Key words Bispecific antibody
Phase I study
T cell activation
Springer Online Journal Archives 1860-2000
Abstract A bispecific antibody directed to T and B cells (CD3×CD19 bsAb) was daily infused intravenously in escalating doses from 10 μg up to 5 mg in three patients with chemotherapy-resistant non-Hodgkin lymphoma; in this way we aimed to activate T cells to kill the malignant B cells. Only limited toxicity was observed, consisting of moderate fever preceded by chills or shivers and mild thrombocytopenia. No human anti-(mouse Ig) antibodies were found. Pharmacokinetics showed a t 1/2 of 10.5 h with peak levels of 200–300 ng/ml after infusion of 2.5 mg bsAb. bsAb in serum was functionally active in vitro. After bsAb infusion a rise in serum tumour necrosis factor α was observed, accompanied by an increase in soluble CD8 and to some extent in soluble interleukin-2 receptor (IL-2R), but not in interferon γ, IL-4 or soluble CD4. No evidence was found for monocyte activation (no increases in IL-6, IL-8 or IL-1β in serum). No gross changes in histology or number of IL-2R+, CD4+ or CD8+ cells were found in the lymph nodes after therapy, but one patient showed activated CD8+ T cells within the tumour nodules. In conclusion, after intravenously administered CD3×CD19 bsAb only moderate toxicity was found, probably due to CD8+ T cell activation and cytokine release, without CD4+ T cell activation.
Type of Medium: