Chronic lymphocytic leukemia (CLL) is a type of cancer in which the bone marrow makes too many of a certain type of white blood cell, called lymphocytes. Lymphocytes consist of either B cells, T cells or Natural killer cells. B-CLL is an incurable chronic disease caused by an expansion of mature B-lymphocytes. Patients with B-CLL can be subdivided about equally to those with stable disease and to those progressing to aggressive disease. The stable form of CLL does not generally affect patient survival while those with more aggressive forms of the disease have typical survivals of 1 to 7 years. B-CLL is one of the most commonly diagnosed leukemias and accounts for approxmately 25% of all leukemias. Though mainly considered a disease of the elderly, approximately one third of patients are less than 60 years of age at diagnosis. B-CLL is currently managed with steroids until the disease progresses, at which time chemotherapy is initiated. There are currently no known cures for this disease with possible exception of experimental stem cell transplant. Current therapies include the chemotherapeutic agents such as fludarabine or cyclophosphamide, radiation, or combination therapies such as fludarabine, cyclophosphamide, and anti-CD20.

Alexion's approach to B-CLL

Alexion researchers have discovered that B-CLL cells, as well as other types of tumors, have an upregulated protein on the surface of the cell called CD200. This protein is a potent immunosuppressant and is involved in shifting the immune system to a less inflammatory state and may be upregulated by the cancer cell as its the tumor attempts to evade the immune system. Alexion is currently testing a humanized antibody therapeutic that blocks CD200 and therefore is designed to prevent the tumor from suppressing the patient's immune system. Alexion plans to continue evaluation of this therapeutic in preclinical studies.

For more information on CLL please see the National Cancer Institute (NCI) at http://cancer.gov.