Radioimmunotherapy for B-Cell Non-Hodgkin Lymphomas
Radioimmunotherapy for B-Cell Non-Hodgkin Lymphomas
CD20 is not the only cell surface marker relatively specific for B cells and B-cell malignancies. CD22 is another rational target for RIT, and epratuzumab is a humanized monoclonal antibody directed to CD22. This agent, labeled with Y, is currently being investigated in a number of clinical trials. Morschhauser et al reported the results of a phase I/II study of a fractionated approach with Y-epratuzumab in NHL, with an OR rate of 78% and a CR rate of 56%.
Y-epratuzumab is currently being used in a phase I/II trial for patients with aggressive or transformed B-cell NHL. Patients are treated with unlabeled veltuzumab (anti-CD20) in 4 weekly infusions, with 2 infusions of the labeled epratuzumab given the third and fourth weeks. An early interim analysis has recently been completed, with promising results to be presented soon. This combination is also currently being investigated in a phase II study as sole treatment for newly diagnosed follicular lymphoma.
CD19, CD45, CD74, and several other targets have been sources for development of other radiolabeled monoclonal antibodies for B-cell and T-cell lymphomas. Other novel approaches include the use of haptens or bispecific antibodies for pretargeting.
Novel RIT Agents for B-Cell NHL
CD20 is not the only cell surface marker relatively specific for B cells and B-cell malignancies. CD22 is another rational target for RIT, and epratuzumab is a humanized monoclonal antibody directed to CD22. This agent, labeled with Y, is currently being investigated in a number of clinical trials. Morschhauser et al reported the results of a phase I/II study of a fractionated approach with Y-epratuzumab in NHL, with an OR rate of 78% and a CR rate of 56%.
Y-epratuzumab is currently being used in a phase I/II trial for patients with aggressive or transformed B-cell NHL. Patients are treated with unlabeled veltuzumab (anti-CD20) in 4 weekly infusions, with 2 infusions of the labeled epratuzumab given the third and fourth weeks. An early interim analysis has recently been completed, with promising results to be presented soon. This combination is also currently being investigated in a phase II study as sole treatment for newly diagnosed follicular lymphoma.
CD19, CD45, CD74, and several other targets have been sources for development of other radiolabeled monoclonal antibodies for B-cell and T-cell lymphomas. Other novel approaches include the use of haptens or bispecific antibodies for pretargeting.
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