Black men with metastatic prostate cancer may benefit from drug combination

A drug combination that shows little overall survival benefit in white men with advanced prostate cancer has a far greater effect in Black men with the disease, according to interim results from a study led by the Duke Cancer Institute.

The study, called PANTHER, administered the hormone therapies apalutamide and abiraterone acetate plus prednisone to parallel groups of Black and white participants with metastatic prostate cancer.

Two years from the start of treatment with the two hormonal therapies, only 14% of Black study participants have died, compared to 33% of the white participants. The findings are being reported in a presentation at the American Society of Clinical Oncology meeting in Chicago (abstract #5015).

"We saw signals of this in an earlier study using one hormonal therapy, but not to this degree," said lead author Daniel George, M.D., professor in the departments of Medicine and Surgery at Duke University School of Medicine." This really speaks to the need to design studies that include more Black participants, because there can be significant differences in the outcomes."

Black men are more likely to develop prostate cancer and are twice as likely to die from the disease than white men. When treated, however, Black men often do as well or better than whites—a finding George and colleagues at Duke have previously published.

In the Duke-led drug combination study, researchers enrolled 93 men with advanced prostate cancer, roughly evenly divided with 43 Black men and 50 white men. Both groups received care at the same institutions by the same care teams and received the same combination of hormonal therapy for two years or until the cancer progresses.

In addition to the overall survival benefit, the interim results show median progression-free survival for the Black participants is 30 months—twice as long as the 15 months for the white men. Black enrollees are also exhibiting greater declines in PSA levels compared to the white men. The study is ongoing.

Abiraterone acetate plus prednisone and apalutamide inhibit testosterone signaling in prostate cancer by different mechanisms and have shown independent overall survival benefit for patients with advanced prostate cancer.

"This research shows the importance of diversity in clinical trials," George said. "Without a larger percentage of Black participants, you would not pick up this important signal that Black men benefit differently than whites. I wonder how many similar signals we are missing because we don't have adequate diversity in studies. You can't assume that a lack of benefit in white patients applies to Blacks."