Sirolimus (Rapamune ) for Relapse Prevention in People With Severe Aplastic Anemia Responsive to Immunosuppressive Therapy

Sirolimus will be started on day 1 for subjects in the Sirolimus arm. A baseline CBC will be obtained within one week of randomization, or on Day 0. Thereafter, CBC will be monitored on a weekly basis for subjects in both arms. In the event of relapse (see definition of outcomes Section 6.7), the patient shall return to the NIH CRC for evaluation to include bone marrow biopsy and aspirate to exclude clonal evolution to MDS. Assessment will include (i) flow cytometry phenotyping of peripheral blood mononuclear cells for regulatory T-cells (Tregs, e.g. CD4+ CD25high FOXP3+) and regulatory dendritic cells (DCregs) and (ii) proteomics assay (research labs).