Sirolimus Combined With ATRA for the Treatment of Auto-Immune Anemia

Overview

Autoimmune anemia (AIA), including autoimmune hemolytic anemia (AIHA), EVENs' syndrome (ES), acquired pure red aplastic anemia (PRCA), is a kind of anemia disease mediated by autoimmunity, which can be primary or secondary to other diseases including autoimmune disease, malignant tumor, infection, etc. Glucocorticoid is the first-line treatment. However, the recurrence rate is very high and some patients may not response to steroids, the latter defined as refractory autoimmune anemia (RAIA). Second-line therapies include cyclosporine A (CSA), cyclophosphamide, 6-mercaptopurine, CD20 monoclonal antibody, anti human lymphocyte immunoglobulin (ATG), and even splenectomy. Cyclosporine A is easy to accept while some patients may have side effects such as renal function damage, gingival hyperplasia, hypertension and so on. Other second-line drugs also have many problems, such as low effective rate, slow onset, expensive price, and large side effects, and some patients do not response to these treatments. The refractory/relapsed AIA patients have increased cardiovascular events, increased opportunities for infections, decreased quality of life, and even death. At present, there is still no effective treatment for these patients. Our previous retrospective study showed that sirolimus was effective in cyclosporine refractory PRCA with an effective rate of 70% and slight side effects. In addition, we used sirolimus in refractory AIHA and ES, with an effective rate of 60-70%. However, there are still some non-responsive patients. Recently, it has been reported that all trans retinoic acid (ATRA) combined with danazol was effective in the treatment of refractory immune thrombocytopenic purpura (ITP). Therefore, we plans to combine sirolimus and ATRA in the treatment of refractory AIA to improve the efficacy. Since both sirolimus and ATRA are cheap and have slight side effects, this combination may reduce the economic burden of patients and reduce the side effects related to treatment.