Inclusion Criteria:

- Histologically or cytologically proven diagnosis of breast cancer with evidence of
unresectable, locally recurrent, or metastatic disease. Locally recurrent disease
must not be amenable to resection or radiation therapy with curative intent.

- Documentation of estrogen and progestin receptor (ER/PR) negative status and HER2/neu
receptor negative status (ie, FISH or CISH (where approved) negative or
immunohistochemistry 0 or +1).

- Prior treatment with an anthracycline, a taxane and alkylating agents alone or in
combination in the neoadjuvant, adjuvant or metastatic disease setting.

- Prior treatment with chemotherapy as follows: Receipt of adjuvant chemotherapy with
RECIST (appendix B) defined disease progression documented during treatment or
disease relapse within 6 months of last treatment, OR Receipt of chemotherapy in the
first-line advanced disease setting with RECIST defined disease stable or progression
documented during treatment, or, if the patient completed treatment with objective
disease response, documented disease progression after discontinuing treatment.
Patients entering the study on the basis of this criterion may have also previously
received neo adjuvant or adjuvant treatment with chemotherapy.

- Measurable disease as per RECIST. Measurable lesions that have been previously
radiated will not be considered target lesions unless increase in size has been
observed following completion of radiation therapy.

- Male or female.

- Patients age > 18 and < 70 years.

- ECOG performance status 0-2.

- Resolution of all acute toxic effects of prior therapy or surgical procedures to
grade ≤1 (except alopecia).

- Life expectancy >6 months.

- A fully HLA-identical sibling donor is available. Patients with one antigen
mismatched donors can be considered but only after discussion with the transplant
team and the Principal Investigator.

- The definitions of minimum adequacy for organ function required prior to study entry
are as follows: serum aspartate transaminase (AST) and serum alanine transaminase
(ALT) ≤2.5 x upper limit of normal (ULN), or AST and ALT ≤5 x ULN if liver function
abnormalities are due to underlying malignancy; total serum bilirubin ≤1.5 x ULN;
serum albumin ≥3.0 g/dL; absolute neutrophil count (ANC) ≥1500/μL; platelets
≥100,000/μL; haemoglobin ≥9.0 g/dL; serum creatinine ≤1.5 x ULN

- Signed and dated informed consent

- Willingness and ability to comply with scheduled visits, treatment plans, laboratory
tests, and other study procedures.

Exclusion Criteria:

- Uncontrolled CNS involvement with disease

- Fertile men or women unwilling to use contraceptive techniques during and for 12
months following treatment

- Females who are pregnant

- Organ dysfunction defined as follows: cardiac ejection fraction <30% or uncontrolled
cardiac failure; pulmonary: DLCO <40% predicted; liver: elevation of bilirubin to >
1.5 X ULN and/or transaminases >5x the upper limit of normal Renal: Serum creatinine
>1.5 x ULN

- ECOG performance status > 2

- Patients with poorly controlled hypertension on multiple antihypertensives

- Documented fungal disease that is progressive despite treatment

- Viral infections: HIV positive patients. Hepatitis B and C positive patients will be
evaluated on a case by case basis

- Psychiatric disorders or psychosocial problems which in the opinion of the primary
physician or Principal Investigator would place the patient at unacceptable risk from
this regimen.

- Patients may not be receiving any other investigational agents.

- History of allergic reactions attributed to compounds of similar chemical or biologic
composition to agents used in the study.

- Any previous or current malignancy at other sites, with the exception of adequately
treated cone-biopsied in situ carcinoma of the cervix and adequately treated basal or
squamous cell carcinoma of the skin.