STRIDE – STimulating Immune Response In aDvanced brEast Cancer

Inclusion Criteria:

Postmenopausal women as defined in the protocol
Estrogen receptor (ER)-positive and/or progesterone receptor (PgR)-positive, histologically or cytologically confirmed primary carcinoma of the breast
Expressing at least one of the following five human leukocyte antigen (HLA) haplotypes, as centrally assessed by HLA genotyping from whole blood: HLA-A2, -A3, -A11, -B7, or -B35
Locally advanced, recurrent, or metastatic breast cancer (Subject must have at least one lesion not located in bone)
Measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST), and inoperable
Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
Adequate hematologic, hepatic, and renal function within two weeks prior to initiation of therapy, as defined by the protocol
Other protocol-defined inclusion criteria may apply

Exclusion Criteria:

Disease Status

PD either during hormonal therapy for early breast cancer (adjuvant therapy) or within 48 months from the initiation of such therapy
Human epidermal growth factor receptor 2-positive (HER2+) breast cancer as defined in the protocol
Autoimmune disease that in the opinion of the investigator could compromise the safety of the subject in this study (Exception will be granted for well-controlled Type I diabetes mellitus)
Recognized immunodeficiency disease, including cellular immunodeficiencies, hypogammaglobulinemia or dysgammaglobulinemia; hereditary or congenital immunodeficiencies
Past or current history of malignant neoplasm other than breast cancer (BRCA), except for curatively treated non-melanoma skin cancer, in situ carcinoma of the cervix, or other cancer curatively treated and with no evidence of disease for at least five years
Known active Hepatitis B infection or carrier state and/or Hepatitis C infection, known Human Immunodeficiency Virus infection, or any other infectious process that in the opinion of the investigator could compromise the subject's ability to mount an immune response or could expose her to the likelihood of more and/or severe side effects

Pre-therapies

Receipt of immunotherapy (for example [e.g.], interferons; tumor necrosis factor; interleukins; growth factors granulocyte macrophage-colony stimulating factor [GM-CSF], granulocyte-colony stimulating factor [G-CSF], macrophage-colony stimulating factor [M-CSF], or monoclonal antibodies), or chemotherapy, within four weeks (28 days) prior to randomization. Note: Subjects who have received monoclonal antibodies for imaging are eligible
Prior receipt of investigational systemic drugs (including off-label use of approved products) or any kind of systemic treatment (chemotherapy, or immunotherapy), with the exception of hormonal therapy (HT) when given for a period not exceeding 4 weeks (28 days) prior to randomization, for treatment of inoperable, locally advanced, recurrent, or metastatic breast cancer
Prior radiotherapy to the site of cancer, if only one site will be used for evaluation of tumor response

Prior use of bisphosphonates or concurrent use while on study treatment is allowed

Physiological Function

Central nervous system disease or brain metastases, as documented by computed tomography (CT) or magnetic resonance imaging (MRI)
Medical or psychiatric conditions that would interfere with the ability to provide informed consent, communicate side effects, or comply with protocol requirements
Clinically significant cardiac disease, e.g., cardiac failure of New York Heart Association (NYHA) classes III-IV; uncontrolled angina pectoris, uncontrolled arrhythmia, uncontrolled hypertension, or myocardial infarction in the previous six months, as confirmed by an electrocardiogram (ECG)
Splenectomy

Standard Criteria

Need for concurrent treatment with a non-permitted therapy (e.g., concurrent chemotherapy, radiotherapy, systemic immunosuppressive drugs, use of herbal medicines or botanical formulations intended to treat cancer) while on protocol therapy. Palliative radiation to painful bone lesions is allowed
Participation in another clinical study within 30 days prior to randomization
Known hypersensitivity to the study drugs
Known alcohol or drug abuse
Legal incapacity or limited legal capacity
Signs and symptoms suggestive of transmissible spongiform encephalopathy, or family members who suffer(ed) from such.
Subject who could be regarded as "vulnerable" according to International Conference on Harmonisation (ICH) Good Clinical Practice (GCP) guidelines (e.g., the subject's willingness to volunteer in a clinical trial may be unduly influenced by the expectation, whether justified or not, of benefits associated with participation, or of a retaliatory response from senior members of a hierarchy in case of refusal to participate, plus persons kept in detention; persons in nursing homes; subjects in emergency situations; homeless persons; and nomads)
Any other reason that, in the opinion of the investigator, precludes the subject from participating in this study