Clinical Trials

NOTE: Waivers to eligibility criteria are not allowed per ACCRU policy.

Inclusion Criteria:

• Female, ≥ 18 years old.
• Resected unilateral or bilateral primary carcinoma of the breast without clinical evidence of metastatic disease (after neoadjuvant chemotherapy and/or adjuvant chemotherapy), negative for estrogen receptor (ER) and progesterone receptor (PR) (cut-off for positivity is > 10% positive tumor cells with nuclear staining), and negative for HER2 as defined by one of the four situations delineated below: 
  • HER2 immunohistochemistry (IHC) expression of 0 or 1+ and in-situ hybridization non-amplified;
  • HER2 IHC expression of 0 or 1+ and in-situ hybridization not done;
  • HER2 IHC expression of 2+ and in-situ hybridization non-amplified; 
  • IHC not done and in-situ hybridization non-amplified. 
    • Note: central review is not required. 
    • Note: If biopsy and surgical specimens are discordant from each other with regard to ER, PR, and/or HER2 status, a patient will be allowed to enroll assuming at least one of the specimens meets the above criteria and no endocrine therapy use is planned going forward.
• Completed planned breast CANCER surgeries, any radiation therapy, and any chemotherapy, whichever is last, ≥ 90 days but not ≥ 546 days prior to randomization. 
  • Note: Reconstructive and prophylactic surgeries are allowed after randomization (during study treatment).
• Patient had at least one of the following: 
  • Biopsy or surgery-proven regional node involvement by cancer;
  • T1c, T2, T3, or T4 (disease with inflammatory disease allowed) identified at the time of surgery or clinically identified prior to neoadjuvant chemotherapy);
  • No complete response to neoadjuvant chemotherapy (those who did achieve complete response are still eligible if a pre-chemotherapy regional nodal biopsy identified cancer or if the pre-chemotherapy tumor measured > 1 cm).
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1.
• The following laboratory values obtained ≤14 days prior to randomization:
  • Absolute neutrophil count (ANC) ≥ 1500/mm^3 obtained ≤ 14 days prior to randomization;
  • Platelet count ≥ 75,000/uL obtained ≤ 14 days prior to randomization;
  • Aspartate transaminase (AST) ≤ 3 x upper limit of normal (ULN) obtained ≤ 14 days prior to randomization;
  • Creatinine ≤ 1.5 x ULN obtained ≤ 14 days prior to randomization.
• Negative serum pregnancy test done ≤ 14 days prior to randomization, for women of childbearing potential only. 
• Provide informed written consent.
• Willing to return to enrolling institution for follow-up.
• Willing to provide tissue and blood samples for correlative research studies.

Exclusion Criteria: 

• Any of the following because this study involves an investigational agent whose genotoxic, mutagenic and teratogenic effects on the developing fetus and newborn are unknown:
  • Pregnant women. 
  • Nursing women.
  • Women of childbearing potential who are unwilling to employ adequate contraception.
• Clinical evidence of local recurrence or distant metastases.
  • Note: New primary tumors are allowed, both contralaterally and ipsilaterally, but a prior breast cancer must have been more than 5 years beforehand 
• Known hypersensitivity reaction to GM-CSF.
• Active autoimmune disease that has required systemic treatment ≤ 30 days (i.e., with use of disease modifying agents, corticosteroids, or immunosuppressive drugs) prior to randomization.
  • Note: replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment; patients with vitiligo, Graves disease, or psoriasis not requiring systemic treatment within the past 30 days are not excluded; patients with Celiac disease controlled with diet modification are not excluded.
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
  • NOTE: Localized fungal or viral infections including of the skin, nails, mouth, and genital area are allowed.
• History of other cancer < 5 years prior to consent (except non-melanoma skin cancer or carcinoma in situ of the uterine cervix), or current receipt of treatment for another cancer (e.g., monoclonal antibody, small molecule pathway inhibitor).
• Treatment with systemic corticosteroid or immune-modulators ≤ 7 days prior to randomization. 
• Concurrent treatment with other experimental drugs or any other systemic anticancer therapy (due to unknown drug-vaccine potential interactions).
  • NOTE: aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), statins, and other medications commonly used to treat nononcologic, non-autoimmune conditions are allowed.
• Immunocompromised patients and patients known to be human immunodeficiency virus (HIV) positive and currently receiving antiretroviral therapy. 
• Prior or concurrent use of trastuzumab.
• Prior or concurrent use of a PD-1 or PD-L1 checkpoint inhibitor including pembrolizumab unless the use was ≥ 3 months prior to randomization.

Eligibility last updated 9/2/21. Questions regarding updates should be directed to the study team contact.