ONX-0914 (PR-957) is primarily used in research settings to study the role of immunoproteasomes in various biological processes. It is a selective inhibitor of the immunoproteasome subunit LMP7, which is involved in the production of peptides presented by major histocompatibility complex (MHC) class I molecules. By inhibiting LMP7, ONX-0914 helps researchers investigate the impact on immune responses, particularly in autoimmune diseases, inflammatory conditions, and cancer. Its application has been instrumental in understanding the mechanisms of diseases like rheumatoid arthritis and multiple sclerosis, as well as exploring potential therapeutic strategies targeting immunoproteasome activity. Additionally, ONX-0914 is used in preclinical studies to evaluate its efficacy in modulating immune system functions and its potential as a treatment for immune-related disorders.