SAN FRANCISCO, Aug. 22 -- A personalized therapeutic breast cancer vaccine was safe and well tolerated when tested in 18 women with metastatic disease overexpressing HER-2, found researchers here.
In the phase 1 trial of the vaccine, lapuleucel-T (APC8024), there were tumor responses in one woman and disease stabilization in three, John W. Park, M.D., of the University of California San Francisco, and colleagues, reported in the Aug. 20 issue of the Journal of Clinical Oncology.
Lymphocyte proliferation and interferon gamma enzyme-linked immunospot assay detected "significant cellular immune responses specific for the immunizing antigen and HER-2 sequences were induced after treatment," they wrote.
All patients were required to have received prior treatment with trastuzumab (Herceptin), the drug that has shown a survival advantage for women with HER-2-positive tumors. Trastuzumab must have been discontinued six weeks before enrollment.
The autologous vaccine consists of peripheral blood mononuclear cells, which are obtained from patients by leukapheresis and activated in vitro with a recombinant fusion protein (BA7072 linked to GM-CSF). These activated cells including antigen-presenting cells are then re-infused intravenously into the patients.
The treatment regimen consisted of three biweekly leukaphereses and infusions. Each infusion was prepared from a single leukapheresis. The infusions were administered in escalated cell dose levels: 2 X 108, 1 X109, and 5 X 109.
Patients underwent physical examination and laboratory testing at baseline, and at two, four, eight, and 12 weeks, and at eight-week intervals thereafter.
