R428 (BGB324) is primarily used in the field of oncology as a selective inhibitor of the AXL receptor tyrosine kinase. This receptor is often overexpressed in various types of cancer, contributing to tumor growth, metastasis, and resistance to chemotherapy. By inhibiting AXL, R428 has shown potential in reducing cancer cell proliferation and enhancing the effectiveness of other anticancer therapies. It is being investigated in clinical trials for its efficacy in treating solid tumors, including breast, lung, and pancreatic cancers. Additionally, R428 is being explored for its role in overcoming drug resistance in cancer treatment, offering a promising approach to improving patient outcomes.