Anti-CD200 Antibody
Alexion's most advanced oncology program is focused on the development of an anti-CD200
antibody for the treatment of several different hematologic malignancies and solid-tumors.
Alexion is developing its CD200 antibody as a potential treatment for patients with
B-chronic lymphocytic leukemia, or B-CLL and other
blood cell cancers such as multiple myeloma. B-CLL is the second most common type
of leukemia in adults, often occurring during or after middle age, and affecting
approximately twice as many men as women. It was estimated that 15,000 people would
be diagnosed with CLL in 2008 in the United States alone.45,46
The anti-CD200 antibody binds to CD200, a protein that is found on the B cells of
patients with B-CLL.47,48,48 The interaction of CD200 on tumor cells
with its receptor (CD200R) may inhibit the body's immune response to tumors.47-49
CD200-mediated immunosuppression could allow for tumor growth and survival in several
types of cancers that over-express CD200, including ovarian, prostate, breast and
colon cancers as well as in multiple myeloma and CLL.
Laboratory data have demonstrated that CD200 on tumor cells protected the tumor from
the immune system and that an anti-CD200 antibody reduced tumor growth.47
The anti-tumor activity of the anti-CD200 antibody was reported in the January 2008
issue of the Journal of Immunology.50 Alexion is currently enrolling
a clinical study of its anti-CD200 antibody in patients with B-chronic lymphocytic
leukemia. In 2009, Alexion announced that it plans to expand the anti-CD200
clinical program to include multiple myeloma patients. The company is also considering
potential evaluation in patients with other CD200-expressing tumors, including melanoma
and ovarian cancer.