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

T-cell-depleted allogeneic transplant without donor leukocyte infusions results in excellent long-term survival in patients with multiply relapsed Lymphoma. Predictors for survival after transplant relapse

We analyzed 67 patients with lymphoma who received alemtuzumab-based conditioning regimens for allogeneic stem cell transplant and no post-transplant DLI. The median age was 54 (24-70), 43% had unrelated donors, 34% had chemotherapy refractory disease, and 25% had an elevated LDH. With a median follow-up for survivors of 35 months, the estimated 3-year progression-free survival (PFS) and overall survival (OS) were 30% and 47%, respectively. Chemosensitivity by CT and pre-transplant LDH were independent prognostic factors for both overall survival and progression-free survival. Patient age, performance status, donor type, lymphoma subtype, disease sensitivity by PET, and conditioning regimen did not correlate with PFS and OS. Patients who relapsed greater than 6 months after allogeneic transplant were frequently able to re-enter a subsequent durable remission. Our experience confirms the curative potential of alemtuzumab-containing RIC regimens for allogeneic HCT in patients with relapsed lymphoma without prophylactic DLI. An elevated pre-transplant LDH and chemorefractory disease prior to transplant confer a worse prognosis, while PET scan findings do not have this same implication. Patients who relapse greater than 6 months after their transplant are likely to achieve a subsequent remission with any of a variety of interventions, suggesting that GVL effects can be operative even after recurrence. Our outcomes challenge the utility of the common practice of prophylactic DLI after T-depleted transplant for lymphoma.

Allogeneic immunotherapy to optimize the graft-versus-tumor effect: concepts and controversies

Allogeneic stem cell transplantation (SCT) can be considered the most successful method of adoptive immunotherapy of cancer. It is successful in part because of the potent graft-versus-tumor (GVT) effects of the donor graft, which are independent of the conditioning regimen. This potent GVT reaction can be harnessed in some cases to treat patients who relapse after allogeneic SCT with the use of donor leukocyte infusions (DLIs). This has led to the rapid development of reduced-intensity conditioning (RIC) regimens for allogeneic SCT, an approach that relies primarily on GVT activity. However, the effects of GVT have clear disease specificity and remain associated with significant GVHD. Optimization of GVT induction will require a better understanding of the important target antigens and effector cells, as well as the development of methods that enhance GVT reactivity without excessive GVHD. The appropriate clinical setting and timing for GVT induction need to be defined more clearly, but ultimately, the immunologic control of cancer through allogeneic adoptive immunotherapy represents one of the most potent and promising therapeutic strategies for patients with hematologic malignancies.

Pharmacokinetic targeting of intravenous busulfan reduces conditioning regimen related toxicity following allogeneic hematopoietic cell transplantation for acute myelogenous leukemia

Optimal conditioning therapy for hematopoietic cell transplantation (HCT) in acute myelogenous leukemia (AML) remains undefined. We retrospectively compared outcomes of a consecutive series of 51 AML patients treated with oral busulfan (1 mg/kg every 6 hours for 4 days) and cyclophosphamide (60 mg/kg IV × 2 days) - (Bu/Cy) with 100 consecutive AML patients treated with pharmacokinetic targeted IV busulfan (AUC < 6000 μM/L*min per day × 4 days) and fludarabine (40 mg/m2 × 4 days) - (t-IV Bu/Flu). The Bu/Cy and t-IV Bu/Flu groups significantly differed according to donor relation, stem cell source, aGVHD prophylaxis, remission status, primary vs. secondary disease, median age, and % blasts prior to HCT (p < 0.01 for each). Conditioning with t-IV Bu/Flu reduced early toxicity including idiopathic pneumonia syndrome (IPS) and hepatic veno-occlusive disease (VOD). Additionally, the trajectory of early NRM (100 day: 16% vs. 3%, and1 year: 25% vs. 15% for Bu/Cy and t-IV Bu/Flu, respectively) favored t-IV Bu/Flu. Grade II-IV aGVHD (48% vs. 82%, p < 0.0001), as well as moderate/severe cGVHD (7% vs. 40%, p < 0.0001) differed between the Bu/Cy and t-IV Bu/Flu groups, due to the predominance of peripheral blood stem cells in the t-IV Bu/Flu group. Pharmacokinetic targeting of intravenous busulfan in combination with fludarabine is associated with reduced conditioning regimen related toxicity compared to oral busulfan and cyclophosphamide. However, multivariable analysis did not demonstrate significant differences in overall survival (p = 0.78) or non-relapse mortality (p = 0.6) according to conditioning regimen delivered.

Phase I study of dose-escalated busulfan with fludarabine and alemtuzumab as conditioning for allogeneic hematopoietic stem cell transplant: reduced clearance at high doses and occurrence of late sinusoidal obstruction syndrome/veno-occlusive disease

Disease recurrence after allogeneic hematopoietic cell transplant (alloHCT) remains common, making improvements in conditioning regimens desirable. A dose-response relationship between busulfan exposure and outcome is known. Using individual real-time monitoring of the busulfan area under the curve (AUC), we aimed to determine the maximum-tolerated busulfan AUC in a conditioning regimen with fludarabine/alemtuzumab. Thirty-six patients with advanced hematologic malignancies were treated. Busulfan levels after a test dose and conditioning dose 1 allowed targeting of subsequent AUCs and dose-escalation above the starting AUC of 4800 µmol-min/L. Clearance of busulfan test doses was not always sufficiently predictive of treatment dose AUC and, on average, test dose clearance was faster than treatment dose clearance. When the study was modified to use conditioning dose 1 pharmacokinetics instead, accurately targeted treatment AUCs were achieved, and dose-escalation was possible. Severe, late-occurring sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) was the dose-limiting toxicity seen in 5/8 patients at an AUC level of 6800 µmol-min/L. The risk for SOS/VOD correlated with the highest observed AUC (AUC(max)) rather than with the average cumulative AUC (AUC(avg)). Busulfan dose-escalation to a maximum-tolerated AUC of 5800 µmol-min/L-higher than that achieved by current standard busulfan regimens-was accurate and achievable using real-time pharmacokinetics monitoring of the first conditioning dose. This AUC is now being studied in phase II for patients receiving busulfan/fludarabine/alemtuzumab as alloHCT conditioning.

Treatment of therapy-related myeloid neoplasms with high-dose cytarabine/mitoxantrone followed by hematopoietic stem cell transplant

Few clinical protocols have focused on patients with therapy-related myeloid neoplasms (t-MN). Therefore, we enrolled 32 patients with previously untreated t-MN on a clinical trial testing the effectiveness of a unified induction regimen of high-dose cytarabine and mitoxantrone. The complete remission (CR) rate was 66% (95% CI 47-81%) and the partial remission (PR) rate was 16% (95% CI 5-33%), for an overall response rate of 82%. Day 30 treatment mortality was 9% (3/32), and the most serious induction toxicity was cardiac dysfunction. Among the patients with CR, 13 (62%) received consolidation therapy using an allogeneic hematopoietic cell transplant (HCT), four (21%) received an autologous HCT, and three (16%) received further chemotherapy. We observed long-term disease-free survival in patients who received all three types of consolidation therapy. The remission induction of high-dose cytarabine and mitoxantrone for t-MN is a well-tolerated efficacious combination, which allows aggressive consolidation and long-term disease-free survival.

Targeted i.v. BU and fludarabine (t-i.v. BU/Flu) provides effective control of AML in adults with reduced toxicity

Myeloablative doses of BU and fludarabine followed by allogeneic hematopoietic cell transplantation offer effective therapy for AML. We anticipated that pharmacokinetic targeting of i.v. BU to 5300 μM/L min/day × 4 (targeted i.v. BU and fludarabine (t-i.v. BU/Flu)) would limit nonrelapse mortality (NRM) in adults up to 70 years of age. We assessed the safety and efficacy of t-i.v. BU/Flu in a series of 100 adults (median age 48, range 22-69 years) with AML in the first CR (CR1) with high risk of treatment failure (n=49), second CR (CR2, n=25), relapsed disease (REL, n=9), primary induction failure (PIF, n=16) and untreated (n=1). NRM was 3% at 100 days and 15% at 1 year. The cumulative incidence of relapse was 30.6% for CR1, 41.7% for CR2, 55.6% for REL and 58.6% for PIF. OS for primary AML in CR1 was 66% (95% confidence interval (CI): 46-80%) at 1 year, and 62% (95% CI: 42-77%) at 2 years. On multivariable modeling, remission status, moderate/severe chronic GVHD and day-90 BM chimerism ≥90% predicted improved OS. Importantly, there was no effect of age. t-i.v. BU/Flu provides effective disease control with encouraging NRM in patients up to age of 70 years.

Allogeneic hematopoietic stem-cell transplantation in patients with hematologic malignancies after dose-escalated treosulfan/fludarabine conditioning

PURPOSE

Treosulfan was introduced recently as a conditioning agent for allogeneic blood stem-cell transplantation. The favorable nonhematologic toxicity profile at 3 x 10 g/m(2) was the basis for dose escalation in this prospective, multicenter trial.

PATIENTS AND METHODS

Fifty-six patients with various hematologic malignancies who were not eligible for standard conditioning were treated with one of three doses: 10 g/m(2), 12 g/m(2), or 14 g/m(2) of intravenous treosulfan, which was administered on days -6 to -4 combined with fludarabine 30 mg/m(2) on days -6 to -2. Patients in complete remission (CR; 42%) or non-CR (58%) received grafts from matched related (47%) or matched unrelated (51%) donors; one patient had a mismatched related donor (2%).

RESULTS

No engraftment failure occurred. Overall, extramedullary toxicity and the nonrelapse mortality rate at 2 years (20%) were low and did not increase with dose. Cumulative incidence of relapse/progression reached 31%. The overall survival and progression-free survival rates were 64% and 49%, respectively, in the total study population. An inverse dose dependency of relapse incidence was indicated in the subgroup receiving transplantations from matched related donors (P = .0568).

CONCLUSION

Treosulfan-based conditioning was feasible at all three doses. The 3 x 14 g/m(2) dose was selected for additional studies, because it combines desired characteristics of low toxicity and a low relapse rate.

Nonmyeloablative allogeneic hematopoietic cell transplantation in patients with acute myeloid leukemia

PURPOSE

Allogeneic hematopoietic cell transplantation (HCT) after high-dose conditioning regimens imposes prohibitively high risks of morbidity and mortality for patients with high-risk acute myeloid leukemia (AML) who are older or have comorbid conditions. Here, we examined outcomes after nonmyeloablative allogeneic HCT in such patients.

PATIENTS AND METHODS

Two hundred seventy-four patients (median age, 60 years) with de novo or secondary AML underwent allogeneic HCT from related (n = 118) or unrelated donors (n = 156) after conditioning with 2 Gy of total-body irradiation (TBI) with or without fludarabine. A calcineurin inhibitor and mycophenolate mofetil were used for postgrafting immunosuppression.

RESULTS

With a median follow-up of 38 months in surviving patients, the estimated overall survival at 5 years was 33%. The estimated 5-year relapse/progression and nonrelapse mortality rates were 42% and 26%, respectively. The cumulative incidences of grades 2, 3, and 4 acute graft-versus-host disease (GVHD) were 38%, 9%, and 5%, respectively. The cumulative incidence of chronic GVHD at 5 years was 44%. Patients in first and second complete remission had better survival rates than patients with more advanced disease (37% and 34% v 18%, respectively). Patients with HLA-matched related or unrelated donors had similar survivals. Unfavorable cytogenetic risk status was associated with increased relapse and subsequent mortality. Chronic GVHD was associated with lower relapse risk.

CONCLUSION

Allogeneic HCT from related or unrelated donors after conditioning with low-dose TBI and fludarabine, relying almost exclusively on graft-versus-leukemia effects, can result in long-term remissions in older or medically infirm patients with AML.

Feasibility of clofarabine cytoreduction before allogeneic transplant conditioning for refractory AML

To control disease before allogeneic hematopoietic cell transplantation (HCT) for relapsed/refractory AML, we used clofarabine cytoreduction. Seventeen patients received clofarabine 30-40  mg/m(2) i.v. daily for 5 days with plans to initiate conditioning during the nadir, 14 days later. Bone marrow biopsy 12 days after clofarabine showed effective cytoreduction (that is,<20% cellularity with <10% blasts) in 10 of 17 patients (59%). Ineffective cytoreduction correlated with lower PFS (3.8 vs 6.4 months; HR=2.7, 95% CI=1.10-14.29, P=0.035) and OS (5.1 vs 16.6 months; HR=2.5, 95% CI=0.98-12.17, P=0.053). Significant toxicities before HCT, attributable to clofarabine, were grade 1-2 hyperbilirubinemia (18%); grade 1-2 (59%) or grade 3-4 (18%) transaminitis; and grade 1-2 (18%) creatinine elevation. Sixteen patients proceeded to HCT infusion 22 days (median) after initiation of clofarabine. Day 100 and 2-year transplant-related mortality were 6 and 36%. Nine patients relapsed. One year PFS and OS were 25 and 38%, respectively. Two patients are alive in remission at 18 and 52 months. Clofarabine cytoreduction followed by immediate HCT is feasible with acceptable toxicity and TRM. Outcomes for this cohort of patients with refractory AML remain poor and we are studying this approach in a prospective manner.

Reduced intensity conditioning prior to allogeneic stem cell transplantation in first complete remission is effective in patients with acute myeloid leukemia and an intermediate-risk karyotype

To evaluate the efficacy of reduced intensity conditioning (RIC) prior to allogeneic stem cell transplantation (alloSCT) in patients with acute myeloid leukemia (AML) in first complete remission (CR1), we retrospectively analyzed the outcome of 93 consecutive patients transplanted at our institution either following RIC (n = 37) or standard myeloablative conditioning (MAC) (n = 56) between 1999 and 2007. Projected overall survival (OS) or disease-free survival (DFS) for all patients at 1, 2, and 5 years was 78 or 70%, 65 or 57%, and 61 or 53% in the RIC group versus 73 or 70%, 68 or 62%, and 56 or 54% in the standard MAC group. In the subgroup of patients with an intermediate-risk karyotype projected OS at 1, 2, and 5 years was 86, 68, and 68% following RIC (n = 21) or 75, 69, and 66% following standard MAC (n = 36). Relapse or treatment-related mortality (TRM) was 15 or 17% (RIC group) and 26 or 14% (standard MAC group). Taken together, these data suggest that RIC-alloSCT may induce stable remissions in patients with AML transplanted in CR1. In particular, patients with an intermediate-risk karyotype ineligible to transplantation following standard MAC may benefit from RIC-alloSCT in CR1 at a low TRM.

Patterns and kinetics of T-cell chimerism after allo transplant with alemtuzumab-based conditioning: mixed chimerism protects from GVHD, but does not portend disease recurrence

We analyzed the kinetics of CD3 chimerism in 120 consecutive allogeneic hematopoietic cell transplantation (HCT) recipients receiving alemtuzumab-based conditioning. Fifty-two received fludarabine/melphalan, 44 received fludarabine/busulfan, and 24 received clofarabine/melphalan in addition to alemtuzumab. Post-transplant GVHD prophylaxis consisted of tacrolimus. No prophylactic donor lymphocyte infusion or other interventions were used for mixed donor chimerism (MDC). Bone marrow (BM) and/or peripheral blood (PB) samples were obtained at 30 days, 100 days, 180 days, and 1 year following HCT. On Day 30, 15% of assessable patients had MDC in the CD3 compartment. This had increased to 50% by Day 100, and to 63% by Day 180. MDC predicted for a lower risk of acute (p = 0.08) and particularly of chronic GVHD (p = 0.01). MDC was not associated with subsequent relapse or TRM (p = 0.67 and 0.72, respectively). A decline of more than 15% in CD3 chimerism between Day 30 and Day 180 predicted for a 40% risk of subsequent disease recurrence. The observation of MDC after alemtuzumab conditioning does not by itself constitute a risk factor for relapse and should not be used to guide therapeutic intervention. By contrast, declining donor chimerism between Day 30 and Day 180 is associated with a somewhat increased risk of disease recurrence. The high incidence of MDC after alemtuzumab containing conditioning contributes to the low risk of acute and chronic GVHD.

A novel GVHD-prophylaxis with low-dose alemtuzumab in allogeneic sibling or unrelated donor hematopoetic cell transplantation: the feasibility of deescalation

Prophylaxis of acute graft-versus-host disease (aGVHD), while maintaining the graft-versus-leukemia (GVL)/lymphoma effect and preventing severe infectious diseases, remains the main challenge in allogeneic hematopoetic cell transplantation (allo-HCT). To evaluate this, we examined the feasibility of deescalating the dose of alemtuzumab (MabCampath) in combination with cyclosporine (CsA) as the sole GVHD-prophylaxis in patients after fludarabine (Flu)-based reduced-intensity conditioning (RIC) in an observational cohort study. We included 127 consecutive patients (median age 63 years) with an unrelated (UD; n=69) or related donor (SIB; n=58) after their first transplantation, mostly presenting with advanced disease. The first 30 patients received 20 mg/day on day -2 and -1 (40 mg), the following 48 patients 10 mg/day on day -2 and -1 (20 mg), and the last 49 patients 10 mg on day -1 (10 mg) alemtuzumab intravenous (i.v.) prior to transplant. We observed no statistical differences comparing the 40 mg, 20 mg, or 10 mg dose groups, in terms of cumulative incidences of aGVHD grade III-IV 7% (confidence interval [CI] 95%; 1-51), 12% (1-40), 6% (1-40), extensive chronic GVHD (cGVHD) 24.4% (3.3-55.8), 17% (2.5-42), and 14.2% (1.5-41.5) and of aGVHD grade II-IV 7 % (0-51.5), 29% (11.9-49.1), 21% (15.3-43.1), respectively. The difference between the 20-mg and 40-mg groups was significant for aGVHD grade II-IV(P < .05). In conclusion, we demonstrate the feasibility of reducing the dose of alemtuzumab as GVHD-prophylaxis to 10 mg absolute in combination with CsA only for UD transplantation in particular.

Impact of pretransplant comorbidities on alemtuzumab-based reduced-intensity conditioning allogeneic hematopoietic SCT for patients with high-risk myelodysplastic syndrome and AML

We report a retrospective analysis of 128 consecutive patients with high-risk myelodysplastic syndrome (MDS) and AML who received an alemtuzumab-based reduced-intensity conditioning hematopoietic SCT (RIC HSCT). The median recipient age was 53 years (range 21-72 years). A total of 49 (38%) recipients had a sibling donor and 79 (62%) had a volunteer-unrelated donor. The hematopoietic cell transplantation-specific comorbidity index (HCT-CI) was assigned to all patients with a score of 0 in 40 (31%), of 1-2 in 45 (35%) and >or=3 in 43 (34%) patients. The 3-year non-relapse mortality (NRM) was 31%, disease-free survival (DFS) was 41% and overall survival (OS) was 46%. The 3-year NRM for patients with a HCT-CI score of 0, 1-2 or >or=3 was 16, 24 and 42%, respectively. The 3-year DFS and OS by HCT-CI was 58 and 69% (score 0), 39 and 39% (score 1-2) and 24 and 32% (score >or=3), respectively. On multivariate analysis, HCT-CI was an independent variable affecting 3-year NRM, DFS and OS (P-value=0.04, 0.01 and <0.01, respectively). Although the disease stage at the time of transplant was an additional independent predictive variable on transplant outcomes, recipient age (>or<50 years) did not have a significant predictive impact. In MDS or AML patients with advanced disease receiving alemtuzumab-based RIC HSCT, the HCT-CI provides an important means of stratifying patients with a high risk of inferior transplant outcomes.

Low-dose total body irradiation-based regimens as a preparative regimen for allogeneic haematopoietic cell transplantation in acute myelogenous leukaemia

Although much progress has been made in understanding the molecular basis of acute myeloid leukaemia (AML), this has not yet led to major improvements in the overall survival of patients. In particular, the treatment of elderly patients with AML remains one of the major challenges in haematology. Despite increases in complete remission rates, relapse remains a major obstacle and the major determinant of overall survival. Allogeneic stem cell transplantation (SCT) is the most efficient antileukaemic treatment for patients with AML, but eligibility for the treatment was confined for a long time to younger patients. More than 10 years ago, SCT protocols were initiated with reduced-intensity conditioning (RIC) rather than ablative chemoradiotherapy, with the intention of inducing a graft-versus-leukaemia effect also in elderly patients and patients with concomitant diseases. Operationally, all protocols below the conventional preparative regimens are referred to as RIC. Low-dose total body irradiation-based protocols result in minimal myelosuppression and are among the most popular. After extensive phase I and phase II studies, associated problems of graft rejection have been largely resolved and transplant-related mortality (TRM) evaluated in more than 3000 patients. TRM does not currently exceed 10-12% in related and 20% in unrelated SCT even in patients up to the age of 75 years, so that relapse after transplantation remains the major problem. A number of strategies for decreasing relapse rates has been developed. The most promising approach consists of monitoring CD34+ donor cell chimerism after transplantation. This has led to decreases in the relapse rate over the past few years. Randomized studies are now being initiated to define the role of SCT in the treatment of elderly patients with AML.

Aging, acute myelogenous leukemia, and allogeneic transplantation: do they belong in the same sentence?

Acute myelogenous leukemia is a disease of the elderly. Disease biology and functional status of this patient population contribute to poorer treatment outcomes with standard therapy. Allogeneic hematopoietic stem cell transplantation is associated with an immunologic "graft-versus-tumor" effect. However, transplantation was restricted until recently to younger patients because of prohibitive treatment-related mortality. The development of reduced-intensity preparative regimens and improvements in supportive care now allow older patients with myeloid leukemia a greater opportunity for cure with transplantation. Donor availability, graft-versus-host disease, delayed immune recovery, and the high prevalence of relapsed or refractory disease remain important obstacles to be overcome in the future. Herein, we review the current literature on transplantation for older patients with this myeloid malignancy.

Fludarabine-melphalan conditioning for AML and MDS: alemtuzumab reduces acute and chronic GVHD without affecting long-term outcomes

The purpose of this study was to determine the effect of alemtuzumab on treatment-related mortality (TRM), relapse, overall survival (OS), and disease-free survival (DSF) in patients with acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS) undergoing reduced intensity conditioning (RIC). We compared the outcome of 95 patients treated at the University of Chicago with fludarabine melphalan (Flu + Mel) + alemtuzumab conditioning and 59 patients treated at the M.D. Anderson Cancer Center with Flu + Mel conditioning. Both groups had similar patient and donor characteristics. There were no significant differences in TRM, relapse, survival, and DFS between the 2 groups. The incidence of acute graft-versus-host disease (aGVHD) grade II-IV (relative risk [RR] 5.5, P < .01) and chronic GVHD (cGVHD) (RR 6.6, P < .01) were significantly lower in patients receiving alemtuzumab. The addition of alemtuzumab to an RIC regimen dramatically reduces the incidence of aGVHD and cGVHD in patients with AML and MDS undergoing allogeneic transplantation. TRM, relapse risk, OS and DFS are not affected.

Allogeneic stem cell transplantation with alemtuzumab-based conditioning for patients with advanced chronic myelogenous leukemia

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the treatment of choice for patients with chronic myelogenous leukemia (CML) who have failed or are intolerant to tyrosine kinase inhibitors (TKI). Myeloablative conditioning regimens have been associated with high treatment-related mortality (TRM) rate in such patients, and reduced-intensity conditioning (RIC) regimens are often preferred but have high rates of disease recurrence and graft-versus-host-disease (GVHD). We report our experience with nine CML patients (four chronic phase and five with accelerated phase or blast crisis) who failed TKI and underwent allo-HSCT using an alemtuzumab-based RIC regimen. The conditioning regimen was well tolerated and induced engraftment in all patients, and complete cytogenetic remission (CCyR) in eight of nine. Four patients, all with a history of accelerated phase or blast crisis, died. Four of the five remaining patients had a cytogenetic relapse a median of 10 months after transplantation. Donor lymphocyte infusion (DLI), TKI or both induced a CCyR in all cases. With a median follow-up of 47 months, five patients, including all those transplanted in first or second chronic phase, are alive and in remission. Allo-HSCT with an alemtuzumab-based conditioning regimen induces remission in patients with CML that have failed TKI therapy and has a low incidence of GVHD. Disease recurrence is frequent but responds to DLI. In some cases, restoration of susceptibility to TKI was observed. Outcomes may improve with the routine administration of post-transplant TKI.

Myelodysplastic syndromes: diagnosis and staging

Myelodysplastic syndromes (MDS) represent a heterogeneous group of hematologic disorders characterized by ineffective hematopoiesis and an increased risk of developing acute myelogenous leukemia (AML). Accurate diagnosis of MDS can be difficult, and its classification requires evaluation of cytopenias, bone marrow morphology, blast percentage, and cytogenetics. These factors, as well as patient performance status and red blood cell transfusion dependence, can be used to predict prognosis in MDS. Accurate diagnosis and classification are essential for subgroup identification and prognostic assessment of patients with MDS. This article reviews essential criteria for staging and subgroup classification and summarizes prognostic scoring systems that aid in risk stratification and selection of optimal therapy. Classification systems such as the World Health Organization (WHO) classification are widely used but do not always provide sufficient prognostic information. This limitation led to the creation of the International Prognostic Scoring System (IPSS). However, this system was designed to be used only at diagnosis and may not be suitable for serial assessment of patients whose disease can evolve over time. The WHO classification-based prognostic scoring system (WPSS) permits dynamic estimation of survival and risk of AML transformation at multiple time points during the natural course of MDS. Prognostic scoring systems such as WPSS allow for prediction of survival and risk of leukemic evolution at any time during the course of the disease. Such an approach may provide a useful adjunct for clinical decision making, including selection of appropriate treatment options.

Graft-versus-disease effect following allogeneic transplantation for acute leukaemia

The graft-versus-leukaemia effect is one of the most important biological effects to influence outcome in patients with acute leukaemia. The recognition of this modality over the past three decades has led to far-reaching changes in the concept and conduct of allogeneic transplantation in acute myeloid leukaemia, and in the infusion of donor lymphocytes as a therapeutic modality. Despite these conceptual advances, there is a considerable need for more structured prospective studies to optimally define the role of reduced-intensity transplantation in both acute myeloid and acute lymphoblastic leukaemia.

Pretreatment C-reactive protein is a predictor for outcomes after reduced-intensity allogeneic hematopoietic cell transplantation

We tested the independent prognostic impact of 2 commonly used biomarkers, C-reactive protein (CRP) and interleukin (IL)-6, on the outcomes of allogeneic hematopoietic cell transplantation (HCT). Consecutive patients who underwent a uniform reduced-intensity conditioning (RIC) regimen of fludarabine (Flu), melphalan (Mel), and alemtuzumab were evaluated retrospectively. Cryopreserved serum samples drawn before the RIC were available to measure CRP levels in 81 patients and IL-6 levels in 79 patients. Patients with CRP levels above the median of 18.5 mg/L had significantly more grade 3-4 hepatic toxicity (P=.01), longer HCT hospital stay (P=.005), more acute graft-versus-host disease (aGVHD) (P=.003), greater nonrelapse mortality (NRM) (P=.01), and inferior overall survival (OS; P=.02). Higher baseline CRP showed no significant correlation with grade 3-4 infectious toxicity (P=.09). In contrast to CRP, pre-HCT IL-6 levels above the median of 78.3 pg/mL did not confer a statistically significant increased risk of toxicity or mortality. An elevated HCT comorbidity index (HCT-CI) did not predict for any measure of HCT morbidity. After adjustment for disease status, comorbidity, performance status, and age, elevated CRP concentration remained predictive of NRM. These data require confirmation in non-T cell-depleted conditioning regimens. If validated, they suggest that preconditioning CRP holds promise for enhancing estimates of transplantation tolerance.

Acute graft-versus-host disease: differing risk with differing graft sources and conditioning intensity

Acute graft-versus-host disease (aGVHD) is a constant component of allogeneic hematopoietic cell transplantation (HCT), with variations in incidence and severity affected by the graft source, human leukocyte antigen (HLA) compatibility, and the preparative regimen. The graft source - related versus unrelated donors, bone marrow (BM) versus peripheral blood (PB), umbilical cord blood (UCB) versus unrelated donor BM - are discussed in this review, as well as myeloablative versus reduced-intensity (RI) preparative regimens. Recent comparisons of matched related versus matched unrelated donor HCT support a minimal difference in aGVHD between these two donor sources. The use of BM versus mobilized PB in the matched related donor (MRD) setting has been compared in randomized as well as phase-II comparative clinical trials which support a slight increase in aGVHD in the adult population. Similar results have been seen in the unrelated donor (URD) setting, although based on minimal comparative data to date. Preliminary comparisons of UCB versus URD BM have shown a decreased incidence of aGVHD with UCB, despite increased HLA mismatching. Haploidentical HCT has continued to be explored, with limitations due to delayed immune reconstitution and disease relapse. Many reduced-intensity preparative regimens have been published, with a reduced or minimal difference in incidence of aGVHD when historically compared to myleoablative preparative regimens. More formal comparisons of the different graft sources as well as preparative regimen intensities will be required to determine a more accurate picture of the differences between these transplantation alternatives.

Impact of alemtuzumab as conditioning regimen component on transplantation outcomes in case of CMV-seropositive recipients and donors

We studied the incidence of cytomegalovirus (CMV) infection, clinical outcomes, and complications in 39 recipients of alemtuzumab-containing conditioning-stem cell transplantation, who were classified into two groups based on the median dose (35 mg) of alemtuzumab. All the recipients and donors were CMV-seropositive before transplantation. The median survival duration was 321 days (range, 46-1098 days) and the 2-year survival rate was 47.8%. The probability of nonrelapse mortality at 100 days and 2 years was 14.6% and 31.2%, respectively. The cumulative incidence of Grade II-IV acute graft-versus-host disease (GVHD) at Day 100 was 21.8%. The overall incidence of chronic GVHD (cGVHD) was 28.6%, including a 17.9% incidence of extensive cGVHD. The cumulative incidence of CMV antigenemia was 68.0%. There were no statistical differences in the engraftment, acute and cGVHD, relapse, CMV antigenemia, and overall survival (OS) between the two groups. Yet, the nonrelapse mortality (NRM) was significantly lower for the low-dose group (5.9% vs. 51.7%, P = 0.010). The present study showed that alemtuzumab was effective for GVHD prevention, yet caused a relatively high incidence of CMV antigenemia, regardless of the dose. Thus, a low dose of alemtuzumab (< or = 35 mg) would seem to be preferable in an allogeneic SCT setting when both the recipient and the donor are CMV seropositive.

Reduced-toxicity conditioning with fludarabine, BCNU, and melphalan in allogeneic hematopoietic cell transplantation: particular activity against advanced hematologic malignancies

Toxicity-reduced conditioning is being used for allogeneic stem cell transplantation in older and/or comorbid patients. We report on the treatment of 133 patients (median age: 55.6 years [23-73 years]) with acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS; n = 81), myeloproliferative syndromes (MPS; n = 20), and lymphoid malignancies (n = 32) using conditioning with FBM: fludarabine (5 × 30 mg/m2), 1,3-bis(2-chloroethyl)-1-nitrosourea (or carmustine, BCNU; 2 × 200 mg/m2), and melphalan (140 mg/m2). Patients 55 years or older received fludarabine with reduced BCNU (2 ×150 mg/m2) and melphalan (110 mg/m2). After engraftment, chimerism analyses revealed complete donor hematopoiesis in 95.7% of patients. With a median follow-up of 58.5 months, 3- and 5-year overall survival (OS) was 53.0% and 46.1%, event-free survival (EFS) was 46.4% and 41.9%. No significant differences in OS and EFS were evident considering disease status (early vs advanced), patient age (<55 vs≥55 years), or donor type (related vs unrelated) in univariate and multivariate analyses. The cumulative 5-year incidence of death due to relapse was 20.1%. Nonrelapse mortality (NRM) after 100 days and 1 year was 15.8% and 26.3%. Among patients with AML/MDS, advanced cases (n = 64, including 61 with active disease) showed an OS of 44.6% and 42.4% after 3 and 5 years, respectively. Therefore, FBM conditioning combines effective disease control with low NRM.

Hematopoietic stem cell transplantation in adults with acute myeloid leukemia

Hematopoietic stem cell transplantation (HSCT) is an integral part of the treatment of many patients with acute myeloid leukemia (AML). Despite extensive study, the appropriate role and timing of allogeneic and autologous transplantation in AML are poorly defined. This review critically analyzes the extensive literature, focusing on the recent advances, and provides practical recommendations for the use of HSCT in AML.

Newer monoclonal antibodies for hematological malignancies

Since the approval of rituximab in 1997, monoclonal antibodies have come to play an important role in the therapy of hematological malignancies. Rituximab, gemtuzumab ozogamicin, and alemtuzumab are US Food and Drug Administration-approved for treatment of B-cell lymphomas, acute myeloid leukemia, and chronic lymphocytic leukemia, respectively. Multiple monoclonal antibodies directed against new and not-so-new cellular antigens are undergoing development and investigation all over the world. Most of these new compounds have undergone primatization or humanization, improving their specificity and decreasing their antigenicity when compared to earlier murine or chimeric products. This review will focus on three major aspects of monoclonal antibody therapy: 1) new therapeutic approaches with currently approved agents; 2) preclinical and clinical experience accumulated on new agents in the last few years; discussion will include available phase I, II, and III data on ofatumumab, epratuzumab, CMC-544, HeFi-1, SGN-30, MDX-060, HuM195 (lintuzumab), galiximab, lumiliximab, zanolimumab, and apolizumab; and 3) the role of naked and radiolabeled monoclonal antibodies in the hematopoietic stem cell transplantation setting.

Reduced-intensity conditioning and allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia

Acute myeloid leukemia (AML) is a hematologic malignancy with a peak incidence over the age of 55 years. AML of older patients is less curable with conventional chemotherapy, and, when it relapses, is almost uniformly fatal. Novel treatments hold the promise of improving the results of therapy, but have failed so far to show dramatic change in the prognosis. Allogeneic stem cell transplantation using traditional myeloablative preparative regimens is not easily tolerated by the elderly and/or frailer patient, and may lead to prohibitive treatment-related mortality rates. Most patients treated in the past were younger and devoid of comorbid clinical conditions. Novel reduced-intensity regimens made allogeneic transplants applicable to the elderly, providing the benefit of the graft-versus-leukemia effect to a larger number of patients in need. Here we review the indications for allogeneic transplants in AML and discuss reduced-intensity conditioning regimens.

Hematopoietic cell transplantation-comorbidity index and Karnofsky performance status are independent predictors of morbidity and mortality after allogeneic nonmyeloablative hematopoietic cell transplantation

BACKGROUND

Elderly and medically infirm cancer patients are increasingly offered allogeneic nonmyeloablative hematopoietic cell transplantation (HCT). A better understanding of the impact of health status on HCT outcomes is warranted. Herein, a recently developed HCT-specific comorbidity index (HCT-CI) was compared with a widely acceptable measure of health status, the Karnofsky performance status (KPS).

METHODS

The outcomes of 341 patients were evaluated, conditioned for either related or unrelated HCT by 2-gray (Gy) total body irradiation given alone or combined with fludarabine at a dose of 90 mg/m(2). Comorbidities were assessed retrospectively by the HCT-CI. Performance status before and toxicities after HCT were graded prospectively using the KPS and National Cancer Institute Common Toxicity criteria, respectively.

RESULTS

Weak Spearman rank correlations were noted between HCT-CI and KPS and between the 2 measures and age, number of prior chemotherapy regimens, and intervals between diagnosis and HCT (all r < 0.20). High-risk diseases correlated significantly with higher mean HCT-CI scores (P = .009) but not low KPS (P = .37). In multivariate models, the HCT-CI had significantly greater independent predictive power for toxicities (P = .004), nonrelapse mortality (P = .0002), and overall mortality (P = .0002) compared with the KPS (P = .05, .13, and .05, respectively). Using consolidated HCT-CI and KPS scores, patients were stratified into 4 risk groups with 2-year survivals of 68%, 58%, 41%, and 32%, respectively.

CONCLUSIONS

HCT-CI and KPS should be assessed simultaneously before HCT. The use of both tools combined likely refines risk-stratification for HCT outcomes. Novel guidelines for assessment of performance status among HCT patients are warranted.

Transplantation in remission improves the disease-free survival of patients with advanced myelodysplastic syndromes treated with myeloablative T cell-depleted stem cell transplants from HLA-identical siblings

From 1985 to 2004, 49 patients with advanced myelodysplastic syndromes (MDS) (> or =5% blasts) or acute myeloid leukemia (AML) transformed from MDS underwent T cell depleted bone marrow or peripheral blood hematopoietic stem cell transplantation (HSCT) from HLA-identical siblings following conditioning with a myeloablative regimen that included total body irradiation (44 patients) or busulfan (5 patients). Thirty-six patients received chemotherapy (3 low dose and 33 induction doses) before conditioning, and 13 patients did not receive any chemotherapy. Prior to transplantation, 22 of the 36 treated patients were in hematologic remission; 4 were in a second refractory cytopenia phase (26 responders); 8 had failed to achieve remission; and 2 of the responders had progression or relapse of their MDS (10 failures). No post-transplantation pharmacologic prophylaxis for graft-versus-host disease (GVHD) was given. The median age was 48 yrs (range 13-61). Forty-five of the 49 patients engrafted; 2 had primary graft failure; and 2 died before engraftment. Only 3 patients developed acute GVHD (aGVHD) (grades I and III) and 1 chronic GVHD (cGVHD). At 3 yrs post-transplantation, the overall survival (OS) was 54% in the responders; 31% in the untreated group; and 0% in the failure group (P=.0004). The disease free survival (DFS) was 50%, 15% and 0% in each group respectively (P=.0008). In multivariate analysis, disease status before cytoreduction remained highly correlated with DFS (P<.001). The cumulative incidence (CI) of relapse at 2-yrs post-transplantation for the responders was 23%; for the untreated group was 38%; and for the failures was 50%. The CI of non-relapse mortality at 2-yrs post-transplantation, for the responders was 23%; for the untreated group was 38%; and for the failures was 40%. All survivors achieved a Karnofsky Performance Status (KPS) of > or =90. These results indicate that patients with advanced MDS who achieve and remain in remission or a second refractory cytopenia phase with chemotherapy before conditioning can achieve successful long-term remissions following a myeloablative T cell depleted allogeneic HSCT.

Allogeneic stem cell transplantation for myelodysplastic syndrome

Although it is only used to treat a minority of patients with myelodysplastic syndromes, stem cell transplantation (SCT) is the only proven curative treatment for this condition. Because MDS occurs in a population of older adults with significant comorbidities, reduced-intensity conditioning (RIC) regimens have been particularly important in extending safe SCT to the large MDS population over the age of 60 years. Extension of the unrelated donor pool together with the introduction of umbilical cord blood transplants in adults has extended the number of patients with suitable donors. Nevertheless overall mortality from SCT is greater than 50% because of relapse and non-relapse mortality (NRM). New developments to improve outcome include the tailoring of the transplant approach to the individual based on age and comorbidity, and the use of pretransplant chemotherapy to reduce disease bulk prior to transplant, as well as the introduction of post-transplant immunotherapy (pre-emptive donor lymphocyte infusions) and chemotherapy to prevent relapse. Further improvements in transplant outcome await better ways to reconstitute immunity and amplify the graft-versus-leukemia (GVL) effect without causing graft-versus-host disease (GVHD), as well as further extension of the donor pool and exploration of risk-adapted regimens for the population of MDS in their seventh to eighth decade.

Hematopoietic transplantation from adult unrelated donors as treatment for acute myeloid leukemia

Transplantation from unrelated donors (URD) is increasingly being used as treatment for hematological malignancies, including acute myeloid leukemia (AML). This increase is the consequence of the availability of more than 11 million URD volunteers and the more efficient donor search process in the recent years. Median time to identify a suitable URD is now 2 months. More than 50% of Caucasian patients have an human leukocyte antigen (HLA)-allele donor match and a one-antigen or allele HLA-mismatched donor may also be acceptable. Complications of URD transplants are particularly frequent and severe, with long-term OS in the registries being 10-20% inferior to HLA-identical sibling transplantation. High resolution DNA techniques for donor and recipient HLA matching have contributed to the survival in experienced centres after unrelated donor SCT approaching that achieved with sibling donors. The introduction of reduced intensity conditioning (RIC) has extended URD transplants to elderly and/or debilitated patients with AML. With this approach, TRM decreases, although graft-versus-host disease-related morbidity and mortality remain a problem. Despite this complication, results after URD transplantation in this age group seem better than those achieved with chemotherapy and/or autologous transplantation. To confirm this possibility, prospective multicenter comparisons of URD transplants after RIC with other treatment options for elderly AML patients have recently been started.

High antileukemic efficacy of an intermediate intensity conditioning regimen for allogeneic stem cell transplantation in patients with high-risk acute myeloid leukemia in first complete remission

The goal of this analysis was to define the role of the moderate-intensity fludarabin Ara-C amsacrin (FLAMSA)-reduced intensity conditioning (RIC) regimen for patients with high-risk AML undergoing allogeneic SCT (alloSCT) in first CR1. High-risk was defined by (1) AML secondary to MDS or radio/chemotherapy, (2) unfavorable cytogenetics or (3) delayed response to induction chemotherapy. A total of 23 of 44 AML patients referred to the University of Munich for alloSCT in CR1 between 1999 and 2006 fulfilled these criteria and received FLAMSA chemotherapy, followed by RIC (4 Gy TBI/cyclophosphamide/ATG) for alloSCT. Twenty-two patients engrafted, one died in aplasia. Two-year cumulative incidences for relapse and nonrelapse mortality (NRM) were 4.6 and 22.5%, respectively. Four-year overall and leukemia-free survival was 72.7% (median follow-up among survivors: 35 months). The results of this high-risk cohort were compared to the outcome of 21 consecutive standard-risk patients <55 years, who had received standard, myeloablative sibling SCT in CR1 AML within the same center and time period. Survival and cumulative incidences of relapse and NRM were identical in both groups. In conclusion, the FLAMSA-RIC regimen produces long-term remission in a high proportion of patients with high-risk AML transplanted in CR1. In this cohort, FLAMSA-RIC showed equivalent antileukemic activity as compared to the standard protocols.

Successful allogeneic transplantation of patients with suspected prior invasive mold infection

Prior invasive fungal infection (IFI) has historically limited the use of allogeneic stem cell transplantation for patients with hematologic malignancies. Transplantation of such patients frequently resulted in recurrent infection and high mortality rates. Several new antifungal agents have been introduced over the past 5 years with broader spectra of activity against molds such as Aspergillus and a favorable toxicity profile. In this study, we present a series of 16 consecutive patients with hematologic malignancy and prior invasive fungal infection who underwent allogeneic transplantation. Of these patients, the majority of whom were treated with voriconazole and/or caspofungin, only four experienced recurrent fungal infection and recurrent fungal infection was the primary cause of death in only one patient. The estimated 45% 2-year survival in this series is similar to that for other patients with high risk hematologic malignancy undergoing stem cell transplantation. We conclude that suspected prior invasive fungal infection should not preclude the use of allogeneic stem cell transplantation.

Reduced intensity conditioning for allogeneic hematopoietic stem cell transplantation in myelodysplastic syndromes and acute myelogenous leukemia

PURPOSE OF REVIEW

The aim of this article is to summarize the outcome in recent studies of patients with acute myelogenous leukemia/myelodysplastic syndromes after reduced intensity conditioning for allogeneic stem cell transplantation.

RECENT FINDINGS

Reduced intensity conditioning has demonstrated the capability to achieve engraftment and to decrease early nonrelapse mortality in older and unfit patients. Most large retrospective studies have demonstrated that reduced intensity conditioning regimens lead to a reduction of nonrelapse mortality in patients with acute myelogenous leukemia and myelodysplastic syndromes, but disease relapse is higher than with standard myeloablative conditioning regimens. Chronic graft-versus-host disease has emerged as one of the more powerful variables reducing relapses and improving overall and disease-free survival. The use of in-vivo T-cell depletion with alemtuzumab or antithymocyte globulin reduces acute graft-versus-host disease but appears to have no impact on survival. Hopefully, a new second generation of reduced intensity conditioning will study new strategies for reducing disease relapse with low nonrelapse mortality.

SUMMARY

Allogeneic stem cell transplantation with reduced intensity conditioning allows many patients considered ineligible for standard myeloablative conditioning to benefit from this therapy. Research must now focus on designing new strategies for reducing the increased risk of disease relapse.

Outcomes of patients with AML and MDS who relapse or progress after reduced intensity allogeneic hematopoietic cell transplantation

We describe treatment, outcomes and prognostic factors for patients who relapse following transplantation with a reduced intensity conditioning regimen. Seventy consecutive patients with high-risk myeloid malignancies underwent transplant and 25 (36%) relapsed, a median of 120 days later. The median percentage of bone marrow blasts at relapse was 24, the median donor chimerism was 73% and new karyotypic abnormalities occurred in 8 out of 20 (40%) evaluable patients. Twenty-one patients (84%) received aggressive treatment for relapse, including chemotherapy (60%), second hematopoietic cell transplantation (HCT; 52%) and/or donor lymphocyte infusion (DLI; 12%). Thirteen achieved a complete response (CR) and four remain in CR. Median overall survival (OS) after relapse was 6 months (95% confidence interval=2.7-9.9 months), and actuarial 1 year OS was 24%. Most deaths were due to disease progression (17/20, 85%). We did not observe an advantage for cellular therapy (DLI or second transplant) compared to chemotherapy. Salvage therapy for relapse after reduced intensity HCT is feasible, associated with low treatment-related mortality, and may result in prolonged survival in select patients. Studies exploring the optimal treatment for relapse following reduced intensity HCT are warranted.

Reduced-intensity conditioning for allogeneic hematopoietic stem cell transplantation with fludarabine and melphalan is associated with durable disease control in myelodysplastic syndrome

We retrospectively evaluated the outcome of reduced-intensity conditioning (RIC) followed by allogeneic hematopoietic stem cell transplantation (HCT) in 43 patients with myelodysplastic syndrome (MDS) or AML arising from MDS. All patients received fludarabine plus melphalan followed by an allogeneic HCT from an HLA-identical sibling (SIB: n=19) or unrelated donor (MUD: n=24). Median age was 58 years (range: 30-71). Diagnoses at transplantation were RA (n=8), RARS (n=1), RAEB (n=13), RAEB-T (n=6), or AML arising from MDS (n=15). Of 28 patients with MDS, two patients had low, 10 had intermediate-1, nine had intermediate-2 and seven had high-risk MDS by IPSS criteria. All patients initially engrafted with the median neutrophil recovery of 15 days (range: 9-27). The 2-year overall survival, disease-free survival, relapse and transplant-related mortality were 53.5% (CI 45.2-61.1), 51.2% (CI 43.3-58.5), 16.3% (CI 7.9-30.7) and 35.2% (26.4-45.7), respectively. Grade II-IV acute graft-versus-host disease occurred in 27 (63%) patients. There was no significant survival difference between SIB and MUD-HCT, but the relapse rate was higher among SIB donor recipients when compared to MUD (38.5 versus 7%, P=0.02). RIC with fludarabine plus melphalan was associated with durable disease control and acceptable toxicity in this high-risk cohort.

Comparison between two fludarabine-based reduced-intensity conditioning regimens before allogeneic hematopoietic stem-cell transplantation: fludarabine/melphalan is associated with higher incidence of acute graft-versus-host disease and non-relapse mortality and lower incidence of relapse than fludarabine/busulfan

Reduced-intensity conditioning (RIC) regimens are increasingly used in allogeneic stem-cell transplantation (SCT). There are no data whether any of these regimens has advantage and in what setting. We retrospectively analyzed SCT outcomes in 151 patients given fludarabine-based RIC for various hematological malignancies; 72 conditioned with fludarabine and intravenous-busulfan (FB) and 79 with fludarabine and melphalan (FM). FM was more myelosuppressive. Grade III-IV organ toxicity occurred in 31 and 53% of FB and FM recipients (P=0.005) and acute graft-versus-host disease grade II-IV in 33 and 53%, respectively (P=0.01). Non-relapse mortality rate (NRM) was 16 and 40%, respectively (P=0.003). Active disease (HR 2.2, P=0.003) and prior autologous SCT (HR 1.7, P=0.04) predicted inferior overall survival (OS). Among patients transplanted in remission, OS was 72 and 36% after FB and FM, respectively (P=0.03) due to increased NRM with FM. Similarly, patients transplanted in active disease experienced higher NRM with FM, however lower relapse rates resulted in equivalent OS. In conclusion, there are marked differences in outcome between RIC regimens that are theoretically dose-equivalent. The FM regimen is more myelosuppressive and toxic but controls disease better. FB was associated with improved survival in patients transplanted in remission. These observations merit further study in prospective studies.

Delayed attainment of full donor chimaerism following alemtuzumab-based reduced-intensity conditioning haematopoeitic stem cell transplantation for acute myeloid leukaemia and myelodysplastic syndromes is associated with improved outcomes

This prospective study evaluated the kinetics of lymphoid (CD3) engraftment in 110 patients with acute myeloid leukaemia (AML) and myelodysplastic syndromes (MDS) after allogeneic transplantation and conditioning with fludarabine, busulphan and alemtuzumab, using ciclosporin for post-transplant immunosuppression. Declining donor CD3 chimaerism beyond day+100 was treated with pre-emptive donor lymphocyte infusion (pDLI). The median age of patients was 53.0 years (range: 19-72 years), and the median follow-up was 690 d (range:168-1470 d). Patients achieving full CD3 donor chimaerism (FDC, n = 46) by day+100 had a significantly inferior disease-free survival (DFS) and overall survival (OS) compared to patients with mixed donor chimaerism (MDC, n = 59). Twenty patients had stable MDC and did not require pDLI. Patients attaining early FDC had a higher transplant-related mortality compared to those who maintained stable levels of MDC (P = 0.02), with no difference between the FDC and pDLI groups (P = 0.07). There was no difference in relapse between all three groups (P = 0.21). On multivariate analysis, only CD3 chimaerism status at day+100 and disease status at transplantation had a significant effect on DFS and OS. In patients with AML/MDS undergoing alemetuzumab based-RIC HSCT, prolonged MDC beyond day+100 is associated with an improved OS. Future studies need to be directed towards establishing the underlying factors that dictate T-cell engraftment, expansion and homing post-transplantation.

Viewpoint: What is the role of allogeneic haematopoietic cell transplantation in the era of reduced-intensity conditioning--is there still an upper age limit? A focus on myeloid neoplasia

Allogeneic haematopoietic cell transplantation (HCT) is the most effective curative therapy in acute myeloid leukaemia (AML) and myelodysplastic syndromes (MDS). Incidence of AML and MDS increases with age, peaking in the seventh decade. Despite improved Ara-C and anthracyclin-based chemotherapy regimens, the prognosis of AML in patients beyond 60 years of age is dismal. The introduction of peripheral blood-derived stem cell grafts into allogeneic HCT and the known anti-leukaemic effect of donor lymphocyte infusions paved the way for reduced-intensity conditioning (RIC) allogeneic stem-cell transplantation, which makes transplant in advanced age possible and significantly reduces transplant-related organ toxicity and mortality. The success of RIC HCT relies on the alloreactivity of the donor immune system and the graft-versus-leukaemia effect. We try to answer the following questions in this paper: who should receive RIC HCT? when and how should the transplant be performed? is there an upper age limit and what is the future of RIC HCT?

Impact of postgrafting immunosuppressive regimens on nonrelapse mortality and survival after nonmyeloablative allogeneic hematopoietic stem cell transplant using the fludarabine and low-dose total-body irradiation 200-cGy

The development of nonmyeloablative (NM) hematopoietic cell transplantation (HCT) has extended the potential curative treatment option of allografting to patients in whom it was previously contraindicated because of advanced age or comorbidity. Acute and chronic graft versus host disease (GVHD) and its consequent nonrelapse mortality (NRM), remains the major limitation of NM HCT. In this report, we analyzed the outcome of 67 patients (median age, 45 years) with hematologic diseases receiving NM conditioning with fludarabine 90 mg/m(2) and total body irradiation (TBI) 200-cGy, followed by filgrastim-mobilized peripheral blood stem cell transplant from HLA identical (n = 61), 5/6 antigen-matched related (n = 1), 6/6 antigen-matched unrelated (n = 3), and 5/6 antigen-matched unrelated (n = 2) donors. The first cohort of 21 patients were given cyclosporine (CSP) and mycophenolate mofetil (MMF) as postgrafting immunosuppression, whereas the subsequent cohort was given additional methotrexate (MTX) and extended duration of CSP/MMF prophylaxis in an attempt to reduce graft-versus-host disease (GVHD). Sixty-four (95%) patients engrafted and 3 (5%) had secondary graft failure. Myelosuppression was moderate with neutrophil counts not declining below 500/microL in approximately 25% of patients, and with more than half of the patients not requiring any blood or platelet transfusion. The 2-year cumulative interval (CI) of grade II-IV, grade III-IV acute GVHD and chronic GVHD were 49%, 30%, and 34%, respectively. The 2-year probability of NRM, overall (OS), and progression-free (PFS) survival were 27%, 43%, and 28%, respectively. GVHD-related death accounted for 85% of NRM. Compared with patients receiving CSP/MMF, patients receiving extended duration of CSP/MMF with additional MTX in postgrafting immunosuppression had a significantly lower risk of grade III-IV acute GVHD (CI 20% versus 52%; P = .009) and NRM (CI at 2 years: 11% versus 62%; P < .001), without any significant adverse impact on the risk of relapse (CI at 2 years: 59% versus 33%; P = .174) Subgroup analysis of a cohort of patients given MTX/CSP/MMF showed that patients with "standard risk" diseases (n = 21) had a 3-year OS and PFS of 85% and 65%, respectively. This compares favorably to the 41% (P = .02) and 23% (P = .03) OS and PFS, respectively, in patients with "high-risk" diseases (n = 25). In conclusion, the addition of MTX onto the current postgrafting immunosuppression regimen with extended CSP/MMF prophylaxis duration provides more effective protection against severe GVHD, and is associated with more favorable outcome in patients receiving NM fludarabine/TBI conditioning than in patients receiving fludarabine/TBI conditioning with CSP and MMF without MTX.

Hematopoietic cell transplantation after reduced-intensity conditioning for older adults with acute myeloid leukemia in complete remission

PURPOSE OF REVIEW

Allogeneic hematopoietic cell transplantation with myeloablative conditioning is a well established therapy for patients with acute myeloid leukemia. Its efficacy depends, in part, on the destruction of recipient acute myeloid leukemia cells by the conditioning regimen and, in part on their removal by donor immune cells contained in the graft (graft-versus-tumor effect). Due to regimen-related toxicities, the use of myeloablative allogeneic hematopoietic cell transplantation has been restricted to younger patients in good condition. More recently, the introduction of allogeneic hematopoietic cell transplantation following reduced-intensity or nonmyeloablative conditioning regimens, which rely mainly on graft-versus-tumor effects for tumor cell eradication, has permitted extending hematopoietic cell transplantation to include older patients and those with medical comorbidities.

RECENT FINDINGS

Early results with allogeneic hematopoietic cell transplantation after nonmyeloablative and reduced-intensity conditioning for patients with acute myeloid leukemia in first complete remission are encouraging, with 2-year survivals after hematopoietic cell transplantation ranging from 48 to 79% among studies. Further, retrospective studies have demonstrated similar outcomes in adult patients with acute myeloid leukemia in complete remission given either myeloablative or nonmyeloablative conditioning.

SUMMARY

Prospective studies are needed to define the place of allogeneic hematopoietic cell transplantation after nonmyeloablative or reduced-intensity conditioning in patients with acute myeloid leukemia in complete remission, and to determine a role for consolidation chemotherapy before hematopoietic cell transplantation, if any.

A prospective multicenter trial of peripheral blood stem cell sibling allografts for acute myeloid leukemia in first complete remission using fludarabine-cyclophosphamide reduced intensity conditioning

The role of allogeneic transplantation in patients with de novo acute myeloid leukemia in first complete remission (AML-CR1) is controversial. Aiming to preserve a graft-versus-leukemia effect, but minimize morbidity and mortality from conditioning-related toxicity and graft-versus-host disease (GVHD), we conducted a prospective multicenter study of reduced-intensity conditioning (RIC) as preparation for peripheral blood stem cell sibling allografts in patients with intermediate or poor risk AML-CR1. Conditioning consisted of fludarabine 125 mg/m(2) and cyclophosphamide 120 mg/kg. Thirty-four patients were transplanted with a median age of 45 years; 85% had intermediate risk cytogenetics. Early toxicity was minimal. The overall incidence of grade II-IV acute GVHD was low (21%), but the 3 patients (9%) who developed grade IV GVHD died. Donor T cell chimerism was rapid and generally complete, but complete myeloid chimerism was delayed. Thirteen patients (38%) relapsed, 12 within a year of transplant. The estimated disease-free survival (DFS) and overall survival at 2 years was 56% (95% confidence interval [CI] 39%-71%) and 68% (95% CI 50%-81%), respectively. The incidence of extensive chronic GVHD (cGVHD) was low (24% of surviving patients at 12 months) and most survivors had an excellent performance status. These observations justify a prospective comparison of RIC versus myeloablative conditioning allografts for AML-CR1.

Novel approaches in allogeneic stem cell transplantation

Allogeneic transplantation remains an integral part of the management of hematologic malignancies. However, transplant-related mortality, graft-versus-host disease, and disease recurrence continue to be major limitations to successful transplant outcomes and challenges to investigators in the field. Newer approaches have focused on reduction of the intensity of the conditioning regimens, harnessing the antitumor effects of the allograft, and development of adoptive immunotherapy strategies to circumvent the limitations. These developments provide physicians with the ability to tailor transplants to specific patients and their diseases.

Prognostic factors for patients with acute myeloid leukaemia or high-risk myelodysplastic syndromes undergoing myeloablative or non-myeloablative allogeneic blood stem cell transplantation

In this uni-centre retrospective study, we studied 120 adults with acute myeloid leukaemia (AML) (n = 88) and myelodysplastic syndrome (MDS) (n = 32) who received first allogeneic HSCT to determine prognostic factors which are correlated with the outcome after myeloablative (MA) or non-myeloablative (non-MA) allogeneic HSCT. The median age of our cohort was 44 years. Fifty-nine per cent of the patients were transplanted in complete remission (CR) and 41% were in relapse or refractory to induction or salvage therapy. A total of 97 patients received a MA regimen and 23 were treated with a non-MA regimen. The prognostic impact for several parameters was assessed by univariate and by multivariate analyses using the Cox regression model. Three-year probabilities of non-relapse mortality (34 vs. 54%; p = 0.9) did not differ in the MA and non-MA groups, but differences were observed in the disease-free survival (DFS) (43 vs. 17%; p = 0.1) and the relapse rate (RR) (29 vs. 62%; p = 0.01). Independently from the regimen, in uni- and multivariate analysis, survival was best in those patients who were transplanted in CR and experienced cGvHD. Interestingly, outcome of patients with complex cytogenetic aberrations was identical to that of better prognostic subgroups. In this study, the clinical benefit of a lower toxicity regimen was offset by higher RR resulting in inferior results in the non-MA group, especially when no CR was achieved by prior induction or salvage therapy.

Performance status and comorbidity predict transplant-related mortality after allogeneic hematopoietic cell transplantation

Comorbidity measurements have recently been used to improve estimation of tolerance to allogeneic hematopoietic cell transplantation (HCT). We sought to determine the independent effect of comorbidity and performance status on HCT outcome and to devise a simple risk classification system for transplant-related mortality. We analyzed 105 consecutively enrolled patients who underwent HCT and received reduced intensity conditioning with fludarabine, melphalan, and alemtuzumab. Comorbid conditions were tabulated using 2 scales, the Charlson Comorbidity Index (CCI) and the Kaplan-Feinstein Scale (KFS). Comorbid conditions were found in 47% of patients by the KFS and in 27% by the CCI (P < .001). Using the Eastern Cooperative Oncology Group Performance Status (PS) scale, 34% had a PS score >0 (range, 0-2). A simple scale combining the KFS and PS enabled separation of high- from low-risk patients, with 6-month cumulative incidences 50% and 15%, respectively for transplant-related mortality (P = .001) and enhanced prognostic power over the CCI alone (P = .018). Prospective studies evaluating more comprehensive functional and comorbidity measurements are warranted.

Reduced intensity conditioning (RIC) haematopoietic cell transplants in elderly patients with AML

Reduced intensity conditioning (RIC) transplants were first developed almost a decade ago to reduce the transplant-related mortality (TRM) of allogeneic haematopoietic cell transplantation (HCT) and to make the graft-versus-leukaemia effect accessible to patients otherwise ineligible for HCT. Acute myelogenous leukaemia (AML) in elderly patients is now a frequent indication for RIC-HCT. The major reasons for these rapid developments have been on the one hand the high median age of patients with AML coupled with the unsatisfactory results with conventional chemotherapy, and on the other hand with the promising results already reported for RIC-HCT. Using RIC-HCT, overall survival rates at 2 years of 45-50% have been observed in patients with AML. This compares favourably with overall survival rates of 10-15% under chemotherapy in AML CR1, or no long-term survivors in patients >CR2. From the available data we conclude that RIC-HCT is a promising treatment for elderly patients with AML. However, phase-III studies with unrelated donors will have to be done in order to formally prove its superiority in comparison to conventional chemotherapy.