SAN FRANCISCO, CA—A total of 40% of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with docetaxel after abiraterone achieved at least a 50% reduction in prostate specific antigen (PSA), according to a study presented at the 2016 Genitourinary Cancers Symposium.
“The chemotherapy docetaxel used to be our first-line therapy for mCRPC. Now we use androgen receptor targeted therapy first,” said principal investigator Thomas W. Flaig, MD, associate director for clinical research at the University of Colorado Cancer Center and associate professor of medicine at the University of Colorado School of Medicine. “The question was whether docetaxel still has a role in these patients treated with abiraterone. We’re no longer using docetaxel first—should we even be using it second?”
For the COU-AA-302 study, researchers enrolled 1088 patients with mCRPC to evaluate the efficacy of abiraterone acetate. Investigators found that after the study, 67% of patients treated with abiraterone then received further therapy. Nearly half of patients who had received abiraterone received subsequent docetaxel therapy.
Results showed that of those who received subsequent docetaxel, 40% had experienced PSA decline by more than half, demonstrating the activity of this particular drug sequence.
“This confirms the activity of abiraterone followed by docetaxel and represents important data on the sequencing of medical therapies under this new paradigm,” Flaig said.
The study also demonstrated that a surprisingly high number of patients received no treatment after docetaxel.
“The fact that a substantial portion of patients received no subsequent therapy after the study was done, needs additional study to be certain we are maximizing effective therapy for these patients.”
Even after anti-androgen therapy, docetaxel remains useful in prostate cancer [news release]. EurekAlert! Web site. http://www.eurekalert.org/pub_releases/2016-01/uoca-eaa011016.php. Posted January 10, 2016. Accessed January 11, 2016.