Experimental Drug Effective Against More Ovarian Cancers

Article date: August 24, 2011

By Stacy Simon

The experimental drug olaparib, which has shown promise against ovarian cancer caused by mutations in the BRCA1 and BRCA2 genes, can also reduce the size of tumors not caused by the mutations, according to a study published in The Lancet Oncology. The drug is so far only available to people who are taking part in clinical trials.

The inherited BRCA gene mutations account for about 5% to 10% of breast and ovarian cancer cases. This study is the first time olaparib has been shown to reduce the size of tumors in ovarian cancer patients without the mutations.

In the study, 90 women with either ovarian or breast cancer took olaparib every day, in 4-week cycles. Among patients with ovarian cancer, 41% with BRCA mutations and 24% of those without BRCA mutations showed a substantial shrinkage in the size of their tumors. The ovarian cancers in the women who weren’t BRCA carriers were aggressive.

“These results are promising, and certainly better progress in treating ovarian cancer is sorely needed,” says Debbie Saslow, PhD, American Cancer Society Director of Breast and Gynecologic Cancer. “It will be important to confirm these findings in a larger study, and to follow the women for a longer time period to see if the observed impact on tumor size translates to improved survival.”

Improvements among the women with breast cancer in the study could not be confirmed, even though previous studies had demonstrated breast tumor shrinkage in women with the BRCA mutation. But only 26 study participants had breast cancer, and they had all had previous therapies that may have interfered with the olaparib.

Olaparib works by blocking the activity of a protein called poly ADP ribose polymerase (PARP). PARP is involved in DNA repair. The drug prevents it from helping cancer cells repair their DNA after it has been damaged.

Side effects of olaparib were mild and included fatigue, nausea, vomiting and decreased appetite.

Reviewed by: Members of the ACS Medical Content Staff

ACS News Center stories are provided as a source of cancer-related news and are not intended to be used as press releases.

Citation: Olaparib in Patients With Recurrent High-Grade Serous or Poorly Differentiated Ovarian Carcinoma or Triple-Negative Breast Cancer: a Phase 2, Multicenter, Open-Label, Non-Randomized Study. Published in the September 2011 issue of The Lancet Oncology (Vol. 12). First author: Karen A. Gelmon, BC Cancer Agency, Vancouver, Canada.