Experimental Pill Fights Inherited Cancer
Study Shows PARP Inhibitors Curb Growth of Some Breast, Ovarian, Prostate Tumors
June 24, 2009 -- For the second time this month, researchers report success using a novel type of anticancer pill to curb the growth of inherited tumors that often defy standard treatment. Called olaparib, the experimental pill is a member of a new class of drugs called PARP inhibitors that prevent unstable cancer cells from repairing themselves.
Two-thirds of 19 patients with cancer caused by mutations in the BRCA1 or BRCA2 genes responded to treatment with olaparib, and in more than half, tumors shrank or stopped growing, says researcher Johann de Bono, MD, PhD, of the Institute of Cancer Research in Sutton, U.K.
Defects in the BRCA1 and BRCA2 genes place women at sharply increased risk of developing aggressive cancers of the breast and ovaries at a young age. BRCA2 gene mutations also raise a man's risk of prostate cancer.
Of 19 patients in the study with BRCA-inherited cancers, 15 had ovarian cancer, three had breast cancer, and one had prostate cancer.
Olaparib did not help 41 other patients with tumors that were not associated with BRCA mutations, de Bono says.
PARP inhibitors "will very likely change the way we treat patients" whose tumors are caused by BRCA defects, says Daniel Silver, MD, PhD, of the Dana-Farber Cancer Institute in Boston. Silver, who was not involved with the work, co-authored an editorial about the study.
The study appears in the June 25 issue of The New England Journal of Medicine.