Clinical and Cost Outcomes of Double Umbilical Cord Blood Versus Bone Marrow and Peripheral Blood Unrelated Hematopoietic Stem Cell Transplants.

Abstract

Umbilical cord blood (UCB) is a viable source of hematopoietic stem cells (HSC) however, because of the increased risk of nonengraftment associated with low total nucleated cell counts (TNC) per kg, double UCB (DCB) transplants are used in larger patients (pts). Minimal data has been collected on cost analysis and clinical outcomes comparing DCB to peripheral blood (PB) and bone marrow (BM) unrelated donor (UD) transplants. Thus, we conducted a retrospective review of DCB transplants (n=30) from January 2004 through April 2008 compared to BM (n= 23, 30%) and PB (n = 54, 70%) UD transplants during the same time period. Median age was 21 yrs (range 13–66) for DCB recipients and 45 yrs (range 0.4–67) for UD pts. UD pts were HLA typed at A, B, C, DR, and DQ and matched with donors at 9(10) (21%) and 10(10) (79%) loci [all mismatches at class I alleles]. Pts were considered for DCB transplant if a suitable 10/10 or 9/10 donor could not be identified. DCB recipients had HLA matches of 6/6, 5/6/, 4/6 and 3/6 as follows: (cord 1/ cord 2): (0.0%/6.7%), (20.0%/30.0%), (76.7%/63.3%), (3.3%/0.0%) [HLA disparity between each UCB unit and recipient was not necessarily at the same loci]. The median TNC/kg in DCB pts was 2.03x107 (range 7.9x106 – 9.3x108). Full intensity preparative regimens (BuCY2 or TBI³ 1200 cGy based) were used in 43% of UD and 50% of DCB pts. Median day to ANC>500/ul for DCB and UD pts was 23 days (range 6–66) and 15 days (range 7–52), and platelet >20,000/ul was 52 days (range 7–130) and 19 days (range 9–63), respectively. Incidences of acute GVHD ≥2 and chronic GVHD in the UD and DCB pts were 61.0% and 51% vs. 53.3% and 45%, respectively. Median follow-up was 143 days (range 12–847) for the DCB group and 242 days (range 34–1506) for the UD pts. Estimated overall survival (OS) at 1 year was 61% (95% CI: 48% to 71%) for UD pts vs. 55% (95% CI: 34% to 72%) in DCB pts (p = NS). Estimated transplant related mortality (TRM) at 100 days for UD pt was 6.5% (95% CI: 2.8% to 14.9%) and 16.7% (95% CI: 7.3% to 35.5%) (p=0.09) in DCB pts. There were 48 total deaths; 14 (46.7%) in the DCB pts and 34 (44.2%) in the UD pts. In both the DCB and UD groups, disease relapse (21.4% and 23.5%) and infection (28.6% and 14.7%) caused the majority of deaths. All facility transplant related costs were reviewed from the transplant center thru the first year post transplant, excluding pretransplant workup and care not received at the transplant center. The total median costs for DCB transplants were significantly more than the UD costs at D30, D100 and 1yr post transplant by differences of $42,067, $50,806, and $52,297, respectively (p<0.05 for each time interval). The median length of stay for initial hospitalization at start of preparative regimen was 22 days (2–144) in the UD pts and 29 days (6–103) in the DCB pts, and 60% of total median costs occurred by D30 in the DCB group compared to 52% in the UD group. In conclusion, DCB provides a viable option for HSC with comparable clinical outcomes to UD transplants, however DCB transplants are more expensive primarily because of inpatient costs in the first 30 days.