Parp Inhibitors

PARP inhibitors are a group of medicines that target an enzyme called poly‑ADP ribose polymerase, or PARP for short. This enzyme helps cells locate and fix small breaks in their DNA, a routine maintenance job that keeps the genetic code intact. By binding to PARP and blocking its activity, these drugs prevent the repair of those single‑strand lesions, allowing damage to accumulate inside the cell.

The importance of this blockade becomes striking in cancers that already carry defects in another repair pathway, most famously those with mutations in the BRCA1 or BRANCA2 genes. Those tumors lack a key method for fixing double‑strand breaks, so when PARP is also disabled the cancer cells are overwhelmed by DNA damage and die—a concept known as synthetic lethality. Because normal cells retain at least one functional repair route, they are less harmed, giving the therapy a degree of selectivity.

PARP inhibitors have moved from laboratory curiosity to standard components of treatment for several solid tumours, especially ovarian, breast, prostate and pancreatic cancers that harbour BRCA or related homologous‑recombination deficiencies. They appear in frontline regimens, as maintenance after surgery or chemotherapy, and are the focus of ongoing trials that combine them with immunotherapy, radiation or other targeted agents. Their success has also sparked broader research into exploiting DNA‑repair weaknesses across many types of cancer.