Residual Disease Test for Leukemia

A new test is designed to detect very low levels of disease, known as minimal residual disease (MRD), in patients with B-cell chronic, lymphocytic leukemia (B-CLL).

MRD refers to undetectable disease in the blood and bone marrow of B-CLL patients in complete remission. According to a study in the May 1, 2005, issue of the Journal of Clinical Oncology, the elimination of disease to this extremely low level may improve the overall survival and treatment-free survival of B-CLL patients. In the study, 84% of patients with no detectable CLL cells after receiving the drug Campath (alemtuzumab) had survived for at least five years, while 20% of these same patients had previously failed to respond or had relapsed after receiving chemotherapy. CLL patients who relapse from or are refractory to chemotherapy have the poorest prognosis, with a median survival of 10 months.

The new test is designed to complement Campath treatment, which is marketed by Schering AG (Berlin, Germany) under a license from Genzyme. Campath is a humanized monoclonal antibody approved for treating B-CLL. It is the first product that has proven to be effective in patients who have failed both alkylating agents and fludarabine phosphate treatment.

Genzyme's four-color flow cytometry test can detect the presence of residual disease in the blood and marrow at far more-sensitive levels than the light microscope or a bone marrow biopsy, traditionally used to detect leukemia. In fact, the new test can identify as few as one single CLL cell in 10,000 white blood cells. The test is based on a protocol developed by investigators at Leeds Teaching Hospitals (UK).

"Genzyme Genetics is as the forefront of a new era of personalized medicine that is intended to provide physicians with the critical information they need to make the best treatment decisions with their patients,” remarked Mara Aspinall, president of Genzyme Genetics, the business of Genzyme Corp. focused on diagnostic testing for cancer and reproductive medicine. "This new test will help oncologists monitor response to therapy in their CLL patients using a highly sensitive, noninvasive technology.”




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