To study the efficacy, safety, pharmacokinetics and immunogenicity of BCD-236 in combination with chemotherapeutic agents (CHT) in 2nd and subsequent lines of therapy of subjects with relapsed and/or metastatic triple negative breast cancer (TNBC).

Main Inclusion Criteria:

• Signed informed consent and the subject's ability to comply with the requirements of the Clinical Study Protocol.
• Age ≥18 years and <75 years at the time of signing the informed consent form.
• Histologically verified diagnosis (there are documented results of relevant studies) of TNBC: ER 0-2 points, PR 0-2 points or ER <1%, PR <1% (ASCO/CAP); HER2 (≤1+) or HER2 (2+) in the absence of amplification of the Her-2-neu gene by ISH.
• TNBC is progressive or relapsing on or after systemic therapy.
• The subject received at least 1 line of systemic therapy for locally advanced unresectable or metastatic TNBC, or she experienced a relapse / progressive disease during or within 6 months after completion of post-operative (adjuvant) chemotherapy.
• Confirmed AXL expression in tumor cells according to immunohistochemistry.
• Availability of fresh (obtained as part of screening or before its start, but after disease progression or relapse on the last line of therapy) and archival (obtained before disease progression or relapse on the last line of therapy, if available) tumor material samples suitable for immunohistochemical examination to determine AXL expression.
• Presence of at least 1 measurable tumor lesion according to RECIST 1.1. criteria for CIR.
• ECOG score 0-1.
• Life expectancy ≥ 4 months from the date of signing of the informed consent form in the opinion of the Investigator.

Main Exclusion Criteria:

• Indications for radical therapy or radiotherapy (excluding minor surgery or radiation therapy for palliative purposes).
• Active CNS metastases and/or carcinomatous meningitis. Subjects with brain metastases may participate in the study provided that the metastases have been adequately treated with surgery or radiotherapy, and if they have been clinically stable for at least 4 weeks prior to randomization (i.e. no neurological symptoms, no need for corticosteroids, and no lesions >1.5 cm) and no evidence of new or increasing CNS metastases. Patients with newly diagnosed CNS metastases during screening may not be included in the study.