Could a pill slow down metastatic breast cancer?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age ≥ 21 years. * Histological or cytological diagnosis of breast carcinoma. * ECOG 0-2. * HER2 negative tumor (IHC 0 -1+ or IHC 2+ and confirmed on HER2 FISH to be negative based on histological report). * Patients with HER2 positive tumor may be enrolled if they have failed at least two lines of anti-HER2 based therapies in the metastatic setting, or are intolerant to trastuzumab * Any hormone receptor status. * Any number of lines of prior palliative endocrine therapy for patients with hormone receptor positive cancer. * Has measureable or evaluable disease based on RECIST 1.1 criteria * Estimated life expectancy of at least 12 weeks. * Has documented progressive disease from last line of therapy. * Has recovered from acute toxicities from prior anti-cancer therapies * Adequate organ function including the following: oBone marrow: (I) Absolute neutrophil (segmented and bands) count (ANC) ≥1.5 x 109/L (ii) Platelets ≥100 x 109/L (ii) Hemoglobin ≥8 x 109/L oHepatic: (I)Bilirubin ≤ 1.5 x upper limit of normal (ULN), (ii)ALT or AST ≤ 2.5x ULN, (or ≤ 5 X with liver metastases) oRenal: (I) Creatinine ≤1.5x ULN * Signed informed consent from patient or legal representative. * Able to comply with study-related procedures. * Prior therapy (patients enrolled in phase Ib may be enrolled if they fulfil prior therapy criteria for either Cohort A or Cohort B) * Cohort A only: Has received at least 2 lines of palliative systemic therapy, including prior fluropyrimidines (capecitabine, TS-1 or 5-fluorouracil) in the palliative setting, or in the adjuvant setting; patients who have only prior exposure to adjuvant fluoropyrimidines must have relapsed within 12 months of completing adjuvant fluoropyrimidines * Cohort B only: Any number of prior lines of palliative chemotherapy and has not received fluoropyrimidines (capecitabine, TS-1 or 5-fluorouracil) in the palliative setting or in the adjuvant setting; patients who have prior exposure to adjuvant fluoropyrimidines are eligible if they have relapsed 12 months from completion of adjuvant fluoropyrimidines. Exclusion Criteria: * Treatment within the last 30 days with any investigational drug. * Concurrent administration of any other tumour therapy, including cytotoxic chemotherapy, hormonal therapy, and immunotherapy. * Major surgery within 28 days of study drug administration. * Active infection that in the opinion of the investigator would compromise the patient's ability to tolerate therapy. * Pregnancy. * Breast feeding. * Serious concomitant disorders that would compromise the safety of the patient or compromise the patient's ability to complete the study, at the discretion of the investigator. * Active bleeding disorder or bleeding site. * Non-healing wound. * Poorly controlled diabetes mellitus. * Second primary malignancy that is clinically detectable at the time of consideration for study enrollment. * Symptomatic brain metastasis. * History of significant neurological or mental disorder, including seizures or dementia. * Unable to comply with study procedures Phase Ib lead-in can recruit patients who fulfil criteria for either Cohort A or Cohort B AND all other inclusion/exclusion criteria