Inclusion Criteria:

          -  Women or men with metastatic breast cancer, measurable or evaluable disease including
             bone metastasis only (as per the Response Evaluation Criteria in Solid Tumors [RECIST]
             v1.1)

          -  No prior systemic treatment for metastatic breast cancer

          -  Pathologic confirmation of metastatic breast cancer diagnosed by core needle biopsy

          -  Metastatic breast cancer with any evidence of ER or PR positivity in ≥ 1% cells in
             biopsy specimens from either a primary or metastatic site

          -  Evidence of HER2 positive metastatic breast cancer in either a primary or metastatic
             site, if 3+ by an IHC method defined as uniform membrane staining for HER2 in 10% or
             more of tumor cells or demonstrate HER2 gene amplification by an ISH method (single
             probe, average HER2 copy number ≥6.0 signals/cell; dual probe HER2/CEP17 ratio ≥2.0
             with an average HER2 copy number ≥4.0 signals/cell; dual probe HER2/chromosome
             enumeration probe (CEP) 17 ratio ≥2.0 with an average HER2 cop number <4.0
             signals/cell; and HER2/CEP17 ratio <2.0 with an average HER2 copy number ≥6.0
             signals/cell) or amplified by FISH > 2.0. High average copy number of HER2 (≥6.0
             signals/cell) is considered positive regardless of the HER2/CEP17 ratio.

          -  Women or men 18 years and older

          -  Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-2

          -  Stable brain metastasis allowed (>2 weeks, clinically stable post treatment with
             surgery +/- radiation or radiation alone and off steroids)

          -  Transthoracic echocardiogram with ejection fraction > 50%

          -  Postmenopausal status or receiving ovarian ablation with a GnRH agonist such as
             goserelin or leuprolide. Postmenopausal status is defined by any one of the following
             criteria:

               -  Prior bilateral oophorectomy.

               -  Prior ovarian radiation for the purpose of ablation.

               -  Age ≥ 60 years.

               -  Age < 60 and amenorrhea for 12 or more months (in the absence of chemotherapy,
                  tamoxifen, or ovarian suppression) and FSH, LH, and estradiol in the
                  postmenopausal range per local normal.

          -  Written informed consent prior to beginning specific protocol procedures, including
             expected cooperation of the patients for the treatment and follow-up, must be obtained
             and documented according to the local regulatory requirements

          -  A baseline CT chest/abdomen/pelvis and bone scan or PET/CT

          -  Negative serum or urine pregnancy test within 7 days prior to starting treatment

          -  Women of child-bearing potential and men must agree to use adequate contraception
             prior to study entry, for the duration of study participation, and for 90 days
             following completion of therapy. Should a woman become pregnant or suspect she is
             pregnant while participating in this study, she should inform her treating physician
             immediately.

        Note: Recommended methods of birth control are: The consistent use of an intrauterine
        device (IUD), double barrier methods (diaphragm with spermicidal gel or condoms with
        contraceptive foam), sexual abstinence (no sexual intercourse) or sterilization.

        Men must agree to use a condom and not father a child for the duration of the study and for
        90 days after completion of therapy

        Laboratory values (≤ 28 days prior to registration)

          -  Absolute Neutrophil Count (ANC) ≥ 1,500/mm3

          -  Platelet Count ≥ 75,000/ mm3

          -  Hg >9 g/dL

          -  Total Bilirubin ≤1.5 x upper limits of normal (ULN)

          -  Serum ALT and AST ≤ 2.5 x ULN (≤ 5 x ULN in patients with liver metastasis)

          -  Creatinine ≤ 1.5 x ULN

        Exclusion Criteria:

          -  HER2 negative metastatic breast carcinoma defined as 0 or 1+ by IHC or with a FISH
             ratio (HER2 gene copy/ chromosome 17) <2 if IHC 2+ by local institution standard
             protocol

          -  Any prior treatment for metastatic breast cancer. (excluding radiation therapy for the
             purpose of ovarian ablation). Note: Prior adjuvant therapy with trastuzumab and
             pertuzumab is permitted after a 6 month window following completion of adjuvant
             therapy has passed.

          -  Patients currently receiving anticancer therapies or who have received anticancer
             therapies within 2 weeks of the start of study drug (including chemotherapy, radiation
             therapy, and biologics). Patients who have received prior endocrine therapy for
             fertility purposes will be eligible.

          -  Patients, who have had a major surgery or significant traumatic injury within 4 weeks
             of start of study drug, patients who have not recovered from the side effects of any
             major surgery (defined as requiring general anesthesia) or patients that may require
             major surgery during the course of the study

          -  Prior treatment with any investigational drug within the preceding 2 weeks

          -  Co-administration with strong CYP3A4 inducers (e.g., phenytoin, rifampin,
             carbamazepine, St John's Wort, bosentan, efavirenz, etravirine, modafinil, and
             nafcillin), strong CYP3A4 inhibitors (e.g., clarithromycin, indinavir, itraconazole,
             ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, posaconazole, ritonavir,
             saquinavir, telaprevir, telithromycin, verapamil, and voriconazole), and CYP3A4
             substrates (e.g., alfentanil, cyclosporine, dihydroergotamine, ergotamine, everolimus,
             fentanyl, pimozide, quinidine, sirolimus and tacrolimus). For a current table of
             Substrates, Inhibitors and Inducers please access the following
             website:http://www.fda.gov/Drugs/DevelopmentApprovalProcess/" See Appendix C.

          -  Uncontrolled brain metastases

          -  Leptomeningeal metastases

          -  Other malignancies within the past 3 years except for adequately treated carcinoma of
             the cervix or basal or squamous cell carcinomas of the skin.

          -  Patients who have any severe and/or uncontrolled medical conditions or other
             conditions that could affect their participation in the study such as:

               -  Symptomatic congestive heart failure of New York heart Association Class III or
                  IV

               -  Unstable angina pectoris, symptomatic congestive heart failure, myocardial
                  infarction within 6 months of start of study drug, serious uncontrolled cardiac
                  arrhythmia or any other clinically significant cardiac disease

               -  Severely impaired lung function as defined as spirometry and DLCO that is 50% of
                  the normal predicted value and/or 02 saturation that is 89% or less at rest on
                  room air

               -  Uncontrolled diabetes as defined by fasting serum glucose >1.5 x ULN

               -  Active (acute or chronic) or uncontrolled severe infections

               -  Liver disease such as cirrhosis, chronic active hepatitis or chronic persistent
                  hepatitis

          -  Impairment of gastrointestinal function or gastrointestinal disease that may
             significantly alter the absorption of palbociclib (e.g., ulcerative disease,
             uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome or small bowel
             resection)

          -  Patients with an active, bleeding diathesis

          -  History of noncompliance to medical regimens

          -  Patients unwilling to or unable to comply with the protocol

          -  Ongoing alcohol or drug addiction

          -  Female patients who are pregnant or breast feeding, or adults of reproductive
             potential who are not using effective birth control methods. If barrier contraceptives
             are being used, these must be continued throughout the trial by both sexes. Hormonal
             contraceptives are not acceptable as a method of contraception. (Women of childbearing
             potential must have a negative urine or serum pregnancy test within 7 days prior to
             starting treatment)

          -  History of allergic reactions attributed to compounds of similar chemical or biologic
             composition to palbociclib, anastrozole, trastuzumab or pertuzumab.