Economic analysis of unrelated allogeneic bone marrow transplantation: results from the randomized clinical trial of T-cell depletion vs unmanipulated grafts for the prevention of graft-versus-host disease

Unrelated-donor marrow transplantation is a potential option for transplant candidates lacking a compatible related donor. The T-cell Depletion Study compared the 3-year disease-free survival for patients receiving T-cell-depleted (TCD) donor marrow (n = 203) vs unmanipulated donor marrow with methotrexate and cyclosporine (M/C) (n = 207). Hospital costs during index admission were documented with billing data, while hospital costs during subsequent 6-month follow-up were estimated from case report forms. Patients with index admission billing were included in the analysis (TCD = 119, M/C = 127). Total hospital length of stay (LOS) was similar across groups, with medians 47.0 days for TCD and 52.0 days for M/C (P = 0.72). Total hospital costs were comparable, 145,115 dollars vs 141,981 dollars (P = 0.63) for TCD and M/C, respectively. However, controlling for site and patient characteristics, TCD was associated with a 12.1% reduction in LOS for the index admission (95% CI -19.4%, -4.3%). Independent of treatment, HLA matching (6/6) was associated with an 8.6% (95% CI -17.4%, +1.2%) reduction in the index admission LOS, while cost was lower by 15.8% (95% CI -26.7%, -3.3%). Treatment costs were similar for TCD and M/C study groups. Savings on reduced cost for treating acute graft-versus-host disease were likely offset by increase in serious infections in the TCD arm.

Isolation and expansion of cytomegalovirus-specific cytotoxic T lymphocytes to clinical scale from a single blood draw using dendritic cells and HLA-tetramers

Cytomegalovirus (CMV) reactivation in immunocompromised recipients of allogeneic stem cell transplantation is a cause of morbidity and mortality from viral pneumonitis. Antiviral drugs given to reactivating patients have reduced the mortality from CMV but have toxic side effects and do not always prevent late CMV disease. Cellular immunotherapy to prevent CMV disease is less toxic and could provide prolonged protection. However, a practical approach to generating sufficient quantities of CMV-specific cytotoxic T cells (CTLs) is required. This study describes a system for generating sufficient CMV-specific CTLs for adoptive immunotherapy of HLA-A*0201 bone marrow transplant recipients from 200 mL donor blood. Donor monocytes are used to generate dendritic cells (DCs) in medium with autologous plasma, interleukin 4, granulocyte-macrophage colony-stimulating factor, and CD40 ligand. The DCs are pulsed with the immunodominant HLA-A*0201-restricted CMV peptide pp65(495-503), and incubated with donor T cells. These cultures are restimulated twice with peptide-pulsed lymphoblastoid cell lines (LCLs) or CD40-ligated B cells and purified with phycoerythrin (PE)-labeled pp65(495-503)/HLA-A*0201 tetramers by flow sorting, or with anti-PE paramagnetic beads. The pure tetramer-positive population is then rapidly expanded to obtain sufficient cells for clinical immunotherapy. The expanded CTLs are more than 80% pure, of memory phenotype, with a Tc1 cytokine profile. They efficiently kill CMV-infected fibroblasts and express the integrin VLA-4, suggesting that the CTLs could cross endothelial barriers. This technique is reproducible and could be used for generating CMV-specific CTLs to prevent CMV disease after allogeneic blood and marrow transplantation. (Blood. 2001;98:505-512)

In vitro generation of Epstein-Barr virus-specific cytotoxic T cells in patients receiving haplo-identical allogeneic stem cell transplantation

Use of a partially mismatched related donor (PMRD) is an option for patients who require allogeneic transplantation but do not have a matched sibling or unrelated donor. Epstein-Barr virus (EBV)-induced lymphoma is a major cause of mortality after PMRD transplantation. In this study, we present a clinical grade culture system for donor-derived EBV-specific cytotoxic T cells (CTLs) that do not recognize haplo-identical recipient cells. The EBV-specific CTLs were tested for cytolytic specificity and other functional properties, including ability to transgress into tissues, propensity for apoptosis, degree of clonality, stability of dominant T-cell clones, and Tc and Th phenotypes. The EBV-specific CTLs were routinely expanded to greater than 80 x 10(6) over a period of 5 weeks, which is sufficient for clinical application. A CD8+ phenotype predominated, and the CTLs were highly specific for donor lymphoblastoid cell lines (LCLs) without killing of recipient targets or K562. Vbeta spectratyping showed an oligoclonal population that was stable on prolonged culture. The EBV-specific CTLs were activated (D-related human leukocyte antigen [HLA-DR+], L-selectin+/-) and of memory phenotype (CD45RO+). Expression of the integrin VLA-4 suggested that these CTLs could adhere to endothelium and migrate into tissues. The Bcl-2 message was upregulated, which may protect the CTLs from the apoptosis. The first demonstration of overexpression of bcl-2 in human memory CTLs. In addition, we show that lymphoblastoid cell lines used to generate CTLs are readily genetically modified with recombinant lentivirus, indicating that genetically engineered antigen presentation is feasible.

Adenovirus infections in hematopoietic stem cell transplant recipients

We report a 12% incidence of adenovirus infections among 532 recipients of hematopoietic stem cell transplant (HSCT) from January 1986 through March 1997. The median time from day of stem cell infusion to first positive culture was 41 days. Recipients of allogeneic stem cells, as opposed to autologous stem cell recipients, were more likely to have a culture positive for adenovirus (16% vs. 3%; P<.0001). Pediatric patients were also more likely than adults to have a positive culture (23% vs. 9%; P<.0001). Among stem cell recipients with partially matched related donors, pediatric recipients appear to be at significantly greater risk for infection than adult recipients (P<.001). Positive cultures were associated with evidence of invasion in 64% of cases (41 of 64). A multiple logistic regression analysis showed that isolating adenovirus from more than 1 site correlated with greater risk for invasive infections (P=.002). Invasive infections were associated with poorer chance of survival.

Outcome of unrelated donor bone marrow transplantation in 40 children with Hurler syndrome

Long-term survival and improved neuropsychological function have occurred in selected children with Hurler syndrome (MPS I H) after successful engraftment with genotypically matched sibling bone marrow transplantation (BMT). However, because few children have HLA-identical siblings, the feasibility of unrelated donor (URD) BMT as a vehicle for adoptive enzyme therapy was evaluated in this retrospective study. Forty consecutive children (median, 1.7 years; range, 0.9 to 3.2 years) with MPS I H received high-dose chemotherapy with or without radiation followed by BMT between January 27, 1989 and May 13, 1994. Twenty-five of the 40 patients initially engrafted. An estimated 49% of patients are alive at 2 years, 63% alloengrafted and 37% autoengrafted. The probability of grade II to IV acute graft-versus-host disease (GVHD) was 30%, and the probability of extensive chronic GVHD was 18%. Eleven patients received a second URD BMT because of graft rejection or failure. Of the 20 survivors, 13 children have complete donor engraftment, two children have mixed chimeric grafts, and five children have autologous marrow recovery. The BM cell dose was correlated with both donor engraftment and survival. Thirteen of 27 evaluable patients were engrafted at 1 year following URD BMT. Neither T-lymphocyte depletion (TLD) of the bone marrow nor irradiation appeared to influence the likelihood of engraftment. Ten of 16 patients alive at 1 year who received a BM cell dose greater than or equal to 3.5 x 10(8) cells/kg engrafted, and 62% are estimated to be alive at 3 years. In contrast, only 3 of 11 patients receiving less than 3.5 x 10(8) cells/kg engrafted, and 24% are estimated to be alive at 3 years (P = .05). The mental developmental index (MDI) was assessed before BMT. Both baseline and post-BMT neuropsychological data were available for 11 engrafted survivors. Eight children with a baseline MDI greater than 70 have undergone URD BMT (median age, 1.5 years; range, 1.0 to 2.4 years). Of these, two children have had BMT too recently for developmental follow-up. Of the remaining six, none has shown any decline in age equivalent scores. Four children are acquiring skills at a pace equal to or slightly below their same age peers; two children have shown a plateau in learning or extreme slowing in their learning process. For children with a baseline MDI less than 70 (median age, 2.5 years; range, 0.9 to 2.9 years), post-BMT follow-up indicated that two children have shown deterioration in their developmental skills. The remaining three children are maintaining their skills and are adding to them at a highly variable rate. We conclude that MPS I H patients with a baseline MDI greater than 70 who are engrafted survivors following URD BMT can achieve a favorable long-term outcome and improved cognitive function. Future protocols must address the high risk of graft rejection or failure and the impact of GVHD in this patient population.

Analysis of 462 transplantations from unrelated donors facilitated by the National Marrow Donor Program

BACKGROUND AND METHODS

Allogeneic bone marrow transplantation is curative in a substantial number of patients with hematologic cancers, marrow-failure disorders, immunodeficiency syndromes, and certain metabolic diseases. Unfortunately, only 25 to 30 percent of potential recipients have HLA-identical siblings who can act as donors. In 1986 the National Marrow Donor Program was created in the United States to facilitate the finding and procurement of suitable marrow from unrelated donors for patients lacking related donors.

RESULTS

During the first four years of the program, 462 patients with acquired and congenital lymphohematopoietic disorders or metabolic diseases received marrow transplants from unrelated donors. The probability of engraftment by 100 days after transplantation was 94 percent, although 8 percent of patients later had secondary graft failure. The probability of grade II, III, or IV acute graft-versus-host disease was 64 percent, and the probability of chronic graft-versus-host disease at one year was 55 percent. The rate of disease-free survival at two years among patients with leukemia and good prognostic factors was 40 percent and among patients at higher risk, 19 percent. Twenty-nine percent of the patients with aplastic anemia were alive at two years, and the rate of two-year disease-free survival among patients with myelodysplasia was 18 percent. For patients with congenital immunologic or nonimmunologic disorders, the probability of survival was 52 percent.

CONCLUSIONS

The National Marrow Donor Program has benefited a substantial number of patients in need of marrow transplants from closely HLA-matched unrelated donors and has facilitated the recruitment of unrelated donors into the donor pool and the access to suitable marrow.