Drugs known as PARP inhibitors are used to treat some women with advanced ovarian cancer that has returned after earlier treatment. Now, results from three new clinical trials show that the drugs might also benefit women who are newly diagnosed with advanced ovarian cancer. The studies—which tested the PARP inhibitors niraparib (Zejula), olaparib (Lynparza), and veliparib, respectively—involved women with high-grade serous epithelial ovarian, fallopian tube, or primary peritoneal cancer. Standard initial treatment for women with newly diagnosed advanced ovarian cancer typically includes first-line therapy with a combination of surgery and chemotherapy, sometimes followed by maintenance therapy—an additional treatment intended to help prevent the cancer from coming back. But for most patients, the cancer still returns within 3 years of initial treatment. In all three studies, the use of a PARP inhibitor as first-line therapy, maintenance therapy, or both substantially delayed the length of time before participants’ cancers came back or got worse. Results from all three trials were presented recently at the European Society for Medical Oncology (ESMO) Congress 2019 in Barcelona, Spain. “After decades studying different chemotherapy approaches, it is the first time we have meaningfully prolonged progression-free survival and hopefully we will improve long-term outcome,” Ana Oaknin, M.D., of Vall d' Hebron Institute of Oncology in Barcelona, an investigator on one of the trials, said in a news release. Christina Annunziata, M.D., Ph.D., of the Women’s Malignancies Branch in NCI's Center for Cancer Research, who was not involved in the studies, said that these results are exciting, but she noted that differences among the study designs and outcomes raises questions about how best to incorporate the different PARP inhibitors into treatment strategies for women with ovarian cancer. Experts are currently working together to draft new guidelines for ovarian cancer treatment, Dr. Annunziata added.