-91516 causes sustained inhibition of the MAPK pathway in BRAF mutant colorectal cancer cells. In addition, CC-91516 also regulates Wnt/β-catenin and YAP pathways in multiple cancer cell lines. CC-91516 shows potent yet selective anti-proliferative activity against a large panel of cancer cell lines. Activating mutations in BRAF or CTNNB1 gene associate with sensitivity to CC-91516-mediated anti-proliferative activity while mutations in RB and PI3K/PTEN pathway associate with resistance. CC-91516 inhibits ex vivo colony formation of PDX models with BRAF and CTNNB1 mutations. In addition, CC-91516 potently induces apoptosis, inhibits survival, and overcomes resistance to MEK inhibitor trametinib of BRAF or CTNNB1 mutant cancer cells in long-term culture assay in vitro. CC-91516 has good oral bioavailability and shows excellent anti-tumor activity in vivo against both BRAF and CTNNB1 mutant xenograft models. DMPK and toxicology studies showed robust oral exposure across preclinical species. In summary, CC-91516 has demonstrated preclinical anti-tumor activities and DMPK and safety profiles in support of its clinical development.

Citation Format: Shuichan Xu, Tam Tran, Dan Zhu, Tao Shi, David Mikolon, Jim Leisten, Philip Chamberlain, Laurie LeBrun, Sogole Bahmanyar, Ning Jiang, Jingjing Zhao, Mehnaz Malek, Ellen Filvaroff, Heather Raymon, Robert Hubbard, John Boylan. Discovery of CC-91516, a potent and selective ERK/NLK inhibitor, with anti-tumor activity in preclinical cancer models harboring BRAF or CTNNB1 mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1180.