A phase 2 single-arm study of the clinical activity and safety of enzalutamide in patients with advanced androgen receptor-positive triple-negative breast cancer.

Abstract

TPS1144 Background: Androgen receptor (AR) expression is observed in 10-30% of patients (pts) with triple-negative breast cancer (TNBC). Experiments using AR+ TNBC cell lines have demonstrated enhanced growth in response to androgen stimulation that is inhibited by enzalutamide (ENZA), a potent oral inhibitor of AR signaling (Richer JK. Abstract presented at the AACR Advances in Breast Cancer Research Meeting, San Diego, CA, 2013 October 3-6 and D'Amato NC. Abstract presented at the SABCS, San Antonio, TX, December 4-8, 2012). AR+ TNBC may represent a subtype driven by AR signaling and which may respond to ENZA. Methods: Women with advanced AR+ TNBC (ER and PgR <1% by IHC and Her2 normal) will receive daily ENZA (160 mg) until disease progression (NCT01889238). The primary endpoint (EP) is clinical benefit rate (CBR) where benefit is defined as complete or partial response (CR or PR) or stable disease (SD) ≥16 weeks (wks) as assessed by the Investigator and according to RECIST 1.1. Additional EPs include ...