Optimization Leading to a Potent and Selective Cbl‐b Inactive-State Inhibitor That Demonstrated In Vivo Efficacy.
Liang, J., Lambrecht, M.J., Huestis, M.P., Zhu, B., Barton, L.M., Castanedo, G.M., Ung, P.M., Larouche-Gauthier, R., Jakalian, A., Leclerc, J.P., Yadav, A., Haghshenas, P., Aubert-Nicol, S., Ismaili, H., Zhao, L., Leblanc, M., de Almeida, H., Wang, Q., Garner, T., Tan, S., Prangley, M.S., Pang, J., Murray, J.M., Yu, C., Hsu, P.L., Rutz, S., Ishizuka, I., Huang, H., Gao, C., Chen, M., Mutter-Rottmayer, L., Kakiuchi-Kiyota, S., Leung, D.H., Kou, P., Bao, L., Wang, X.(2026) ACS Med Chem Lett 17: 1258-1265
- PubMed: 42305193 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1021/acsmedchemlett.6c00104
- Primary Citation Related Structures: 
10YS, 10ZF - PubMed Abstract: 
In the preceding work in this issue (10.1021/acsmedchemlett.6c00103), we described our initial structure-activity relationship (SAR) optimization that led to a pan-Cbl inhibitor ( 6 ) that demonstrated efficacy in a mouse CT26 syngeneic model. Unfortunately, attempts to improve TGI with higher doses of 6 resulted in poor tolerability which we attributed to a lack of selectivity between Cbl-b and c-Cbl (∼2× by surface plasmon resonance (SPR)). Herein, we report our continued efforts that led to a breakthrough in achieving Cbl-b selectivity (up to 37×). The lead compound 33 demonstrated 14× selectivity against c-Cbl by SPR, was potent in a PBMC cell assay, and showed good oral exposure in mice. When tested in a CT26 model, 33 displayed improved tumor growth inhibition compared to our previously reported pan-Cbl inhibitor 6 (TGI 145% vs 82%). More importantly, 33 was better tolerated than 6 , supporting our hypothesis that a selective Cbl-b inhibitor could be advantageous relative to a pan-Cbl inhibitor.
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States.
Organizational Affiliation: 
















