Niraparib

**Semantic type:** Pharmacologic Substance

**Definition:** An orally bioavailable inhibitor of poly (ADP-ribose) polymerase (PARP) types 1 and 2 (PARP-1 and -2), with antineoplastic activity. Upon administration, niraparib binds to and inhibits the activity of PARP-1 and -2, thereby inhibiting PARP-1 and -2-mediated DNA repair, enhancing the accumulation of DNA strand breaks, promoting genomic instability and resulting in apoptosis. The PARP family of proteins catalyzes post-translational ADP-ribosylation of nuclear proteins and is activated by single-strand DNA (ssDNA) breaks.

**Synonyms:** - MK 4827 - MK-4827 - MK4827 - NIRAPARIB