PARP Inhibitors: What They Are, How They Work, and Which Treatments They Support

When your cells can't fix broken DNA, cancer can grow unchecked. PARP inhibitors, a class of targeted cancer drugs that block the PARP enzyme involved in repairing damaged DNA. Also known as poly (ADP-ribose) polymerase inhibitors, they exploit a weakness in cancer cells with faulty DNA repair systems—like those carrying BRCA mutations. These drugs don’t attack all cells. They zero in on cancer cells that already struggle to fix DNA, making them die while sparing healthy ones.

This is why PARP inhibitors are so powerful for certain breast, ovarian, pancreatic, and prostate cancers. They work best when the tumor has a BRCA mutation, a genetic flaw that disables one of the main DNA repair pathways. Without that backup system, blocking PARP leaves the cancer cell with no way to survive. It’s like cutting the last rope when the person is already hanging by one. Doctors now use these drugs after chemotherapy or even as maintenance therapy to delay recurrence. They’re not a cure, but they buy time—and sometimes a lot of it.

PARP inhibitors don’t work alone. They’re often part of a bigger plan that includes targeted therapy, treatments designed to hit specific cancer weaknesses, and sometimes even DNA repair, the biological process that keeps cells from turning cancerous. But here’s the catch: not everyone responds. If your cancer doesn’t have a known repair defect, these drugs may not help. That’s why testing for BRCA and other markers is critical before starting. Side effects like fatigue, nausea, and low blood counts are common, but most people manage them well.

What you’ll find below isn’t just a list of articles. It’s a collection of real-world insights—how these drugs fit into daily treatment, what patients need to know about interactions, how kidney function affects dosing, and why some people respond better than others. You’ll see how genetics, medication safety, and even insurance rules play into who gets access and why. These aren’t theoretical discussions. They’re based on what’s happening in clinics and pharmacies right now.