LFM-A13 is primarily used in biochemical and medical research as a selective inhibitor of the Btk (Bruton's tyrosine kinase) enzyme. It is employed to study signaling pathways in immune cells, particularly in B-cells, where Btk plays a key role in activation and proliferation. Due to its inhibitory action, LFM-A13 has been investigated for its potential in suppressing the growth of certain cancer cells, especially in B-cell malignancies such as leukemia and lymphoma. Researchers also use it to explore the role of Btk in autoimmune diseases and allergic responses. Its application remains largely experimental, serving as a tool compound in preclinical studies to understand disease mechanisms and evaluate therapeutic strategies.