In the largest clinical trial to date to examine the efficacy of PARP inhibitor therapy in BRCA 1/2 carriers with diseases other than breast and ovarian cancer, the oral drug olaparib was found to be effective against advanced pancreatic and prostate cancers. Results of the study, led by researchers from the Perelman School of Medicine at the University of Pennsylvania and Sheba Medical Center in Tel Hashomer, Israel, will be presented during the American Society of Clinical Oncology’s annual meeting in Chicago in early June (Abstract #11024).

The multi-center research team, including investigators from across the United States, Europe, Australia and Israel, studied nearly 300 patients with inherited BRCA1 and BRCA2 mutations who had advanced cancers that were still growing despite standard treatments. Study participants, comprised of patients with breast, ovarian, pancreatic, prostate and other cancers, all took olaparib.

“Our results show that the BRCA1 or BRCA2 genes inherited by some patients can actually be the Achilles heel in a novel, personalized approach to treat any type of cancer the patient has,” says the study’s senior author, Susan Domchek, MD, director of the Basser Research Center for BRCA in Penn’s Abramson Cancer Center. “As many as 3 percent of patients with pancreatic and prostate cancer have an inherited mutation in BRCA1 or BRCA2. Our findings have implications for many patients beyond those with breast and ovarian cancer.”

Five of 23 pancreatic cancer patients (22 percent) and four of eight prostate cancer patients (50 percent) responded to the therapy, as measured by objective clinical criteria. Importantly, the therapy also appeared to halt disease progression even in those whose tumors did not shrink: an additional eight (35 percent) of the pancreatic cancer patients studied had stable disease at 8 weeks after beginning olaparib, as did two (25 percent) of the prostate patients. Overall survival at one year was 41 percent for the pancreatic cancer patients, and 50 percent for the prostate cancer patients.

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