Used in chemotherapy to treat various cancers, particularly ovarian cancer, small cell lung cancer, and cervical cancer. It works by inhibiting topoisomerase I, an enzyme involved in DNA replication, leading to DNA damage and cancer cell death. Due to its ability to cross the blood-brain barrier, it is also considered for treating brain tumors or cancers that have spread to the central nervous system. Administered intravenously, it is often used when other treatments have failed, making it a valuable option in advanced or recurrent cancer cases.