Study on Dendritic Cell Vaccine with Trastuzumab or Nivolumab for Breast Cancer with Leptomeningeal Disease

Inclusion Criteria

• Confirmed diagnosis of breast cancer or definite LMD from breast cancer.
• Must have LMD with cancer cells in the cerebrospinal fluid (CSF) or specific radiographic signs.
• Performance status score of 2 or less, indicating ability to carry out light work.
• Preferably have received specific types of radiation therapy before the study.
• Stable brain or spinal cord metastases that do not need treatment at enrollment.
• Previous brain radiation or surgery must be at least 2 weeks before starting the vaccine.
• Aged 18 or older.
• Life expectancy of at least 8 weeks.
• Adequate organ function based on lab tests.
• Able to understand and sign consent forms.
• Can take low doses of corticosteroids for symptom control.
• May continue current cancer treatments if disease progresses before consent.
• Negative pregnancy test for women of childbearing potential, repeated monthly.
• Use effective contraception during and after treatment (90 days for men, 5-7 months for women).
• Have a device for accessing CSF and administering the vaccine.
• Able to undergo MRI scans with contrast.

Exclusion Criteria

• Receiving other LMD treatments recently, except certain allowed therapies.
• Recent use of immunotherapy within 4 weeks.
• Unable or unwilling to have a contrast-enhanced brain MRI.
• Other progressing cancers needing treatment, except certain skin or cervical cancers.
• Active infection needing treatment.
• Recent major surgery or injury, except for specific allowed procedures.
• Have shunts or history of certain brain conditions.
• Conditions or treatments that could interfere with the study.
• Psychiatric or substance abuse issues affecting participation.
• Pregnant, breastfeeding, or planning to conceive during the study.
• Known HIV, hepatitis B, or hepatitis C infections.
• Previous organ transplants.
• Severe medical or psychiatric conditions that increase study risks.
• Recent live vaccine within 30 days before starting the study drug.