PARP Inhibitors

PARP inhibitors (PARPis) are experimental medications that were found in early studies to be specifically effective against BRCA-related cancers. These drugs block an enzyme used by cells to mend breaks in DNA. Cancer cells in people with BRCA mutations have problems repairing DNA already, and the PARPis make that worse. Theoretically, these drugs should spare healthy cells that have at least one working copy of the BRCA gene, with limited side effects or toxicity. Because they are not yet FDA-approved, PARPis are not available outside clinical trials, but several such trials are currently recruiting participants.

Early PARPi research generated a lot of excitement. In the first trials, the drugs effectively treated some people with BRCA mutations and advanced cancers, including those who have already undergone multiple prior treatments with standard chemotherapy drugs. Overall, PARPis were well tolerated, although some patients developed fatigue, nausea, anemia, and low platelet counts. After early successes, trials that expanded to include more people without BRCA mutations were less successful. 

Despite setbacks in research on larger populations, PARPi research continues and is now focused on the population for which these drugs were initially developed: people with BRCA mutations. If these studies are successful, PARPi research could expand to earlier-stage cancers or prevention.

The participation of the HBOC community in PARPi research is critical. If you are interested in participating, ask your oncologist about studies in your area. Prior treatment sometimes affects participation eligibility; if you are newly diagnosed with a primary or recurring cancer, consider enrolling in a PARP inhibitor trial as early after diagnosis as possible. Share this information with friends and relatives.

Review the featured research section of our website and visitclinical trial search tool to find PARPi studies that are enrolling patients.