**4. Unrelated donor cord blood transplantation for thalassemia**

Three single cases employing unrelated CBT for thalassemia were reported early on, with all three patients achieving neutrophil engraftment and transfusion independence [65–67]. Busulfan/cyclophosphamide/ATG-containing preparative regimen was used in all three; however, Fang et al. and Tan et al. used methotrexate-containing GvHD prophylaxis [65, 66]. Nucleated cell dose was high, with the minimum of 6 × 107 nucleated cells/kg. One patient received a 6/6 HLA A/B/DR-matched CB and two were transplanted with 4/6 HLA-matched CB. None of the patients experienced chronic GvHD or Grade IV acute GvHD. Vanichsetakul et al. [68] reported on six patients transplanted with three 6/6, one 5/6 and two 4/6 HLAmatched CB from unrelated donors. Patients were ranged from 2 to 15 years old with a median of 5.5 years. Busulfan, cyclophosphamide and fludarabine conditioning regimen was used with cyclosporine and methylprednisolone GvHD prophylaxis. Median TNC dose was 2.8 × 107 nucleated cells /kg with a range of 1.5–5.3 × 107 nucleated cells. Five of six patients engrafted and survived, while one expired due to infection prior to engraftment. Soni et al. [60] reported on unrelated CBT of two Pesaro class 3 patients with reduced intensity conditioning, with one recipient requiring re-transplantation with CB. After re-transplant, both patients engrafted and were thalassemia-free, with a follow-up of 7 and 8 years. Lastly, Kharbanda et al. [59] reported on the use of unrelated CB supplemented with co-infusion of third-party mesenchymal stromal cells (MSC) in two thalassemia patients, using a reduced intensity condition regimen. Only one patient engrafted, with neither patient survived.

grafts but not significantly (10.4 vs. 7.4%; p = 0.33). Eight of the patients who received CB graft experienced graft failure. Cumulative incidence of primary graft failure was 9 ± 4% and 6 ± 4% after CBT and BMT, respectively. Six patients experienced secondary graft failure after CBT at a median of day +151 (range day +51 to 202). The cumulative incidence of neutrophil engraftment was 90 ± 4% and 92 ± 1% (p = 0.01), and 83 ± 5% and 85 ± 5% for platelet engraftment after CBT and BMT, respectively. For patients who engrafted, the median time to neutrophil recovery was day +23 for CBT and day +19 for BMT, and day +38 and day +25 for CBT and BMT for platelet engraftment, respectively (p = 0.004). The proportion of long-term sustained mixed chimerism was significantly higher after CBT than for BMT (37 versus 22%; p = 0.01). Only 11% of CBT recipients experienced grade II–IV acute GvHD (no grade IV), versus 21% of BMT recipients (2% grade IV acute GvHD), with a cumulative incidence 10 ± 3% and 21 ±  2%, respectively (p = 0.04). Only six of 84 evaluable CB recipients experienced chronic GvHD with no extensive grade versus 42 of 355 (12 extensive) patients of BMT who survived past 100 days, with the cumulative incidence of chronic GvHD at 5 ± 3% and 12 ± 2%, respectively (p = 0.12), and extensive chronic GvHD at 0% and 5 ± 9%, respectively. Twenty-one patients expired from transplant-related causes—three after CBT and 18 after BMT. Most importantly, with a median follow-up of 70 months, the 6-year DFS was 80 and 86% for CB- and BMtransplanted patients, respectively, with no difference in multivariate analysis. This study proved that CBT using related donor for thalassemia is as efficacious and safe as related donor BMT, with potentially better long-term quality of life due to reduced chronic GvHD with minimal extensive grades. The authors point out that the quality of life for BMT patients with

188 Umbilical Cord Blood Banking for Clinical Application and Regenerative Medicine

extensive chronic GvHD is worse than patients on medical therapy.

**4. Unrelated donor cord blood transplantation for thalassemia**

Nucleated cell dose was high, with the minimum of 6 × 107

Three single cases employing unrelated CBT for thalassemia were reported early on, with all three patients achieving neutrophil engraftment and transfusion independence [65–67]. Busulfan/cyclophosphamide/ATG-containing preparative regimen was used in all three; however, Fang et al. and Tan et al. used methotrexate-containing GvHD prophylaxis [65, 66].

nucleated cells/kg. One patient

nor engraftment.

The author speculated that due to the higher nucleated cell dosage for most of the CB recipients, nucleated cell dosage was not shown to influence engraftment or disease-free survival. For CBT, methotrexate was shown in multivariate analysis negatively influencing DFS (HR 3.81, CI 1.40–10.87; p = 0.004), with 6-year DFS at 90 ± 4% if methotrexate was avoided versus 60 ± 11% (p < 0.001). Similar to previous studies, thiotepa-containing preparative regimen and Pesaro classification 1 were shown to correlate with better outcome after CBT. These series using related CBT demonstrate the efficacy and high margin of safety of related CB as a source of HSCT for thalassemia. The studies confirmed that even with persistent mixed chimerism, patients are still transfusion independent. Methotrexate GvHD prophylaxis was proven to be detrimental to favorable outcome and the addition of thiotepa to busulfan and cyclophosphamide conditioning regimen favored sustained doIn 2004, Tang-Her Jaing at Chang Gung Medical Center and Robert Chow at StemCyte embarked on a long-term collaborative study using unrelated CBT for thalassemia patients in Taiwan with the hypothesis that if conditions were optimized, HLA-mismatched unrelated CBT may produce results as favorable as unrelated BMT as well as approach that of related BMT and CBT. One strategy was to transplant patients as early as possible when disease stage is least severe. Most importantly, several approaches to optimize stem, progenitor and nucleated cell doses were employed: (1) utilization of CB products that were not reduced in RBC (MaxCell CB) whenever possible. Such non-RBC reduced, plasma depleted/reduced MaxCell ("MaxCell" or "MC") CB products have been shown to have significantly higher recovery for nucleated cell, CD34+ cells and colony-forming units (CFU) following parallel processing comparisons against RCR CB units [5, 8, 35, 39, 47, 48, 50]; (2) avoidance of postthaw washing unless contraindicated, which has been shown by us and several other groups to be safe, offering enhanced infused cell dose due to zero cell loss from post-thaw washing [5, 6, 26, 32–34, 36–50, 69–71]; and (3) double CBT whenever cell dosage for single CB units was insufficient to meet the study thresholds for nucleated and CD34+ cell doses [9, 31–35]. In practice, the study complied with the first two conditions completely for all Chang Gung patients who have been reported, by sourcing all of its CB products from a single manufacturer of red cell-replete MaxCell CB products (StemCyte). Consequently, the average and median cell dosages achieved in Chang Gung patients were higher than every other large unrelated CBT series for thalassemia. The myeloablative conditioning and GvHD prophylaxis regimens consisted of the standard busulfan, cyclophosphamide and ATG, as well as cyclosporine and methylprednisolone, respectively. IV busulfan accompanied by drug level monitoring and adjustment replaced oral busulfan after a cluster of several autologous recoveries. Initially, prefreeze nucleated and CD34+ cell dose criteria were set at 2 × 107 /kg and 1.7 × 105 /kg, respectively, and were later raised to 2.5 × 107 /kg (for single CBT) and 2.0 × 105 /kg, respectively. Importantly, the outcome data for Chang Gung transplant recipients were audited by CIBMTR appointed auditors on site using actual patient charts as routine for StemCyte supplied CB, which has been verified to be 97.3% accurate, with only minor errors and no errors for survival, mortality, engraftment, GvHD or relapse.


Optimization of Unrelated Donor Cord Blood Transplantation for Thalassemia: Implications for Other... http://dx.doi.org/10.5772/66190 191


**MC CBT Jaing et al. [26]**

Median/range 1.3–19.9 1.7–19.9

100% MC CB/ NW/±DCBT/CD34+

Priority

Graft failure 4 Primary 5 Primary

Approaches to maximize cell dose

Engraftment CI
