Testing the Addition of Copanlisib to Eribulin in Metastatic Triple Negative Breast Cancer

Inclusion Criteria: * Male or female patients must have metastatic or unresectable carcinoma of the breast that is estrogen receptor (ER) negative (less than 10%), progesterone receptor (PR) negative (less than 10%), and HER2 negative/unamplified * Patients must have had prior treatment with an anthracycline and taxane in the neoadjuvant, adjuvant, or metastatic setting, unless contraindicated or deemed to be suboptimal therapy per the treating physician * Patients must have progressed on at least one and not more than five prior chemotherapy regimens, including in the neoadjuvant, adjuvant, and metastatic settings. Prior chemotherapy in the neoadjuvant and/or adjuvant setting counts as one prior line. Prior endocrine therapy, anti-HER2 directed therapies, PARP inhibitors, immunotherapy alone, or other targeted therapy will not count as a prior therapy line, as long as the patient meets the eligibility criteria prior to enrollment. Immunotherapy combined with chemotherapy will be considered one line * All patients must agree to provide archival tumor material (most recent archival tumor tissue immediately prior to enrollment is strongly preferred) for research and must agree to undergo research tumor biopsy before treatment if presence of easily accessible lesions (judged by the treating physician). For patients with bone only disease, or patients without easily accessible lesions for the baseline research biopsy, availability of archival tumor material (2 x 4-5 micron secti…