Zevalin® (Yttrium-90 [(90)Y] ibritumomab tiuxetan) appears to provide effective, long-term anticancer responses for patients with follicular lymphoma whose cancer has progressed following an autologous stem cell transplant. The details of this small study appeared in an early online publication of Leukemia-Lymphoma of July 15, 2008.
Non-Hodgkin’s 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. The main cells in the lymph system are lymphocytes, of which there are two types: B and T-cells. Each of these cells has a specific function in helping the body to fight infection.
NHL is characterized by the excessive accumulation of atypical (cancerous) lymphocytes. These lymphocytes can crowd the lymph system and suppress the formation and function of other immune and blood cells. NHL is categorized by the type of lymphocyte it involves and by the rate at which the cancer grows. Follicular lymphoma tends to be slow-growing and is referred to as an indolent type of NHL. It is the most common type of NHL.
High-dose chemotherapy generally kills more cancer cells than moderate doses, but this approach also results in more side effects. One particular side effect is damage to the blood-producing hematopoietic stem cells; these immature blood cells are produced in the bone marrow and mature into red blood cells (which carry oxygen to tissues), white blood cells (which fight infection), and platelets (which aid in blood clotting). To restore stem cells that are depleted by high-dose chemotherapy, patients may undergo an autologous stem cell transplant. An autologous stem cell transplant involves collection of the patient’s own stem cells prior to chemotherapy; these cells are then reinfused after chemotherapy.
Patients with follicular NHL whose cancer progresses following an autologous stem cell transplant have limited effective treatment options. Researchers have been investigating novel therapeutic strategies for NHL; particularly, approaches that reduce side effects and maintain quality of life.
Radioimmunotherapy is a novel approach that involves treatment with a radioactive substance linked to an antibody. The antibody attaches to cancer cells when injected into the body. By delivering the radiation directly to the cancer, a larger amount of normal tissue is spared from radiation and there are fewer side effects. Zevalin, a radioimmunotherapeutic agent, contains an antibody portion that attaches to a certain protein found only on the surface of B-lymphocytes, or cancerous B-cells found in many forms of NHL. The radioactivity that is spontaneously emitted targets the B-cell and destroys it.
Results from several clinical trials have demonstrated that Zevalin is effective in the treatment of NHL. However, physicians must refer patients to radiologists or a nuclear medicine specialist for treatment with Zevalin. There is speculation that the referral process may contribute to low use of Zevalin among patients who might derive great benefit from its effects.
Researchers from France recently conducted a clinical trial to evaluate Zevalin for the treatment of eight patients with follicular NHL whose cancer had progressed following an autologous stem cell transplant. Patients received nine courses of treatment with Zevalin.
- Five patients achieved a complete disappearance of detectable cancer.
- Two patients achieved a partial regression of their cancer.
- One patient achieved stabilization of cancer.
- At one year seven patients had survived and one had died from infection.
- Other than one patient suffering from low blood cell levels (the patient who had died), Zevalin appeared to be well tolerated.
The researchers concluded: “Standard-dose [radioimmunotherapy] seems feasible and potentially effective after [autologous stem cell transplantation] in correctly selected patients with follicular lymphoma.”
Patients with follicular lymphoma whose cancer has progressed despite prior therapies may with to speak with their physician regarding their individual risks and benefits of treatment with Zevalin.
Reference: Peyrade F, Trilby C, Stama B, et al. Radioimmunotherapy in relapsed follicular lymphoma previously treated by autologous bone marrow transplantation: a report of 8 new cases and a literature review. Leukemia-Lymphoma [early online publication]. July 25, 2008.
Related News:Zevalin® Significantly Improves Progression-free Survival in Follicular NHL (12/13/2007)
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