Phase I Study of Anti-CD3 x Anti-Her2 Bispecific Antibody in Metastatic Castrate Resistant Prostate Cancer Patients

摘要

Background. New nontoxic targeted approaches are needed for patients with castrate resistant prostate cancer (CRPC). Our preclinical studies show that activated T cells (ATC) armed with anti-CD3 x anti-Her2 bispecific antibody (Her2Bi) kill prostate cancer cells lines, induce a Th_1 cytokine pattern upon engagement of tumor cells, prevent the development of prostate tumors, and retard tumor growth in immunodeficient mice. These studies provided strong rationale for our phase I dose-escalation pilot study to test ATG armed with Her2Bi (aATC) for safety in men with CRPC. Methods. Seven of 8 men with CRPC were evaluable after receiving two infusions per week for 4 weeks. The men received 2.5, 5 or 10 x 109 aATC per infusion with low dose interleukin-2 and granulocyte-macrophage colony stimulating factor. Results. There were no dose limiting toxicities, and there was 1 partial responder and 3 of 7 patients had significant decreases in their PSA levels and pain scores. Immune evaluations of peripheral blood mononudear cells in 2 patients before and after immunotherapy showed increases in IFN-gamma EliSpot responses and Th_1 serum cytokines. Conclusions. These results provide a strong rationale for developing phase II trials to determine whether aATC are effective for treating CRPC.