The poster presented by Traina et al attracted great interest at the 2014 San Antonio Breast Cancer Symposium. One viewer who was impressed was Ramesh Narayanan, PhD, of the University of Tennessee Health Science Center in Memphis. He noted that the clinical benefit rate of 24% at 24 weeks in the intent-to-treat population is not substantially better than the 19% rate seen with bicalutamide in a phase II study; however, patients receiving bicalutamide were required to have at least 10% of cells stain positive, compared to > 0% staining in this study, to qualify for treatment. In other words, there were “androgen receptor–low” patients who still responded.
“I am encouraged to see the androgen receptor evolving as a new therapeutic target in triple-negative and estrogen receptor–positive breast cancer,” Dr. Narayanan said, noting that these agents will probably be associated with less bone loss, muscle complaints, and other side effects than traditional hormonal therapies. “These results are quite good, and enzalutamide is definitely a better drug than bicalutamide,” he commented. ■
Disclosure: Dr. Narayanan reported no potential conflicts of interest.
The androgen receptor inhibitor enzalutamide (Xtandi) showed encouraging activity as a single agent in advanced triple-negative breast cancer patients expressing the androgen receptor, according to an international study presented at the 2014 San Antonio Breast Cancer Symposium.1