The Food and Drug Administration (FDA) has approved Zevalin™ for the treatment of low-grade Non-Hodgkin’s lymphoma that has stopped responding to standard therapies. The approval indicates that Zevalin™ must be used in combination with Rituxan™.
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 very specific function in aiding 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. While NHL is categorized by the type of lymphocyte it involves, it is also further defined by the rate at which the cancer grows, based on the appearance of the cells under a microscope. High-grade or aggressive NHL is the fastest growing and low-grade or indolent lymphoma is the slowest growing.
Zevalin™ (90Yttrium-2b8 ibritumomab tiuxetan) is a novel biological agent that has demonstrated significant anti-cancer responses in the treatment of B-cell NHL. Zevalin™ is a type of treatment that uses two separate strategies to target and kill cancer cells. It is comprised of ibritumomab, which is a monoclonal antibody that is attached by the molecule tiuxetan to a radioactive substance called Yttrium 90 (90Y). The monoclonal antibody portion of Zevalin™ binds to proteins found only on the surface of B-cells. Once Zevalin™ binds to the cancer cells, the immune system is stimulated to attack the cancer cells, while the attached 90Y destroys these cells by spontaneous emission of its radiation. This type of treatment not only provides two separate treatment strategies, but also allows the delivery of greater amounts of radiation to the cancer cells compared with external radiation therapy, while minimizing radiation exposure to normal cells.
Rituxan™ is a monoclonal antibody that also binds to B-cells and is currently approved for the treatment of low-grade NHL. Clinical studies have indicated that the combination of Zevalin™ and Rituxan™ appears safe and effective in the treatment of low-grade B-cell NHL.
The results of two large clinical studies have indicated that Zevalin™ plus Rituxan™ is safe and effective in the treatment of low-grade NHL. In the first trial, 54 patients with low-grade B-cell NHL who were no longer responding to chemotherapy or Rituxan™ received Zevalin™ plus Rituxan™. The overall anti-cancer response rate was 74%. In the second trial, 143 patients with low-grade B-cell NHL who were not responding to chemotherapy but had not yet received Rituxan™ received the combination of Zevalin™ plus Rituxan™. The overall anti-cancer response rate was 80%. However, further studies are needed to determine when in the course of the disease and in what treatment combination Zevalin™ will prove most effective in patients with low-grade B-cell NHL.
Patients with low-grade NHL who have stopped responding to standard therapies may wish to speak with their physician about the risks and benefits of treatment with Zevalin™ or the participation in a clinical trial further evaluating Zevalin™. Two sources of information regarding ongoing clinical trials include comprehensive, easy-to-use listing services provided by the National Cancer Institute (www.cancer.gov) and www.eCancerTrials.com eCancerTrials.com also provides personalized clinical trial searches on behalf of patients.