A Randomized Trial of Recombinant Humanized Anti-IL-2 Receptor Antibody (Daclizumab) Versus Antithymocyte Globulin (ATG) to Treat the Cytopenia of Myelodysplastic Syndrome (MDS)
Many bone marrow failure syndromes in humans are now recognized to result from immunological
mechanisms. These diseases include aplastic anemia, pure red cell aplasia, and some types of
myelodysplasia. Patients with these conditions, who may suffer variable degrees of anemia,
leukocytopenia, and thrombocytopenia, alone or in combination, have been shown to respond to
a wide variety of immunosuppressive agents, ranging from corticosteroids to cyclosporine
(CSA) and antithymocyte globulin (ATG), however, nonresponse and relapse continues to be a
problem. Why some patients do not respond initially or others respond and then relapse is
unclear. Autoreactive T cells may be resistant to the effect of ATG/CsA (nonresponders),
while in others residual autoreactive T cells expand post-treatment leading to hematopoietic
stem cell destruction and recurrent pancytopenia (relapse). Therefore, novel, less toxic
immunosuppressive regimens that increase response rates and hematologic recovery and
decrease relapse rates are needed.
One such novel therapy, Daclizumab, a humanized anti-interleukin-2 receptor (lL-2R)
monoclonal antibody (mAb), acts against activated lymphocytes, thus sharing an important
mechanism of action with ATG. The mAb is much less toxic than ATG and may be administered
to outpatients at relatively infrequent intervals (every 2 weeks). Treatments with ATG
alone and CsA alone have demonstrated varying degrees of success in alleviating the
cytopenia of MDS. Our experience suggests that ATG rather than CSA is the more effective
agent inducing hematological responses in susceptible MDS patients and that certain
variables including the patient's age, whether or not they were HLA DR15, and days of red
cell transfusion dependence prior to treatment were predictive of response.
We therefore propose this randomized phase II study to evaluate and compare a new
immunosuppressive therapy, Daclizumab, with antithymocyte globulin (ATG) to treat the
cytopenia of MDS in a population of subjects with intermediate or high predicted probability
of response.
Interventional
Endpoint Classification: Safety/Efficacy Study, Primary Purpose: Treatment
United States: Federal Government
040026
NCT00072969
November 2003
August 2005
Name | Location |
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National Heart, Lung and Blood Institute (NHLBI) | Bethesda, Maryland 20892 |