Therapy of Early Stage Myelodysplastic Syndrome (MDS) with Anti-Thymocyte Globulin (ATG) and Etanercept.

Immunosuppressive therapies have proven valuable in treating ineffective hematopoiesis in patients with Myelodysplastic Syndrome (MDS). Following an encouraging pilot trial, we evaluated the combination of equine anti-thymocyte globulin (ATGAM) and the soluble TNF receptor etanercept in a phase 2 trial. So far 23 patients with MDS (6-RA, 4-RARS, 12-RCMD, 1-RAEB-1) in IPSS risk groups low (n=8) or intermediate-1 (n=15) have been enrolled. All patients were platelet or red blood cell transfusion dependent. Nineteen patients completed therapy with I.V. ATGAM at 40mg/kg/day for four consecutive days, followed by etanercept, 25mg s.c. twice a week for 2 weeks every month for 4 months. The regimen was well tolerated and the majority of adverse events were anticipated infusional reactions related to ATGAM administration. Responses were assessed by modified International Working Group criteria. Twelve patients had hematological improvement (HI)-erythroid, 2 HI-neutrophil, and 3 HI-platelet. Five patients achieved red blood cell and one patient platelet transfusion independence. There was one complete remission in a patient with a co-existing diagnosis of multiple sclerosis. Thus, the overall response rate by intent to treat analysis among the 23 patients was 61%. Four patients did not complete their first course of therapy due to anaphylactic reaction, thrombosis of a pre-existing femoral graft, myocardial infarction, and patient preference. Among patients who completed treatment 74% had a hematological response, with duration of at least 5 months. Combination therapy with ATG and etanercept was active and safe in unselected patients with low and intermediate-1 risk MDS.