The PARP inhibitor Lynparza (olaparib)—approved for ovarian and breast cancer—also delays prostate cancer progression, a new study shows.

The Phase III PROfound trial enrolled nearly 400 men with castration-resistant metastatic prostate cancer. They were randomized to take Lynparza or one of two newer hormone therapies, Xtandi (enzalutamide) or Zytiga (abiraterone acetate).

In men with BRCA mutations or another faulty DNA repair gene, Lynparza reduced disease progression or death by 66%. After 12 months, 28% of Lynparza recipients were progression-free versus just 9% of Xtandi or Zytiga recipients. Men taking Lynparza were also more likely to experience tumor regression and less likely to have worsening pain. Early results suggest the PARP inhibitor may improve overall survival as well.

“Prostate cancer has lagged behind all other common solid tumors in the use of molecularly targeted treatment, so it is very exciting that now we can personalize an individual’s treatment based on specific genomic alterations in their cancer cells,” says Maha Hussain, MD, of Robert H. Lurie Comprehensive Cancer Center.