Fenebrutinib is primarily investigated for its potential in treating autoimmune diseases, particularly rheumatoid arthritis and systemic lupus erythematosus. It works by selectively inhibiting Bruton's tyrosine kinase (BTK), a key enzyme involved in B-cell signaling pathways. By blocking BTK, it helps reduce the activation and proliferation of B-cells, which play a critical role in the immune response and inflammation associated with these conditions. Clinical trials are ongoing to evaluate its efficacy and safety, with promising early results suggesting it could offer a targeted therapeutic option for patients with limited response to conventional treatments. Additionally, its potential applications extend to other B-cell-mediated disorders, making it a versatile candidate in immunology research.