Marizomib is primarily used in the treatment of multiple myeloma, a type of blood cancer that affects plasma cells. It is often administered to patients who have not responded well to other treatments or have relapsed after initial therapy. The compound works by inhibiting the proteasome, a complex that breaks down proteins in cells, leading to the accumulation of damaged proteins and ultimately causing cancer cell death. This mechanism makes it a valuable option in combination therapies, where it is used alongside other drugs to enhance overall treatment efficacy. Additionally, marizomib is being investigated for its potential in treating other types of cancers, such as glioblastoma, due to its ability to cross the blood-brain barrier. Its role in clinical trials continues to expand as researchers explore its effectiveness in various oncological conditions.