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

Results of a Phase II Trial of Allogeneic Hematopoietic Stem Cell Transplantation Using 90Y-Ibritumomab Tiuxetan (Zevalin) in Combination With Fludarabine and Melphalan in Patients With High-Risk B-Cell Non-Hodgkin's Lymphoma

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (alloHCT) is potentially curative for relapsed/refractory (r/r) B-cell non-Hodgkin's lymphoma (B-cell NHL). However, relapse remains a major cause of treatment failure, especially in patients with either positron emission tomography (PET)-positive and/or chemoresistant disease prior to alloHCT. 90Y-ibritumomab tiuxetan (Zevalin) is a radiolabeled anti-CD20 antibody which is a safe and effective therapy in multiple histologic subtypes of B-cell NHL and has also been incorporated in both autologous HCT (autoHCT) and alloHCT conditioning regimens.

OBJECTIVES

The purpose of this study was to evaluate the efficacy and confirm the safety of the radiolabeled anti-CD20 antibody ibritumomab tiuxetan (Zevalin) combined with the reduced intensity conditioning (RIC) regimen of fludarabine and melphalan (Flu/Mel) in patients with high-risk B-cell NHL.

STUDY DESIGN

We conducted a phase II trial (NCT00577278) of Zevalin with Flu/Mel in patients with high-risk B-cell NHL. We enrolled 41 patients from October 2007 to April 2014, all of whom had either a fully matched sibling or 8/8 or 7/8 matched unrelated donor (MUD). Patients received 111In-Zevalin (5.0 mCi) on day -21 pre-HCT, followed by 90Y-Zevalin (0.4 mCi/kg) on day -14. Fludarabine (25 mg/m2 daily) was given from days -9 to -5 and melphalan (140 mg/m2) was administered on day -4. All patients received rituximab 250 mg/m2 on day +8 and an additional dose on either day +1 or -21 depending on the baseline rituximab level. Patients with a low rituximab level were given rituximab on days -21 and -15. All patients received tacrolimus/sirolimus (T/S) with or without methotrexate (MTX) for graft-versus-host disease (GVHD) prophylaxis starting on day -3, and stem cells were infused on day 0.

RESULTS

The 2-year overall survival (OS) and progression-free survival (PFS) for all patients were 63% and 61%, respectively. The incidence of relapse at 2 years was 20%. Nonrelapse mortality (NRM) at day +100 and 1 year were 5% and 12%, respectively. The overall cumulative incidence of grade II-IV and III-IV acute GVHD (aGVHD) were 44% and 15%, respectively. Extensive chronic GVHD (cGVHD) occurred in 44% of patients. On univariate analysis, histology (diffuse large B cell lymphoma (DLBCL) vs. others) was negatively predictive for OS (P = .0013) and PFS (P = .0004), while histology (DLBCL vs. others, P = .0128) predicted for relapse. PET positivity pre-HCT did not correlate with any of the efficacy endpoints.

CONCLUSION

Addition of Zevalin to Flu/Mel is safe and effective in high-risk NHL and met the prespecific endpoint. Results were suboptimal in patients with DLBCL.

Room for Improvement: A 20-Year Single Center Experience with Allogeneic Stem Cell Transplantation for Myelodysplastic Syndromes

Allogeneic stem cell transplantation (allo-SCT) remains the only curative therapeutic approach for patients with myelodysplastic syndromes (MDS). The aim of the study was to assess the efficacy/safety of allo-SCT as well as to identify factors influencing post-transplant survival. One hundred and two MDS patients (median age: 48 years; 57 males) who underwent allo-SCT were retrospectively evaluated. Twenty seven patients were transplanted from HLA-matched sibling and 75 patients received grafts from unrelated donors. Peripheral blood was a source of stem cell for 79 patients. Reduced intensity conditioning was used in 64 subjects. Acute and chronic graft versus host disease (GvHD) developed in 61 and 19 of patients, respectively. In total, 61 patients have died. The causes of deaths included infectious complications (n = 30), steroid-resistant GvHD (n = 17), MDS relapse (n = 9) and transformation to AML (n = 5). Non-relapse mortality and cumulative incidence of relapse at 2 years were 49.8% and 9%, respectively. 41 patients are alive at last contact and present full donor chimerism. 38 patients remain in complete hematological remission (CHR), 3 patients had CHR with incomplete platelet recovery. Median follow-up from diagnosis of MDS and transplantation are 27.1 months and 7 months respectively. Overall survival and relapse-free survival were 41% at 2 years. Increased serum ferritin level > 1000 ng/ml, presence of acute GvHD, grades III–IV acute GvHD and high hematopoietic cell transplantation-comorbidity index were found to negatively influenced survival. Allo-SCT for MDS is feasible procedure with a proportion of patients to be cured.

Peritransplant Ruxolitinib Administration is Safe and Effective in Patients with Myelofibrosis: a Pilot Open-Label Study

Peritransplantation ruxolitinib was safe and well tolerated in patients with myelofibrosis, with MTD determined as 10 mg twice daily.

We report results of our prospective pilot trial evaluating safety/feasibility of peritransplantation ruxolitinib for myelofibrosis treatment. Primary objectives were to determine safety and maximum tolerated dose (MTD) of ruxolitinib. Ruxolitinib was administered at 2 dose levels (DLs) of 5 and 10 mg twice daily, with fludarabine/melphalan conditioning regimen and tacrolimus/sirolimus graft-versus-host disease (GVHD) prophylaxis. We enrolled 6 and 12 patients at DL1 and DL2, respectively. Median age at transplantation was 65 years (range, 25-73). Per Dynamic International Prognostic Scoring System, 4 patients were high and 14 intermediate risk. Peripheral blood stem cells were graft source from matched sibling (n = 5) or unrelated (n = 13) donor. At each DL, 1 patient developed dose-limiting toxicities (DLTs): grade 3 cardiac and gastrointestinal with grade 4 pulmonary DLTs in DL1, and grade 3 kidney injury in DL2. All patients achieved engraftment. Grade 2 to 4 and 3 to 4 acute GVHD cumulative incidence was 17% (95% confidence interval [CI], 6-47) and 11% (95% CI, 3-41), respectively. Cumulative incidence of 1-year chronic GVHD was 42% (95% CI, 24-74). With 22.6-month (range, 6.2-25.8) median follow-up in surviving patients, 1-year overall and progression-free survival were 77% (95% CI, 50-91) and 71% (95% CI, 44-87), respectively. Causes of death (n = 4) were cardiac arrest, GVHD, respiratory failure, and refractory GVHD of liver. Our results show peritransplantation ruxolitinib is safe and well tolerated at MTD of 10 mg twice daily and associated with dose-dependent pharmacokinetic and cytokine profile. Early efficacy data are highly promising in high-risk older patients with myelofibrosis. This trial was registered at www.clinicaltrials.gov as #NCT02917096.

Myelodysplastic Syndromes in the Postgenomic Era and Future Perspectives for Precision Medicine

Simple Summary

With demographic ageing, improved cancer survivorship and increased diagnostic sensitivity, incident cases of patients with Myelodysplastic Syndromes (MDS) are continuously rising, leading to a relevant impact on health care resources. Disease heterogeneity and various comorbidities are challenges for the management of the generally elderly patients. Therefore, experienced physicians and multidisciplinary teams should be involved in the establishment of the correct diagnosis, risk-assessment and personalized treatment plan. Next-generation sequencing allows for early detection of clonal hematopoiesis and monitoring of clonal evolution, but also poses new challenges for its appropriate use. At present, allogeneic hematopoietic stem cell transplantation remains the only curative treatment option for a minority of fit MDS patients. All others receive palliative treatment and will eventually progress, having an unmet need for novel therapies. Targeting compounds are in prospect for precision medicine, however, abrogation of clonal evolution to acute myeloid leukemia remains actually out of reach.

Abstract

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal disorders caused by sequential accumulation of somatic driver mutations in hematopoietic stem and progenitor cells (HSPCs). MDS is characterized by ineffective hematopoiesis with cytopenia, dysplasia, inflammation, and a variable risk of transformation into secondary acute myeloid leukemia. The advent of next-generation sequencing has revolutionized our understanding of the genetic basis of the disease. Nevertheless, the biology of clonal evolution remains poorly understood, and the stochastic genetic drift with sequential accumulation of genetic hits in HSPCs is individual, highly dynamic and hardly predictable. These continuously moving genetic targets pose substantial challenges for the implementation of precision medicine, which aims to maximize efficacy with minimal toxicity of treatments. In the current postgenomic era, allogeneic hematopoietic stem cell transplantation remains the only curative option for younger and fit MDS patients. For all unfit patients, regeneration of HSPCs stays out of reach and all available therapies remain palliative, which will eventually lead to refractoriness and progression. In this review, we summarize the recent advances in our understanding of MDS pathophysiology and its impact on diagnosis, risk-assessment and disease monitoring. Moreover, we present ongoing clinical trials with targeting compounds and highlight future perspectives for precision medicine.

Decision Analysis of Transplantation for Patients with Myelodysplasia: "Who Should We Transplant Today?"

PURPOSE OF REVIEW

Myelodysplastic syndrome (MDS) is a heterogeneous hematological disorder characterized by a spectrum of clinical presentation, cytogenetic, and somatic gene mutations and the risk of transformation to acute leukemia. Management options include observation, supportive care, blood transfusion, administration of growth factors and/or hypomethylating agents, and hematopoietic cell transplant (HCT) either upfront or after disease progression.

RECENT FINDINGS

Currently, HCT is the only curative therapy available for patients with MDS, with multiple factors such as donor availability, patient, and disease characteristics being involved in making the decision to proceed with transplant. In this article, we summarize (1) overall prognosis and natural history of MDS, (2) currently available non-HCT therapy with a focus on hypomethylating agents (HMA), (3) outcomes after HCT in patients with MDS, (4) factors to be considered to proceed to HCT for treatment of MDS, and (5) more recent/ongoing studies relevant to HCT decision-making processes.

Long-Term Outcomes of Allogeneic Hematopoietic Cell Transplant with Fludarabine and Melphalan Conditioning and Tacrolimus/Sirolimus as Graft-versus-Host Disease Prophylaxis in Patients with Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is associated with poor survival in older adults, and allogeneic hematopoietic cell transplant (HCT) with reduced-intensity conditioning (RIC) has been an increasingly used strategy in this population. At City of Hope we conducted a retrospective analysis of 72 patients who underwent allogeneic HCT with fludarabine and melphalan (FluMel) as the conditioning regimen between 2005 and 2018, from either a matched sibling or fully matched unrelated donor while in complete remission. Tacrolimus and sirolimus (T/S) were used as graft-versus-host disease (GVHD) prophylaxis. Overall survival and progression-free survival at 4 years post-HCT were 58% and 44%, respectively. The cumulative incidences of relapse/progression and nonrelapse mortality at 4 years were 34% and 22%, respectively. Patients with Philadelphia chromosome-positive (Ph+) ALL had a significantly lower cumulative incidence of relapse/progression (20% versus 48% for patients with Ph-negative status, P = .007). In conclusion, RIC HCT with FluMel conditioning and T/S GVHD prophylaxis was associated with favorable outcomes in patients with Ph+ ALL and should be considered as a viable consolidative therapy for adult patients with ALL.

Reduced-intensity stem cell transplantation for acute myeloid leukemia with fludarabine-based conditioning with intravenous busulfan versus melphalan

Reduced-intensity conditioning (RIC) has been facilitating allogeneic hematopoietic cell transplantation (allo-HCT) for patients originally considered ineligible for HCT with myeloablative conditioning. Fludarabine (Flu) with reduced doses of busulfan (Bu) (Flu + Bu) and Flu with reduced doses of melphalan (Mel) (Flu + Mel) are widely used RIC regimens for acute myeloid leukemia (AML). A nationwide retrospective study comparing clinical outcomes of adult patients with AML receiving first allo-HCT after RIC between 2001 and 2010 was performed. Cumulative incidences of relapse were not significantly different among the Flu + ivBu-based (FBiv), Flu + poBu-based (FBpo), and Flu + Mel-based (FM) groups (p = 0.29). Non-relapse mortality (NRM) was significantly lower in patients receiving FBiv compared with FBpo (p = 0.003) and FM (p < 0.001). On multivariate analysis, there was no significant difference in overall survival, but FM was associated with a significantly lower risk of relapse (hazard ratio (HR) = 0.65, 95% confidence interval (CI): 0.50-0.85, p = 0.002), higher NRM (HR = 1.60, 95% CI: 1.10-2.33, p = 0.013) and better leukemia-free survival (HR = 0.77, 95% CI: 0.63-0.95, p = 0.015) compared with FBiv. These results suggest that Flu + Mel has a more intense disease control potential and Flu + ivBu is less toxic than the other. Both RIC regimens provide similar survival outcomes and are effective and useful regimens for patients with AML who received allo-HCT.

Melphalan-Based Reduced-Intensity Conditioning is Associated with Favorable Disease Control and Acceptable Toxicities in Patients Older Than 70 with Hematologic Malignancies Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (alloHCT) is offered increasingly to elderly patients with hematologic malignancies. However, outcome data in those who are 70 years or older are limited, and no standard conditioning regimen has been established for this population. In this retrospective study we evaluated the outcome of 53 consecutive patients aged 70 years and older who underwent alloHCT with melphalan-based reduced-intensity conditioning (RIC) at City of Hope. Engraftment was prompt, with median time to neutrophil engraftment of 15 days. More than 95% of patients achieved complete donor chimerism within 6 weeks from HCT, consistent with the "semiablative" nature of this regimen. With a median follow-up of 31.1 months, the 2-year overall survival (OS), progression-free survival (PFS), and nonrelapse mortality (NRM) were 68.9%, 63.8%, and 17.0%, respectively. Cumulative incidence of relapse at 1 and 2 years was 17.0% and 19.3%, respectively. One hundred-day cumulative incidence of grades II to IV acute graft-versus-host disease was 37.7% (grades III to IV, 18.9%), and 2-year cumulative incidence of chronic graft-versus-host disease was 61.9% (extensive, 45.9%). The only significant predictor for poor OS was high/very high disease risk index. Transplant-related complications and morbidities observed here did not differ from the commonly expected in younger patients treated with RIC. In conclusion, alloHCT with a melphalan-based conditioning regimen is associated with acceptable toxicities and NRM, lower incidence of relapse, and favorable OS and PFS in patients aged 70 years or older.

Favorable impact of allogeneic stem cell transplantation in patients with therapy-related myelodysplasia regardless of TP53 mutational status

Therapy-related myelodysplastic syndrome is a long-term complication of cancer treatment in patients receiving cytotoxic therapy, characterized by high-risk genetics and poor outcomes. Allogeneic hematopoietic cell transplantation is the only potential cure for this disease, but the prognostic impact of pre-transplant genetics and clinical features has not yet been fully characterized. We report here the genetic and clinical characteristics and outcomes of a relatively large cohort of patients with therapy-related myelodysplastic syndrome (n=67) who underwent allogeneic transplantation, comparing these patients to similarly treated patients with de novo disease (n=199). The 5-year overall survival was not different between patients with therapy-related and de novo disease (49.9% versus 53.9%; P=0.61) despite a higher proportion of individuals with an Intermediate-2/High International Prognostic Scoring System classification (59.7% versus 43.7%; P=0.003) and high-risk karyotypes (61.2% versus 30.7%; P<0.01) among the patients with therapy-related disease. In mutational analysis, TP53 alteration was the most common abnormality in patients with therapy-related disease (n=18: 30%). Interestingly, the presence of mutations in TP53 or in any other of the high-risk genes (EZH2, ETV6, RUNX1, ASXL1: n=29: 48%) did not significantly affect either overall survival or relapse-free survival. Allogeneic stem-cell transplantation is, therefore, a curative treatment for patients with therapy-related myelodysplastic syndrome, conferring a similar long-term survival to that of patients with de novo disease despite higher-risk features. While TP53 alteration was the most common mutation in therapy-related myelodysplastic syndrome, the finding was not detrimental in our case-series.

A Chemotherapy-Only Regimen of Busulfan, Melphalan, and Fludarabine, and Rabbit Antithymocyte Globulin Followed by Allogeneic T-Cell Depleted Hematopoietic Stem Cell Transplantations for the Treatment of Myeloid Malignancies

We sought to develop a myeloablative chemotherapeutic regimen to secure consistent engraftment of T-cell depleted (TCD) hematopoietic stem cell transplantations (HSCT) without the need for total body irradiation, thereby reducing toxicity while maintaining low rates of graft-versus-host disease (GVHD) and without increasing relapse. We investigated the myeloablative combination of busulfan (Bu) and melphalan (Mel), with the immunosuppressive agents fludarabine (Flu) and rabbit antithymocyte globulin (r-ATG) as cytoreduction before a TCD HSCT. No post-transplantation immunosuppression was administered. Between April 2001 and May 2008, 102 patients (median age, 55 years) with a diagnosis of primary or secondary myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) underwent cytoreduction with Bu/Mel/Flu, followed by TCD grafts. TCD was accomplished by CD34⁺-selection followed by E-rosette depletion for peripheral blood stem cell grafts and, for bone marrow grafts, by soybean agglutination followed by E-rosette depletion. Donors included matched and mismatched, related and unrelated donors. Risk stratification was by American Society for Blood and Marrow Transplantation risk categorization for patients with primary disease. For patients with secondary/treatment-related MDS/AML, those in complete remission (CR) 1 or with refractory anemia were classified as intermediate risk, and all other patients were considered high risk. Neutrophil engraftment occurred at a median of 11 days in 100 of 101 evaluable patients. The cumulative incidences of grades II to IV acute and chronic GVHD at 1 year were 8.8% and 5.9%, respectively. Overall- and disease-free survival (DFS) rates at 5 years were 50.0% and 46.1%, respectively, and the cumulative incidences of relapse and treatment-related mortality were 23.5% and 28.4%, respectively. Stratification by risk group demonstrated superior DFS for low-risk patients (61.5% at 5 years) compared with intermediate- or high-risk (34.2% and 40.0%, respectively, P = .021). For patients with AML, those in CR1 had superior 5-year DFS compared with those in ≥CR2 (60% and 30.6%, respectively, P = .01), without a significant difference in incidence of relapse (17.1% and 30.6%, respectively, P = .209). There were no differences in DFS for other patient, donor, or disease characteristics. In summary, cytoreduction with Bu/Mel/Flu and r-ATG secured consistent engraftment of TCD transplantations. The incidences of acute/chronic GVHD and disease relapse were low, with favorable outcomes in this patient population with high-risk myeloid malignancies.

The immune landscape of myelodysplastic syndromes

Even though the pathogenesis of myelodysplastic syndromes (MDS) is dominated by specific molecular defects involving hematopoietic precursors, also immune mechanisms seem to play a fundamental functional role. In this review we will first describe the clinical and laboratory autoimmune manifestations often detectable in MDS patients. We will then focus on studies addressing the possible influence of different immune cell subpopulations on the disease onset and evolution. We will finally consider therapeutic approaches based on immunomodulation, ranging from immunosuppressants to vaccination and transplantation strategies.

Pushing the envelope-nonmyeloablative and reduced intensity preparative regimens for allogeneic hematopoietic transplantation

Allogeneic hematopoietic cell transplantation (HCT) was originally developed to allow delivery of myeloablative doses of chemotherapy and radiotherapy. With better understanding of disease pathophysiology, the graft vs malignancy (GVM) effect of allogeneic hematopoietic transplantation and toxicities associated with myeloablative conditioning (MAC) regimens, the focus shifted to developing less toxic conditioning regimens to reduce treatment-related morbidity without compromising survival. Although HCT with MAC is preferred to reduced intensity conditioning (RIC) for most patients ⩽60 years with AML/myelodysplastic syndrome and ALL, RIC and nonmyeloablative (NMA) regimens allow HCT for many otherwise ineligible patients. Reduced intensity preparative regimens have produced high rates of PFS for diagnoses, which are highly sensitive to GVM. Relapse of the malignancy is the major cause of treatment failure with RIC/NMA HCT. Incorporation of novel agents like bortezomib or lenalidomide, addition of cellular immunotherapy and use of targeted radiation therapies could further improve outcome. In this review, we discuss commonly used RIC/NMA regimens and promising novel regimens.

Some aspects of allogeneic stem cell transplantation in patients with myelodysplastic syndrome: advances and controversy

Myelodysplastic syndrome (MDS) is a heterogeneous group of myeloid disorders. MDS remains a disease of elderly patients; moreover, the incidence of high risk MDS is proportionally greater in elderly patients, with increased frequency of secondary acute myeloid leukemia, as well as adverse cytogenetic abnormalities. Allogeneic stem cell transplantation is a therapeutic approach with known curative potential for patients with MDS that allows the achievement of long-term disease control. Numerous controversies still exist regarding transplantation in MDS: timing of transplantation, disease status at transplantation and comorbidity, conditioning intensity, pretransplant therapy, and stem cell source. Various transplant modalities of different intensities and alternative donor sources are now in use. Current advances in transplant technology are allowing the consideration of older patients. This should result in a greater number of older patients benefiting from this potentially curative treatment modality. Despite advances in transplantation technology, there is still considerable morbidity and mortality associated with this approach. Nevertheless, with the introduction of reduced-intensity conditioning and thereby reduced early mortality, transplant numbers in MDS patients have significantly increased. Moreover, recent new developments with innovative drugs, including hypomethylating agents, have extended the therapeutic alternatives for MDS patients. Hypomethylating agents allow the delay of allogeneic stem cell transplantation by serving as an effective and well-tolerated means to reduce disease burden.

Multicenter biologic assignment trial comparing reduced-intensity allogeneic hematopoietic cell transplant to hypomethylating therapy or best supportive care in patients aged 50 to 75 with intermediate-2 and high-risk myelodysplastic syndrome: Blood and Marrow Transplant Clinical Trials Network #1102 study rationale, design, and methods

The introduction of reduced-intensity conditioning (RIC) regimens made it possible to offer allogeneic hematopoietic cell transplantation (alloHCT) to older patients with myelodysplastic syndromes (MDS). However, the relative risks and benefits of alloHCT compared with novel nontransplant therapies continue to be the source of considerable uncertainty. We will perform a prospective biologic assignment trial to compare RIC alloHCT with nontransplant therapies based on donor availability. Primary outcome is 3-year overall survival. Secondary outcomes include leukemia-free survival, quality of life, and cost-effectiveness. Four hundred patients will be enrolled over roughly 3 years. Planned subgroup analyses will evaluate key biologic questions, such as the impact of age and response to hypomethylating agents on treatment effects. Findings from this study potentially may set a new standard of care for older MDS patients who are considered candidates for alloHCT.

Treatment of older patients with high-risk myelodysplastic syndromes (MDS): the emerging role of allogeneic hematopoietic stem cell transplantation (Allo HSCT)

MDS are myeloid clonal hematologic disorders that are most commonly diagnosed in the seventh decade of life. Several treatment options are currently available. However, allo HSCT remains the only curative therapy. Unfortunately, despite the higher incidence of MDS in the older population, less than 10 % of patients undergoing allo HSCT for MDS are > 65 years old. In this paper we discuss the various treatment options in older patients with high-risk MDS with particular emphasis on the role of allo HSCT in older MDS patients.

Total lymphoid irradiation-antithymocyte globulin conditioning and allogeneic transplantation for patients with myelodysplastic syndromes and myeloproliferative neoplasms

Allogeneic hematopoietic cell transplantation (allo HCT) is the only curative therapy for the myelodysplastic syndromes (MDS) and myeloproliferative neoplasms (MPN), but treatment toxicity has been a barrier to its more widespread use. The nonmyeloablative regimen of total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) permits the establishment of donor hematopoiesis necessary for the graft-versus-malignancy effect and is protective against acute graft-versus-host disease (aGVHD), but it has minimal direct cytotoxicity against myeloid diseases. We explored the use of TLI-ATG conditioning to treat 61 patients with allo HCT for MDS (n = 32), therapy-related myeloid neoplasms (n = 15), MPN (n = 9), and chronic myelomonocytic leukemia (n = 5). The median age of all patients was 63 years (range, 50 to 73). The cumulative incidence of aGVHD grades II to IV was 14% (95% confidence interval [CI], 4% to 23%) and for grades III to IV, 4% (95% CI, 0 to 9%), and it did not differ between patients who received allografts from related or unrelated donors. The cumulative incidence of nonrelapse mortality (NRM) at 100 days, 12 months, and 36 months was 0%, 7%, and 11%. Overall survival and progression-free survival were 41% (95% CI, 29% to 53%) and 35% (95% CI, 23% to 48%), respectively. The safety and tolerability of TLI-ATG, as exemplified by its low NRM, provides a foundation for further risk-adapted or prophylactic interventions to prevent disease progression.

Role of reduced-intensity conditioning allogeneic hematopoietic stem-cell transplantation in older patients with de novo myelodysplastic syndromes: an international collaborative decision analysis

PURPOSE

Myelodysplastic syndromes (MDS) are clonal hematopoietic disorders that are more common in patients aged ≥ 60 years and are incurable with conventional therapies. Reduced-intensity conditioning (RIC) allogeneic hematopoietic stem-cell transplantation is potentially curative but has additional mortality risk. We evaluated RIC transplantation versus nontransplantation therapies in older patients with MDS stratified by International Prognostic Scoring System (IPSS) risk.

PATIENTS AND METHODS

A Markov decision model with quality-of-life utility estimates for different MDS and transplantation states was assessed. Outcomes were life expectancy (LE) and quality-adjusted life expectancy (QALE). A total of 514 patients with de novo MDS aged 60 to 70 years were evaluated. Chronic myelomonocytic leukemia, isolated 5q- syndrome, unclassifiable, and therapy-related MDS were excluded. Transplantation using T-cell depletion or HLA-mismatched or umbilical cord donors was also excluded. RIC transplantation (n = 132) stratified by IPSS risk was compared with best supportive care for patients with nonanemic low/intermediate-1 IPSS (n = 123), hematopoietic growth factors for patients with anemic low/intermediate-1 IPSS (n = 94), and hypomethylating agents for patients with intermediate-2/high IPSS (n = 165).

RESULTS

For patients with low/intermediate-1 IPSS MDS, RIC transplantation LE was 38 months versus 77 months with nontransplantation approaches. QALE and sensitivity analysis did not favor RIC transplantation across plausible utility estimates. For intermediate-2/high IPSS MDS, RIC transplantation LE was 36 months versus 28 months for nontransplantation therapies. QALE and sensitivity analysis favored RIC transplantation across plausible utility estimates.

CONCLUSION

For patients with de novo MDS aged 60 to 70 years, favored treatments vary with IPSS risk. For low/intermediate-1 IPSS, nontransplantation approaches are preferred. For intermediate-2/high IPSS, RIC transplantation offers overall and quality-adjusted survival benefit.

Fifty years of melphalan use in hematopoietic stem cell transplantation

Melphalan remains the most widely used agent in preparative regimens for hematopoietic stem cell transplantation (SCT). From its initial discovery more than 50 years ago, it has been gradually incorporated in the conditioning regimens for both autologous and allogeneic transplantations because of its myeloablative properties and broad antitumor effects as a DNA alkylating agent. Melphalan remains the mainstay conditioning for multiple myeloma and lymphomas, and it has been used successfully in preparative regimens of a variety of other hematological and nonhematological malignancies. The addition of newer agents to conditioning, such as bortezomib or lenalidomide for myeloma or clofarabine for myeloid malignancies, may improve antitumor effects for transplantation, whereas melphalan in combination with alemtuzumab may represent a backbone for future cellular therapy because of reliable engraftment and low toxicity profile. This review summarizes the development and the current use of this remarkable drug in hematopoietic SCT.

Reduced intensity allogeneic hematopoietic stem cell transplantation for MDS using tacrolimus/sirolimus-based GVHD prophylaxis

We report a consecutive series of 59 patients with MDS who underwent reduced-intensity hematopoietic stem cell transplantation (RI-HSCT) with fludarabine/melphalan conditioning and tacrolimus/sirolimus-based GVHD prophylaxis. Two-year OS, EFS, and relapse incidences were 75.1%, 65.2%, and 20.9%, respectively. The cumulative incidence of non-relapse mortality at 100 days, 1 year, and 2 years was 3.4%, 8.5%, and 10.5%, respectively. The incidence of grade II-IV acute GVHD was 35.4%; grade III-IV was 18.6%. Forty of 55 evaluable patients developed chronic GVHD; of these 35 were extensive grade. This RI-HSCT protocol produces encouraging outcomes in MDS patients, and tacrolimus/sirolimus-based GVHD prophylaxis may contribute to that promising result.

Hematopoietic stem cell transplantation for myelodysplastic syndrome: a review

Allogeneic hematopoietic stem cell transplantation (HSCT) continues to be the only curative option for myelodysplastic syndrome (MDS). Since the majority of the patients with this disease are often older and frail, treatment-related mortality and morbidity remain major obstacles to be overcome. Reduced-intensity conditioning and continued lines of investigation in the field of allogeneic transplantation are expected to ultimately improve the overall therapeutic approach to MDS. In this review we summarize current recommendations and controversies surrounding HSCT for MDS, as well as the use of novel therapeutics in the peri-transplant period.

Reduced-toxicity conditioning with treosulfan and fludarabine in allogeneic hematopoietic stem cell transplantation for myelodysplastic syndromes: final results of an international prospective phase II trial

BACKGROUND

An alternative reduced-toxicity conditioning regimen for allogeneic transplantation, based on treosulfan and fludarabine, has recently been identified. The rationale for this study was to investigate the efficacy and safety of this regimen prospectively in patients with a primary myelodysplastic syndrome.

DESIGN AND METHODS

A total of 45 patients with primary myelodysplastic syndromes were conditioned with 3×14 g/m(2) treosulfan and 5×30 mg/m(2) fludarabine followed by allogeneic hematopoietic stem cell transplantation. Subtypes of myelodysplastic syndromes were refractory anemia with excess blasts-2 (44%), refractory cytopenia with multilineage dysplasia (27%), refractory anemia (9%), refractory anemia with ringed sideroblasts (4%), refractory cytopenia with multilineage dysplasia and ringed sideroblasts (4%), refractory anemia with excess blasts-1 (2%), and myelodysplastic syndrome with isolated del (5q) (2%). The myelodysplastic syndrome was unclassified in 7% of the patients. Forty-seven percent of the patients had a favorable karyotype, 29% an unfavorable one, and 18% an intermediate karyotype. Patients were evaluated for engraftment, adverse events, graft-versus-host disease, non-relapse mortality, relapse incidence, overall survival and disease-free survival.

RESULTS

All but one patient showed primary engraftment of neutrophils after a median of 17 days. Non-hematologic adverse events of grade III-IV in severity included mainly infections and gastrointestinal symptoms (80% and 22% of the patients, respectively). Acute graft-versus-host disease grade II-IV developed in 24%, and extensive chronic graft-versus-host disease in 28% of the patients. After a median follow-up of 780 days, the 2-year overall and disease-free survival estimates were 71% and 67%, respectively. The 2-year cumulative incidences of non-relapse mortality and relapse were 17% and 16%, respectively.

CONCLUSIONS

Our safety and efficacy data suggest that treosulfan-based conditioning therapy is a promising treatment option for patients with myelodysplastic syndromes. clinicaltrials.gov identifier: NCT01062490.

Hematopoietic stem cell transplantation for treatment of myleodysplastic syndromes

Allogeneic stem cell transplantation is a potentially curative treatment for myelodysplastic syndromes. Transplants are clearly indicated in patients with intermediate-2 and high risk disease; there is controversy regarding when transplantation should be performed in patients with low and intermediate-1 risk disease. Most patients with MDS are over age 65 and Medicare has recently provisionally approved transplants, but only when performed as part of a comparative clinical trial which still must be finalized. Nonmyeloablative preparative regimens allow treatment of older patients with MDS, and novel approaches are under evaluation to reduce the risk of relapse and treatment related morbidity and mortality.

Role and timing of hematopoietic cell transplantation for myelodysplastic syndrome

Allogeneic hematopoietic cell transplantation (HCT) is the only curative treatment for patients with myelodysplastic syndromes (MDS). Most patients with MDS are older than 60 years and age-associated morbidities limit the patients’ options for curative transplant therapy. Since the development of conditioning regimens with reduced toxicity, the age limitations for HCT have waned for those patients with good performance status. This review will discuss the role of HCT for MDS based on prognostic features, the optimal timing of HCT, and outcomes based on patient age.

NCI First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation: report from the Committee on the Epidemiology and Natural History of Relapse following Allogeneic Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is increasingly being used for treatment of hematologic malignancies, and the immunologic graft-versus-tumor effect (GVT) provides its therapeutic effectiveness. Disease relapse remains a cause of treatment failure in a significant proportion of patients undergoing alloHSCT without improvements over the last 2-3 decades. We summarize here current data and outline future research regarding the epidemiology, risk factors, and outcomes of relapse after alloHSCT. Although some factors (eg, disease status at alloHSCT or graft-versus-host disease [GVHD] effects) are common, other disease-specific factors may be unique. The impact of reduced-intensity regimens on relapse and survival still need to be assessed using contemporary supportive care and comparable patient populations. The outcome of patients relapsing after an alloHSCT generally remains poor even though interventions including donor leukocyte infusions can benefit some patients. Trials examining targeted therapies along with improved safety of alloHSCT may result in improved outcomes, yet selection bias necessitates prospective assessment to gauge the real contribution of any new therapies. Ongoing chronic GVHD (cGVHD) or other residual post-alloHSCT morbidities may limit the applicability of new therapies. Developing strategies to promptly identify patients as alloHSCT candidates, while malignancy is in a more treatable stage, could decrease relapses rates after alloHSCT. Better understanding and monitoring of minimal residual disease posttransplant could lead to novel preemptive treatments of relapse. Analyses of larger cohorts through multicenter collaborations or registries remain essential to probe questions not amenable to single center or prospective studies. Studies need to provide data with detail on disease status, prior treatments, biologic markers, and posttransplant events. Stringent statistical methods to study relapse remain an important area of research. The opportunities for improvement in prevention and management of post-alloHSCT relapse are apparent, but clinical discipline in their careful study remains important.

Optimal sequencing of treatments for patients with myelodysplastic syndromes

PURPOSE OF REVIEW

Myelodysplastic syndromes (MDS) are characterized by chronic cytopenias and a high risk of transformation to acute myeloid leukemia. To date, only allogeneic stem cell transplantation has shown curative potential in MDS. The heterogeneous nature of MDS, and the paucity of randomized studies make individual therapeutic decisions, still largely based on the international prognostic scoring system, difficult.

RECENT FINDINGS

In lower-risk MDS, recent advances include demonstration of a possible survival advantage with erythropoiesis stimulating agents, the role of lenalidomide in cases with del 5q (which lead to its approval in the treatment of lower-risk MDS with del 5q by the Food and Drug Administration), and recognition of the importance of iron overload on prognosis. In higher-risk patients, progress has come from the use of reduced intensity conditioning allogeneic SCT in elderly patients, and from results obtained with the hypomethylating agents azacytidine and decitabine, leading to their approval for the treatment of symptomatic MDS by the Food and Drug Administration. In particular, results of a phase III trial show a significant survival benefit for azacytidine over conventional treatments in higher-risk MDS. This is the first time a drug demonstrates a survival impact in higher-risk MDS.

SUMMARY

We review these recent advances in this paper.

The role of cytotoxic therapy with hematopoietic stem cell transplantation in the therapy of myelodysplastic syndromes: an evidence-based review

Clinical research examining the role of hematopoietic stem cell transplantation (SCT) in the therapy of myelodysplastic syndromes (MDS) in adults is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are presented in Table 3, and were reached unanimously by a panel of MDS experts. The identified priority areas of needed future research in MDS include: (1) the benefit of using alternative donor sources (eg, cord blood; haploidentical family donors) for patients without matched sibling or unrelated donors; (2) the role and appropriate timing of allogeneic SCT in combination with hypomethylating and immunomodulatory treatment regimens; (3) randomized trials comparing the safety and efficacy of various novel agents for treating MDS; and (4) the influence of the various MDS treatment modalities on patient-reported quality-of-life outcomes.

Allogeneic stem cell transplantation for adults with myelodysplastic syndromes: importance of pretransplant disease burden

Allogeneic stem cell transplantation is the only known curative therapy for myelodysplastic syndromes (MDS). We present the transplant outcomes for 84 adult MDS patients, median age 50 (18-69 years), undergoing allogeneic hematopoietic stem cell transplantation (HSCT) at the University of Minnesota between 1995 and 2007. By WHO criteria 35 (42%) had refractory anemia with excess blasts (RAEB-1 or 2), 23 (27%) had refractory cytopenia with multilineage dysplasia (RCMD) or RCMD and ringed sideroblasts (RCMD-RS), and the remaining 26 (31%) had refractory anemia (RA), myelodysplastic syndrome-unclassifiable (MDS-U), chronic myelomonocytic leukemia (CMML), myelodysplastic/myeloproliferative disease (MDS/MPD), or myelodysplastic syndrome-not otherwise specified (MDS-NOS). Graft source was related in 47 (56%), unrelated donor (URD) marrow in 11 (13%), and unrelated cord blood (UCB) in 26 (31%). The conditioning regimen included total body irradiation (TBI) in 94% of transplantations; 52 (62%) myeloablative (MA) and 32 (38%) nonmyeloablative (NMA) regimens. Cumulative incidence of neutrophil engraftment by day +42, acute graft-versus-host disease (aGVHD) by day +100, and chronic GVHD (cGVHD) by 1 year were 88% (80%-96%, 95% confidence interval [CI]), 43% (36%-50%, 95% CI), and 15% (10%-20%, 95% CI), respectively. One-year treatment-related mortality (TRM), relapse, disease-free survival (DFS), and overall survival (OS) were 39% (28%-50%, 95% CI), 23% (12%-32%, 95% CI), 38% (28%-48%, 95% CI), and 48% (38%-58%, 95% CI) respectively. Cumulative incidence of relapse at 1 year in patients with pre-HCT complete remission (CR) or <5% blasts was improved at 18% (8%-28%, 95% CI) compared to 35% (16%-54%, 95% CI) in patients with 5%-20% blasts (P = .07). Additionally, with MA conditioning, the incidence of relapse at 1 year trended lower at 16% (6%-26%, 95% CI) versus 35% (18%-52%, 95% CI) in NMA (P = .06), and a statistically significant decrease in relapse was noted in patients entering HCT with CR or <5% blasts with an incidence of 9% (0%-18%, 95% CI) (MA) versus 31% (11%-51%, 95% CI) (NMA) (P = 0.04). For those patients with > or =5% blasts, MA conditioning did not significantly decrease relapse rates. One-year TRM was similar between MA and NMA conditioning. For patients entering transplant in CR or with <5% blasts, prior treatment to reach this level did not impact rates of relapse or transplant-related mortality when all patients were analyzed; however, when broken down by conditioning intensity, there was a trend toward improved DFS in those NMA patients who were pretreated. Finally, 1-year DFS was similar using related donor peripheral blood stem cell (PBSC)/marrow, URD marrow, or UCB grafts. These data suggest that (1) blast percentage <5% at HSCT is the major predictor of improved DFS and relapse and prior treatment to reach this disease status may have value in leading to improved DFS; (2) MA conditioning is associated with lower relapse risk, particularly in patients with CR or <5% blasts, but is not able to overcome increased disease burden; (3) NMA conditioning yields equivalent TRM, DFS, and OS, and is reasonable in patients unsuited for MA conditioning; (4) the donor sources tested (PBSC, bone marrow [BM], or UCB) yielded similar outcomes.

What is the role of reduced-intensity transplantation in the treatment of older patients with AML?

Acute myelogenous leukemia (AML), either de novo or arising out of antecedent myelodysplasia, increases with age and is rarely curable by standard treatments used for younger patients. Recent clinical trials using reduced-intensity allogeneic transplantation regimens suggest that a proportion of patients with this disease can be cured, with results comparable to those achieved in younger patients undergoing fully ablative transplant. Although those patients who undergo transplant in a first remission often do well, the vast majority of older patients have not benefited because of the low successful remission achieved with standard therapy, the delay in initiating a donor search, and the lack of significant benefit from transplantation in patients who are not in remission. New approaches to induction, improvements in reduced-intensity regimens, and earlier donor identification will help expand the potential clinical benefit to a larger number of older patients with the disease.

Predictors of outcome following myeloablative allo-SCT for therapy-related myelodysplastic syndrome and AML

Administration of alkylating agents (Alk), topoisomerase II inhibitors (Topo II) and radiotherapy (RT) can result in therapy-related myelodysplastic syndrome or acute myelogenous leukaemia (t-MDS/t-AML), the optimal treatment for which is allo-SCT. A retrospective review was performed of 24 patients who underwent related- or unrelated-donor SCT for t-MDS/t-AML at our institution. Eight patients remain alive and in continuous remission (median follow-up 54 months (range, 12-161)) with estimated 5-year EFS being 30% (95% confidence intervals 16-58%). Corresponding actuarial risks of relapse and non-relapse mortality (NRM) are 39% (19-60%) and 30% (13-50%), respectively. EFS was 40% in Alk/RT-related t-MDS/t-AML and 11% in Topo II-related t-MDS/t-AML (P=0.05), with an increased risk of relapse in the latter (56 vs 29%, respectively (P=0.05)). In multivariate analysis, development of acute GVHD (P=0.009) and Topo II-related t-MDS/t-AML (P=0.018) were associated with inferior EFS. Patients with acute GVHD had an increased risk of NRM (P=0.03) whereas risk of relapse was higher for patients of advanced age (P=0.046) and for patients who underwent bone marrow (vs blood) SCT (P=0.032). Allo-SCT can result in long-term survival for individuals with t-MDS/t-AML although outcome in Topo II-related t-MDS/t-AML patients remains suboptimal.