PARP Inhibitors For Ovarian Cancer

PARP inhibitors have exploded onto the scene of ovarian cancer treatment — and exciting new research is showing that more women may be eligible to receive them.

PARP inhibitors are available to almost all women, though women with BRCA gene mutations or who are HRD proficient may benefit the most from these drugs. However, the American Society of Clinical Oncology (ASCO) guidelines recommend PARP inhibitors be offered to women, with or without genetic mutations, who are newly diagnosed with stage III or IV ovarian cancer and have improved with chemotherapy.

PARP inhibitors are primarily still used in women whose disease has come back, or as part of an ongoing course of treatment called maintenance therapy. In maintenance therapy, women whose ovarian cancer has recurred take PARP inhibitors following 4-6 cycles of platinum-based chemotherapy. The goal: keep the cancer in remission for as long as possible.

PARP inhibitors are best used in women as maintenance therapy if they’ve responded well to platinum-based chemotherapy. These types of patients are known as ‘platinum-sensitive’, meaning they responded well to a chemotherapy that uses platinum as its base.

One of the key things to know about PARP inhibitors is that your genetic makeup and specific features of your cancer will have a significant impact on how effective these drugs may be. Experts tell SurvivorNet that every woman with ovarian cancer should get a genetic test to determine if they have a mutation called BRCA, because the mutation enables PARP inhibitors to function much more powerfully. As of now, women with BRCA mutations can receive PARP inhibitors earlier on in the course of their treatment as one of the first steps (after their cancer has responded to platinum-based chemotherapy).

Women with BRCA mutations respond best to PARP inhibitors. But why? Tumor cells with BRCA mutations have problems repairing DNA already, and the PARP inhibitors make that worse, causing cancer cells to die. Nonetheless, women without BRCA mutations at all have still shown more benefit as compared to observation or ‘watchful waiting.’

Importantly, there is increasing data that even women without BRCA mutations can still derive some benefit from these drugs. Again, it’s really important to know that many doctors are still getting comfortable with PARP inhibitors, and because the research is developing so quickly, your genetic makeup and the stage of your cancer may well make you a potential candidate.

Ultimately, while PARP inhibitors can be beneficial for many women with ovarian cancer, it doesn’t necessarily mean everyone should take them. There are some significant side effects to consider, and thus, the decision to take PARP inhibitors should be made in consultation with your individual oncologist.