BI-3406 is a potent, selective, and orally bioavailable small molecule that allosterically disrupts the protein-protein interaction between the SHP2 phosphatase and SOS1 guanine nucleotide exchange factor, thereby inhibiting activation of the RAS/MAPK signaling pathway. It is primarily used in cancer research to target tumors driven by RTK/RAS pathway mutations, such as KRAS-mutant non-small cell lung cancer, pancreatic cancer, and colorectal cancer. By preventing SHP2-mediated activation of SOS1, BI-3406 blocks RAS nucleotide exchange, reducing downstream signaling that promotes tumor cell proliferation, survival, and metastasis. It exhibits strong synergy with MEK inhibitors in preclinical models, enhancing anti-tumor efficacy and overcoming adaptive resistance mechanisms common in single-agent therapies. BI-3406 is a valuable research tool for developing targeted combination therapies against RAS-pathway-dependent cancers and is currently being evaluated in early-phase clinical trials for oncology indications.