A Study to Determine Whether Therapy With Daclizumab Will Benefit Patients With Bone Marrow Failure

Study Summary

Participants in this study are suffering from rare and serious blood disorders. In aplastic anemia, the bone marrow stops producing red blood cells, platelets, and white blood cells. In pure red cell aplasia, the bone marrow stops producing red cells, and in amegakaryocytic thrombocytopenic purpura, the bone marrow stops producing platelets. Current treatment approaches for these disorders include bone marrow transplant and/or immunosuppression. However, bone marrow transplant is not always possible, and immunosuppression has serious side effects. This study will investigate whether daclizumab can be used to treat these disorders. Daclizumab is a genetically engineered human antibody that blocks the interleukin-2 receptor on immune cells. It has been used successfully in many transplant patients to reduce the rate of organ rejection. Participants will undergo a complete history and physical examination. A bone marrow aspiration and biopsy will be performed to confirm the type of bone marrow failure. About 5 tablespoons of blood will be drawn for baseline tests and research purposes. Daclizumab will be administered every 2 weeks by vein in a 30-minute infusion. The first dose will be given at NIH and the next four may be given at NIH or by the participant's primary hematologist. The treatment will last 8 weeks. Participants must also see their referring physician or NIH physicians every 2 weeks for blood counts. In the fourth and eighth weeks of the study and at the 3-month follow-up visit, 2 tablespoons of blood will be drawn at NIH. At the 1-month follow-up visit to NIH, 5 tablespoons of blood will be drawn and another bone marrow aspiration and biopsy performed. Risks from bone marrow aspiration and biopsy and blood draws include discomfort. Daclizumab is usually well-tolerated; however, it may weaken immunity against certain bacteria and viruses.

Primary Outcome

Number of participants with hematologic response at 3 months following Daclizumab, 1 mg/kg, will be given for a total of 5 intravenous infusions to subjects diagnosed with moderate aplastic anemia (MAA), pure red cell aplasia (PRCA), Diamond Blackfan anemia (DBA), relapse and refractory severe aplastic anemia (SAA) will receive treatment. A complete hematologic response will be considered an achievement of normal blood counts. A partial response was defined as any response less than a complete

Interventions

• DRUG Daclizumab