The main purpose of this study is to see if pegfilgrastim (Neulasta) is safe and useful in supporting people through dose-dense chemotherapy, and to see if a long-acting red blood cell growth factor, darbepoetin alfa(Aranesp) can reduce the need for blood transfusion in chemotherapy recipients.

• Patients will receive chemotherapy every 2 weeks for up to 8 cycles (spread out of approximately 16 weeks, total) of treatment. On the day of chemotherapy treatment patients may receive an injection of darbepoetin alfa in addition to chemotherapy if their red blood cell count is below normal levels.
• On the day after chemotherapy treatment, patients will receive an injection of pegfilgrastim. There is one pegfilgrastim shot given per treatment cycle, for a total of 8 injections. Once the patient has finished chemotherapy and the last of the pegfilgrastim shots, their participation in this trial will be complete.
• While on this study the following procedures will be performed: a physical exam will be done every 2 weeks, vital signs will be done every 2 weeks, and blood tests every 2 weeks.
• This study also involves a Quality of Life Questionnaire done at the beginning of study treatment, at 2 months, 4 months, 6 months, and 1 year after starting the study treatment.
• Patients will remain on this study unless they experience unacceptable side effects from any of the treatment drugs.

Inclusion Criteria:

• Histologically or cytologically confirmed breast cancer clinical stage I, II or III disease. Patients must be deemed of sufficient risk for tumor or recurrence
• Patients may receive the defined adjuvant chemotherapy treatment either following definitive breast surgery or prior to definitive breast surgery
• 18 years of age or older
• ECOG performance status 0 or 1
• ANC > 1,500/uL
• Hemoglobin > 9 g/dL
• Platelets > 100,000/ul
• Total bilirubin less than or equal to ULN
• AST/ALT < 1.5 x ULN
• Creatinine within normal institutional limits
• PT/PTT < institutional upper limit of normal
• LVEF > 50%

Exclusion Criteria:

• Previous cytotoxic chemotherapy or therapeutic radiation therapy
• Pregnant or lactating women
• Receiving any other investigational agents
• Stage IV breast cancer
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to pegfilgrastim or darbepoetin
• Previous exposure to G-CSF or pegfilgrastim or to recombinant erythropoetin-related growth factors.
• On antibiotics within 72 hours of registration
• Patients with immune deficiency who are at increased risk of lethal infections when treated with marrow-suppressive therapy, or HIV-positive patients receiving anti-retroviral therapy
• Sickle cell disease
• Known positive antibody response to any erythropoietic agent
• Known hematologic diseases
• Known history of hyperviscosity syndrome
• Patients on lithium
• RBC transfusion within past 4 weeks