Vaccination of Metastatic Breast Cancer Patients With a CD80-modified Allogeneic Cancer Cell Line (KS2422)

Phase 1 Study: Induction of Systemic Immune Responses in Metastatic Breast Cancer Patients by Vaccination With a CD80-modified, Devitalized HLA-*A0201+ Breast Cancer Cell Line (KS24.22)

In the last few years there has been a great attempt to develop active immunotherapies for breast cancer patients (BCPs) using undefined as well as selected antigens to activate tumor specific T-lymphocytes. The purpose of this phase-I study was to determine the safety and feasibility of vaccinations with an allogeneic breast cancer cell line, KS24.22, genetically modified to express CD80 and Her-2/neu, and to evaluate the efficacy of inducing tumor antigen-specific immune responses in human leukocyte antigen(HLA)-A*02-matched patients with metastatic breast cancer.

The trial was designed as an open label phase-I. Informed consent was given twice by the patients (1st for HLA-typing, 2nd for participation in the vaccination trial).

The first four vaccinations, which were given every two weeks, were followed by four monthly vaccinations. Additional vaccinations were permitted on request for patients who exhibited stable disease (SD).

Immediately before administration, KS24.22 cells were thawed and lethally irradiated. KS24.22 cells were adjusted to 10E7/ml in Ringer-Lactate-solution, transferred to 1 ml syringes and stored on ice until injected within a time frame of 2h. Vaccinations were given i.d. in the thigh with a total volume of 1 ml divided between two injection sites.

Inclusion Criteria:

• proven diagnosis of carcinoma of the breast with distant metastatic disease
• patient received either anthracycline- or taxane-based chemotherapy ("state of the art")
• Karnofsky Score (performance status) 80%
• HLA-*A0201-positive
• minimum life expectancy of 6 month
• written informed consent
• activation of patient's T-lymphocytes by mitogen antibodies and the cell line used for vaccination

Exclusion Criteria:

• manifestation of CNS metastases
• immunosuppressive disease like AIDS, autoimmune disease
• no serious concomitant systemic medical disorders or active acute or systemic infection
• pregnancy
• chemotherapies or radiotherapies in the 4 weeks preceding study entry
• biological response modifiers (antibodies, TNF, cytokines) or other immune therapies in the 6 weeks preceding study entry (exclusion: hematopoetic growth factors)
• organ transplanted patients