Abstract
Introduction: Acute Graft-versus-Host Disease (aGVHD) is a frequent complication of Allogeneic Hematopoietic cell transplants (allo-HCT). It can be lethal with increased morbidity and mortality and can occur in upto 40-50% of allo-HCT. Various agents such as calcineurin inhibitors, anti-metabolites and anti T cell antibodies, have been variably used for GVHD prophylaxis. Use of Post-transplant Cyclophosphamide (PTCy) has recently been used extensively in haplo-identical transplant setting with promising results, but has mainly been used in patients with BM as a stem cell source. In those patients receiving PBSC as a stem cell source, PTCy alone could reduce the risk of acute and chronic GVHD significantly. Anti-Thymocyte Globulin (ATG) has been associated with decrease in chronic but not acute GVHD. As most of our patients use PBSC as a graft source, we hypothesized that combination of ATG and PTCy can reduce the incidence of both acute and chronic GVHD. Since we had also used ATG for GVHD prophylaxis in a historical cohort, we compared the results of this approach with the current GVHD prophylaxis regimen.
Methods: A total of 28 patients with hematological malignancies, who had an unrelated donor underwent allo-HCT at our center from 1 Oct 2015 to 31 Mar 2016. After interim analysis, when increased non-hematological toxicity was observed with myeloablative conditioning, all patients subsequently received reduced intensity conditioning. Peripheral blood was used as a stem cell source in all patients. The GVHD prophylaxis consisted of a combination of ATG-PTCy-CsA, with rabbit ATG administered on Days -3 (0.5 mg/Kg), -2 (2 mg/Kg) and -1 (2 mg/Kg), PTCy at dose of 50 mg/kg on Days +3 and +4 and CsA from Day+5 onwards. Filgrastim was used from day +7 onwards for 13 patients. Emphasis was given to incidence of acute GVHD, especially Steroid Refractory (SR-GVHD).
Results: Out of total of 28 patients, aGVHD was seen in 6 (21.4%) patients, five of which had skin involvement (Grade I- II) and one suspected liver involvement (Grade III), all of which responded rapidly to steroids with no cases of SR-GVHD. Secondary graft failure and EBV reactivations; each were seen in 10% of cases. Primary disease relapse was seen in 3 patients, two of which had minimal residual disease prior to transplantation. These results were then compared to the historical cohort of 27 patients who received a combination of ATG-CsA plus Mycophenolate Mofetil (MMf) (Table 1). The incidence of acute GVHD was 26% vs 22% (p=0.99), with severe Grade III-IV aGVHD of 4% vs 20% (p=0.085) in the ATG-PTCy-CsA and ATG-CsA-MMf cohorts, respectively; both were statistically not signifcant. There were five patients with SR-GVHD in the ATG-CsA-MMf cohort and none in the current GVHD prophylaxis arm. In the historical cohort, the main cause of death in 7 out of 11 patients was severe GVHD as compared to 1 out of 9 in the ATG-PTCy-CsA cohort.
Conclusions: Combination of ATG-PTCy-CsA is an effective strategy to reduce aGVHD; especially severe Grade III-IV and doesnot increase the risk of SR-GVHD, in unrelated donor transplants as compared to ATG-CsA-MMf. However, a long term follow up is needed to assess relapse and cGVHD.
No relevant conflicts of interest to declare.
This feature is available to Subscribers Only
Sign In or Create an Account Close Modal