KRAS Secondary Mutations That Confer Acquired Resistance to KRAS G12C Inhibitors,Sotorasib and Adagrasib,and Overcoming Strategies: Insights From In Vitro Experiments

IntroductionKRAS mutations have been recognized as undruggable for many years. Recently, novel KRAS G12C inhibitors, such as sotorasib and adagrasib, are being developed in clinical trials and have revealed promising results in metastatic NSCLC. Nevertheless, it is strongly anticipated that acquired resistance will limit their clinical use. In this study, we developed in vitro models of the KRAS G12C cancer, derived from resistant clones against sotorasib and adagrasib, and searched for secondary KRAS mutations as on-target resistance mechanisms to develop possible strategies to overcome such resistance.MethodsWe chronically exposed Ba/F3 cells transduced with KRAS^G12C to sotorasib or adagrasib in the presence of N-ethyl-N-nitrosourea and searched for secondary KRAS mutations. Strategies to overcome resistance were also investigated.ResultsWe generated 142 Ba/F3 clones resistant to either sotorasib or adagrasib, of which 124 (87%) harbored secondary KRAS mutations. There were 12 different secondary KRAS mutations. Y96D and Y96S were resistant to both inhibitors. A combination of novel SOS1 inhibitor, BI-3406, and trametinib had potent activity against this resistance. Although G13D, R68M, A59S and A59T, which were highly resistant to sotorasib, remained sensitive to adagrasib, Q99L was resistant to adagrasib but sensitive to sotorasib.ConclusionsWe identified many secondary KRAS mutations causing resistance to sotorasib, adagrasib, or both, in vitro. The differential activities of these two inhibitors depending on the secondary mutations suggest sequential use in some cases. In addition, switching to BI-3406 plus trametinib might be a useful strategy to overcome acquired resistance owing to the secondary Y96D and Y96S mutations.     

KRAS突变型肺癌作用机制与治疗策略的最新进展

肺癌是全球最常见的恶性肿瘤之一,KRAS是肺癌发生基因突变的重要位点。由于KRAS突变亚型中常缺乏药理学药物靶向的口袋,KRAS突变位点一直被认为是“不可成药”的靶点。本文主要概括了KRAS突变型肺癌的作用机制和KRAS成药所面临的困难,并对KRAS突变的治疗策略和耐药机制的最新进展进行阐述。