Androgen Receptor–Targeted Treatment in Triple-Negative Breast Cancer
Posted: Monday, March 26, 2018
In reportedly the largest prospective trial to date of an androgen receptor (AR)-targeted treatment of advanced triple-negative breast cancer, enzalutamide showed a clinical benefit, according to a study reported in the Journal of Clinical Oncology, and adverse events were consistent with the known safety profile of this agent.
“Data from this phase II study in a group of patients with AR-positive [triple-negative breast cancer] support and build upon the findings from others that there seems to exist a subset of patients with androgen-driven [triple-negative breast cancer] who may benefit from an AR-targeted agent,” stated Tiffany A. Traina, MD, of Memorial Sloan Kettering Cancer Center, and colleagues.
From 45 sites in 7 countries, 118 patients with triple-negative breast cancer and an AR-positive tumor (nuclear AR staining > 0%) received enzalutamide at 160 mg daily until disease progression. An evaluable subgroup of 78 patients had tumors expressing ≥ 10% nuclear AR.
The median duration of treatment for all patients was 8.1 weeks. The study found the clinical benefit rate at 16 weeks was higher in the evaluable subgroup (33%) than in the intent-to-treat population (25%). The median overall survival was 17.6 months in the evaluable subgroup and 12.7 months in the intent-to-treat population, and the median progression-free survival was 3.3 months and 2.9 months, respectively. As for toxicity, fatigue (3.4%) was the only treatment-related grade ≥ 3 adverse event occurring in more than 2% of patients.