Bicalutamide and Abemaciclib in Inoperable or Metastatic Androgen Receptor-positive Triple-negative Breast Cancer

Required: AR overexpression (≥1% of cells staining on IHC)

AR+ assessed locally and defined as ≥1% of cells staining on IHC of last recurrent/metastatic breast cancer specimen

Required: ESR1 expression ≤10% of cells by IHC (≤10% of cells by IHC)

positive IHC for ER and/or PR in ≤10% of cells

Required: PR (PGR) expression ≤10% of cells by IHC (≤10% of cells by IHC)

positive IHC for ER and/or PR in ≤10% of cells

Required: HER2 (ERBB2) negative per ASCO/CAP-guidelines (negative per ASCO/CAP-guidelines)

negative for HER2 per ASCO/CAP-guidelines

Allowed: BRCA1 pathogenic germline variant

Patients with known germline BRCA1/2 pathogenic variants should have received previous treatment with PARP inhibitors in the early/locally advanced or metastatic setting, unless contraindicated.

Allowed: BRCA2 pathogenic germline variant

Patients with known germline BRCA1/2 pathogenic variants should have received previous treatment with PARP inhibitors in the early/locally advanced or metastatic setting, unless contraindicated.

Must have received: cytostatic chemotherapy — advanced

must have had prior treatment with at least 1 prior cytostatic regimen in advanced setting unless treatment with a cytostatic regimen is contraindicated as judged by Investigator

Must have received: endocrine therapy — advanced

Patients with 1-10% cells with positive IHC for ER in the last recurrent/metastatic site must be treated with at least one line of endocrine therapy in advanced setting

Must have received: PARP inhibitor — early/locally advanced or metastatic

Patients with known germline BRCA1/2 pathogenic variants should have received previous treatment with PARP inhibitors in the early/locally advanced or metastatic setting, unless contraindicated.

Cannot have received: abemaciclib (abemaciclib)

Any prior exposure to abemaciclib

Cannot have received: anti-androgen therapy (bicalutamide, abiraterone, enzalutamide)

Any prior exposure to anti-androgen therapy (bicalutamide, abiraterone, and/or enzalutamide)

Cannot have received: CDK4/6 inhibitor (palbociclib, ribociclib)

Exception: allowed if at least 6 months have elapsed between last administration and start of study treatment

Prior treatment with palbociclib or ribociclib is allowed, provided at least 6 months have elapsed between last administration and start of study treatment