Posted on January 24th, 2013 by
Radioimmunotherapy treatment with Zevalin® (ibritumomab tiuxetan) is effective in patients with non-Hodgkin’s lymphoma that is refractory to treatment with Rituxan® (rituximab), according to the results of a study published in the Journal of Clinical Oncology.
Understanding Zevalin and RIT
Zevalin therapy combines the monoclonal antibody Rituxan with Zevalin, which is comprised of an anti-CD20 monoclonal antibody and Yttrium-90, a radioisotope that delivers the radiation. This is referred to as radioimmunotherapy (RIT). When injected into the body, Zevalin attaches to a protein (CD20) found only on the surface of B-lymphcytes, such as cancerous B-cells found in many forms of non-Hodgkin’s lymphoma. The radioactivity that is spontaneously emitted targets the B-cell and destroys it. This approach protects healthy tissue.
Zevalin has been shown to be a highly effective treatment-and has the added benefit of being administered over a single short period of time. Zevalin is administered on an outpatient basis and the total duration of therapy is less than 10 days. Zevalin offers active patients the opportunity to spend less time undergoing treatment than more conventional chemotherapy.
Treating Relapsed Follicular Lymphoma
NHL is a form of cancer that begins in the cells of the lymph system. The lymph system includes the spleen, thymus, tonsils, bone marrow, lymph nodes, and circulating immune cells. Follicular lymphoma is a type of NHL that is considered to be a low-grade or indolent lymphoma, meaning it is a slow-growing subset of NHL. It involves a type of white blood cell known as a B cell.
Relapsed or refractory NHL refers to cancer that has returned or progressed following prior therapies or has stopped responding to standard therapies. Finding effective treatment options for relapsed or refractory NHL tends to be more difficult than initial therapy for the disease.
Rituxan is a targeted therapy commonly used in the treatment of relapsed or refractory NHL. Rituxan binds to a marker known as CD20 on the surface of B-cells. This binding prompts the immune system to destroy the cell, and may also have direct anticancer effects on the cell. Unfortunately NHL can grow refractory to Rituxan—and it stops responding to the treatment.
Zevalin and Rituximab-Refractory Follicular Lymphoma
Another approach to treating refractory NHL is RIT with Zevalin—which is an effective and fast way to target cancerous B-cells.
Researchers conducted a study to evaluate Zevalin in the treatment of Rituxan-refractory follicular NHL. The study included 57 patients who were refractory to Rituxan—meaning they experienced no objective response to Rituxan or they experienced disease progression within less than six months of treatment.
Patients were pretreated with Rituxan on days one and eight to deplete peripheral blood B cells and then received an intravenous dose of Zevalin on day eight—administered on an outpatient basis. The overall response rate was 74 percent, with 15 percent experiencing complete responses and 59 percent experiencing partial responses. The estimated time to progression was 6.8 months for all patients and 8.7 months for responders.
Adverse events were primarily blood related—35 percent experienced neutropenia, 9 percent experienced thrombocytopenia, and 4 percent experienced anemia.
The researchers concluded that Zevalin is effective in patients with follicular NHL refractory to Rituxan.
Witzig TE, Flinn IW, Gordon LI, et al. Treatment with Ibritumomab Tiuxetan Radioimmuotherapy in patients with rituximab-refractory follicular non-Hodgkin’s lymphoma. Journal of Clinical Oncology. 2002; 20(15): 3262-3269.
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