Bendamustine and Erlotinib in Treating Patients With Stage IIIB, Stage IIIC, or Stage IV Breast Cancer

RATIONALE: Drugs used in chemotherapy, such as bendamustine, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Erlotinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth and by blocking blood flow to the tumor. Giving bendamustine together with erlotinib may kill more tumor cells. PURPOSE: This phase I/II trial is studying the side effects and best dose of giving bendamustine together with erlotinib in treating patients with stage IIIB, stage IIIC, or stage IV breast cancer.

OBJECTIVES: Primary * To determine the phase II dose and assess the toxicity of bendamustine hydrochloride and erlotinib hydrochloride in patients with triple-receptor (estrogen receptor, progesterone receptor, and HER-2)-negative, stage IIIB, IIIC, or IV breast cancer. (Phase I) * To determine the efficacy of this regimen in these patients. (Phase II) Secondary (Correlative) * To assess the correlation between tumor EGFR expression and EGFR gene amplification and treatment efficacy and toxicity. * To assess for differences in treatment efficacy between basal-like and non-basal-like cancers. * To assess for differences in treatment efficacy between tumors with and without expression of DNA damage-response (DDR) checkpoint proteins. * To assess for differences in the activation state of DDR checkpoint proteins based on breast cancer subtype. OUTLINE: This is a multicenter, phase I dose-escalation study followed by a phase II study. Patients receive bendamustine hydrochloride IV over 30 minutes on days 1-2 and oral erlotinib hydrochloride once daily on days 5-21. Treatment repeats every 28 days for at least 6 courses in the absence of disease progression or unacceptable toxicity. Patients with no evidence of disease progression may continue with daily single-agent oral erlotinib hydrochloride on days 1-28. Treatment continues every 28 days in the absence of disease progression or unacceptable toxicity. Breast cancer tissue blocks from prior procedures are obtained for correlative studies. After a tissue microarray (TMA) and a TMA map are prepared, TMA slides are used for hematoxylin and eosin (H\&E) staining, FISH, and IHC. After completion of study treatment, patients are followed every 3 months for 2 years.