A Phase II Study Using Fostamatinib to Treat Post-Hematopoietic Stem Cell Transplant Immune-Mediated Cytopenias
Background: People who have a blood stem cell transplant can sometimes develop cytopenia. This means that their levels of one or more types of blood cell, such as the red cells or platelets, are lower than they should be. This can occur because a person s immune system might attack these cells after a stem cell transplant. Cytopenia can lead to anemia, severe bleeding, infections, and other problems. Treatments are needed to help keep blood cell levels stable after blood stem cell transplant.
Objective: To test a study drug (fostamatinib) in people who have cytopenia after a blood stem cell transplant.
Eligibility: People aged 18 to 75 years who have cytopenia after a blood stem cell transplant.
Design: Participants will be screened. They will have a physical exam. They will have blood, urine, and stool tests. Fostamatinib is an oral tablet taken by mouth. Participants will take the pills 2 times a day for 12 weeks. Participants will have a medical assessment every 2 weeks; their vital signs will be checked, and they will have blood and stool tests. Participants must come to the NIH clinic for these visits in weeks 4 and 12. Other visits may be done by telephone or telehealth; the blood and stool tests can be sent to the researchers from a local lab. After 4 weeks, some participants may begin taking a higher dose of the drug. Participants will return for a final medical assessment 2 weeks after they finish taking the drug. Participants who complete this study and show evidence that fostamatinib has increased their blood cell counts may enroll in an extension study to continue taking fostamatinib.
• Ages 18-75 years inclusive
• Ability to comprehend the investigational nature of the study and provide informed consent
• Female patients of reproductive potential agree to avoid pregnancy through abstinence or the use two forms of highly effective birth control during and for 1 month after the last study treatment and agree not to donate eggs during this time
• male patients of reproductive potential agree to avoid pregnancy of a partner through abstinence or the use two forms of highly effective birth control during and for 1 month after the last study treatment and agree not to donate sperm during this time.
• Diagnosis of an immune mediated cytopenia (anemia and/or thrombocytopenia) in a patient that either:
‣ Failed or relapsed after at least one line of therapy including steroids, IVIG, TPO mimetics, rituximab, azathioprine, cyclophosphamide, cyclosporine, tacrolimus, danazol, vincristine, ESA or splenectomy
⁃ Or remains transfusion dependent (\>=1 transfusion(s)/2 weeks)
⁃ Or is steroid dependent
• Subjects are \>=60 days post-allogeneic transplant with:
‣ Thrombocytopenia, defined as average platelets count \<30 x 10\^9/L for 3 consecutive available readings at least 2 weeks apart, after other cell lines have engrafted, with no counts \>40 x 10\^9/L unless from rescue transfusions. Subjects failed at least one line of therapy outlined above with a clinical diagnosis of immune mediated thrombocytopenia.
⁃ Anemia, transfusion dependent, or defined as hemoglobin \<=9 g/dL for 3 consecutive available readings at least 2 weeks apart, after other cell lines have engrafted OR if hemoglobin 9-10 g/dL, subject must have symptomatic anemia or ongoing treatment for immune hemolytic anemia that have failed at least one line of therapy outlined above. Symptomatic anemia is defined as anemia with fatigue, weakness, shortness of breath, palpitations/fast heartbeat, lightheadedness, and/or chest pain, and these symptoms are attributed to anemia. Laboratory evaluation are recommended but not required for the diagnosis, such as a positive DAT, low haptoglobin \<lower limit of normal (LLN), indirect bilirubin \> upper limit of normal (ULN), or lactate dehydrogenase (LDH) \>ULN.
• Subjects must test negative for HIV, HBV, and HCV by standard serologic tests within the previous six months
• Subjects on other standard of care therapeutic regimens for GVHD or cytopenias should be on a stable dose of medication (no change \>=25%) for at least 15 days prior to enrollment.
• Patients with a history of hypertension should be maintained on a stable antihypertensive regimen and with controlled blood pressure (Systolic blood pressure \< 140 mmHg and diastolic blood pressure \<90 mmHg) for at least one week prior to enrollment.
• Peripheral blood or bone marrow T-cell chimerism \>=50% donor cells
• Immune mediated anemia in subjects with auto or alloantibodies identified due to ABO or non-ABO mismatch transplant, or thrombocytopenia due to identified HLA/HPA antibody. Other causes of immune mediated cytopenias include clinically diagnosed (with or without serologic confirmation) idiopathic thrombocytopenic purpura or autoimmune hemolytic anemia. Subjects with cytopenias attributable to GVHD will be included. Subjects with idiopathic immune mediated cytopenias can also be included. Subjects with evidence for graft rejection per the investigator's opinion ARE NOT eligible for treatment.
∙ Steroid dependence is defined as inability to tolerate a corticosteroid taper after demonstrating a response to an initial corticosteroid dose (typically 1-2 mg/kg/day). Patients will meet our definition of steroid dependence if their cytopenias relapse or progress before achieving a 50% decrease in the initial corticosteroid dose and/or are unable to have their steroid dose tapered to a dose of less than 20 mg/day of prednisone.