According to Genome Web, A new trial held at the Institute of Cancer Research in London has found that a drug previously approved for the treatment of ovarian cancer can also be beneficial for certain prostate cancer patients. The drug was found most effective in patients with a certain DNA mutation that rendered them more likely to respond to the treatment.

Approved by the US Food and Drug Administration for patients with advanced ovarian cancer, the drug is called Lynparza. In trials, the drugged proved most effective with advanced ovarian cancer patients with specific mutations, called germline BRCA mutations.

The company that produces the drug, called AstraZeneca, is investigating its use for the treatment of metastatic castrate-resistant prostate cancer.

Lynparza, known in the medical community as olaparib, has been theorized by researchers to be effective in prostate cancer patients who also have mutations in DNA repair genes.

Among other things, olaparib blocks enzymes involved in DNA repair, making it potentially useful for patients with mutated DNA repair genes.

One trial involved 50 patients, 49 of which were evaluated. 16 responded to the treatment, or 33%. These 33% were found to have mutations in DNA repair genes. Patients with the mutation were dubbed “biomarker positive.”

The usefulness of the treatment was also tested among prostate cancer patients without the mutation. Two of the 33 prostate cancer patients without the mutation also responded to the treatment.

Even among patients with this highly specific diagnosis, the true usefulness of the treatment is yet to be understood. Researchers pointed out that patients’ responses to Lynparza lasted more than six months and were associated with “impressive falls in circulating tumor-cell counts.” However, they cannot yet determine Lynparza’s overall improvement of survival rates among patients who are “biomarker positive.”