Lead Optimization of Multimutant KRAS Switch-II Pocket Macrocyclic Inhibitors via Isosteric Replacement to Improve ADME and Oral Exposure.
Phillips, D.P., Alper, P.B., Borkin, D., Han, D., Kochanek, S.E., Gurjar, J., Mathison, C.J.N., Nelson, J.M., Pei, W., Nguyen, B.N., Hoffman, T., Okram, B., Nguyen, T.N., Jiang, S., Masick, B.T., Wang, Z., Cho, C.Y., Yin, H., Chen, Y., Juarez, J., Jia, Y., Zhou, V., Liu, G., Wright, C., Nguyen, T., Knee, D.A., Liu, Q., Liu, J., Li, J., Virata, C., de Oliveira, C., DiDonato, M., Bursulaya, B., Vidal-Biggart, A., Jones, D.H., Witmer, D., Chu, C., Jin, H., Herath, A., Richmond, W., Groessl, T., Shapiro, M., Effenberger, K., Arroyo, K., Bretz, A., Honda, A., Gordon, W.P., Molteni, V., Haling, J.R.(2026) J Med Chem 69: 20698-20718
- PubMed: 42720494 Search on PubMed
- DOI: https://doi.org/10.1021/acs.jmedchem.6c01454
- Primary Citation Related Structures: 
12FF, 12FG - PubMed Abstract: 
Starting from our internally discovered, potent panKRAS inhibitor BRSD-143 (1), we executed a targeted bioisosteric optimization of the naphthol and fluoropyrrolizidine motifs to preserve (or increase) KRAS pan-inhibitory potency while improving DMPK/ADME liabilities. These studies delivered 12 (BRSD-212), a highly potent and efficacious lead in which (2-azabicyclo[4.2.0]octan-6-yl)methanol (ABO) serves as a bioisostere for the widely deployed 2-fluoropyrrolizidine substituent. In parallel, replacement of the naphthol moiety with an indazole afforded 21, which demonstrated improved pharmacokinetic performance and ADME characteristics by mitigating glucuronidation-mediated clearance as the dominant metabolic pathway.
- Novartis Biomedical Research , 10675 John Jay Hopkins Drive, San Diego, California92121, United States.
Organizational Affiliation: 

