Used primarily in the treatment of ovarian, breast, fallopian tube, and prostate cancers with specific genetic mutations, particularly BRCA1 and BRCA2. It works by inhibiting the PARP enzyme, which cancer cells rely on to repair their DNA. In tumors with BRCA mutations, this inhibition leads to accumulated DNA damage and ultimately cancer cell death. This targeted approach improves outcomes in patients with these genetic profiles and is often used when other treatments have failed. It is taken orally and allows for long-term management of certain advanced cancers.