CPI-203 is primarily used in research settings to study its effects on bromodomain-containing proteins, particularly BRD4. It is a selective inhibitor that helps in understanding the role of these proteins in gene regulation and cellular processes. Researchers utilize CPI-203 to explore its potential in targeting diseases like cancer, where abnormal gene expression plays a critical role. By inhibiting BRD4, it may suppress the growth of certain cancer cells, making it a valuable tool in preclinical studies for developing novel therapeutic strategies. Additionally, it aids in investigating epigenetic mechanisms and their influence on various pathological conditions.