Reduced-intensity conditioning for unrelated donor hematopoietic stem cell transplantation as treatment for myeloid malignancies in patients older than 55 years

Recombinant human erythropoietin therapy after allogeneic hematopoietic cell transplantation with a nonmyeloablative conditioning regimen: Low donor chimerism predicts for poor response

PURPOSE

After allogeneic hematopoietic stem cell transplantation with nonmyeloablative conditioning (NMHCT), many patients experience prolonged anemia and require red blood cell (RBC) transfusions. We enrolled 60 consecutive patients undergoing NMHCT in a phase II trial to determine the optimal utilization of recombinant human erythropoietin (rHuEPO) therapy in this setting.

PATIENTS AND METHODS

The first 14 NMHCT recipients did not receive rHuEPO (control group). Nineteen patients were scheduled to start rHuEPO on day 0 (EPO group 2) and 27 patients on day 28 after the transplant (EPO group 1). RHuEPO was administered subcutaneously once weekly at a dose of 500 U/kg/wk with the aim of achieving hemoglobin (Hb) levels of 13 g/dL. The 3 groups were well balanced for major characteristics.

RESULTS

During the first month (p < 0.0001) as well as days 30 to 100 (p < 0.0001) and days 100 to 180 (p < 0.0001), Hb values were higher in patients receiving rHuEPO compared to those not receiving it. However, transfusion requirements were significantly decreased only in the first month in EPO group 2 (p = 0.0169). T-cell chimerism above 60% on day 42 was the best predictor of Hb response (p < 0.0001) or Hb correction (p = 0.0217), but myeloid chimerism above 90% also predicted for Hb response (p = 0.0069). Hb response was also decreased in patients receiving CD8-depleted grafts and increased in the few patients not receiving TBI, but only in univariate analysis.

CONCLUSIONS

Anemia after NMHCT is sensitive to rHuEPO therapy, but less so than after conventional allogeneic HCT. RHuEPO decreases transfusion requirements only in the first 30 days posttransplant. T-cell chimerism below 60% on day 42 impaired Hb response, suggesting possible inhibition of donor erythropoiesis by residual recipient lymphocytes. A prospective randomized trial should be performed with rHuEPO starting on the day of transplantation to assess its clinical benefit in terms of transfusion requirements and quality of life.

Allogeneic transplantation for the elderly patient with acute myelogenous leukemia or myelodysplastic syndrome

Acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) are diseases of the elderly. Allogeneic hematopoietic stem cell transplantation (HSCT) offers the possibility of cure for these malignancies, but until recently its use was restricted to younger patients due to prohibitive treatment-related mortality. Improvements in supportive care and development of reduced-intensity preparative regimens have allowed patients in the sixth, seventh, and to a lesser extent, eighth decade of life to be treated with allogeneic transplantation. Major obstacles to extending this form of treatment to older patients are lack of promptly available donors, graft-versus-host disease (GVHD), delayed immune recovery, and the high prevalence of refractory and relapsed disease intrinsic to the natural history of these myeloid malignancies. Here we review current results of allogeneic blood and marrow transplantation for AML and MDS in the elderly.

The role of purine analogues in low-intensity regimens with allogeneic hematopoietic stem cell transplantation

Host conditioning prior to allogeneic bone marrow transplantation (BMT) has traditionally involved the use of high-dose, myeloablative chemotherapy and irradiation, focusing on maximal tumor cytoreduction as well as adequate immunosuppression to allow engraftment of allogeneic stem cells. High-dose chemoradiation conditioning regimens have been associated with a significant incidence of organ toxicity and acute and chronic graft-versus-host disease (GVHD). Recent efforts to diminish the acute transplant-associated toxicities have focused on the development of relatively nontoxic, nonmyeloablative, or less myeloablative conditioning regimens, with the emphasis being predominantly on induction of immunosuppression to enable engraftment. Without ablative chemotherapy, disease control in these regimens is largely relegated to the graft-versus-leukemia/lymphoma (GVL) effect. While the evolution these regimens has resulted in successful engraftment of allogeneic stem cells with minimal toxicity, acute and chronic GVHD occurs in 20% to 50% of patients and remains a major cause of transplant-associated morbidity. Strategies to lower the incidence of acute GVHD have primarily focused on more precise molecular donor/recipient matching, alternative stem cell sources, and T-cell depletion of the graft. While successful in lowering the frequency and severity of GVHD, T-cell-depleted grafts have been associated with compromised the graft-versus-disease effect. Recent studies have suggested that, in addition to T-effector cells within the graft, donor and host dendritic cells may play a role in GVHD. Purine analogues have been evaluated as part of these regimens. While fludarabine and cladribine have been shown to be effective, these agents have been associated with an increased incidence of serious infection and severe acute GVHD. Pentostatin has a different mechanism of action and was also investigated as part of these preparative regimens. Regimens using pentostatin/extracorporeal photopheresis (ECP)/total body irradiation (TBI) have been shown to be well tolerated and associated with early full donor engraftment with a predominance of donor dendritic cell (DC)2 cells and a low incidence of acute GVHD. Further investigation evaluating this preparative regimen is warranted.

Outcome of reduced-intensity allogeneic hematopoietic stem cell transplantation (RISCT) using antilymphocyte antibodies in patients with high-risk acute myeloid leukemia (AML)

Hemopoietic stem cell transplantation (SCT) with fully ablative conditioning is associated with an age-related increase in treatment-related mortality. It is therefore particularly unsuited to older individuals, who are most at risk of developing acute myeloid leukemia (AML). Reduced-intensity SCT (RISCT) may be of value in this group. We report 17 consecutive patients with high-risk AML whose median age was 58 years and who received stem cells from HLA-matched siblings (n=5), or alternative donors (n=12). We used lymphodepleting antibodies as a part of the reduced-intensity conditioning regimen to limit the risk of graft rejection and graft-versus-host disease (GVHD). All patients engrafted. One patient developed severe fatal GVHD, and two patients died of infection. At a median follow-up of 861 days (372-1957 days), seven patients are alive in remission, which includes two patients treated in relapse and five patients who lacked an MHC identical sibling donor. Both progression-free survival and overall survival are 40% (95% CI, 17-64%). Hence, RISCT using lymphodepleting antibodies may be of value for older patients with AML, even in those with active or high-risk disease, and even if they lack an MHC-identical sibling donor.

Stable Engraftment after a Conditioning Regimen with Fludarabine and Melphalan for Bone Marrow Transplantation from an Unrelated Donor

Graft failure and nonrelapse mortality (NRM) are major obstacles after the first unrelated-donor bone marrow transplantation (UD-BMT) with reduced-intensity conditioning. We evaluated UD-BMT with fludarabine (5 x 25 mg/m2) and melphalan (2 x 90 mg/m2) treatment combined with short-term methotrexate and tacrolimus (n = 20) or cyclosporine (n = 2) therapy for 22 patients with hematologic malignancies who were ineligible for conventional conditioning. Only 9 patients were in remission at transplantation. Seventeen patients underwent HLA-matched or DRB1 allele-mismatched transplantation, and 5 patients underwent HLA-A allele-mismatched or serologically HLA-DR-mismatched transplantation. Regimen-related toxicities were tolerable, although transient oral mucositis, hepatobiliary enzyme elevation, and diarrhea were observed frequently. All evaluable patients achieved sustained neutrophil engraftment, and all patients tested showed complete donor chimerism on day 28. With a median follow-up of 16 months, NRM and overall survival rates at 1 year were 19% and 81%, respectively, among the patients who underwent HLA-matched or DRB1 allele-mismatched transplantation. Acute graft-versus-host disease (GVHD) of grades II to IV occurred in 26% of the patients. The cumulative incidence of chronic GVHD was 44%. Despite the small number of patients and the short follow-up period, this reduced-intensity regimen enabled satisfactory engraftment and achievement of rapid complete donor chimerism with tolerable toxicities in the patients, including those who underwent HLA-mismatched UD-BMT.

Fludarabine phosphate and melphalan: a reduced intensity conditioning regimen suitable for allogeneic transplantation that maintains the graft versus malignancy effect

Reduced intensity conditioning (RIC) for allogeneic stem cell transplantation allows stable donor cell engraftment with the maintenance of a graft versus malignancy effect. Many different regimens exist employing various combinations of chemotherapy, radiotherapy and T-cell depletion. We examined the role of non-T-cell depleted RIC regimens in 56 patients with haematological malignancies. Patients received fludarabine phosphate for 5 days (30 mg/m2 in 35 patients, 25 mg/m2 in 21 patients) and melphalan for 1 day (140 mg/m2 in 36 patients, 100 mg/m2 in 20 patients). Immunosuppression was with CyA alone in 33 patients and CyA/MTX in 23 patients. Twenty-four of the 26 patients with chimerism data showed >95% donor chimerism at 3 months post transplant. aGVHD occurred in 18% of patients receiving CyA/MTX compared to 53% of patients receiving CyA. The 100-day mortality rate was 0.16 (95%CI 0.08-0.28) and 1-year nonrelapse mortality was 0.24 (95%CI 0.13-0.38). Thirty-three patients remained alive and in CR at a median of 19 months post transplant (range 3-38 months). We have shown that patients transplanted with fludarabine phosphate, melphalan 100 mg/m2 and with CyA/MTX as post transplant immunosuppression can achieve good disease control with an acceptable level of toxicity. Further studies are required to confirm these findings.

Comparative outcome of reduced intensity and myeloablative conditioning regimen in HLA identical sibling allogeneic haematopoietic stem cell transplantation for patients older than 50 years of age with acute myeloblastic leukaemia: a retrospective survey from the Acute Leukemia Working Party (ALWP) of the European group for Blood and Marrow Transplantation (EBMT)

Results of reduced intensity conditioning regimen (RIC) in the HLA identical haematopoietic stem cell transplantation (HSCT) setting have not been compared to those after myeloablative (MA) regimen HSCT in patients with acute myeloblastic leukaemia (AML) over 50 years of age. With this aim, outcomes of 315 RIC were compared with 407 MA HSCT recipients. The majority of RIC was fludarabine-based regimen associated to busulphan (BU) (53%) or low-dose total body irradiation (24%). Multivariate analyses of outcomes were used adjusting for differences between both groups. The median follow-up was 13 months. Cytogenetics, FAB classification, WBC count at diagnosis and status of the disease at transplant were not statistically different between the two groups. However, RIC patients were older, transplanted more recently, and more frequently with peripheral blood allogeneic stem cells as compared to MA recipients. In multivariate analysis, acute GVHD (II-IV) and transplant-related mortality were significantly decreased (P=0.01 and P<10(-4), respectively) and relapse incidence was significantly higher (P=0.003) after RIC transplantation. Leukaemia-free survival was not statistically different between the two groups. These results may set the grounds for prospective trials comparing RIC with other strategies of treatment in elderly AML.

Cytomegalovirus (CMV) infections and CMV-specific cellular immune reconstitution following reduced intensity conditioning allogeneic stem cell transplantation with Alemtuzumab

We studied the incidence and recurrence of Cytomegalovirus (CMV) infection and reactivation in 38 recipients of Alemtuzumab reduced intensity conditioning-stem cell transplantation, and used CMV-HLA tetramer studies to discover if these events correlated with recovery of circulating CMV-specific CD8+ T cells (cytotoxic T lymphocyte (CTLs)). The cumulative incidence of CMV infection was 60% at 1 year (95% CI, 45-78%) with a median reactivation time of 24 days (range 5-95 days). All patients with CMV reactivation received Ganciclovir or Foscarnet, and only one developed CMV disease. More strikingly, only 8/21 patients had relapse of CMV antigenemia. Tetramer analysis in 13 patients showed that 11 reconstituted CMV CTLs (7/11 by day 30 and 10/11 by day 90). The development of CMV infection was accompanied by a >5-fold rise of CMV CTLs. Recurrence of CMV infection occurred only in the patients who failed to generate a CTL response to the virus. Hence, recipients of SCT using Alemtuzumab-RIC are initially profoundly immunosuppressed and have a high incidence of early CMV reactivation. However, in the majority of patients, infection is transient, and antiviral T cell reconstitution is rapid. Monitoring with CMV-specific CTLs may help identify the subset of patients at risk from recurrent infection or disease.

Allogeneic Stem-Cell Transplantation Using a Reduced-Intensity Conditioning Regimen Has the Capacity to Produce Durable Remissions and Long-Term Disease-Free Survival in Patients With High-Risk Acute Myeloid Leukemia and Myelodysplasia

Purpose

The toxicity of allogeneic stem-cell transplantation can be substantially reduced using a reduced-intensity conditioning (RIC) regimen. This has increased the proportion of patients with myeloid malignancies eligible for allogeneic transplantation. However, the capacity of RIC allografts to produce durable remissions in patients with acute myeloid leukemia (AML) and myelodysplasia (MDS) has not yet been defined, and consequently, the role of RIC allografts in the management of these diseases remains conjectural.

Patients and Methods

Seventy-six patients with high-risk AML or MDS received an allograft using a fludarabine/melphalan RIC regimen incorporating alemtuzumab. The median age of the cohort was 52 years (range, 18 to 71 years).

Results

The 100-day transplantation-related mortality rate was 9%, and no patient developed greater than grade 2 graft-versus-host disease. With a median follow-up of 36 months (range, 13 to 70 months), 27 patients were alive and in remission, with 3-year actuarial overall survival (OS) and disease-free survival (DFS) rates of 41% and 37%, respectively. The 3-year OS and DFS rates of patients with AML in complete remission at the time of transplantation were 48% and 42%, respectively. Disease relapse was the most common cause of treatment failure and occurred at a median time of 6 months after transplantation. All but one patient destined to relapse did so within 24 months of transplantation.

Conclusion

The extended follow-up in this series identifies a high risk of early disease relapse but provides evidence that RIC allografts can produce sustained DFS in a significant number of patients with AML who would be ineligible for allogeneic transplantation with myeloablative conditioning.

Treatment for acute myelogenous leukemia by low-dose, total-body, irradiation-based conditioning and hematopoietic cell transplantation from related and unrelated donors

PURPOSE

The use of low-dose, irradiation-based preparative regimens have allowed the extension of allografting to older and medically infirm patients. The study reported here assessed outcomes for patients with acute myeloid leukemia (AML) in different stages of their disease, who were not considered candidates for conventional hematopoietic cell transplantation (HCT) because of age and/or other known risk factors and were given minimal conditioning followed by HCT from related or unrelated donors.

PATIENTS AND METHODS

The present study included 122 patients with AML, who were conditioned with 2 Gy total-body irradiation (TBI) on day 0 with or without preceding fludarabine (30 mg/m2/d from days -4 to -2), and given postgrafting cyclosporine at 6.25 mg/kg twice daily from day -3 and mycophenolate mofetil at 15 mg/kg twice daily from day 0.

RESULTS

Durable engraftment was observed in 95% of the patients. Cumulative incidences of acute graft-versus-host disease grades 2 to 4 at 6 months were 35% after related and 42% after unrelated HCT, respectively. With a median follow-up of 44 months (range, 26 to 79 months), 51 patients were alive, of whom 48 were in complete remission (CR). Cumulative nonrelapse mortalities were 10% and 22%, and cumulative mortalities from disease progression were 47% and 33% at 2 years for related and unrelated recipients, respectively. Overall, 2-year survival was 48%, and disease-free survival was 44%. Patients receiving transplantation in CR1 had 2-year overall survivals of 44% after related and 63% after unrelated HCT, respectively.

CONCLUSION

We conclude that HCT from related and unrelated donors after low-dose TBI is a promising treatment for elderly patients with AML.

Do minitransplants have minicosts? A cost comparison between myeloablative and nonmyeloablative allogeneic stem cell transplant in patients with acute myeloid leukemia

Allogeneic hematopoietic stem cell transplantation (SCT) is a widely used, cost-intensive procedure. Although pretransplant nonmyeloablative (NMA) or reduced-intensity conditioning regimens appear very promising, prospective studies comparing this approach with the conventional myeloablative (MA) approach in specific hematologic diseases are necessary, especially in patients in whom the conventional approach is not contraindicated. Cost may be an important factor in the decision-making process. We compared the costs of MA and NMA transplants in patients with acute myeloid leukemia (AML). We estimated 1-year resource utilization in 12 consecutive MA patients (median age: 39 years) and in 11 consecutive NMA patients (median age: 58 years) who underwent HLA-identical sibling SCT for AML. Resources care expenses were valued using the average daily rate for personnel costs, supplies, and room costs. Other data were directly collected from the patients' charts. Despite a trend for lower costs in NMA patients during the first 6 months, costs during the 6-12-month period were significantly higher after NMA due to late complications and readmissions (P=0.03). Finally, mean 1-year costs were not different in MA and NMA patients (P=0.75). Prospective studies comparing conventional and NMA approaches in homogeneous populations should include economic items.

Allogeneic hematopoietic cell transplantation (HCT) following reduced-intensity conditioning in patients with acute leukemias

The majority of patients with acute leukemia enter complete remission following induction therapy, but relapse despite consolidation and maintenance chemotherapy. Allogeneic hematopoietic cell transplantation (HCT) is the most effective consolidation therapy but unfortunately associated with high transplant-related mortality (TRM). In order to decrease TRM but still apply a graft-versus-tumor effect, allogeneic HCT protocols with reduced-intensity conditioning were developed and more than 5000 HCT, of which 1500 for acute leukemia, performed. Detailed information is available on more than 400 patients with acute leukemia. The results, summarized in this article, confirm that reduced-intensity preparative regimens lead to full donor chimerism and to generation of graft-versus-leukemia (GvL) effects with curative potential in older patients (>60 years). Prospective-controlled clinical trials are needed in younger patients to compare results of HCT after reduced-intensity conditioning to those of HCT with conventional conditioning.

Biology and management of relapsed acute myeloid leukaemia

Disease relapse remains the major cause of treatment failure in adults with acute myeloid leukaemia (AML). This reflects both the failure of current salvage regimens and the absence of effective strategies to secure long-term disease-free survival in those patients who achieve a second remission. Recent progress in understanding the pathogenesis of relapsed disease has enabled the identification of a variety of dysregulated molecular pathways and these now provide a rational basis for the design of novel targeted therapies. At the same time, advances in allogeneic stem-cell transplantation have permitted the extension of the curative potential of allografting to patients in whom it was previously contraindicated. As a result, a range of novel drug and transplant therapies has become available in patients with relapsed AML, and it is realistic to anticipate that a co-ordinated assessment of their clinical and biological impact will provide the basis for the design of future, more effective treatments in relapsed disease.

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.

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.

Impact of human leucocyte antigen mismatch on graft-versus-host disease and graft failure after reduced intensity conditioning allogeneic haematopoietic stem cell transplantation from related donors

The impact of human leucocyte antigen (HLA) incompatibility between donor and recipient on graft-versus-host disease (GVHD) and graft failure after reduced-intensity conditioning stem cell transplantation (RICT) remains to be elucidated. We retrospectively analysed outcome in 341 patients who underwent RICT from related donors for haematological malignancies. The overall cumulative incidence of grade II-IV acute GVHD (aGVHD) was 40% for all subjects; 39% in recipients with HLA-matched donors, 44% in those with one-locus-mismatched donors, and 50% in those with two- to three-loci-mismatched donors. In a Cox regression model adjusted for potential confounders, the tendency for grade II-IV aGVHD (P=0.01), chronic GVHD (cGVHD) (P=0.05) and graft failure (P=0.033) increased with HLA disparity. Use of peripheral blood grafts instead of marrow was a risk factor for cGVHD. Use of antithymocyte globulin was associated with reduced aGVHD and cGVHD. Overall survival (OS) in recipients of two- to three-loci-mismatched RICT at 2 years (18%) was significantly worse than that in patients who received one-locus-mismatched RICT (51%) and HLA-matched RICT (48%) (P<0.0001). A two- to three-loci mismatch was identified as an independent risk factor for OS (P<0.001), but there was no significant difference in OS between HLA-matched and one-locus-mismatched RICT. HLA incompatibility between the donor and recipient is an important risk factor for graft failure, aGVHD, cGVHD and OS after RICT. RICT from a one-locus-mismatched donor may represent an effective alternative approach in patients with high-risk malignancies who lack HLA-matched related donors.

Fludarabine, melphalan, and alemtuzumab conditioning in adults with standard-risk advanced acute myeloid leukemia and myelodysplastic syndrome

PURPOSE

This prospective phase II study evaluated toxicity, relapse rate, progression-free survival, and overall survival after allogeneic transplantation and conditioning with fludarabine, melphalan, and alemtuzumab in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

PATIENTS AND METHODS

Fifty-two consecutive adults with AML and MDS were enrolled onto the study. Median age was 52 years (range, 17 to 71 years) and the majority of patients had high-risk disease, comorbidities, and/or modest reduction in performance status. Fifty-six percent of patients had unrelated or mismatched related donors.

RESULTS

After a median follow-up of 18 months (range, 2 to 34 months), 1-year survival was 48% (95% CI, 34% to 61%), progression-free survival was 38% (95% CI, 25% to 52%), relapse rate was 27% (95% CI, 15% to 40%), and treatment-related mortality was 33% (95% CI, 20% to 46%). The cumulative probability of extensive chronic graft-versus-host disease (GVHD) was only 18% (95% CI, 8% to 40%); extensive chronic GVHD was only observed in recipients of unrelated donor transplants. Performance score and disease status were the major predictors of outcome. High-risk disease (ie, active AML or MDS with > 5% blasts) or even modest decreases in performance status were associated with poor outcomes. Patients with standard-risk leukemia (first or second complete remission) or MDS (< 5% blasts) had excellent outcomes despite unfavorable disease characteristics.

CONCLUSION

Fludarabine and melphalan combined with in vivo alemtuzumab is a promising transplantation regimen for patients with AML or MDS and low tumor burden. For patients with active disease, this regimen provides at best modest palliation. Despite a low incidence of GVHD, transplantation is still associated with considerable nonrelapse mortality in patients with decreased performance status.

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.

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.

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.

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.

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.

Evidence-based guidelines for the management of neutropenia following outpatient hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) involves the transfer of stem cells to establish hematopoiesis in patients who have received myeloablative chemotherapy with or without whole body irradiation. Following high-dose therapy and HSCT, all patients experience a period of neutropenia. Outpatient care delivery models place expanded responsibilities on patients and their families for the management of this treatment side effect. Proactive management of neutropenia is critical to decrease the depth and duration of neutropenia following HSCT, limit exposure to opportunistic and nosocomial pathogens, and ensure prompt intervention should febrile neutropenia or infection develop. Patient and family education, psychosocial support, and coordination of care are key nursing responsibilities.

Low-intensity allogeneic hematopoietic stem cell transplantation for myeloid malignancies: separating graft-versus-leukemia effects from graft-versus-host disease

PURPOSE OF REVIEW

Over the past several years, significant advances in allogeneic hematopoietic cell transplantation (HCT), specifically the development of nonablative and reduced-intensity conditioning regimens, have enabled the extension of transplantation to include older or medically infirm patients with myeloid malignancies. The regimens rely largely on graft-versus-leukemia effects rather than high-dose therapy to eliminate malignant cells. Studies have demonstrated that the regimens allow sustained engraftment with relatively low transplant-related mortality. However, conclusions regarding the ultimate efficacy of these regimens for myeloid malignancies have been limited, given the small numbers of patients who have had transplants so far. This review summarizes recent studies of nonablative or reduced-intensity regimens for patients with myeloid malignancies (acute and chronic myelogenous leukemia, myelodysplastic syndrome, and myeloproliferative disorders). In addition, this review evaluates what is currently known regarding the association of graft-versus-leukemia responses and graft-versus-host disease (GVHD). When possible, graft-versus-leukemia responses are highlighted in the articles discussed.

RECENT FINDINGS

This review covers six articles and four abstracts that have been published since September 2003 on patients with myeloid malignancies who received HCT following nonmyeloablative or reduced-intensity conditioning. Due to the heterogeneity of the conditioning and GVHD prophylaxis regimens, direct comparisons between studies are difficult. However, these studies have demonstrated encouraging overall survivals (30 to 74%), disease-free/event-free or progression-free survivals (19 to 62%), and nonrelapse mortalities (15 to 55%). In addition, these studies demonstrated evidence for graft-versus-leukemia responses. However, relapse and progressive disease continued to be problems, particularly in patients with large tumor burdens at time of HCT.

SUMMARY

Over the past 10 years, significant advances have been made in the field of transplantation. Nonmyeloablative and reduced-intensity HCT have promised patients with hematologic and nonhematologic malignancies potential cures. However, disease relapse and nonrelapse mortality, mainly from GVHD and its therapy, continue to be problems. Future studies are needed to increase our understanding of GVHD and graft-versus-leukemia responses, which will greatly improve outcome. In addition, a better understanding of minor histocompatibility antigens may lead to more targeted immunotherapy and enhance the precision and success of transplantation.

Reduced-Intensity Conditioning Regimens for Hematologic Malignancies: What Have We Learned over the Last 10 Years?

Reduced-intensity conditioning (RIC) regimens have been investigated for more than 10 years as an alternative to traditional myeloablative conditioning regimens. RIC regimens are being commonly used in older patients as well as in disorders in which traditional myeloablative conditioning regimens are associated with high rates of non-relapse mortality. Hodgkin disease, myeloma, and low-grade lymphoid malignancies have been the diseases most impacted by RIC regimens. RIC regimens have also been shown to be safe and effective in older patients as well as patients with co-morbidities, although patients with chemorefractory disease still have high relapse rates and poor outcomes. Patients with chemosensitive disease have outcomes similar to those obtained with conventional ablative therapies, and thus comparative trials are warranted. RIC regimens are associated with lower rates of severe toxicity and non-relapse mortality; however, infections, graft-versus-host disease, and relapse of primary disease remain the most common obstacles to a successful outcome. The impact on survival and the relative benefits of RIC allografting compared with traditional conditioning regimens or alternative therapy remain to be defined. Incorporating targeted therapies as part of the conditioning regimens or as maintenance therapies is currently being explored to reduce relapse rates without increasing toxicity.

Hematopoietic stem-cell transplantation from unrelated donors in elderly patients (age>55 years) with hematologic malignancies: older age is no longer a contraindication when using reduced intensity conditioning

Allogeneic stem cell transplantation (SCT) is a potentially curative approach for patients with hematological malignancies. Reduced-intensity conditioning regimens allow SCT in elderly patients; however, there are only limited data on the feasibility and outcomes of unrelated donor SCT in these patients. In this study, we analyzed, retrospectively, data of 36 patients with various hematological malignancies and median age 58 years (range, 55-66), who were given unrelated donor SCT after reduced-intensity conditioning. The preparative regimen consisted of fludarabine combined with oral busulfan (8 mg/kg, n=8), intravenous busulfan (6.4 mg/kg, n=11), treosulfan (30 g/m(2), n=5) or melphalan (100-150 mg/m(2), n=12). Patients were also given serotherapy, ATG (n=32), or alemtuzumab (n=4). The probabilities of overall survival, disease-free survival, and nonrelapse mortality at 1 year after SCT were 52, 43, and 39%, respectively. Acute graft-versus-host disease (GVHD) grade II-IV and chronic GVHD occurred in 31 and 45%, respectively. Multivariable analysis determined that survival rates were higher in patients with chemosensitive disease (HR 4.5), and patients conditioned with intravenous busulfan or treosulfan (HR 3.9). Unrelated donor SCT is feasible in elderly patients, with outcomes that are similar to younger patients. Favorable outcome was observed in patients with myeloid malignancies, and those transplanted in remission and early in the course of disease. Age alone should not be considered a contraindication to unrelated donor SCT.

Comparative outcome of nonmyeloablative and myeloablative allogeneic hematopoietic cell transplantation for patients older than 50 years of age

Nonmyeloablative stem cell transplantation (NST) is increasingly used in older patients. The impact of the shift from myeloablative transplantation to NST on relapse, transplant complications, and outcome has yet to be fully examined. We performed a retrospective analysis of 152 patients older than 50 years undergoing NST or myeloablative transplantation. Seventy-one patients received nonmyeloablative conditioning, fludarabine (30 mg/m(2)/d x 4) and intravenous busulfan (0.8 mg/kg/d x 4); 81 patients received myeloablative conditioning, primarily cyclophosphamide and total body irradiation. NST patients were more likely to have unrelated donors (58% versus 36%; P = .009), a prior transplant (25% versus 4%; P = < .0001), and active disease at transplantation (85% versus 59%; P = < .001). Despite the adverse characteristics, overall survival was improved in the NST group at 1 year (51% versus 39%) and 2 years (39% versus 29%; P = .056). There was no difference in progression-free survival (2 years, 27% versus 25%; P = .24). The incidence of grade 2 to 4 graft-versus-host disease was similar (28% versus 27%). The nonrelapse mortality rate was lower for NST patients (32% versus 50%; P = .01), but the relapse rate was higher (46% versus 30%; P = .052). Our experience suggests that, in patients over age 50, NST with fludarabine and low-dose busulfan leads to an overall outcome at least as good as that following myeloablative therapy.

Unanswered questions in acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a heterogeneous disease that presents with a range of morphological, cytogenetic, immunophenotypic, and biomolecular features. Over the past 20 years, application of new cytogenetic and molecular techniques has greatly improved knowledge of the pathophysiology of AML, resulting in new potential therapeutic applications. However, the results of current therapy are still unsatisfactory, especially in patients who have adverse prognostic factors at the time of diagnosis. Furthermore, some pivotal questions about the procedures of induction and postinduction therapy of AML remain unanswered, and substantial controversy exists on the optimum therapeutic approach for the disorder.

Low transplant-related mortality with allogeneic stem cell transplantation in elderly patients

Historically, age >60 years was considered a contraindication for allogeneic stem cell transplantation (allo-SCT). In recent years, elderly (>60 years) patients have become eligible for allo-SCT due to the application of reduced intensity conditioning (RIC). The present report summarizes our cumulative experience in a cohort of 17 elderly patients (age 60-67, median 62.5 years) with hematological malignancies treated with 18 allo-SCT procedures, mostly nonmyeloablative. In all, 14 patients received fludarabine and busulfan/busulfex regimen, three patients were conditioned with the fludarabine and low-dose TBI and one patient received busulfan alone. All patients displayed tri-lineage engraftment. The time to recovery of absolute neutrophil count >/=0.5 x 10(9)/l was 9-27 days (median 14 days). The time interval to platelet recovery >/=20 x 10(9)/l was 3-96 days (median 11 days). Veno-occlusive disease occurred only in 3/18 procedures and subsided with conventional treatment. Nonfatal transplant-related complications occurred in 6/18 (33.3%) procedures including: renal failure, arrhythmia, CNS bleeding, cystitis, typhlitis and gastrointestinal bleeding. Transplant-related mortality occurred in 6/18 (33.3%) episodes. Of the 17 patients, 12 (12/18 episodes) were discharged. Five of 17 (29%) patients survived (median follow-up 11 m, range 8-53 m). Our data suggest that RIC-allo-SCT may be safely applied in the elderly, suggesting that allogeneic immunotherapy may become an important tool for treatment of hematological malignancies without an age limit.

Chimerism and clinical outcomes of 110 recipients of unrelated donor bone marrow transplants who underwent conditioning with low-dose, single-exposure total body irradiation and cyclophosphamide

We hypothesized that low-dose (550-cGy), single-exposure, high dose rate (30 cGy/min) total body irradiation (TBI) with cyclophosphamide as conditioning for HLA-compatible unrelated donor (URD) bone marrow transplantation (BMT) would result in donor chimerism (DC) with a low risk for serious organ toxicity and treatment-related mortality (TRM). Twenty-six patients with good risk diagnoses (acute leukemia in first complete remission [CR] and chronic-phase chronic myelogenous leukemia [CML]) and 84 with poor risk diagnoses underwent this regimen and URD BMT. Unsorted marrow nucleated cells were assessed for chimerism using VNTR probes. All DC occurred in 78 (86%) of 91 evaluable patients at 1 or more follow-up points. Graft failure occurred in 7 (7.7%) patients. Fatal organ toxicity occurred in only 2% of patients. TRM rates through 2 years of follow-up were 19% and 42% in those with good and poor risk diagnoses, respectively. Overall and disease-free survival rates in the good risk group were 47% and 40%, respectively, and in the poor risk group they were 25% and 21%, respectively, at a median follow-up for living patients of 850 days (range, 354-1588 days). This regimen resulted in 100% DC in most patients undergoing URD BMT with a relatively low risk for fatal organ toxicity and TRM.

Feasibility of reduced intensity hematopoietic stem cell transplantation from an HLA-matched unrelated donor

To evaluate the feasibility of reduced intensity stem cell transplantation (RIST) with bone marrow from a matched unrelated donor (MUD), we retrospectively investigated 20 patients with hematological disorders who received RIST in the Tokyo SCT consortium from January 2000 to October 2002. The preparative regimens were fludarabine-based (150-180 mg/m(2), n=18) or cladribine-based (0.77 mg/kg, n=2). To enhance engraftment, antithymocyte globulin (ATG) and 4 or 8 Gy total body irradiation (TBI) were added to these regimens in nine and 11 patients, respectively. GVHD prophylaxis was cyclosporine with or without methotrexate. In all, 19 achieved primary engraftment. Three developed graft failure (one primary, two secondary), and five died of treatment-related mortality within 100 days of transplant. Seven of the 19 patients who achieved initial engraftment developed grade II-IV acute GVHD, and seven of 13 patients who survived >100 days developed chronic GVHD. At a median follow-up of 5.5 months, estimated 1-year overall survival was 35%. Compared with a TBI-containing regimen, an ATG-containing regimen was associated with a high risk of graft failure (30 vs 0%, P=0.0737). This study supports the feasibility of RIST from MUD; however, procedure-related toxicities remain significant in its application to patients.