Immune T cells can transfer and boost anti-breast cancer immunity

ABSTRACTThis proof-of-concept study investigates the immune effects in metastatic breast cancer (MBC) patients after “vaccination” with activated T cells (ATC) armed with anti-CD3 x anti-HER2 bispecific antibody (HER2 BATs) followed by immune consolidation with immune ATC “boost” after high dose chemotherapy (HDC) and autologous stem cell transplant (SCT). Approximately 2 weeks after completion of vaccination portion of the study, immune T cells were obtained by leukopheresis, activated and expanded ex vivo and re-infused after HDC and SCT to test the hypothesis that transfer of immune unarmed ATC would accelerate reconstitution of anti-tumor activity after SCT. Eight metastatic breast cancer (MBC) patients received 8 infusions of HER2 BATs, low dose IL-2, and GM-CSF in the first part of the protocol to induce adaptive cellular and humoral responses. In the “boost” portion of the protocol, 6 of 8 patients received multiple infusions of unarmed ATC post SCT. There were no dose-limiting toxicities or delays...