On January 6, 2025, Glecirasib, a KRAS-G12C inhibitor by Gakos, published its phase II clinical data online in the top global medical journal Nature Medicine. The data showed an objective response rate (ORR) of 47.9%, median overall survival (OS) of 13.6 months, and significantly lower gastrointestinal side effects compared to similar drugs. This drug offers a new targeted therapy option for second-line and beyond patients with KRAS-G12C mutated non-small cell lung cancer (NSCLC), with potential to improve survival benefit and quality of life.
KRAS Mutation: From “Undruggable” to Targeted Breakthrough
The KRAS gene acts as a central “switch” in cell signal transduction, precisely regulating cell growth, proliferation, and differentiation under normal conditions. Once mutated, it persistently activates cell proliferation signals, driving tumorigenesis. Statistics show about 30% of human cancers are related to KRAS mutations. In targeted cancer therapy, KRAS mutations were long considered “undruggable targets” due to the lack of effective targeted treatments. In 2021, the global approval of the first KRAS-G12C inhibitor marked a breakthrough in this research area. However, the mutation types at the KRAS-G12 site extend far beyond G12C, including subtypes like G12A, G12V, G12R, and G12S, which are also prevalent in pancreatic, colorectal, lung cancers, and others. Historically, research on these subtypes has been blind due to the lack of precise models. With advances in gene editing, “knock-in” technology emerged as a crucial tool to dissect KRAS-driven tumor mechanisms and opened new directions in tumor research.
Knock-in Models: Dissecting KRAS Subtypes and Combination Therapies
The KRAS-G12C knock-in model provides a key preclinical validation platform for drug development. For example, Sotorasib (AMG510) and Adagrasib (MRTX849) demonstrated efficacy via this model and were subsequently approved based on the KRYSTAL-1 and CodeBreaK 100 clinical trials, respectively. These drugs inhibit tumors by locking KRAS-G12C in its inactive conformation. With ongoing improvements in gene editing, mutant cell lines with G12A, G12V, G12R, and G12S have also been successfully constructed. For instance, the G12V-mutant MC38 cell line activates the RAS-MAPK pathway but shows differences in activation intensity and downstream regulation compared to G12C, providing clues to tumor heterogeneity. These new knock-in models serve as powerful tools for screening targeted drugs. For KRAS-G12A mutant cell lines, small molecule compounds that block downstream signaling have already been discovered. Because different mutant subtypes activate diverse signaling pathways, combination therapies have become a research focus. In KRAS-G12R mutant tumor models, combining RAS-MAPK pathway inhibitors with immunotherapy significantly enhances tumor cell sensitivity to immune attack.
Globally, the development of treatment regimens for KRAS-mutant NSCLC is booming. Besides approved Sotorasib and Adagrasib, pharmaceutical companies and research institutes actively push forward new drugs and combination therapies. Domestically, Innovent Biologics’ IBI 351 has been accepted and prioritized for review; EQRx’s D-1553 received breakthrough therapy designation; and Gakos’ Glecirasib phase II data is promising. Internationally, Eli Lilly’s LY4066434 shows over 80% tumor regression in preclinical studies, with better results when combined with cetuximab; Erasca’s ERAS-4001 can “double kill” G12X mutants and wild types, shrinking pancreatic tumors by 83%. In combination therapies, Elironrasib plus PD-1 inhibitors induced remission in all KRAS-G12C mutant lung cancer patients (TPS>50%, ORR and DCR reached 100%); Schrodinger’s SGR-4174 combination therapy increased tumor regression rates by 300%. These advances promise more therapeutic options for patients.
Products and Services List
To support KRAS inhibitor drug development, Kyinno Biotechnology has established the CT26-KRAS-G12C cell line, with CT26-KRAS-G12A/V/R/S lines under construction, assisting cancer therapy research. Notably, CT26 cells originate from BALB/c mice; implanting KRAS-mutated CT26 cells into syngeneic immunocompetent mice minimizes immune rejection and enables stable tumor formation in vivo. This allows construction of tumor models that closely mimic physiological states, useful for studying tumor initiation and progression in a complete immune system environment, and for evaluating the real effects of various treatments. These models provide crucial support for cancer therapy research.
Cell lines list：
- CT26-KRAS-G12C-KI
- CT26-KRAS-G12A-KI ongoing
- CT26-KRAS-G12V-KI ongoing
- CT26-KRAS-G12R-KI ongoing
- CT26-KRAS-G12S-KI ongoing
- CT26-KRAS-G12C-KI-Abca1a-KO ongoing
- CT26-KRAS-G12C-KI-Abca1a-KO-Abca1b-KO ongoing
Functional Validation
Reference：
- Shi YK, Fang J, Xing LG, et al. Glecirasib in KRASG12C-mutated nonsmall-cell lung cancer: a phase 2b trial. Nat Med. 2025 Mar;31(3):894-900. doi: 10.1038/s41591-024-03401-z. Epub 2025 Jan 6. PMID: 39762419.
- Liu J, Kang R, Tang DL. The KRAS-G12C inhibitor: activity and resistance. Cancer Gene Therapy. 2022 Jul;29(7):875-878. doi: 10.1038/s41417-021-00383-9. PMID: 34471232.
- Fukuda K, Otani S, Takeuchi S, et al. Trametinib overcomes KRAS-G12V-induced osimertinib resistance in a leptomeningeal carcinomatosis model of EGFR-mutant lung cancer. Cancer Sci. 2021;112(11):4023-4034. doi: 10.1111/cas.15035. PMID: 34145930.
- Zhao MH, Wu AW. Targeting KRAS G12C mutations in colorectal cancer. Gastroenterology Report. 2023;11:goac083. doi:10.1093/gastro/goac083.
