View clinical trials related to Pure Red Cell Aplasia.
Filter by:Diamond Blackfan anemia (DBA) is a rare inherited pure red cell aplasia. The two main non-stem cell transplant therapeutic options are corticosteroids and red blood cell (RBC) transfusions. About 80% of DBA patients initially respond to corticosteroids, however, half of the patients cannot continue due to side effects or loss of response. These patients are then typically dependent on RBC transfusions throughout life. Each of these treatments is fraught with many side effects and significant morbidity and mortality are potential consequences of hematopoietic stem cell transplantation (SCT). The majority of individuals with DBA have mutations in genes encoding structural proteins of the small or large ribosomal subunit leading to deficiency of the particular ribosomal protein (RP). Using the RP deficient zebrafish embryo model, high throughput drug screens have demonstrated a strong hematologic response to several calmodulin inhibitors. One of these chemicals is trifluoperazine (TFP). TFP treatment of a mouse model of DBA also increased the red blood cell count and the hemoglobin (Hb) levels in the mice. TFP is a FDA-approved typical antipsychotic agent that has been available since 1958 with a well-known safety profile. In the United States, TFP is approved for the short-term treatment of generalized non-psychotic anxiety; treatment or prevention of nausea and vomiting of various causes; and, management of psychotic disorders. This study aims to determine the safety/tolerability of TFP in adult subjects with DBA. TFP's expected dose-limiting toxicity is primarily neurologic (extrapyramidal) when used long-term at typical anti-psychotic doses (range 10-50 mg daily). Non-neurologic adverse effects in subjects with DBA have not been investigated. We will perform a dose escalation study to define the safety and tolerability of lower doses of this agent in subjects with DBA. To mitigate the potential risks of administering TFP to this new population, we will (1) start dosing at dose levels well below those prescribed for psychosis, (2) dose escalate to a maximum of 10 mg daily (the lowest dose typically prescribed for psychosis), and (3) perform weekly safety monitoring. Given the positive signal in DBA animal models and the 60-year clinical experience with higher doses of TFP, this drug warrants a trial in humans to assess tolerability in DBA.
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.