A new monoclonal antibody that targets B cells could prove to be as effective as rituximab (Rituxan) for treating non-Hodgkin lymphoma (NHL), as well as other lymphomas and leukemias, Duke University researchers are reporting. Many lymphomas are of B cell origin.
In a study published October 10 in the early online edition of the Proceedings of the National Academy of Sciences, Dr. Thomas Tedder and colleagues report that, in mouse models, use of monoclonal antibodies (mAbs) that target a protein on the surface of B cells called CD19 was highly effective at eliminating B cells - both mature cells as well as precursor and immature B cells. Rituximab, which targets the CD20 protein on B cells, only aids in the depletion of mature B cells. It is effective in approximately half of NHL patients.
In addition, use of the CD19-targeted mAbs in 10 mice with malignant B cell lymphomas eliminated the presence of tumor cells in the circulation and tissue for up to 7 weeks, the study found.
While some earlier efforts were made to target CD19, they were limited by various shortcomings. Since those experiments, the mechanism by which antibodies to proteins such as CD20 and CD19 aid the immune system in killing cells is better understood. "Now we know the mechanism, we know how to choose the patients better, we know how to choose better antibodies, and we've done the pharmacokinetics and dosing," says Dr. Tedder.
Planning is underway to test the CD19-targeted mAbs in early clinical trials through a company Dr. Tedder founded, and which was recently purchased by the biotechnology company MedImmune.
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