New drug combo targets Hard-to-Treat 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: A patient will be eligible for androgen receptor expression testing (STEP 1) if the following criteria are met: * Female * Pathologically confirmed invasive cancer of the breast * ER/PR status (ER or PR defined as positive if ≥1%; ER/PR is defined as negative if \<1%): * Phase I: Patients may have ER/PR(-) breast cancer. * HER2 normal (IHC 0-1; FISH \< 2.0) * Non-measurable or measurable, metastatic disease * Available tissue for AR testing for research purposes A patient will be eligible for participation in the therapeutic trial (STEP 2) if the following criteria are met: * Androgen receptor expression testing confirms that the patient's tumor is AR (+). AR is considered positive if ≥1% of cell nuclei are immunoreactive using the Dako antibody (clone AR441). Receptor testing may be performed on either primary tumor specimen or tissue from a metastatic site. Local testing permitted for eligibility but will require confirmation at MSKCC. * There is no limit to the number of prior chemotherapy or endocrine therapy regimens allowed. Patients with ER(+) AR(+) breast cancer must have had at least 1 prior line of endocrine therapy to be eligible for the phase I portion of the trial. * At least 2 weeks since last cytotoxic chemotherapy, hormonal therapy, or radiotherapy. Toxicities related to prior therapy must either have returned to grade 1, or baseline (excluding alopecia) * Patient may receive bisphosphonates/denosumab for the palliation of bone metastases * If patient has a history of brain metastases or leptomeningeal disease, lesions must be stable for at least 3 months (as documented by either head CT or brain MRI) * Prior treatment with bicalutamide will not be allowed * At least 3 weeks from major surgery with full recovery * ECOG performance status 0-2 * Age 18 years or greater * Postmenopausal. Use of LHRH agonist permitted. * Patients must not have another, non-breast, active malignancy that requires treatment. * The effects of palbociclib on the developing human fetus at the recommended therapeutic dose are unknown. Women of child-bearing potential must agree to use adequate contraception (barrier method of birth control; abstinence). Women must not breast feed while on study. * Ability to understand and the willingness to sign a written informed consent document. * Ability to swallow intact palbociclib capsules and bicalutamide tablets. * Adequate organ and marrow function as defined below (ULN indicates institutional upper limit of normal): * Absolute neutrophil count ≥ 1.5 10\^9/ * Hemoglobin ≥ 9.0 g/dL * WBC ≥ 3.0 10\^9/L * Platelets ≥ 100 10\^9/L * Total bilirubin ≤ 1.5 ULN except for patients with known Gilbert syndrome * AST(SGOT)/ALT(SGPT) ≤ 3 institutional ULN * Plasma creatinine ≤ 1.5 ULN or Creatinine Clearance \> 50 mL/min (calculated by Cockcroft-Gault method) * QTc interval ≤ 470 msec Exclusion Criteria: * Patients who have not recovered from adverse events of prior therapy to ≤ NCI CTCAEv4.0 Grade 1. * Patients receiving any other investigational anti-cancer agents. * Patients who have received prior treatment with a selective CDK4/6 inhibitor * Patients who have received prior anti-androgen therapy * History of allergic reactions attributed to compounds of similar chemical or biologic composition to palbociclib. * Uncontrolled intercurrent illness including, but not limited to, known ongoing or active infection, including HIV, active hepatitis B or C, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia (specifically, uncontrolled atrial fibrillation or ventricular dysrhythmias except ventricular premature contractions), or psychiatric illness/social situations that would limit compliance with study requirements. * Pregnant women and women who are breast-feeding. * Patients with a history of long-QT syndrome or documented family history of long-QT syndrome. Patients who must remain on drugs that prolong the QT interval. * Palbociclib is a substrate of CYP3A. Caution should be exercised when dosing palbociclib concurrently with CYP3A inducers or inhibitors. Furthermore, patients who are taking concurrent medications that are strong inducers/inhibitors or substrates of CYP3A4 should be switched to alternative medications to minimize any potential risk.