Telomerase vaccination of metastatic breast cancer patients induces antigen-specific tumor infiltrating lymphocytes and tumor necrosis

2505 Background: The telomerase reverse transcriptase hTERT represents a promising target for cancer immunotherapy because of its near universal expression in cancer and its critical role in oncogenesis. CD8+ T lymphocytes recognize peptides derived from hTERT and kill hTERT+ tumors cells of multiple histologies in vitro. Methods: We report the immunologic and biologic effects of vaccinating metastatic BrCa patients with hTERT peptide. Fourteen HLA-A2+ women with metastatic BrCa were vaccinated sq with 10 ug (n=6), 100 ug (n=5), or 1000 ug (n=3) of hTERT I540 peptide in adjuvant with GM-CSF for up to 8 vaccinations. Results: Most patients experienced Grade 1 and 2 injection site reactions and a syndrome of tumor pain or tumor-site itchiness after vaccination. One patient had a minor response following regression chest wall lesions. Three patients had stable disease after completing all 8 vaccinations. Peptide/MHC tetramer analysis of PBMC showed that 7 of 14 patients responded immunologically to the vacci...