Hydroxychloroquine in Metastatic Estrogen Receptor-Positive Breast Cancer Progressing on Hormonal Therapy

Inclusion Criteria: 1. Patients ≥ 18 years of age with histologically confirmed, metastatic ER + breast cancer with clinical progression of disease (including radiographically stable disease with at least 50% increment of an elevated tumor marker by two measurements at least 2 weeks apart (this particular tumor marker will be used for disease status assessment in the study) on current hormonal therapy with PFS for at least 3 months. 2. Karnofsky Performance Status (KPS) ≥70% and a life expectancy \>3 months. 3. Participants must have at least one target visceral lesion that allows for evaluation of tumor response or in the case of bone-only metastases, patients need to have a positive imaging study such as bone scan, magnetic resonance imaging (MRI) or positron emission tomography-computed tomography (PET-CT) or CT, and an elevated tumor marker at least twice as high as upper limit. 4. Absolute neutrophil count \> 1500 mm3, platelet count ≥ 80×109 L, hemoglobin ≥ 8.5 g/dL 5. Creatinine clearance ≥ 30 mL/min, total bilirubin ≤ 2 mg/dL, AST/ALT ≤ 3 times the upper limit of normal range 6. No remaining grade 2 or higher toxicity from prior cancer therapies unless judged to be clinically insignificant by the Principal Investigator 7. At least two (2) weeks from prior major surgery 8. Willingness to provide permission to biopsy one of the lesions if applicable before the study (All the patients are encouraged to have post-therapy biopsy upon progression of disease, but it is optional) as well as blood samples for pertinent laboratory studies 9. Women of child-bearing potential (i.e., women who are pre-menopausal or not surgically sterile) must be willing to use an acceptable non-hormonal contraceptive method (abstinence, or double barrier method) for the duration of the study and for 30 days following the last dose of study drug, and must have a negative urine or serum pregnancy test within 2 weeks prior to beginning treatment on this trial - Exclusion Criteria: 1. On combination hormonal therapy with everolimus or any other investigational agent 2. Patients have symptomatic untreated brain metastasis or leptomeningeal metastases or treated but still symptomatic requiring the use of steroid 18Jul2014 Protocol v3: ABC 01 Anti-Autophagy for Met Breast Cancer Page 4 of 16 3. Lymphangitic carcinomatosis involving ≥ 50% of the lungs; evidence of metastases involving more than one third of the liver on sonogram or computed tomography 4. Lactating females 5. Uncontrolled cardiac disease, congestive heart failure, angina or hypertension 6. Myocardial infarction or unstable angina within 2 months of treatment 7. Known human immunodeficiency virus (HIV) infection or chronic active Hepatitis B or C (patients are NOT required to be tested for the presence of such viruses prior to therapy on this protocol) 8. Active clinically serious infection \> CTCAE (version 4.03) Grade 2 9. Serious non-healing wound, ulcer, or bone fracture 10. Concurrent psychiatric illness/social situations that would limit safety and compliance with study requirements 11. Inability to complete informed consent process and adhere to the protocol treatment plan and follow-up requirements 12. Currently receiving any other investigational therapeutic agents 13. Patients with known glucose-6-phosphate dehydrogenase deficiency, porphyria, cirrhosis or any other conditions with potential significant known risks 14. Patients with history of retinal damage