520 Investigating the impact of hematopoietic cell transplant on morbidity and mortality of children with sickle cell disease

Objectives/Goals: Our main objective was to compare 5-year survival and organ function between patients with sickle cell disease (SCD) who underwent hematopoietic cell transplant (HCT) and those who did not undergo HCT. We hypothesized that organ function would be improved in those with SCD who underwent HCT when compared to those who remained on standard therapy. Methods/Study Population: This IRB-approved, retrospective study includes patients with SCD treated at Children’s Healthcare of Atlanta. Cases underwent HCT between 2010 and 2016. They were randomly matched with 2 patients with SCD who did not undergo HCT. Match criteria included age, sex, disease genotype, and disease severity, which was determined by the number of hospitalizations in the 5 years pre-HCT, prior intensive care unit admission, and prior chronic transfusion therapy. Data extracted included SCD treatment, hospitalizations, emergency department visits, and organ function pre-HCT and 1-, 2-, 3-, and 5-years post-HCT. Organ-specific outcomes and overall survival were compared between the two groups using cumulative incidence curves and Kaplan–Meier analyses. Normal FEV1 and FVC in this analysis were >80% predicted. Results/Anticipated Results: Thirty-seven cases who had undergone HCT were matched with 74 controls who continued with standard medical therapy. The median age was 8 years for both groups and 59% were females. The median disease severity score was 2 in both groups. At baseline, 70.3% of the HCT group completed pulmonary function tests (PFTs) compared to 35.1% of the non-HCT group. Of these, 73% in both groups had a normal FEV1. In terms of FVC, 57.7% of HCT patients and 76.9% of non-HCT patients had a normal FVC pre-HCT. At 5 years post-HCT, 56.8% of the HCT group had PFTs completed compared to 21.6% of the non-HCT group. Among these, 85.7% in the HCT group had a normal FEV1 compared to 75% in the non-HCT group, while 90.6% had a normal FVC in the HCT group compared to 75% in the non-HCT group. Two of 37 in the HCT group and 1 of 74 in the non-HCT group died (p = 0.21). Discussion/Significance of Impact: Our data suggest that post-HCT, the proportion of patients falling in the normal range for FEV1 and FVC increases. This increase is not seen in the non-HCT group, indicating that HCT may improve this organ function. There was no difference in survival between the groups, indicating the risk of HCT mortality may not be greater than the risk of living with SCD.