Abatacept Decreases the Rate of Acute and Chronic Gvhd in Children with Sickle Cell Disease Undergoing Matched Sibling Transplants

Abstract

<h3>Introduction</h3> We wanted to study the role of abatacept on the incidence of graft versus host disease (GVHD) in patients with sickle cell disease (SCD) undergoing allogeneic hematopoietic stem cell transplant (HSCT). <h3>Methods</h3> We conducted a retrospective chart review of patients who received an allogeneic HSCT for SCD at Cincinnati Children's Hospital Medical Center and compared various transplant characteristics between patients with and without abatacept for acute GVHD prophylaxis. <h3>Results</h3> Sixteen patients were transplanted for SCD at our center. Nine patients received a calcineurin inhibitor, methotrexate and abatacept at 10 mg/kg intravenously on days -1, +5, +14 and +28 while 7 patients received a calcineurin inhibitor with methotrexate and methylprednisolone for acute GVHD prophylaxis (table 1). No abatacept infusion related adverse effects were observed. Neutrophil engraftment was comparable at a median of 12.5 days (range 11-21) in patients without abatacept versus 13 days (range 12-16 days) in the abatacept cohort. Incidence of grade 2-4 GVHD was 0/9 in the abatacept cohort versus 3/7 patients in the no-abatacept cohort. Two of the 3 acute GVHD patients in the no-abatacept cohort had visceral involvement. One patient in the abatacept cohort had mild chronic GVHD compared to 3 patients in the no-abatacept cohort with mild (n=1) and moderate (n=2) chronic GVHD. Six patients in the no-abatacept cohort had viral reactivation compared to 8/9 patients in the abatacept cohort. No patient in either cohort had viral disease. One patient in the abatacept cohort had secondary graft loss and was transplanted again with the same donor and conditioning regimen successfully. There was no graft loss in patients who did not receive abatacept. The disease-free survival was 100% in both groups at last follow up of 1925 days (range 837-8164 days) in the no-abatacept group and 770 days (range 112-1634 days) after HSCT in the abatacept cohort. <h3>Conclusions</h3> Abatacept is well tolerated and decreases the incidence of acute and chronic GVHD in children with SCD undergoing fully matched sibling transplants. Larger studies are needed to definitively determine the impact of abatacept in GVHD prophylaxis in the matched sibling donor setting.