In a new study, researchers found men with metastatic, hormone-resistant prostate cancer, who were treated based on the genetic makeup of their cancer, survived much longer than those treated with traditional hormone treatments.
They found olaparib, currently used to treat breast, ovarian and pancreatic cancer, was used successfully to treat prostate cancers with an inability to repair damaged DNA.
The research was conducted by a team from Northwestern Medicine and elsewhere.
The study treated men with metastatic prostate cancer that had progressed after several types of prior standard therapies, including hormone therapy.
The team preselected patients who have genetic alterations in the genes that enable cells to repair themselves from damage.
Those most commonly known are the BRACA 1, BRACA 2, and ATM genes, but there are several others.
Patients were randomly assigned to receive olaparib, which has been used in other cancers with similar genetic alterations, or standard hormone therapy with either abiraterone and prednisone or enzalutamide.
There were two cohorts of patients based on their cancer genetic mutations.
The median duration of overall survival in patients in cohort A with mutations on BRCA1, BRCA2, or ATM genes was 19.1 months with olaparib compared to 14.7 months with control therapy, a number considered clinically and statistically significant.
In cohort B patients (those with other genetic mutations) the median overall survival was 14.1 months with olaparib and 11.5 months with control therapy, but this was not statistically significant.
In 2020, there will be an estimated 191,930 new cases of prostate cancer and about 33,330 deaths from it.
Prostate cancer continues to be the second leading cause of cancer death in men in the United States. In 2016, there were an estimated 3,100,000 men living with prostate cancer in the U.S.
The team had previously reported a delay in disease progression for this group of men with DNA repair faults in their tumors — but these final published results offer a longer follow-up and conclusively demonstrate an improvement in survival for men who were given olaparib.
The team says olaparib blocks PARP, a protein that helps damaged cells repair themselves.
Some cancer cells rely on PARP to keep their DNA healthy. When PARP is stopped from repairing DNA damage, the cancer cells die.
One author of the study is Northwestern Medicine oncologist Dr. Maha Hussain.
The study is published in the New England Journal of Medicine.
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