- Researchers report that a drug used to treat ovarian and breast cancer did well in a clinical trial with men with prostate cancer.
- They said the medication olaparib blocks a protein that helps damaged cancer cells repair themselves.
- In the study, it took twice as long for the cancer to spread in men with advanced, metastatic prostate cancer who took olaparib.
Researchers have discovered an effective way of attacking prostate cancer by targeting a protein that helps damaged cancer cells repair themselves.
A study presented Monday in Barcelona at the 2019 European Society for Medical Oncology states that going after prostate cancer at the genetic level can lengthen the lives of men who have the disease as well as delay severe pain.
The PROfound trial was conducted by researchers from Northwestern University and other institutions.
It hasn’t been published yet in a peer-reviewed journal.
“Treatments for metastatic, hormone-resistant prostate cancer have continued to use one-size-fits-all approaches, overlooking the genetic makeup of the tumor,” Dr. Maha Hussain, a professor of medicine at Northwestern’s Feinberg School of Medicine as well as a principal co-investigator of the study, said in a press release.
“Our results show the potential of a genetically targeted treatment for patients with advanced disease. I am confident we are now entering a new era of personalized care and precision medicine for metastatic prostate cancer,” she said.
Using targeted therapy, researchers said the drug olaparib can block PARP, a protein that helps damaged cancer cells repair themselves. If PARP isn’t assisting cancer cells, those cells can die.
Olaparib is a treatment approved by the Food and Drug Administration (FDA) that’s already used in treating ovarian and breast cancer.
It’s the first time prostate cancer has been successfully treated based on its genetic makeup.
Men participating in the study had advanced, metastatic prostate cancer that had progressed after several prior therapies.
This is a significant advance, according to Northwestern researchers, as the treatment of prostate cancer has lagged behind other cancers in terms of precision therapy, which is now the standard in breast, ovarian, and lung cancers.
“This is a very important study, because it is a first example of the concept of precision cancer treatment that can be applied to patients with advanced prostate cancer,” said Dr. Przemyslaw Twardowski, the director of clinical research in the department of urology at the John Wayne Cancer Institute at Providence Saint John’s Health Center in Santa Monica, California.
“Patients with metastatic prostate cancer who were not responding to standard hormonal therapies and/or chemotherapy underwent detailed analysis of their tumor tissue on a DNA level,” Twardowski, who worked on the study, told Healthline.
“If a certain type of mutation was detected — an example includes mutation in the BRCA gene — they were randomly assigned to receive a drug called olaparib or a different kind of hormone therapy. Olaparib previously was shown to be effective in other tumor types, like breast and ovarian cancer, with similar DNA mutations,” he said.
He says that, so far, as many as 30 percent of men with advanced prostate cancer have similar mutations.
“It will potentially open up a new, exciting therapeutic option, pending review by regulatory authorities,” Twardowski said. “The drug is given in pill form and is well tolerated. It’s a very important development and good news for patients dealing with this difficult disease.”
The National Cancer Institute (NCI) estimates there will be 174,650 new cases of prostate cancer in the United States this year. Those will result in an estimated 31,620 deaths. In 2016, the NCI estimates 3.1 million men in the United States had prostate cancer.
One oncologist told Healthline the study could change how cancer screening is done.
“This highlights the importance of testing tumor tissue sample for tumor molecular profiling,” said Dr. Timothy Byun, an oncologist at the center for Cancer Prevention and Treatment at St. Joseph Hospital in California.
“Certainly, if this drug gets approved by the FDA, then tissue tumor profiling should be considered on every metastatic, castrate-resistant prostate cancer patient to determine olaparib eligibility,” he said.
The trial looked at men with genetic alterations in genes enabling cells to repair themselves when damaged, the most common of which are the BRACA1, BRACA2, and ATM genes.
Researchers randomly gave patients olaparib or standard hormone therapy.
“We want to prevent those renegade cancer cells from repairing themselves,” Hussain said.
Participants with alterations in BRACA1, BRACA2, or ATM genes who took olaparib saw the disease take more than twice as long to spread than the participants who received standard hormone therapy — 7.4 months to 3.6 months.
In the 6 months following treatment, 60 percent of men receiving olaparib showed no disease progression, compared to 23 percent in the control groups. As soon as the men in the control groups showed disease progression, they were given olaparib.
The benefits of olaparib occurred across the board, regardless of the cancer’s location, previous treatment, where the cancer spread, and the participant’s age.
Application of olaparib also extended the time until participants felt significant pain.
According to Northwestern, researchers are still following participants who will still likely die from their cancer. But the percentages of participants surviving for 6, 12, and 18 months are higher with the drug: 73 percent versus 57 percent at 1 year, and 56 percent versus 42 percent at 18 months.
This recent trial is a breakthrough in treating prostate cancer, Dr. Mark Scholz, an oncologist for 25 years and author of two books on prostate cancer, told Healthline.
“Prostate cancer is the only type of cancer that is still primarily managed by surgeons, urologists, instead of medical oncologists,” said Scholz, the medical director of Prostate Oncology Specialists in Marina del Rey, California.
“Precision therapy and more personalized treatment options are not as likely to be part of the treatment discussion. The prostate cancer industry is rapidly changing, not only with developments in genetics, but also with advancements in prostate imaging and improvements in treatment options. So, it’s difficult for nonspecializing doctors to stay up to date with all of the latest developments,” he said.
Scholz says it’s important, especially with prostate cancer, to find a doctor “who really understands the disease.”
“Look for a disease-specific specialist. The better the expert understands the disease and the greater the breadth of their knowledge, the more likely they will be to accurately subcategorize the disease’s stage,” Scholz said.
“By knowing the exact subcategory, they will be more equipped to suggest a custom treatment protocol that incorporates every aspect of the specific individual’s uniqueness,” he added.
While the trial is encouraging for some men with the specific genetic makeup, Scholz says there’s still work to be done.
“Many men with prostate cancer don’t have treatable mutations,” he said. “So, until we have additional therapies available, the overall impact is limited. However, when a specific, treatable mutation is discovered, it makes a big difference in that individual patient.”