Bexxar Effective in Advanced Follicular Non-Hodgkin Lymphoma
According to results recently presented at the 45th annual meeting of the American Society of Hematology (ASH), Bexxar® (tositumomab and Iodine I 131 tositumomab) produces long-term anti-cancer responses in patients with advanced follicular non-Hodgkin lymphoma.
Follicular lymphoma is a type of non-Hodgkin lymphoma (NHL), which 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. Follicular lymphoma is a low-grade or indolent lymphoma that is slow growing.
Due to the side effects associated with chemotherapy and radiation, researchers have been investigating novel therapeutic strategies including radioimmunotherapy. Radioimmunotherapy involves treatment with a radioactive substance that is linked to an antibody that will attach to cancer cells when injected into the body. By delivering the radiation directly to the cancer, more normal tissue is spared from radiation and there are fewer side effects.
Bexxar is a new radioimmunotherapeutic agent that has recently been approved by the U.S. Food and Drug Administration (FDA) for the treatment of patients with CD20-positive, follicular NHL, whose disease has stopped responding to Rituxan® or has recurred following chemotherapy. Bexxar is an antibody with radioactive iodine 131 attached. The monoclonal antibody portion of the drug attaches to a protein (CD20) found only on the surface of B-lymphocytes, such as cancerous B-cells found in many forms of NHL. The radioactivity that is spontaneously emitted targets the B-cell and destroys it.
The results presented at the 2003 ASH meeting included five studies evaluating Bexxar in the treatment of advanced follicular lymphoma. The entire patient population included 250 patients who had received several prior therapies. Some patients had stopped responding to the monoclonal antibody agent Rituxan, and some patients had never received Rituxan. The overall anti-cancer response rate following treatment with Bexxar was 56 percent, with a complete disappearance of detectable cancer occurring in 30 percent of patients.
Progression-free survival for at least one year (durable complete response) occurred in 28 percent of patients who had stopped responding to Rituxan, and 23 percent of patients who had never been treated with Rituxan. With an average follow-up of approximately 4.6 years, 75 percent of patients who achieved a durable complete response remained free of detectable cancer. Among patients who had never been treated with Rituxan, the average duration of anti-cancer response was nearly five years. Among patients who experienced a cancer recurrence following Rituxan, the average duration of anti-cancer response had not been reached at nearly four years.
The researchers concluded that Bexxar appears to provide high rates of durable complete responses in patients with follicular lymphoma who had received previous therapy. In addition, previous treatment with Rituxan did not appear to affect the effectiveness of Bexxar in the treatment of follicular lymphoma. Patients who had recurrent follicular lymphoma may wish to speak with their physician about the risks and benefits of treatment with Bexxar.
Follicular lymphoma is a type of non-Hodgkin lymphoma (NHL), which 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. Follicular lymphoma is a low-grade or indolent lymphoma that is slow growing.
Due to the side effects associated with chemotherapy and radiation, researchers have been investigating novel therapeutic strategies including radioimmunotherapy. Radioimmunotherapy involves treatment with a radioactive substance that is linked to an antibody that will attach to cancer cells when injected into the body. By delivering the radiation directly to the cancer, more normal tissue is spared from radiation and there are fewer side effects.
Bexxar is a new radioimmunotherapeutic agent that has recently been approved by the U.S. Food and Drug Administration (FDA) for the treatment of patients with CD20-positive, follicular NHL, whose disease has stopped responding to Rituxan® or has recurred following chemotherapy. Bexxar is an antibody with radioactive iodine 131 attached. The monoclonal antibody portion of the drug attaches to a protein (CD20) found only on the surface of B-lymphocytes, such as cancerous B-cells found in many forms of NHL. The radioactivity that is spontaneously emitted targets the B-cell and destroys it.
The results presented at the 2003 ASH meeting included five studies evaluating Bexxar in the treatment of advanced follicular lymphoma. The entire patient population included 250 patients who had received several prior therapies. Some patients had stopped responding to the monoclonal antibody agent Rituxan, and some patients had never received Rituxan. The overall anti-cancer response rate following treatment with Bexxar was 56 percent, with a complete disappearance of detectable cancer occurring in 30 percent of patients.
Progression-free survival for at least one year (durable complete response) occurred in 28 percent of patients who had stopped responding to Rituxan, and 23 percent of patients who had never been treated with Rituxan. With an average follow-up of approximately 4.6 years, 75 percent of patients who achieved a durable complete response remained free of detectable cancer. Among patients who had never been treated with Rituxan, the average duration of anti-cancer response was nearly five years. Among patients who experienced a cancer recurrence following Rituxan, the average duration of anti-cancer response had not been reached at nearly four years.
The researchers concluded that Bexxar appears to provide high rates of durable complete responses in patients with follicular lymphoma who had received previous therapy. In addition, previous treatment with Rituxan did not appear to affect the effectiveness of Bexxar in the treatment of follicular lymphoma. Patients who had recurrent follicular lymphoma may wish to speak with their physician about the risks and benefits of treatment with Bexxar.
posted by TM at 8:33 AM
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