Abstract
BACKGROUND: Catumaxomab is an antibody that binds with one arm epithelial cell adhesion molecule (EpCAM) positive tumors and with the other arm CD3+ T cells. Intravenous application of therapeutic antibodies may result in intravascular cytokine release. AIM: In this pilot trial we assessed whether cytokine release can be controlled by ex vivo cell opsonization and cytokine wash-out before administration of catumaxomab, preserving its anti-cancer activity. In addition, preliminary data on safety of and clinical response to catumaxomab coated autologous immune cells were acquired. METHODS: Peripheral blood mononuclear cells (PBMNC) of four patients with recurrent head and neck carcinoma were collected by leukapheresis, incubated ex vivo with catumaxomab for 24 h and cleared from released cytokines. Each patient received an escalated number of antibody-coated PBMNC equivalent to 1 x 10(4), 1 x 10(5), 1 x 10(6) and 1 x 10(7) CD3(+) cells/kgBW intravenously at bi-weekly intervals. RESULTS: After opsonization, PBMNC released substantial amounts of interferon gamma (IFNgamma) and tumor necrosis factor alpha (TNFalpha) in vitro, which were removed before administration. Catumaxomab up-regulated CD25, CD69, and CD83 on PBMNC, and catumaxomab loaded PBMNC released IFNgamma and granzyme B when coincubated with EpCAM(+) BHY cells, suggesting cell activation and target directed biological activity. During the study period, one patient died of aspiration pneumonia and one patient needed a tracheotomy. Treatment related adverse events (AE) occurred at the highest cell dose in two patients, whereas 1 x 10(6) loaded CD3(+) cells/kgBW were well tolerated by all patients. One patient showed stable disease for 6 months and one patient is in complete remission for 27 months. CONCLUSION: Ex vivo opsonization of PBMNC with catumaxomab provided biologically active, tumor targeting cells. Extracorporeal PBMNC coating may be an option to control intravascular cytokine release induced by therapeutic antibodies.