LY127809 is primarily used in pharmaceutical research as a selective antagonist for the leukotriene B4 (LTB4) receptor. It is employed to study inflammatory processes, particularly in models of immune-mediated diseases such as arthritis, psoriasis, and respiratory conditions like asthma and chronic obstructive pulmonary disease (COPD). By blocking the LTB4 receptor, LY127809 helps reduce neutrophil recruitment and activation, making it a valuable tool in understanding the role of LTB4 in inflammation and evaluating potential anti-inflammatory therapies. Its application is mainly confined to preclinical research, where it aids in validating the therapeutic potential of targeting the LTB4 pathway.