Hematopoietic cell transplantation in older patients with hematologic malignancies: replacing high-dose cytotoxic therapy with graft-versus-tumor effects

Cyclosporine inhibits the development of green fluorescent protein (GFP)-specific immune responses after transplantation of GFP-expressing hematopoietic repopulating cells in dogs

Green fluorescent proteins (GFPs) have been widely used to monitor gene transfer and expression after lentiviral and oncoretroviral transduction of hematopoietic cells. Studies have shown a complete disappearance of GFP-containing cells after transplantation of GFP-transduced repopulating cells in nonhuman primates that was further shown to be mediated by transgene-specific immune responses. We wished to evaluate whether cyclosporine could prevent immune responses to GFP. We first determined whether an immune response to GFP was responsible for the disappearance of gene-modified cells in dogs. We performed immune assays in two dogs transplanted with lentivirally transduced CD34+ cells. Blood samples were obtained twice per week for up to 800 days and the GFP transgene product was measured by flow cytometry in blood leukocytes. Peripheral blood leukocytes were stimulated in vitro for 5 days, using a panel of GFP peptides. Intracellular levels of tumor necrosis factor alpha (TNF-alpha), measured by flow cytometry, and T cell proliferation after GFP peptide stimulation were measured. Dogs that exhibited a decrease in GFP marking developed potent immune responses in vitro to the transgene product GFP as shown by an increase in GFP-specific TNF-alpha production (p < 0.05) when compared with nontransplanted controls. T cells from dogs with low GFP marking exhibited a significant increase in proliferation in response to GFP peptide stimulation in vitro (p < 0.05). To study whether cyclosporine could inhibit the development of GFP-specific immune responses, we treated five dogs with cyclosporine after transplantation of GFP-transduced hematopoietic cells. Dogs treated with cyclosporine after hematopoietic stem cell transplantation showed stable GFP marking in blood leukocytes over 800 days. Our data suggest that cyclosporine prevents immunoactivation against transgene products after transplantation of GFP-transduced hematopoietic stem cells as indicated by stable GFP marking.

188Re or 90Y-labelled anti-CD66 antibody as part of a dose-reduced conditioning regimen for patients with acute leukaemia or myelodysplastic syndrome over the age of 55: results of a phase I-II study

In a phase I-II study for patients aged 55-65 years, we employed radioimmunotherapy using an anti-CD-66 antibody as part of a dose-reduced conditioning regimen, which was followed by a T-cell-depleted graft. 20 patients with a median age of 63 years suffering from acute leukaemia (n=17) or myelodysplastic syndrome (n=3) received the antibody labelled either with 188Rhenium (n=8) or with 90Yttrium (n=12) during conditioning. Radioimmunotherapy provided a mean dose of 21.9 (+/-8.4) Gy to the bone marrow with a significantly higher dose when 90Yttrium was used. Additional conditioning was fludarabine-based plus anti-thymocyte globulin in matched related donor transplants (n=11), or plus melphalan in matched unrelated donor transplants (n=9). Regimen-related toxicity was low, with two patients developing three episodes of grade III organ toxicity. All patients engrafted, grade II-IV acute graft-versus-host disease (GvHD) was observed in one patient (5%) and chronic GvHD in three patients (15%). The cumulative incidence of non-relapse mortality was 25%, the cumulative incidence of relapse 55%. The probability of survival was estimated to be 70% at 1 year and 52% at 2 years post-transplant, although no plateau was reached afterwards. In conclusion, radioimmunotherapy using the anti-CD66 antibody was feasible and safe in our elderly patient group and provided a high marrow dose.

What role is there for antithymocyte globulin in allogeneic nonmyeloablative canine hematopoietic cell transplantation?

We investigated whether pretransplantation immunosuppression with canine-specific rabbit antithymocyte globulin (ATG), combined with a suboptimal dose of 1 Gy of total body irradiation (TBI), would permit engraftment of canine dog leukocyte antigen-identical marrow. Cumulative ATG doses of 2 to 5 mg/kg produced a T-cell depletion of 1 log in the peripheral blood and 50% in the lymph nodes. Serum levels of ATG peaked on days 4 to 6 after initiation of therapy and became undetectable by day 13 as a result of canine antibody responses to ATG. ATG prolonged allogeneic skin graft survival to 14 days (n = 5), compared with 8 days in control dogs (P = .0003). Five dogs were given marrow transplants after ATG (3.5-5 mg/kg) and 1 Gy of TBI. Posttransplantation immunosuppression consisted of mycophenolate mofetil and cyclosporine. All dogs showed initial engraftment, with maximum donor chimerism levels of 25%. However, only 1 dog achieved sustained engraftment, and 4 rejected their grafts. The duration of engraftment ranged from 8 to > or = 36 weeks (median, 11 weeks), and this is comparable to that in 6 historical controls not given ATG (range, 3-12 weeks; median, 10 weeks; P = .20). The total nucleated cell doses in the marrow grafts had the highest correlation coefficient with the duration of engraftment: 0.82 (P = .09). We concluded that administering ATG before an otherwise suboptimal conditioning dose of 1 Gy of TBI failed to secure uniform stable hematopoietic engraftment.

Influence of the intensity of the conditioning regimen on the characteristics of acute and chronic graft-versus-host disease after allogeneic transplantation

The graft-versus-host disease (GVHD) characteristics of 150 consecutive patients undergoing reduced intensity conditioning allogeneic (allo-RIC) transplants and 88 patients undergoing myeloablative conditioning regimen were analysed. All patients received the same GVHD prophylaxis and peripheral blood stem cells from a human leucocyte antigen identical sibling. The cumulative incidence of acute GVHD (aGVHD) was 67% and 44% in the myeloablative and allo-RIC regimen groups, respectively (P < 0.001), and was 39% vs. 29%, respectively (P = 0.043), for grades 2-4 aGVHD. Only conditioning type (myeloablative versus allo-RIC) significantly influenced the incidence of aGVHD in multivariate analysis: Hazard ratio (HR) = 2.16 [95% confidence interval (CI): 1.52-3.07], P < 0.0001. The cumulative incidence of chronic GVHD (cGVHD) was 63% and 71% among myeloablative and allo-RIC patients respectively (P = 0.084). This trend was because of the higher incidence of limited cGVHD, but not extensive cGVHD among allo-RIC recipients [HR = 3.3 (95% CI: 1.42-8.08), P = 0.0017]. Moreover, among patients who developed cGVHD, the cumulative incidence of limited cGVHD was significantly lower in the myeloablative group than in the allo-RIC group (7% vs. 25%, P = 0.007). Duration of immunosuppression was shorter among allo-RIC patients (35.5% vs. 68.8% required systemic immunosuppression 36 months after transplant, P = 0.028). Although prospective controlled trials are required to further evaluate the effect of the conditioning regimen on GVHD, our results suggest that RIC modifies the incidence and characteristics of both acute and cGVHD after allogeneic transplantation, and decreases the immunosuppression requirements in long-term follow up when compared with myeloablative conditioning.

Limiting Dilution Analysis of Interleukin-2 Producing Helper T-cell Frequencies as a Tool in Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

A reliable in vitro test that estimates the level of ongoing alloreactivity would be valuable in allogeneic hematopoietic cell transplantation (HCT) as a help to guide clinical interventions such as donor lymphocyte infusions and changes in the immunosuppression. In the present study, the use of limiting dilution analysis of interleukin-2 (IL-2) producing helper T lymphocyte frequencies (HTL assay) as a way to quantify alloreactivity following HCT was investigated.

METHODS

Serial HTL assays were performed following allogeneic HCT with myeloablative or nonmyeloablative conditioning in 26 patients with hematologic malignancies.

RESULTS

Deviations from single-hit kinetics were frequently observed in the HTL assays and a nonlinear model was therefore used for analysis. The results of this analysis suggested the presence of an inhibitory cell population. Inhibition was observed in the majority of patients and was not restricted to a specific transplant regimen. Inhibition occurred more often with high frequencies of IL-2 producing cells, indicating a physiological role of the putative inhibitory cell population in the regulation of an immune response. Higher frequencies of IL-2 producing cells were observed in patients with acute graft-versus-host disease grades II-IV than in patients with grades 0-I (P = 0.046), indicating that the degree of ongoing alloreactivity is indeed quantified by the HTL assay.

CONCLUSIONS

We find that the HTL assay may yield interesting insight into regulation of immune responses following allogeneic HCT, but because of the complexity of the results obtained, its use as a routine procedure to guide immunosuppression cannot be recommended.

Reduced-intensity allogeneic stem cell transplantation in adults and children with malignant and nonmalignant diseases: end of the beginning and future challenges

During the last 10 years, multiple studies using reduced-intensity (RI) conditioning followed by allogeneic stem cell transplantation (AlloSCT) have been reported in adult and, less so, pediatric recipients. RI AlloSCT allegedly eradicates malignant cells through a graft-versus-leukemia/graft-versus-tumor effect provided by alloreactive donor T lymphocytes, natural killer cells, or both. Various studies have clearly demonstrated a graft-versus-leukemia/graft-versus-tumor effect in hematologic malignancies and solid tumors. Acute short-term toxicity, including infection and organ decompensation after myeloablative conditioning therapy, can result in a significant incidence of early transplant-related mortality. More importantly, long-term late effects-including growth retardation, infertility, and secondary malignancies-are major complications after myeloablative conditioning therapy, especially in vulnerable children, who are more susceptible to these complications. Recent results comparing RI conditioning with myeloablative conditioning followed by HLA-matched sibling AlloSCT have demonstrated a significant reduction in use of blood products, risk of infections, transplant-related mortality, length of hospitalization, and feasibility of conditioning therapy in outpatient settings. Despite the success of RI AlloSCT, large prospective randomized multicenter studies are necessary to define the appropriate patient population, optimal conditioning regimens and pretransplantation immunosuppression, role of donor lymphocyte infusions, duration of hospitalization, overall survival, cost-benefit ratio, and differences in long-term effects to evaluate the role of RI AlloSCT more fully. We review the recent experience of RI AlloSCT in adults and children with both malignant and nonmalignant diseases and discuss the challenges for the future.

Autologous transplantation followed closely by reduced-intensity allogeneic transplantation as consolidative immunotherapy in advanced lymphoma patients: a feasibility study

We report outcomes in advanced lymphoma patients (n = 32) who enrolled in a trial of prospectively planned combined autologous/reduced-intensity transplantation (RIT) (n = 25) or who received RIT shortly after prior autografting because of high relapse risk or progressive disease (n = 7). Nine patients on the autologous/RIT transplant protocol did not proceed to planned RIT because of patient choice (n = 4), disease progression (n = 3), toxicity (n = 1), or no adequate donor (n = 1). Among the 23 other patients, RIT was started a median of 59 days (range 31-123) after autologous transplant. Fifteen patients had related donors, five patients had unrelated donors, and three patients had cord blood donors. Among all patients completing RIT, the median overall survival time was 385 days (95% CI 272-792), and the median relapse-free survival time was 157 days (95% CI 119-385). At the time of reporting, six patients (26%) remain alive and three patients (13%) remain alive without relapse. The 100-day transplant-related mortality (TRM) was 9% among all patients and was 0% among matched sibling donors. Overall TRM was 43%. Tandem transplant is feasible in advanced lymphoma with low early TRM. However, practical challenges associated with the strategy were significant and high levels of late TRM due to graft-versus-host disease and infections suggest that modifications of the procedure will be needed to improve outcomes and patient retention.

Comparison of lung function after myeloablative and 2 Gy of total body irradiation-based regimens for hematopoietic stem cell transplantation

Lung function decline is a well-recognized occurrence after myeloablative hematopoietic stem cell transplantation (HCT) that has not been studied after nonmyeloablative conditioning regimens. We examined the lung function of patients before and after 2-Gy total body irradiation-based nonmyeloablative and myeloablative preparative regimens. Before HCT, at day 100, and 1 year after HCT, nonmyeloablative patients had lower 1-second forced expiratory volume (FEV1), forced vital capacity, total lung capacity, residual volume, and carbon monoxide diffusion capacity. However, after transplantation, the risk for experiencing a >20% per year decrease of FEV 1 was significantly lower for nonmyeloablative than myeloablative patients >50 years of age (odds ratio, 0.3; 95% confidence interval, 0.1-0.8; P = .01). Lower pretransplantation FEV 1 was associated with a higher mortality rate for both groups, with the highest mortality risk among patients with a pretransplantation FEV 1 <60% (nonmyeloablative: hazard ratio, 3.9; 95% confidence interval, 1.9-8.0; myeloablative: hazard ratio, 7.2; 95% confidence interval, 2.5-21.2). These results suggest that despite having worse lung function, patients who receive the 2-Gy total body irradiation-based nonmyeloablative regimen will likely experience less pulmonary toxicity than patients who receive a myeloablative regimen, and this may have important clinical implications when deciding on a conditioning regimen for patients >50 years of age with compromised pretransplantation lung function.

Survival after reduced-intensity conditioning is not inferior to standard high-dose conditioning before allogeneic haematopoietic cell transplantation in acute leukaemias

To assess the role of allogeneic stem cell transplantation (SCT) after reduced-intensity conditioning (RIC) in acute leukaemias, we retrospectively compared 25 patients with acute lymphoblastic leukaemia or acute myelogenous leukaemia after RIC to a historical group of 50 matched controls after high-dose conditioning. Engraftment, acute GvHD and severe infections were comparable in both groups. During the observation period, 1/25 patients (4%) after RIC and 14/50 (28%) after standard SCT died due to transplant-related causes; cumulative nonrelapse mortality (NRM) was 4% after RIC and 24% after standard SCT (P=0.029). In total, 15/25 patients (60%) relapsed after RIC and 20/50 (40%) after standard SCT; probability of disease-free survival (DFS) at 3 years was 43% after RIC and 49% after standard SCT (NS). Overall survival (OS) was 40% after RIC and 37% after standard SCT (NS). Stage of disease, cytogenetic risk profile, acute and chronic GvHD, chimerism status at day 90 and severe infections after transplantation were risk factors with significant impact on DFS and/or OS. In retrospective analysis, patients with acute leukaemias who receive RIC because of contraindications against standard SCT have a comparable outcome to standard SCT, but the higher relapse rate warrants further studies.

Sequential Regimen of Chemotherapy, Reduced-Intensity Conditioning for Allogeneic Stem-Cell Transplantation, and Prophylactic Donor Lymphocyte Transfusion in High-Risk Acute Myeloid Leukemia and Myelodysplastic Syndrome

Purpose

To improve the effect of allogeneic stem-cell transplantation by sequential use of intensive chemotherapy, reduced-intensity conditioning (RIC), and prophylactic donor lymphocyte transfusions (pDLTs) in high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

Patients and Methods

In a prospective study of 75 consecutive patients (median age, 52.3 years), high risk was defined by progressive or refractory disease (n = 59), second remission after early relapse (n = 8), or first remission with poor prognosis based on cytogenetics or delayed response to induction therapy (n = 8). Unfavorable karyotypes were found in 49% of informative patients, and 68 patients had medical contraindications against standard conditioning. Fludarabine (30 mg/m2), cytarabine (2 g/m2), and amsacrine (100 mg/m2) for 4 days were used for cytoreduction. After 3 days of rest, RIC consisted of 4 Gy total-body irradiation, antithymocyte globulin, and 80 to 120 mg/kg cyclophosphamide. Thirty-one patients had an HLA-identical sibling donor; 44 patients had an unrelated and/or HLA-mismatched donor. pDLT was given from day +120 in patients who were not receiving immunosuppression and were free of graft-versus-host disease (GvHD).

Results

Complete remission was induced in 66 patients (88%). With a median follow-up of 35.1 months (range, 13.6 to 47.6 months), 2-year overall and leukemia-free survival were 42% and 40%, respectively. Outcome of patients with refractory disease or with complex cytogenetic aberrations was identical to that of better prognostic subgroups. Survival was best in patients who received high CD34+ cell numbers, and in patients with limited GvHD.

Conclusion

Sequential use of intensive chemotherapy, RIC transplantation, and pDLT represents a promising approach to the treatment of high-risk AML and MDS, particularly in patients with most unfavorable prognoses.

Intensive graft-versus-host disease prophylaxis is required after unrelated-donor nonmyeloablative stem cell transplantation

Nonmyeloablative stem cell transplantation (NST) harnesses the graft-versus-tumor effect while minimizing regimen-related toxicity, and can result in donor chimerism and remission. Acute graft-versus-host disease (GVHD) and infections are major complications after sibling NST. Toxicity of unrelated-donor (UD) NST and the most appropriate GVHD prophylaxis in this setting remain poorly defined. We describe 25 patients who received UD-NST conditioned with fludarabine and cyclophosphamide. The first six patients received cyclosporine (Cs) and mycophenolate mofetil (MMF) (n=5) or methotrexate (MTX) (n=1) as GVHD prophylaxis (group 1) and all developed grade III-IV acute GVHD. The next 19 patients received the same conditioning regimen with the addition of alemtuzumab, and all received Cs/MTX post-transplant. Engraftment and donor chimerism were achieved in all but one evaluable patient. In all, 15 patients died: five of six deaths in group 1 were attributable to acute GVHD, while deaths in group 2 were due to infection or progressive disease (P=0.05). The combination of Cs/MMF is inadequate GVHD prophylaxis for UD-NST. The use of Cs, MTX, and alemtuzumab eliminated severe acute GVHD; its impact on response merits further study.

Drug therapy for acute myeloid leukemia

Although improvement in outcomes has occurred in younger adults with acute myeloid leukemia (AML) during the past 4 decades, progress in older adults has been much less conspicuous, if at all. Approximately 50% to 75% of adults with AML achieve complete remission (CR) with cytarabine and an anthracycline such as daunorubicin or idarubicin or the anthracenedione mitoxantrone. However, only approximately 20% to 30% of the patients enjoy long-term disease survival. Various postremission strategies have been explored to eliminate minimal residual disease. The optimal dose, schedule, and number of cycles of postremission chemotherapy for most patients are not known. A variety of prognostic factors can predict outcome and include the karyotype of the leukemic cells and the presence of transmembrane transporter proteins, which extrude certain chemotherapy agents from the cell and confer multidrug resistance and mutations in or over expressions of specific genes such as WT1, CEBPA, BAX and the ratio of BCL2 to BAX, BAALC, EVI1, KIT, and FLT3. Most recently, insights into the molecular pathogenesis of AML have led to the development of more specific targeted agents and have ushered in an exciting new era of antileukemia therapy. Such agents include the immunoconjugate gemtuzumab ozogamicin, multidrug resistance inhibitors, farnesyl transferase inhibitors, histone deacetylase and proteosome inhibitors, antiangiogenesis agents, Fms-like tyrosine kinase 3 (FLT3) inhibitors, and apoptosis inhibitors.

Evidence for ineffective erythropoiesis in severe sickle cell disease

Peripheral destruction of sickled erythrocytes is a cardinal feature of sickle cell disease (SCD). Less well established is the potential contribution of ineffective erythropoiesis to the pathophysiology of this hemoglobinopathy. Since patients with SCD frequently develop mixed hematopoietic chimerism after allogeneic nonmyeloablative stem cell transplantation, we used this opportunity to directly compare the differentiation and survival of SCD and donor-derived erythropoiesis in vivo. Donor and recipient erythropoiesis was compared in 4 patients with SCD and 4 without SCD who developed stable mixed hematopoietic chimerism following transplant. Molecular analysis of chimerism in peripheral blood and bone marrow demonstrated higher expression of donor-derived beta-globin RNA relative to the level of donor-derived genomic DNA in patients with SCD. Analysis of chimerism in immature (glycophorin A-positive [GYPA(+)], CD71(hi)) and mature (GYPA(+), CD71(neg)) erythroblasts confirmed the intramedullary loss of SS erythroblasts with progressive maturation. In patients with SCD, relative enrichment of donor erythroid precursors began to appear at the onset of hemoglobinization. Ineffective erythropoiesis of homozygous hemoglobin S (SS) progenitors thus provides a maturation advantage for homozygous hemoglobin A (AA) or heterozygous hemoglobin S/hemoglobin A (SA) donor erythroid precursor cells that results in greater donor contribution to overall erythropoiesis following stem-cell transplantation and improvement of clinical disease.

Reduced-intensity conditioning containing low-dose alemtuzumab before allogeneic peripheral blood stem cell transplantation: graft-versus-host disease is decreased but T-cell reconstitution is delayed

OBJECTIVE

In vivo administration of alemtuzumab (an anti-CD52 antibody) is effective to decrease the incidence of graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (allo-SCT). However, posttransplant immune reconstitution is impaired, increasing the infection risk. We investigated the effect of in vivo administration of a low-dose alemtuzumab on GVHD prevention and kinetics of immune reconstitution.

PATIENTS AND METHODS

Twenty-seven patients entered a pilot study employing reduced-intensity conditioning and low-dose alemtuzumab (15 or 7.5 mg/m2) before peripheral blood allo-SCT from human leukocyte antigen-identical or one antigen-mismatched sibling donors. All lymphoid subsets were longitudinally studied at 1-3, 6, 9, 12 months after transplantation. T-cell receptor (TCR) spectratyping and T-cell receptor excision circles (TRECs) were also analyzed at various time points after allo-SCT.

RESULTS

All patients but one were engrafted. The probability of nonrelapse mortality at 100 days and 1 year were 7 and 11%, respectively; the overall survival at 2 years was 77%. The cumulative incidence of grade II-IV acute GVHD at day 100 was 11%. The overall incidence of chronic GVHD was 28%. The median time to achieve more than 200 CD4+/microL and 500 CD8+/microL were 6 and 9 months, respectively. Natural killer cells remained between the value of 300/microL and 500/microL throughout the period of follow-up whereas the median time to reach CD19+ blood concentrations of >200 cells/microL was 9 months. The normalization of TCR repertoire and increase of TREC counts began at 6 months after allo-SCT.

CONCLUSION

We have shown that low-dose alemtuzumab is effective for GVHD prevention, but its use still impairs the immune reconstitution.

Comparison between antithymocyte globulin and alemtuzumab and the possible impact of KIR-ligand mismatch after dose-reduced conditioning and unrelated stem cell transplantation in patients with multiple myeloma

We compared antithymocyte globulin (ATG) with alemtuzumab in 73 patients with multiple myeloma, who underwent reduced conditioning with melphalan/fludarabine, followed by allogeneic stem cell transplantation from human leucocyte antigen-matched or -mismatched unrelated donors. The ATG group had more prior high-dose chemotherapies (P < 0.001), while bone marrow was used more as the stem cell source in the alemtuzumab group (P < 0.001). Alemtuzumab resulted in faster engraftment of leucocytes (P = 0.03) and platelets (P = 0.02) and in a lower incidence of acute graft versus host disease (GvHD) grades II-IV (24% vs. 47%, P = 0.06). More cytomegalovirus (CMV) seropositive patients in the alemtuzumab group experienced CMV reactivation (100% vs. 47%, P = 0.001). The cumulative incidence of treatment-related mortality at 2 years was 26% [95% confidence interval (CI) = 12-37%] for ATG vs. 28% (95% CI = 15-55%) for alemtuzumab, P = 0.7. There was no significant difference in the estimated 2-year overall and progression-free survival between ATG and alemtuzumab: 54% (95% CI: 39-75%) vs. 45% (95% CI: 28-73%) and 30% (95% CI: 16-55%) vs. 36% (95% CI: 20-62%) respectively. In multivariate analysis, treatment with alemtuzumab had a higher risk for relapse (hazard ratio: 2.37; P = 0.05) while killer immunoglobulin-like receptor (KIR)-ligand mismatch was protective for relapse (P < 0.0001). We conclude that alemtuzumab produced less acute GvHD, but higher probability of relapse. The data implicated a major role of KIR-ligand mismatched transplantation in multiple myeloma.

The influence of blood group differences in allogeneic hematopoietic peripheral blood progenitor cell transplantation

BACKGROUND

Severe immunohematologic complications after ABO-mismatched allogeneic blood peripheral blood progenitor cell (PBPC) transplantation (PBPCT), including pure red cell aplasia and immune hemolysis, have been described. Although several studies have addressed this issue, the clinical influence of blood group differences on transfusion requirements and survival is still discussed controversially, especially in the case of PBPCT.

STUDY DESIGN AND METHODS

This single-center study is based on 143 patients receiving PBPCT after standard or reduced-intensity conditioning. The influence of blood group differences in the ABO, Rh, and Kell systems on red blood cell, platelet, and plasma transfusion requirements; length of hospitalization in transplantation unit; survival; and occurrence of graft-versus-host disease was investigated. Additionally, the influence of the conditioning regimen and irregular antibodies on the measures mentioned above was analyzed.

RESULTS

Multivariate analysis demonstrated that minor and bidirectional ABO mismatch (p = 0.028) and Rh difference (p = 0.020) independently led to poorer survival. The Kell difference did not show significant influences on the measures mentioned above. A clinically relevant influence of blood group differences on transfusion requirements could not be demonstrated. Irregular antibodies also did not show significant influences.

CONCLUSION

These findings indicate an influence of blood group differences in PBPCT on survival and must be studied in further detail.

Reduced-intensity stem-cell transplantation for adult acute lymphoblastic leukemia: a retrospective study of 33 patients

Efficacy of reduced-intensity stem-cell transplantation (RIST) for acute lymphoblastic leukemia (ALL) was investigated in 33 patients (median age, 55 years). RIST sources comprised 20 HLA-identical related donors, five HLA-mismatched related, and eight unrelated donors. Six patients had undergone previous transplantation. Disease status at RIST was first remission (n=13), second remission (n=6), and induction failure or relapse (n=14). All patients tolerated preparatory regimens and achieved neutrophil engraftment (median, day 12.5). Acute and chronic graft-versus-host disease (GVHD) developed in 45 and 64%, respectively. Six patients received donor lymphocyte infusion (DLI), for prophylaxis (n=1) or treatment of recurrent ALL (n=5). Nine patients died of transplant-related mortality, with six deaths due to GVHD. The median follow-up of surviving patients was 11.6 months (range, 3.5-37.3 months). The 1-year relapse-free and overall survival rates were 29.8 and 39.6%, respectively. Of the 14 patients transplanted in relapse, five remained relapse free for longer than 6 months. Cumulative rates of progression and progression-free mortality at 3 years were 50.9 and 30.4%, respectively. These findings suggest the presence of a graft-versus-leukemia effect for ALL. RIST for ALL is worth considering for further evaluation.

Reduced-intensity allogeneic hematopoietic stem cell transplantation for acute leukemias: ‘what is the best recipe?’

Reduced-intensity stem cell transplantation (RIST) has been shown to be a safe and useful alternative transplant method for patients including elderly and medically unfit patients. RIST conditioning regimens vary widely in the intensity of myeloablation, immunoablation, and antileukemia effects, and thus optimal regimen for each disease entity is yet to be determined. Most reports on RIST to date are small, single-institution experiences or retrospective studies with heterogeneous patient populations and primary diseases, complicating any direct comparison between studies. In acute myeloid leukemia (AML), moderate-intensity regimens may be effective, achieving 30-70% 1-year disease-free survival in various series, but minimal-intensity regimens are associated with high relapse rates. In acute lymphoblastic leukemia (ALL), not even moderate-intensity regimens are effective and most patients with advanced ALL relapse post transplant. Thus, the risk/benefit ratios of graft-versus-host disease/graft-versus-leukemia effect differ among diseases. Larger, prospective, multi-center clinical trials are needed to determine the best use of RIST in hematologic malignancies.

Control of advanced and refractory acute myelogenous leukaemia with sirolimus-based non-myeloablative allogeneic stem cell transplantation

Non-myeloablative conditioning has extended the use of allogeneic haematopoietic transplant to many previously ineligible patients. We added the immunosuppressive and antitumour agent sirolimus (rapamycin) to an established transplant regimen of fludarabine 25 mg/m(2) days -7 through -3 and cyclophosphamide 1000 mg/m(2) days -7 and -6, with tacrolimus and methotrexate immunoprophyllaxis. A total of 23 patients with acute myelogenous leukaemia (AML) were treated, with a median age of 59 years (range: 28-72) at transplant. Only seven patients in total were in complete remission prior to transplantation. Nine patients were in chemotherapy-refractory progression and seven were primarily refractory to induction therapy. Six patients received matched sibling, 11 unrelated donor, 1-5/6 matched and five haploidentical (haplo - three of six or four of six matched) transplants. The haplo-recipients also received antithymocyte globulin, all patients engrafted. Only two, both recipients of haploidentical cells, have died from transplant-related causes. Twelve of 23 patients survived at 198-1162-d post-transplant (median 578). Four of 12 survivors relapsed at 83, 88, 243 and 508 d and three were in remission after chemotherapy and donor lymphocyte infusion. Although follow up is short, this data suggests that non-myeloablative haematopoietic cell transplantation with sirolimus (rapamycin)-based immunosuppression may provide disease control over several years in some patients with advanced and poor prognosis AML.

Evaluation and Automation of Hematopoietic Chimerism Analysis Based on Real-Time Quantitative Polymerase Chain Reaction

Abstract Chimerism analysis is an essential tool in the follow-up of patients after allogeneic stem cell transplantation. High-resolution methods for chimerism analysis based on real-time quantitative polymerase chain reaction (RQ-PCR) with a detection limit of 0.1% marker-specific cells are especially valuable in the detection of patient-derived subpopulations for the monitoring of minimal residual disease. Using artificial chimeric mixtures of genotypically different cells, we optimized and evaluated the intrasample variation, accuracy, and detection limit of chimerism analysis based on RQ-PCR of short insertion and deletion polymorphisms. Furthermore, automated setup by robot was evaluated. The results were accurate, with acceptable intrasample variation at and above 0.1% marker-specific cells. The sensitivity was mainly limited by background values. Chimerism results based on RQ-PCR were similar to results based on PCR of short tandem repeats when samples from recipients of transplants with nonmyeloablative conditioning were analyzed. Furthermore, automated setup was feasible in a time-, labor-, and reagent-conserving manner.

Hematopoietic cell transplantation (HCT)-specific comorbidity index: a new tool for risk assessment before allogeneic HCT

We previously reported that the Charlson Comorbidity Index (CCI) was useful for predicting outcomes in patients undergoing allogeneic hematopoietic cell transplantation (HCT). However, the sample size of patients with scores of 1 or more, captured by the CCI, did not exceed 35%. Further, some comorbidities were rarely found among patients who underwent HCT. Therefore, the current study was designed to (1) better define previously identified comorbidities using pretransplant laboratory data, (2) investigate additional HCT-related comorbidities, and (3) establish comorbidity scores that were suited for HCT. Data were collected from 1055 patients, and then randomly divided into training and validation sets. Weights were assigned to individual comorbidities according to their prognostic significance in Cox proportional hazard models. The new index was then validated. The new index proved to be more sensitive than the CCI since it captured 62% of patients with scores more than 0 compared with 12%, respectively. Further, the new index showed better survival prediction than the CCI (likelihood ratio of 23.7 versus 7.1 and c statistics of 0.661 versus 0.561, respectively, P < .001). In conclusion, the new simple index provided valid and reliable scoring of pretransplant comorbidities that predicted nonrelapse mortality and survival. This index will be useful for clinical trials and patient counseling before HCT.

Successful Low Toxicity Hematopoietic Stem Cell Transplantation for High-Risk Adult Chronic Granulomatous Disease Patients

BACKGROUND

Allogeneic hematopoietic stem cell transplantation for chronic granulomatous disease (CGD) is associated with a significant risk of transplant-related mortality. Adult age, overt infection, and residual inflammatory disease at transplant are major risk factors.

METHODS

Here we report the favorable outcome after bone marrow transplantation in three high-risk adult CGD patients (ages 18, 35, and 39) with severe disease-related complications (overt pneumonia, liver abscess, steroid-dependent granulomatous colitis, diabetes, restrictive lung disease, renal insufficiency, epilepsia). Bone marrow donors were human leukocyte antigen-matched related or unrelated. The conditioning regimen consisted of 2 x 4 mg/kg oral busulphan (d -3, -2), fludarabine 6 x 30 mg/qm (d -7 to -2), rabbit anti-T-cell-globulin (Fresenius) 4 x 10 mg/kg (d -4 to -1). Graft versus host disease prophylaxis consisted of cyclosporine A and mycophenolate-mofetil.

RESULTS

Mean neutrophil and platelet engraftment was observed at day +18.5 and +22.5, respectively. All infectious and inflammatory lesions resolved and restrictive lung disease improved. No signs of grade II-IV acute or chronic graft versus host disease were observed. With a follow-up of 12 to 27 months, all patients are alive and well with full donor chimerism, normalized superoxide production, and documented T- and B-cell function.

CONCLUSION

This modified reduced intensity conditioning protocol is a promising treatment modality for high-risk adult CGD patients.

Engraftment of Allogeneic Hematopoietic Stem Cells Requires Both Inhibition of Host-Versus-Graft Responses and ‘Space' for Homeostatic Expansion

BACKGROUND

The establishment of host-versus-graft (HvG) tolerance is the primary aim of reduced intensity conditioning (RIC) regimens for allogeneic stem cell transplantation (SCT). It remains to be clarified to what extent recipient myeloablation is fundamental in the establishment of donor chimerism.

METHODS

We have addressed this question in a murine model of RIC SCT in which the donor-recipient combination produces HvG against the male specific minor histocompatibility antigen HY. In this system engraftment can be monitored by RT-PCR and HvG effectors enumerated by tetramer analysis.

RESULTS

We demonstrate that the dose of irradiation influences donor hemopoietic engraftment and affects generation of anti-donor specific T cells. Chimeric recipients do not mount a HvG immune response, becoming selectively tolerant, as demonstrated by the long term acceptance of skin grafts of donor but not third party origin. However, HvG tolerance is not sufficient to secure engraftment since, even in the absence of HvG, partial myeloablation was still required. The "space" produced by myeloablation and the consequent potential for donor cell expansion could also affect HvG tolerance, since its induction is severely impaired when donor hematopoietic cells have reduced proliferative capacity.

CONCLUSIONS

We conclude that both some degree of myeloablation and HvG tolerance are required for successful engraftment, and that the capacity of donor cells to proliferate influences the induction of HvG tolerance.

Prognostic relevance of 'early-onset' graft-versus-host disease following non-myeloablative haematopoietic cell transplantation

We retrospectively analysed outcomes among 395 patients with haematologic malignancies who underwent non-myeloablative haematopoietic cell transplantation (HCT) from human leucocyte antigen (HLA)-matched related (n = 297) or unrelated donors (n = 98) in order to identify a possible correlation between the time of onset of graft-versus-host disease (GVHD) and survival. The non-myeloablative regimen consisted of 2 Gy total body irradiation with or without fludarabine, followed by postgrafting immunosuppression with mycophenolate mofetil and cyclosporine. The cumulative incidences of grades II-IV acute GVHD and extensive chronic GVHD were 45% and 47%, respectively, with related donors, and 68% and 68%, respectively, with unrelated donors. High-dose corticosteroid treatment for acute or chronic GVHD was started at a median of 79 (range, 8-799) days and 30 (range, 5-333) days after transplantation from related and unrelated donors respectively. With related donors, the cumulative incidence of non-relapse mortality among patients with GVHD was 55% at 4 years when prednisone was started before day 50 (n = 72), compared with 29% when treatment was started after day 50 (n = 115) (P < 0.001). With unrelated donors, time to onset of treatment for GVHD was not associated with survival. Patients with early-onset GVHD after non-myeloablative HCT from HLA-identical related donors might benefit from intensified primary immunosuppressive treatment.

High doses of transplanted CD34+ cells are associated with rapid T-cell engraftment and lessened risk of graft rejection, but not more graft-versus-host disease after nonmyeloablative conditioning and unrelated hematopoietic cell transplantation

This report examines the impact of graft composition on outcomes in 130 patients with hematological malignancies given unrelated donor granulocyte-colony-stimulating-factor-mobilized peripheral blood mononuclear cells (G-PBMC) (n = 116) or marrow (n = 14) transplantation after nonmyeloablative conditioning with 90 mg/m(2) fludarabine and 2 Gy TBI. The median number of CD34(+) cells transplanted was 6.5 x 10(6)/kg. Higher numbers of grafted CD14(+) (P = 0.0008), CD3(+) (P = 0.0007), CD4(+) (P = 0.001), CD8(+) (P = 0.004), CD3(-)CD56(+) (P = 0.003), and CD34(+) (P = 0.0001) cells were associated with higher levels of day 28 donor T-cell chimerism. Higher numbers of CD14(+) (P = 0.01) and CD34(+) (P = 0.0003) cells were associated with rapid achievement of complete donor T-cell chimerism, while high numbers of CD8(+) (P = 0.005) and CD34(+) (P = 0.01) cells were associated with low probabilities of graft rejection. When analyses were restricted to G-PBMC recipients, higher numbers of grafted CD34(+) cells were associated with higher levels of day 28 donor T-cell chimerism (P = 0.01), rapid achievement of complete donor T-cell chimerism (P = 0.02), and a trend for lower risk for graft rejection (P = 0.14). There were no associations between any cell subsets and acute or chronic GVHD nor relapse/progression. These data suggest more rapid engraftment of donor T cells and reduced rejection rates could be achieved by increasing the doses of CD34(+) cells in unrelated grafts administered after nonmyeloablative conditioning.

Chronic myeloid leukemia: a model for oncology

Leukemias have traditionally served as model systems for research on neoplasia because of the easy availability of cell material from blood and marrow for diagnosis, monitoring and studies on pathophysiology. Beyond these more technical aspects, chronic myeloid leukemia (CML) became the first neoplasia in which the elucidation of the genotype led to a rationally designed therapy of the phenotype. Targeting of the pathogenetically relevant BCR-ABL tyrosine kinase with the selective kinase inhibitor imatinib has induced remissions with almost complete disappearance of any signs and symptoms of CML. This therapeutic success has triggered an intensive search for target structures in other cancers and has led to the development of numerous inhibitors of potential targets, which are being studied in preclinical and clinical trials worldwide. This review deals with some of the recent developments that have evolved since our last review in this journal in 2000 (Hehlmann R, Hochhaus A, Berger U, Reiter A (2000) Current trends in the management of chronic myelogenous leukemia.

Reduced-Intensity Conditioning Allogeneic Blood Stem Cell Transplantation with Fludarabine and Oral Busulfan with or without Pharmacokinetically Targeted Busulfan Dosing in Patients with Myeloid Leukemia Ineligible for Conventional Conditioning

We prospectively compared outcomes after a fludarabine (Flu) plus oral busulfan (Bu)-containing reduced-intensity conditioning regimen (150 mg/m2 Flu and 10 mg/kg oral Bu), with (n = 32; Flu- T Bu group) or without (n = 30; Flu-Bu group) therapeutic dose monitoring and dose adjustment of Bu. All patients received peripheral blood stem cells from a genoidentical sibling, and study cohorts had similar patient characteristics. Dose adjustments of Bu were required in 20 (63%) patients in the Flu- T Bu group (median final dose, 8.89 mg/kg; range, 6.3-13.34 mg/kg). Donor T-cell and granulocyte engraftments were similar, and early conditioning-related toxicities were mild and similar in both study groups. With a median follow-up of 45 months (51 months in the 37 survivors), posttransplantation outcomes did not differ between cohorts. The strongest predictor of 2-year overall survival and leukemia-free survival was the presence of chronic graft-versus-host disease (77% versus 34% for overall survival and 74% versus 34% for leukemia-free survival; P < .001 for both outcomes). In conclusion, therapeutic dose monitoring of oral Bu in a reduced-intensity conditioning setting does not seem to affect outcome, although further studies may identify very-high-risk patients who benefit from this strategy.

Hematopoietic stem cell transplantation for multiply transfused patients with sickle cell disease and thalassemia after low-dose total body irradiation, fludarabine, and rabbit anti-thymocyte globulin

Patients with sickle cell disease (N = 3) and thalassemia (N = 1) with high-risk features received hematopoietic stem cell transplantations (HCT) to induce stable (full or partial) donor engraftment. Patients were 9-30 years of age. Fludarabine, rabbit anti-thymocyte globulin (ATG), and 200 cGy total body irradiation were administered pre-transplant. Patients received bone marrow (N = 3) or peripheral blood stem cells (N = 1) from HLA-identical siblings, followed by mycophenolate mofetil and cyclosporine for post-grafting immunosuppression. Significant lymphopenia, but only moderate neutropenia and thrombocytopenia developed post transplant. No grade IV nonhematological toxicities or acute graft-versus-host disease (GVHD) were observed. At 3 months after transplantation, three of four patients had evidence of donor myeloid chimerism (range, 15-100%). However, after post transplant immunosuppression was discontinued, graft rejection occurred in all but one patient. This patient is now doing well 27 months post transplant with full donor engraftment. One patient died after a second transplant, and another patient experienced a stroke as her graft was being rejected. These results suggest that stable donor engraftment after nonmyeloablative HCT is difficult to achieve among immunocompetent patients with hemoglobinopathies and that new approaches will need to be developed before wider application of this transplantation method for hemoglobinopathies.

Outcome following alemtuzumab (CAMPATH-1H)-containing reduced intensity allogeneic transplant regimen for relapsed and refractory non-Hodgkin's lymphoma (NHL)

We report the outcome following RIT for NHL in 88 patients (LG-NHL n = 41, HG-NHL n = 37, MCL n = 10). Thirty-seven had received prior autografts and 21 were in CR at transplant. Conditioning was with alemtuzumab, fludarabine and melphalan. Sixty-five patients received PBSC from HLA-identical siblings and 23 received BM from matched unrelated donors. GVHD prophylaxis was with cyclosporin A. Grade III-IV acute GVHD developed in 4 patients and chronic GVHD in 6 patients. With a median follow-up of 36 months (range 18-60), the actuarial overall survival (OS) at 3 years was 34% for HG-NHL, 60% for MCL and 73% for LG-NHL (p < or = 0.001). The 100-day and 3-year TRM for patients with LG-NHL were 2% and 11%, respectively, and were better (p = 0.01) than for patients with HG-NHL (27% and 38%, respectively). The actuarial current progression free survival (PFS) at 3 years, including those who achieved remission following DLI for progression, was 65% for LG-NHL 50% for MCL and 34% for HG-NHL (p = 0.002). Twenty-one patients received DLI for MRD, persistent disease or relapse and 15 received DLI for mixed hematopoietic chimerism. Patients with relapsed LG-NHL and CLL achieve excellent PFS with extremely low TRM and GVHD, even when matched family donors are unavailable.

Use of a T cell-specific monoclonal antibody, T10B9, in a novel allogeneic stem cell transplantation protocol for hematologic malignancy high-risk patients

To reduce the toxicity of traditional conditioning regimens for allogeneic stem cell transplantation (allo-SCT), we used single-agent chemotherapy conditioning with either busulfan (total cumulative dose, 16 mg/kg) or melphalan (200 to 240 mg/m 2 ), followed by the anti-T cell-specific monoclonal antibody T10B9 (MEDI-500) daily for 3 days. T cell-replete SCT was performed from HLA-identical sibling donors. Acute graft-versus-host disease (aGVHD) prophylaxis consisted of 7 additional days of T10B9 and delayed onset of cyclosporine (ie, on day +4 or +5). Twenty-six high-risk hematologic malignancy patients were entered onto this study. All 24 patients who survived longer than 8 days engrafted, although 1 patient experienced late graft failure. Deaths occurred in 21 of 26 patients because of infection (n = 7), progression/recurrence of primary disease (n = 6), aGVHD (n = 4), regimen-related toxicity (n = 1), and other causes (n = 3). Five of these patients are enjoying disease-free survival with a median survival of 1193 days after allo-SCT. The conditioning regimen induced modulation of surface expression of CD3 (but not CD4 or CD8) and was associated with decreasing tumor necrosis factor-alpha (but not interleukin-6) serum levels. In conclusion, single-agent chemotherapy conditioning with T10B9 produced durable engraftment and long-term survival in some patients who would not have qualified for a traditional allo-SCT.

Kinetics of engraftment following allogeneic hematopoietic cell transplantation with reduced-intensity or nonmyeloablative conditioning

Nonmyeloablative or reduced-intensity conditioning regimens have been used to condition elderly or ill patients with hematological malignancies for allogeneic hematopoietic cell transplantation (HCT). Initial mixed donor/host chimerism (i.e. the coexistence of hematopoietic cells of host and donor origin) has been observed in most patients after such transplants. Here, we describe both factors affecting engraftment kinetics in patients given a nonmyeloablative or a reduced-intensity conditioning, and associations between peripheral blood cell subset chimerism levels and HCT outcomes.

Successful reduced-intensity stem cell transplantation (RIST) for a patient with malignant lymphoma and an ileostomy

A 56-year-old man was admitted for treatment of non-Hodgkin's lymphoma (NHL). He had undergone a partial small bowel and colon resection and had ileostomy due to bowel perforation induced by chemotherapy. After the operation, his disease status was in partial remission (PR), and reduced-intensity allogeneic stem cell transplantation (RIST) was therefore performed for further improvement of disease status. The conditioning regimen consisted of fludarabine and busulfan. Graft-versus-host disease (GVHD) prophylaxis was performed using cyclosporin and short-term methotrexate. The occurrence of serious infection during the period of neutropenia was prevented by the administration of amphotericin B, fluconazole and acyclovir. This case report provides important information on the appropriate strategy for treating patients who have ileostomy.

CD52 and CD45 monoclonal antibodies for reduced intensity hemopoietic stem cell transplantation from HLA matched and one antigen mismatched unrelated donors

Allogeneic hemopoietic stem cell transplantation (HSCT) is the only curative option for many patients with hematological malignancies. Since many of these patients lack HLA-identical sibling donors and are older or have comorbidity, a fully ablative HSCT is not feasible and an alternative approach is required. We studied 22 consecutive patients who could not have myeloablative conditioning because of comorbidity or age - 21/22 being over the age of 50 years (median 58 years range 20-70 years). A conditioning regimen consisting of fludarabine, total body radiation 450 cGy and alemtuzumab (CD52 mAb) was used for 15 patients. A second group of seven patients received CD45 monoclonal antibodies in addition. Unrelated donor stem cells were HLA matched (15 patients - 68%) or one locus mismatched (seven patients - 32%). In all, 16 patients had high-risk disease, including 12 with active malignancy at the time of transplant. With a median follow-up of 715 (216-1470) days, nonrelapse mortality, actuarial event-free and overall survival is 27, 45 and 45%, respectively. Hence the outcome of reduced intensity HSCT with lymphodepleting antibodies in older patients with intermediate/high-risk hematological malignancies appears comparable to that obtained with fully ablative transplantation in younger patients, even when these older recipients lack HLA-identical sibling donors.

Allogeneic hematopoietic cell transplantation for metastatic renal cell carcinoma after nonmyeloablative conditioning: toxicity, clinical response, and immunological response to minor histocompatibility antigens

PURPOSE

This phase I trial assessed the safety, efficacy, and immunologic responses to minor histocompatibility antigens following nonmyeloablative allogeneic hematopoietic cell transplantation as treatment for metastatic renal cell carcinoma.

EXPERIMENTAL DESIGN

Eight patients received conditioning with fludarabine and low-dose total body irradiation followed by hematopoietic cell transplantation from an HLA-matched sibling donor. Cyclosporine and mycophenolate mofetil were administered as posttransplant immunosuppression. Patients were monitored for donor engraftment of myeloid and lymphoid cells, for clinical response by serial imaging, and for immunologic response by in vitro isolation of donor-derived CD8(+) CTLs recognizing recipient minor histocompatibility (H) antigens.

RESULTS

All patients achieved initial mixed hematopoietic chimerism with two patients rejecting their graft and recovering host hematopoiesis. Four patients developed acute, grade 2 to 3, graft-versus-host disease and four patients developed extensive chronic graft-versus-host disease. Five patients had progressive disease, two patients had stable disease, and one patient experienced a partial response after receiving donor lymphocyte infusions and IFN-alpha. CD8(+) CTL clones recognizing minor H antigens were isolated from five patients studied. Clones from three patients with a partial response or stable disease recognized antigens expressed on renal cell carcinoma tumor cells.

CONCLUSIONS

Treatment of metastatic renal cell carcinoma with allogeneic hematopoietic cell transplantation after nonmyeloablative conditioning with fludarabine/total body irradiation is feasible and may induce tumor regression or stabilization in some patients. CD8(+) CTL-recognizing minor H antigens on tumor cells can be isolated posttransplant and could contribute to the graft-versus-tumor effect. Such antigens may represent therapeutic targets for posttransplant vaccination or adoptive T-cell therapy to augment the antitumor effects of allogeneic hematopoietic cell transplantation.

Nonmyeloablative stem cell transplantation in metastatic renal cell carcinoma: delayed graft-versus-tumor effect is associated with chimerism conversion but transplantation has high toxicity

Seven out of 29 patients with metastatic renal cell carcinoma (RCC) considered eligible for allogeneic stem cell transplantation underwent nonmyeloablative stem cell transplantation (NST) from HLA-identical donors. Conditioning comprised cyclophosphamide, fludarabine and antithymocyte globulin. Prolonged mixed chimerism (MC) after engraftment converted to complete donor chimerism (CC) after infusion of donor lymphocytes and/or graft-versus-host disease (GvHD) in six patients. Five patients developed severe GvHD. Two of seven patients had a delayed tumor response after conversion to CC. After a median follow-up of 10 months (4-24 months), 5/7 patients are alive, one in very good partial remission (PR), one with stable and three with progressive disease. One of the seven patients died from sepsis in PR and 1/7 died from rapid tumor progression after sustained MC. None of the 22 nontransplanted patients responded to further therapies. Survival after 1 year was 59% in transplanted and 66% in nontransplanted patients (n.s.). A pooled data analysis from the literature suggests a graft-versus-tumor effect after transplant in patients with metastatic RCC, which becomes effective after chimerism conversion. Available data demonstrate high nonrelapse mortality in these patients. NST in RCC still has to be regarded as an investigational approach requiring careful patients' selection and longer follow-up within clinical studies.

Pilot study of reduced-intensity conditioning followed by allogeneic stem cell transplantation from related and unrelated donors in patients with myelofibrosis

A prospective pilot study was performed to evaluate the effect of reduced-intensity conditioning with busulphan (10 mg/kg), fludarabine (180 mg/qm) and anti-thymocyte globulin followed by allogeneic stem cell transplantation from related (n = 8) and unrelated donors (n = 13) in 21 patients with myelofibrosis. The median age of the patients was 53 years (range, 32-63). No primary graft failure occurred. The median time until leucocyte (>1.0 x 10(9)/l) and platelet (>20 x 10(9)/l) engraftment was 16 (range, 11-26) and 23 d (range, 9-139) respectively. Complete donor chimaerism on day 100 was seen in 20 patients (95%). Acute graft-versus-host disease (GvHD) grades II-IV and III/IV occurred in 48% and 19% of cases and 55% of the patients had chronic GvHD. Treatment-related mortality was 0% at day 100 and 16% [95% confidence interval (CI): 0-32%] at 1 year. Haematological response was seen in 100% and complete histopathological remission was observed in 75% of the patients and 25% of the patients showed partial histopathological remission with a continuing decline in the grade of fibrosis. After a median follow-up of 22 months (range, 4-59), the 3-year estimated overall and disease-free survival was 84% (95% CI: 67-100%).

Cyclosporine A and Mycophenolate Mofetil vs Cyclosporine A and Methotrexate for graft-versus-host disease prophylaxis after stem cell transplantation from HLA-identical siblings

The combination of Cyclosporin A (CSA) and Methotrexate (MTX) is considered to be the standard regimen for the prevention of graft-versus-host disease (GVHD) after stem cell transplantation (SCT) from HLA-identical siblings. Mycophenolate Mofetil (MMF) has been widely used for GVHD prophylaxis after nonmyeloablative SCT, but experience following myeloablative therapy is still limited. We retrospectively compared CSA/MTX and CSA/MMF in 93 patients (median age 35 years, range 17-59 years, male subjects 48, female subjects 45) with acute myeloid leukemia (n=33), myelodysplastic syndrome (MDS) (n=3), acute lymphoblastic leukemia (ALL) (n=20) or chronic myeloid leukemia (n=37) who received CSA/MMF (n=26) or CSA/MTX (n=67) as GVHD prophylaxis following high-dose therapy and allogeneic SCT from HLA-identical siblings. No statistically significant differences were found in overall survival, relapse rate, treatment-related mortality and acute or chronic GVHD. Time to myeloid recovery was significantly shorter in patients who received CSA/MMF. We conclude that the combination of CSA/MMF appears equivalent to CSA/MTX for GVHD prophylaxis in patients receiving conventional-intensity SCT from HLA-identical siblings.

Graft-versus-tumor effects after allogeneic hematopoietic cell transplantation with nonmyeloablative conditioning

PURPOSE

We have used a nonmyeloablative conditioning regimen consisting of total-body irradiation (2 Gy) with or without fludarabine (30 mg/m(2)/d for 3 days) for related and unrelated hematopoietic cell transplantation (HCT) in patients with hematologic malignancies who were not candidates for conventional HCT because of age, medical comorbidities, or preceding high-dose HCT. This approach relied on graft-versus-tumor (GVT) effects for control of malignancy.

PATIENTS AND METHODS

We analyzed GVT effects in 322 patients given grafts from HLA-matched related (n = 192) or unrelated donors (n = 130).

RESULTS

Of the 221 patients with measurable disease at HCT, 126 (57%) achieved complete (n = 98) or partial (n = 28) remissions. In multivariate analysis, there was a higher probability trend of achieving complete remissions in patients with chronic extensive graft-versus-host disease (GVHD; P = .07). One hundred eight patients (34%) relapsed or progressed. In multivariate analysis, achievement of full donor chimerism was associated with a decreased risk of relapse or progression (P = .002). Grade 2 to 4 acute GVHD had no significant impact on the risk of relapse or progression but was associated with increased risk of nonrelapse mortality and decreased probability of progression-free survival (PFS). Conversely, extensive chronic GVHD was associated with decreased risk of relapse or progression (P = .006) and increased probability of PFS (P = .003).

CONCLUSION

New approaches aimed at reducing the incidence of grade 2 to 4 acute GVHD might improve survival after allogeneic HCT after nonmyeloablative conditioning.

Hematopoietic cell transplantation after nonmyeloablative conditioning for advanced chronic lymphocytic leukemia

PURPOSE

Patients with chemotherapy-refractory chronic lymphocytic leukemia (CLL) have a short life expectancy. The aim of this study was to analyze the outcome of patients with advanced CLL when treated with nonmyeloablative conditioning and hematopoietic cell transplantation (HCT).

PATIENTS AND METHODS

Sixty-four patients diagnosed with advanced CLL were treated with nonmyeloablative conditioning (2 Gy total-body irradiation with [n = 53] or without [n = 11] fludarabine) and HCT from related (n = 44) or unrelated (n = 20) donors. An adapted form of the Charlson comorbidity index was used to assess pretransplantation comorbidities.

RESULTS

Sixty-one of 64 patients had sustained engraftment, whereas three patients rejected their grafts. The incidences of grades 2, 3, and 4 acute and chronic graft-versus-host disease were 39%, 14%, 2%, and 50%, respectively. Three patients who underwent transplantation in complete remission (CR) remained in CR. The overall response rate among 61 patients with measurable disease was 67% (50% CR), whereas 5% had stable disease. All patients with morphologic CR who were tested by polymerase chain reaction (n = 11) achieved negative molecular results, and one of these patients subsequently experienced disease relapse. The 2-year incidence of relapse/progression was 26%, whereas the 2-year relapse and nonrelapse mortalities were 18% and 22%, respectively. Two-year rates of overall and disease-free survivals were 60% and 52%, respectively. Unrelated HCT resulted in higher CR and lower relapse rates than related HCT, suggesting more effective graft-versus-leukemia activity.

CONCLUSION

CLL is susceptible to graft-versus-leukemia effects, and allogeneic HCT after nonmyeloablative conditioning might prolong median survival for patients with advanced CLL.

HLA-matched unrelated donor hematopoietic cell transplantation after nonmyeloablative conditioning for patients with chronic myeloid leukemia

We evaluated 10/10 HLA antigen-matched unrelated hematopoietic cell transplantation (HCT) after nonmyeloablative conditioning with fludarabine 3 x 30 mg/m2 and 2 Gy of total body irradiation as treatment for patients with chronic myeloid leukemia who were ineligible for conventional HCT. Data from 21 consecutive patients in first chronic phase (CP1; n = 12), accelerated phase (AP; n = 5), second CP (CP2; n = 3), and blast crisis (n = 1) were analyzed. Stem cell sources were bone marrow (n = 4) or granulocyte colony-stimulating factor-mobilized peripheral blood mononuclear cells (G-PBMCs; n = 17). The patient who underwent transplantation in blast crisis died on day 21 (too early to be evaluated for engraftment) from progressive disease. Sustained engraftment was achieved in 5 of 12 patients who underwent transplantation in CP1, 4 of 5 patients who underwent transplantation in AP, and 2 of 3 patients who underwent transplantation in CP2, whereas 9 patients rejected their grafts between 28 and 400 days after HCT. Specifically, 1 of 4 marrow recipients and 10 of 17 G-PBMC recipients achieved sustained engraftment. Graft rejections were nonfatal in all cases and were followed by autologous reconstitution with persistence or recurrence of chronic myeloid leukemia. Seven of 11 patients with sustained engraftment--including all 5 patients in CP1, 2 of 4 patients in AP, and neither of the 2 patients in CP2--were alive in complete cytogenetic remissions 118 to 1205 days (median, 867 days) after HCT. Two of the remaining 4 patients died of nonrelapse causes in complete (n = 1) or major (n = 1) cytogenetic remissions, and 2 died of progressive disease. Further efforts are directed at reducing the risk of graft rejection by exclusive use of G-PBMC and increasing the degree of pretransplantation immunosuppression.

Hematopoietic cell transplantation from HLA-identical sibling donors after low-dose radiation-based conditioning for treatment of CML

A total of 24 patients (median age 58; range, 27-71 years) with chronic myeloid leukemia (CML) in first chronic (CP1) (n=14), second chronic (n=4), or accelerated phase (n=6) who were not candidates for conventional hematopoietic cell transplantation (HCT), received nonmyeloablative HCT from HLA-matched siblings a median of 28.5 (range, 11-271) months after diagnosis. They were conditioned with 2 Gy total body irradiation (TBI) alone (n=8) or combined with fludarabine, 90 mg/m(2) (n=16). Postgrafting immunosuppression included cyclosporine and mycophenolate mofetil. All patients initially engrafted. However, 4 of 8 patients not given fludarabine experienced nonfatal rejection while all others had sustained engraftment. With a median follow-up of 36 (range, 4-49) months, 13 of 24 patients (54%) were alive and in complete remission. There were five (21%) deaths from nonrelapse mortality, one (4%) during the first 100 days after transplant. The proportions of grade II, III, and IV acute GVHD were 38, 4, and 8%, respectively. The 2-year estimate of chronic GVHD was 32%. The 2-year survival estimates for patients in CP1 (n=14) and beyond CP1 (n=10) were 70 and 56%, respectively. This study shows encouraging remission rates for patients with CML not eligible for conventional allografting.

Unrelated donor hematopoietic stem cell transplantation for patients with hematologic malignancies using a nonmyeloablative conditioning regimen of fludarabine, low-dose total body irradiation, and rabbit antithymocyte globulin

Hematopoietic stem cell chimerism can be established after low-dose conditioning regimens, although the risk of donor cell rejection increases for unrelated donor transplantations. We added pretransplantation rabbit antithymocyte globulin (6 mg/kg) to an established conditioning regimen of fludarabine (90 mg/m2) and single-fraction total body irradiation (200 cGy) followed by postgrafting immunosuppression with cyclosporine A and mycophenolate mofetil for 22 patients with hematologic malignancies. One patient rejected the graft and successfully underwent transplantation with cells from a second donor by using the same conditioning regimen. The actuarial probability of developing acute graft-versus-host disease grade II to IV before day 100 was 40%, although 9 of 14 patients who survived beyond 100 days developed chronic graft-versus-host disease. These data support a hypothesis that the addition of antithymocyte globulin decreases the risk of graft-versus-host and host-versus-graft reactions when combined with a nonmyeloablative conditioning regimen of fludarabine and total body irradiation.

Perspective: fundamental and clinical concepts on stem cell homing and engraftment: a journey to niches and beyond

In many ways, the homing of hematopoietic stem cells to bone marrow and other tissues defines these cells and their immediate and long-term fates Once homed, an inevitable series of proliferative and differentiative events presumptively follows. These comments, of course, hold for both homing to marrow, or alternatively, to other nonmarrow tissues. In this review, we will specifically focus on homing and engraftment to bone marrow because this is the best-studied and clinically applicable system.

Regimen-related toxicity following reduced-intensity stem-cell transplantation (RIST): comparison between Seattle criteria and National Cancer Center Common Toxicity Criteria (NCI-CTC) version 2.0

Acute regimen-related toxicity (RRT) is minimal in reduced-intensity stem-cell transplantation (RIST). However, the Seattle RRT grading (Bearman et al), developed in the context of conventional-intensity transplantation, is frequently applied to RIST. We compared the National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 2.0 with the Seattle criteria after RIST in 86 patients. RRT within 30 days of transplant graded by both sets of criteria were significantly associated with the outcome confirming the predictive value of both the systems. A total of 15 patients died of disease progression, and 12 of transplant-related mortality: RRT (n = 2), graft-versus-host disease (GVHD) (n = 7), infection (n = 1), and others (n = 2). GVHD-related deaths primarily resulted from infections after steroid treatment (n = 6) and bronchiolitis obliterans (n = 1). This study shows that NCI-CTC is appropriate in toxicity evaluation of RIST, and that its application to RIST enables a toxicity comparison between RIST and other types of cancer treatments. Since GVHD is a significant problem in RIST, modifications are required to evaluate immunological complications following RIST.

Allogeneic immune replacement as cancer immunotherapy

The graft-versus-leukaemia (GVL) reaction that occurs after allogeneic haematopoietic cell transplantation (HCT) can cure patients with a variety of haematological malignancies. A heightened appreciation of the GVL effect has resulted in the development of reduced intensity transplant approaches, where antitumour effects occur predominantly as a consequence of the transplanted donor immune system. The recent success of these transplants in patients with acute and chronic leukaemias has led to trials investigating for graft-versus-tumour (GVT) effects in patients with treatment-refractory metastatic solid tumours. This review discusses evidence that immune replacement following allogeneic HCT is a potent form of cancer immunotherapy for patients with haematological and non-haematological malignancies.

Anti-tumour response despite loss of donor chimaerism in patients treated with non-myeloablative conditioning and allogeneic stem cell transplantation

Based on a murine model, we conducted a series of trials of m-myeloablative human leucocyte antigen (HLA)-matched or mismatched related donor stem cell transplantation (SCT) with the intention of inducing mixed chimaerism (MC), then administering prophylactic donor lymphocyte infusions (DLIs), for the treatment of advanced haematologic malignancies. Preparative therapy consisted of cyclophosphamide, equine anti-thymocyte globulin (ATG) or MEDI-507 (an anti-CD2 monoclonal antibody) for in-vivo T-cell depletion, thymic irradiation on day -1 and cyclosporine alone for graft-versus-host disease (GVHD) prophylaxis. DLIs were given as early as 5 weeks post-SCT in patients with MC without evidence of GVHD. Twenty-two patients ultimately lost their graft (<1% donor cells) that could no be rescued by DLIs. Nine of 22 (41%) patients who lost donor chimaerism achieved an objective response, including three patients who showed evidence of disease regression following DLI, despite continued absence of macrochimaerism. Six patients were alive at 2.5-5.5 years following SCT, including four in continuous complete remission. In summary, it is possible to achieve sustained remission in patients with chemorefractory malignancies following non-myeloablative allogeneic SCT, even in the absence of sustained donor macrochimaerism; DLI may contribute to an ongoing anti-tumour effect in these patients. Immunological mechanisms that correlated with rejection of the graft may have a role in anti-tumour responses via a cell or cytokine-mediated pathway.

Cyclosporine and mycophenolate mofetil prophylaxis with fludarabine and melphalan conditioning for unrelated donor transplantation: a prospective study of 22 patients with hematologic malignancies

In an attempt to decrease toxicity in high-risk patients undergoing unrelated donor hematopoietic stem cell transplantation (URD HSCT), we tested a combination of cyclosporine (CSP) and mycophenolate mofetil (MMF) as graft-versus-host disease (GVHD) prophylaxis with the reduced-intensity conditioning regimen fludarabine/melphalan (Flu/Mel). A total of 22 adult patients with advanced myeloid (n=15) and lymphoid (n=7) malignancies were treated. All patients received Flu 25 mg/m2 for 5 days and Mel 140 mg/m2, with CSP 3 mg/kg daily and MMF 15 mg/kg three times a day. The median age was 49 years (range 18-66). Durable engraftment was seen in all but one patient with myelofibrosis. The 1-year nonrelapse mortality was 32%, 27% from GVHD. The cumulative incidence of acute GVHD grade 2-4 and 3-4 was 63 and 41%, respectively. With a median follow-up of 18 months, the disease-free survival (DFS) and overall survival (OS) are 55 and 59%, respectively. For patients with AML and MDS (n=14), the DFS and OS is 71%. For patients undergoing a second transplant (n=14), the DFS and OS is 57%. In conclusion, this regimen is associated with acceptable toxicity but high rates of GVHD in high-risk patients undergoing URD HSCT. Encouraging disease control for patients with advanced myeloid malignancies was observed.

The role of allogeneic transplantation in non-Hodgkin's lymphoma

The evolution of combination chemotherapy regimens, combined with improvements in supportive care, has incrementally improved survival outcomes for patients with non-Hodgkin's lymphomas (NHL). Although 40-60% of younger patients with diffuse large cell lymphoma can now expect to be cured, significant numbers will either fail to achieve a remission or relapse after attaining a remission. In addition, certain histological subtypes are associated with particularly poor prognoses with combination chemotherapy alone (e.g. mantle cell lymphoma, B-cell prolymphocytic leukaemia). Relatively few of these patients can achieve long-term responses. Other NHL subtypes, whilst associated with more favourable prognoses in terms of overall survival, are rarely, if ever, cured (e.g. most low grade NHL including follicular lymphoma, chronic lymphocytic leukaemia and small lymphocytic lymphoma). For these reasons dose escalation and allogeneic transplantation have been investigated as potential ways of improving outcome, although this has mainly been in the setting of advanced disease. Any possible benefits have frequently been out-weighed by procedural morbidity and mortality. The parallel development of transplantation approaches that limit procedural toxicity along with advances in supportive care require that the role of allogeneic haematopoietic stem cell transplantation in the management of lymphoma be re-evaluated.