Dose-finding Study of Empegfilgrastim for Neutropenia Prophylaxis in Patients With Breast Cancer

Inclusion Criteria:

* Signed informed consent form;
* Histologically verified diagnosis of stage IIb/III/IV breast cancer;
* Age of 18-70 years inclusive;
* If the patient had received the chemotherapy for breast cancer, it should be finished 30 days before the beginning of the study;
* ECOG Performance Status of 0, 1 or 2, not increasing within during 2 weeks before randomization;
* ANC level of 1500/μL and more at the beginning of the study
* Platelet count of 100 000/μL and more at the beginning of the study
* Hemoglobin level of 90 g/l and more
* Creatinine level \<1.5 mg/dl
* Total bilirubin level \<1.5 × the upper limit of normal (ULN)
* ALT and/or AST levels \<2.5×ULN (5×ULN for patients with liver metastases);
* Alkaline phosphatase \<5×ULN;
* Left ventricular ejection fraction \>50% and more;
* If the patient had received adjuvant and/or neoadjuvant therapy, the cumulative dose of anthracyclines should not exceed 500 mg/m2 for doxorubicin or 500 mg/m2 for epirubicin;
* Ability of the participant to follow the protocol requirements, according to the Investigator's opinion;
* Patients of childbearing potential must implement reliable contraceptive measures during the study treatment, starting 4 weeks prior randomization and for 6 months after the last administration of the study drug.

Exclusion Criteria:

* Patient has received two or more chemotherapy regimens for the metastatic breast cancer;
* Documented hypersensitivity to filgrastim, pegfilgrastim, docetaxel, doxorubicin, dexamethasone and/or its excipients, PEGylated drugs, recombinant proteins.
* Pregnancy or breastfeeding;
* Systemic antibiotic therapy within 72 h prior empegfilgrastim/filgrastim administration;
* Concomitant radiotherapy (except selective radiotherapy of bone metastases);
* Surgery, radiotherapy (except selective radiotherapy of bone metastases), administration of any experimental drugs within 30 days prior randomization;
* History of bone marrow/stem cell transplantation;
* Conditions limiting the patient's ability to follow the protocol;
* CTCAE grade 2/4 neuropathy
* HIV, HCV, HBV, T.Pallidum infection(s);
* Acute or active chronic infections.