Selection of optimal alternative graft source: mismatched unrelated donor, umbilical cord blood, or haploidentical transplant. Blood. 2012;119:1972-1980. [PMID: 22210876 DOI: 10.1182/blood-2011-11-354563]

The prevalent predicament of relapsed acute myeloid leukemia

A majority of patients with acute myeloid leukemia (AML) will relapse after achieving complete remission. At relapse, patients should be risk stratified and a decision made about the appropriateness of intensive therapy and whether a potentially curative allogeneic stem cell transplantation (allo-SCT) is possible. Risk factors include duration of first complete remission and adverse cytogenetics, as well as age and FLT3 mutation status. Available therapies are steadily increasing, but for the most part should be regarded as either best palliation or as a bridge to allo-SCT. Simple symptomatic therapies for patients with extreme age or the worst prognosis should also be considered. Newer therapeutic options include novel cytotoxic chemotherapies including clofarabine, immunomodulatory agents, targeted therapies against FLT3 and mTOR, and immunoconjugates. All patients with relapsed AML should be considered for an appropriate clinical trial.

Haploidentical, unmanipulated, G-CSF-primed bone marrow transplantation for patients with high-risk hematologic malignancies

Eighty patients with high-risk hematologic malignancies underwent unmanipulated, G-CSF–primed BM transplantation from an haploidentical family donor. Patients were transplanted in first or second complete remission (CR, standard-risk: n =45) or in > second CR or active disease (high-risk: n =35). The same regimen for GVHD prophylaxis was used in all cases. The cumulative incidence (CI) of neutrophil engraftment was 93% 0.1%. The 100-day CIs for II-IV and III-IV grade of acute GVHD were 24% 0.2% and 5% 0.6%, respectively. The 2-year CI of extensive chronic GVHD was 6% 0.1%. The 1-year CI of treatment-related mortality was 36% 0.3%. After a median follow-up of 18 months, 36 of 80 (45%) patients are alive in CR. The 3-year probability of overall and disease-free survival for standard-risk and high-risk patients was 54% 8% and 33% 9% and 44% 8% and 30% 9%, respectively. In multivariate analysis, disease-free survival was significantly better for patients who had standard-risk disease and received transplantations after 2007. We conclude that unmanipulated, G-CSF–primed BM transplantation from haploidentical family donor provides very encouraging results in terms of engraftment rate, incidence of GVHD and survival and represents a feasible, valid alternative for patients with high-risk malignant hematologic diseases, lacking an HLA identical sibling and in need to be urgently transplanted.

KEY POINTS

Haploidentical, unmanipulated, G-CSF-primed bone marrow transplantation. Haploidentical hematopoietic stem cell transplantation for hematologic malignancies.

Single cord blood combined with HLA-mismatched third party donor cells: comparable results to matched unrelated donor transplantation in high-risk patients with hematologic disorders

Matched unrelated donor (MUD) transplantation is the first alternative in the absence of a matched sibling donor. For patients without a suitable adult donor, we have adopted the dual stem cell transplantation protocol consisting of cord blood (CB) in combination with CD34(+) cells from a third party HLA-mismatched donor. We analyzed the outcomes of patients undergoing both procedures in a single center. Starting in 2004, a total of 20 patients with high-risk disease underwent 22 dual transplants and 25 patients underwent myeloablative MUD transplantation. The 30-day cumulative incidence of neutrophil engraftment was similar in both groups (91% and 95%), with a median time to engraftment of 14 and 16 days, respectively. Grade II-IV acute graft-versus-host disease was more frequent in the MUD group (40% versus 5%). Except for a tendency toward a higher incidence of viral hemorrhagic cystitis in the dual transplantation group, posttransplantation infectious events were comparable in the 2 groups. The 3-year cumulative incidence rates of relapse (41% versus 44%) and nonrelapse mortality (30% versus 25%) were similar in the MUD and dual transplantation cohorts. Estimated 3-year overall survival and disease-free survival were 47% and 41%, respectively, with no survival advantage for either group. In our experience, dual transplantation offers survival rates comparable to those from myeloablative MUD transplantation with similar nonrelapse mortality rates.

Optimal approach to treatment of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: how to best use all the available tools

Approximately 20% of adult and 50% of elderly patients with acute lymphoblastic leukemia (ALL) express the t(9;22) chromosome translocation with BCR-ABL rearrangement. The use of tyrosine kinase inhibitors (TKIs) has resulted in higher rates of complete remission (95-100%), and many fit patients are able to receive allogeneic hematopoietic stem cell transplant (HSCT). TKI-containing induction followed by myeloablative allogeneic HSCT has resulted in long-term survival between 50 and 60% in young adults, and recent reports show promising results in patients submitted to non-myeloablative HSCT. The prognosis of elderly patients with Philadelphia chromosome-positive (Ph+) ALL is poor despite a high complete remission (CR) rate with TKIs and minimal chemotherapy, and improvements are clearly needed in this subgroup of patients. This review summarizes and discusses current challenges in the treatment of patients with Ph+ ALL, such as selection of the appropriate induction therapy, minimization of transplant toxicity, correct use of TKIs after transplant, BCR-ABL monitoring, the study of mutations which confer resistance to TKIs and new drugs to overcome this resistance.

The expanding frontier of hematopoietic cell transplantation

Over the past several decades there has been a tremendous expansion of the indications for hematopoietic cell transplantation. This growth has been possible because of advances in supportive care, more effective graft versus host disease prophylaxis and the advent of reduced intensity conditioning regimens which have greatly reduced transplant related morbidity and allowed for the transplantation of older patients and patients with significant co-morbid disease. The role of flow cytometry in transplantation is crucial to both clinical care, for accuracy of diagnosis and monitoring of disease, and research. In this review, we highlight some of the important advances that have been made in the field, including the use of alternative donors for transplantation, novel therapies for the myeloid malignancies, which remain the prototype diseases for transplantation, and advances in diagnosis and treatment of graft versus host disease, which is the principal complication of allogeneic hematopoietic cell transplantation. Future directions in hematopoietic cell transplantation, particularly those that attempt to modulate the post-transplant cellular environment to favor separation of graft versus host disease from the graft versus tumor effects of the transplant are discussed.

Prevention of graft-vs.-host disease

INTRODUCTION

Allogeneic hematopoietic cell transplantation (HCT) is a curative treatment for many malignant and non-malignant hematologic disorders. However, graft-vs.-host disease (GVHD) remains a major complication of allogeneic HCT and limits the success of this approach.

AREAS COVERED

This paper reviews recent developments in the prevention of acute and chronic GVHD. In the setting of acute GVHD prevention, recent trials of T-cell depletion using Fresenius-ATG are reviewed, as well as studies testing total lymphoid irradiation, mesenchymal stromal cells, rituximab, statins, sirolimus and other investigational agents. In the setting of chronic GVHD, results with Fresenius-ATG are reviewed, as well as B-cell depletion with rituximab, and the potential role of the B-cell regulatory cytokine BAFF in chronic GVHD is also discussed. Finally, the emerging role of resident skin and gut bacterial flora-the so-called microbiome-in the pathogenesis of GVHD is covered.

EXPERT OPINION

Current methods of acute GVHD prevention are highly successful, and a number of investigational approaches promise to further reduce the risk of this complication. By contrast, chronic GVHD is more poorly understood and more difficult to prevent. Future studies are required to delineate the roles of these approaches and to abrogate GVHD without sacrificing the beneficial immunologic graft-vs.-tumor effect.

Feasibility of unmanipulated haploidentical stem cell transplantation using standard GVHD prophylaxis for HLA-homozygous patients

HLA-haploidentical hematopoietic stem cell transplantation (haplo-SCT) in HLA-homozygous patients is accompanied by HLA mismatches only in the host-versus-graft vector, and thus theoretically could be performed with standard graft-versus-host disease (GVHD) prophylaxis. However, the risk of GVHD remains uncertain, and graft failure could be a problem. In this study, we assessed nine HLA-homozygous patients who underwent haplo-SCT. Preparative treatment was cyclophosphamide/total body irradiation-based regimen in five patients, fludarabine/busulfan-based regimen in two, and other regimens in two. GVHD prophylaxis consisted of cyclosporine and methotrexate in seven patients, cyclosporine and mycophenolate mofetil in one, and cyclosporine alone in one. Seven patients achieved neutrophil engraftment and platelet recovery. The median times to neutrophil engraftment and platelet recovery were 15 and 44 days, respectively. Two patients developed graft failure, including one who achieved engraftment with a second SCT from the same donor. Grade II GVHD was observed in half of the evaluable patients; grades III and IV were not observed. Two patients died from treatment-related causes. Five patients were alive after a median follow-up period of 563 days. The probability of overall survival at 5 years was 65 %. These findings may serve as a rationale for considering haplo-SCT as a treatment option for HLA-homozygous patients.