Phase II trial of bicalutamide in patients with androgen receptor-positive, estrogen receptor-negative metastatic breast cancer

Ayca Gucalp, Sara Tolaney, Steven J. Isakoff, James N. Ingle, Minetta C. Liu, Lisa A. Carey, Kimberly Blackwell, Hope Rugo, Lisle Nabell, Andres Forero, Vered Stearns, Ashley S. Doane, Michael Danso, Mary Ellen Moynahan, Lamia F. Momen, Joseph M. Gonzalez, Arooj Akhtar, Dilip D. Giri, Sujata Patil, Kimberly N. FeiginClifford A. Hudis, Tiffany A. Traina

Research output: Contribution to journalArticlepeer-review

395 Scopus citations


Purpose: Patients with hormone receptor-negative breast cancer generally do not benefit from endocrine- targeted therapies. However, a subset with androgen receptor (AR) expression is predicted to respond to antiandrogen therapies. This phase II study explored bicalutamide in AR-positive, estrogen receptor (ER), and progesterone receptor (PgR)-negative metastatic breast cancer. Experimental Design: Tumors from patients with ER/PgR-negative advanced breast cancer were tested centrally for AR [immunohistochemistry (IHC) < 10% nuclear staining considered positive]. If either the primary or a metastatic site was positive, patients were eligible to receive the AR antagonist bicalutamide at a dose of 150 mg daily. Clinical benefit rate (CBR), the primary endpoint, was defined as the total number of patients who show a complete response (CR), partial response (PR), or stable disease (SD) < 6 months; secondary endpoints included progression-free survival (PFS) and toxicity. Correlative studies included measurement of circulating endocrine markers and IHC surrogates for basal-like breast cancer. Results: Of 424 patients with ER/PgR-negative breast cancer, 12% tested AR-positive. The 6-month CBR was19%[95% confidence interval (CI), 7%-39%]for bicalutamide. The median PFS was 12 weeks (95% CI, 11-22 weeks). Bicalutamide was well-tolerated with no grade 4/5 treatment-related adverse events observed. Conclusion: AR was expressed in 12% of patients with ER/PgR-negative breast cancer screened for this trial. The CBR of 19% observed with bicalutamide shows proof of principle for the efficacy of minimally toxic androgen blockade in a select group of patients with ER/PgR-negative, AR-positive breast cancer.

Original languageEnglish (US)
Pages (from-to)5505-5512
Number of pages8
JournalClinical Cancer Research
Issue number19
StatePublished - Oct 1 2013

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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