PT2399 is primarily used in scientific research as a potent and selective inhibitor of the HIF-2α (hypoxia-inducible factor 2 alpha) pathway. It is widely applied in studies related to cancer biology, especially in tumors where HIF-2α plays a key role in promoting cell proliferation and survival under low oxygen conditions. Researchers use PT2399 to probe the function of HIF-2α in clear cell renal cell carcinoma (ccRCC), where this pathway is often dysregulated due to VHL mutations. By blocking HIF-2α dimerization with its partner protein ARNT, PT2399 disrupts the transcription of downstream genes involved in angiogenesis, iron metabolism, and tumor growth. This makes it a valuable tool for validating HIF-2α as a therapeutic target and for assessing the effects of its inhibition on tumor progression in preclinical models. In addition to oncology research, PT2399 has been used to study the role of hypoxia signaling in other pathological conditions, including inflammation and metabolic diseases. Its application remains confined to laboratory settings, mainly in cell culture and animal models, and it is not approved for clinical or therapeutic use in humans.