Cord Blood Establishing a National Hematopoietic Stem Cell Bank Program (2005) / Chapter Skim
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Appendix E: A Cost-Benefit Analysis of Increasing Cord Blood Inventory Levels
Appendix E: A Cost-Benefit Analysis of Increasing Cord Blood Inventory Levels
Pages 221-241
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From page 221... ...
The larger the inventory, the greater the likelihood that transplant candidates will match to a stored unit. Processing new cord blood units is costly, however, so the access benefits must be weighed against the storage costs.
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From page 222... ...
For cord unit match probabilities, the model uses the cell count distribution of cord units in the National Marrow Donor Program database and the empirical weight distribution of transplant candidates to estimate probabilities for a given minimum cell dose threshold. In the baseline analysis, we assume a threshold of 2.5 × 107 total nucleated cells per kilogram of body weight (TNC/Kg)
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From page 223... ...
. Cord blood match probabilities represent the likelihood of finding a matched cord unit for a minimum cell dose of 2.5 × 107 TNC/Kg, averaged across the empirical weight distribution of transplant candidates' age 20.
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From page 224... ...
Given that bone marrow transplantation is the more established therapy, one could argue that the appropriate end point is the impact of an increase in inventory size on the marginal likelihood of finding a matched source of stem cells. Rows 8, 11, and 14 of Tables E-1 and E-2 show the impact of increasing inventory size on the proportion of patients who have a 6/6, 5/6, and 4/6 cord unit match but lack a 6/6 adult unrelated donor match, respectively.
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From page 225... ...
, based on a recent analysis of International Bone Marrow Transplant Registry (2004) data reporting the breakdown of allogeneic marrow transplants by age group (20 versus <20)
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Not all transplant candidates who theoretically match to a bone marrow donor or cord blood unit undergo transplantation. Some never initiate a donor or cord blood search, some die before the transplant occurs, and others select alternative therapies.
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Numbers may not add up to total due to rounding. brate these probabilities so that with a 50,000-cord blood-unit inventory the model yields estimates of total bone marrow and total cord blood transplants that are close to the actual figures of around 2,000 bone marrow and 600 cord blood transplants, two-thirds of which occur in pediatric patients.
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From page 228... ...
Table E-3 displays the number of patients who would receive cord blood transplants at various cord blood inventory levels. The number of patients receiving bone marrow transplants does not vary, but the number undergoing transplantation with cord blood increases from 617 with an inventory of 50,000 units to 670 with an inventory of 300,000 units.
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From page 229... ...
Life Years Gained Using data from the International Bone Marrow Transplant Registry on adult unrelated bone marrow transplants occurring between 1988 and 1996 (Flomenberg et al., 2004) , we calculated 5-year survival rates by match level and age group.
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a greater number of transplants among patients who match to an unrelated marrow donor on 6/6 or 5/6 antigens at low resolution but have more than one mismatch at high resolution, and in scenario 1 only (3) increased longevity among patients who are able to obtain a 6/6 or 5/6 cord match with a large inventory but would receive a poorer match at a low inventory level.
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Scenario 1: Survival rates vary by cord match level. Scenario 2: Survival rates do not vary.
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232 CORD BLOOD of processing a unit that is discarded prior to storage (so that cPD < cPS) , cS the annual cost of storing a unit, and A the annual cost of administration, the annual costs for a cord blood bank are: C = (1- )
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From page 233... ...
In their analysis of Milano Cord Blood Bank costs, Sirchia et al.
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Based on data listed on www.bmdw.org, there are approximately 80,000 cord blood units currently in storage in the United States. However, the quality of these units is uncertain because many were processed and stored using protocols that would not meet the standards likely to be adopted by the committee.
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Failing to take account of how survival rates vary by match level ignores the survival gains from this first effect. EQUITY Equity between racial groups is an important motivation behind the establishment of a national cord bank.
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From page 236... ...
Increasing inventory size reduces the absolute difference between groups in the likelihood of obtaining a 4/6 cord blood match from 20 to 8 percentage points. Life years gained per patient are lower for African Americans at all inventory levels, but the incremental gains from increasing inventory size are larger.
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. SENSITIVITY ANALYSES We re-estimated incremental cost per life years gained and racial differences in match probabilities under the following assumptions, using scenario 1 assumptions for cord blood survival rates.
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From page 238... ...
Break-even per cord fee $15,336 $31,107 $46,613 $62,014 $92,675 Total life years 77,003 77,437 77,672 77,830 78,042 Incremental cost per life year NA $37,667 $55,873 $75,953 $106,948 Proportion of patients who are urgent is 40% Break-even per cord fee $13,882 $27,963 $41,817 $55,583 $82,998 Total life years 74,029 74,502 74,758 74,931 75,164 Incremental cost per life year NA $35,723 $51,959 $69,995 $97,931 5 year survival rate without a transplant is 30% Break-even per cord fee $15,336 $31,107 $46,613 $62,014 $92,675 Total life years 108,978 109,285 109,465 109,592 109,769 Incremental cost per life year NA $53,206 $72,875 $94,820 $128,329 Overcollection of non-Caucasian cord units Break-even per cord fee $15,523 $31,335 $46,845 $62,239 $92,875 Total life years 76,770 77,224 77,469 77,635 77,858 Incremental cost per life year NA $37,757 $54,814 $73,713 $103,025 NOTE: In the baseline model the proportion of patients who are urgent is 25 percent, the 5 year survival rate without a transplant is 15 percent, and cord units are collected proportionately by race. Total life years include life years from bone marrow recipients and patients who do not receive a transplant of any kind.
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From page 239... ...
In the absence of definitive evidence, we estimated cost-effectiveness ratios under two scenarios, representing extreme cases. In the first, cord transplant survival rates vary by match level, mirroring differences in marrow transplant survival rates.
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From page 240... ...
2004. Impact of HLA class I and class II high-resolution matching on outcomes of unrelated donor bone marrow transplantation: HLA-C mismatching is associated with a strong adverse effect on transplantation outcome.
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From page 241... ...
2004. Transplants of umbilical-cord blood or bone marrow from unrelated donors in adults with acute leukemia.
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