Outcomes and mutational analysis of patients with lower-risk non-del5q myelodysplastic syndrome treated with antithymocyte globulin with or without ciclosporine A

Immunosuppressive treatment is a disease-modifying therapy for lower-risk myelodysplastic syndromes (MDS). However, IST is relatively rarely used and long-term outcomes of patients are seldom reported. We retrospectively studied outcomes of 20 patients with lower-risk non del 5q MDS with transfusion dependency, with horse or rabbit antithymocyte globulin ± ciclosporine A, and frontline eltrombopag in two of them. IPSS-R was low, intermediate and high in 30%, 55% and 10% of the patients, respectively. Fifty-five percent of the patients had hypocellular bone marrow (BM). Baseline mutations were detected in 31.5% of the patients and were more frequent in patients with normo/hypercellular MDS than in patients with hypocellular MDS. Transfusion independence rate for both red blood cells (RBC) and platelets was achieved in 45% of patients. RBC transfusion duration ≤6 months, B-cell counts >0.2 G/L and, marginally, BM blasts ≤2% were associated with higher transfusion independence rate. Age and cellularity did not influence the response rate. Median transfusion independence duration was 53 months. Cumulative incidence of progression to a more aggressive myeloid disease was 0 in patients without baseline mutations and 33% in patients with baseline mutations (P = .008). Median progression-free and overall survival after treatment onset and median overall survival after loss of transfusion independence were 45.5 months, 68 months and not reached, respectively. In conclusion, antithymocyte globulin ± ciclosporine A results in durable responses in MDS, irrespective of age, in patients with lower-risk disease without B-cell lymphopenia and treated early in the course of the disease.