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Study Shows Long-Term Responses in Non-Hodgkin's Lymphoma Patients Treated With Ibritumomab Tiuxetan
"This study demonstrates that Zevalin offers patients an effective treatment option when previous therapies fail to achieve a durable response," said Russell Schilder, M.D., a medical oncologist at Philadelphia's Fox Chase Cancer Center. "Of note, 37 percent of the patients whose cancer responded long-term to Zevalin did not respond to their last therapy. Failure to respond to prior therapy does not appear to affect the ability to achieve a long-term response with Zevalin."
Patients whose cancer did not progress until after 12 months were considered to have a long-term response. A high proportion of these patients was older than 60 years and had received at least three prior therapies for their disease. Long-term responses were achieved in 37 percent of all patients and 39 percent of patients with follicular lymphoma. Such responses to Zevalin previously have been observed with ongoing follow-up, but until now had not been more fully characterized.
Long-term response (LTR) patients were defined as those experiencing a time to progression of their disease (TTP) of 12 or more months following treatment with Zevalin. Durable responses were achieved by 78 (37 percent) of the 211 patients in the study. Characteristics of these LTR patients were as follows: median age of 58 years (range, 24-80), 44 percent greater than 60 years old, 55 percent were male and 41 percent had lymphoma involvement in the bone marrow. Long-term response patients had a median of two prior regimens (range, one to 9): 59 percent had greater than two prior therapies, 33 percent had greater than three prior therapies and 37 percent had no response to their last prior therapy. Thirty percent of LTR patients had bulky disease (tumor size greater than five centimeters) and 83 percent had stage III/IV disease. The complete response rate (confirmed [CR] and unconfirmed [CRu]) among LTR patients was 65 percent, and the median DR and TTP were 29 and 31 months respectively, for CR/CRu patients.
At the time of analysis, the median duration of response (DR) and TTP for long-term response patients were 28 months (rang, 11-80) and 29 months (range, 12-82), respectively, with a media follow-up of 50 months (range, 13-82). Fifty-nine of the 78 LTR patients (76 percent) had follicular lymphoma. Compared to the overall LTR patient populations, LTR patients with follicular lymphoma had similar disease characteristics, DR, TTP and CR/CRu rates.
Non-Hodgkins Lymphoma (NHL) is a type of malignant disease that occurs within the lymphatic system. It originates from lymphocytes, a type of white blood cell, which can be divided into two main types, B lymphocytes and T lymphocytes (also called B-cells or T-cells). In adults, approximately 85 percent of NHL cases are of B-cell origin.
The overall prevalence of NHL in the United States is approximately 186,000, with an annual incidence of about 56,000. The overall prevalence of NHL in the European Union is about 230,000, with an annual incidence of about 70,000. This incidence is currently increasing in Europe by four percent per year.
Non-Hodgkins lymphomas can be divided clinically into two general categories: indolent lymphomas, which tend to grow relatively slowly, and aggressive lymphomas, which grow more rapidly. Indolent lymphomas include follicular NHL and were formerly commonly classified as "low-grade". Patients with indolent lymphomas often live for 10 years or more. Typically, the disease advances or transforms over time and because indolent lymphomas are usually not curable, these patients need new treatment alternatives. Indolent NHL represents around 45-50 percent of all non-Hodgkins lymphoma. The median age at diagnosis is 55-60 years.
NHL is slightly more common in men than women. Some risk factors include pre-existing infection (particularly HIV, Epstein-Barr virus and T-lymphotropic virus type 1), exposure to certain chemicals, previous organ transplant and family history of the disease.
Zevalin is the first commercially available radioimmunotherapy to treat forms of NHL. It combines the targeting power of an anti-CD20 monoclonal antibody with the radioisotope yttrium-90. It was approved by the United States Food and Drug Administration for use in the treatment of relapsed or refractory low-grade follicular or transformed NHL in February 2002. Schering AG received European Union approval for Zevalin for the treatment of adult patients with rituximab relapsed or refractory CD20-positive follicular B-cell non-Hodgkin's lymphoma (NHL) in January 2004.
Web site: https://www.foxchase.org/
Source: Fox Chase Cancer Center