GSK2983559 is a potent and selective inhibitor of phosphoinositide 3-kinase delta (PI3Kδ), primarily developed for the treatment of respiratory inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD). As an active metabolite or related compound, it targets the PI3Kδ signaling pathway to modulate immune responses and reduce airway inflammation. Administered via inhalation, it aims to provide localized effects with minimized systemic exposure. Clinical trials have evaluated its efficacy, safety profile, and potential in managing moderate-to-severe asthma. Ongoing research explores its role in other inflammatory conditions, though it is not primarily indicated for autoimmune diseases like rheumatoid arthritis or psoriasis, nor for cancer.