Nonablative allogeneic hematopoietic transplantation as adoptive immunotherapy for indolent lymphoma: low incidence of toxicity, acute graft-versus-host disease, and treatment-related mortality

Challenges and opportunities of CAR T cell therapies for CLL

Chimeric antigen receptor (CAR) T-cell therapies have transformed the treatment landscape of blood cancers. These engineered receptors which endow T cells with antibody-like target cell recognition combined with the typical T cell target cell lysis abilities. Introduced into the clinic in the 2010s, CAR T-cells have shown efficacy in chronic B lymphocytic leukemia (CLL), but a majority of patients do not achieve sustained remission. Here we discuss the current treatment landscape in CLL using small molecules and allogeneic stem cell transplantation, the niche CAR T-cells filled in this context, and what we have learned from biomarker and mechanistic studies. Several product parameters and improvements are introduced as examples of how the bedside-to-bench is translated into improved CAR T-cells for CLL. We hope to convey to our readers the crucial role translational medicine plays in transforming the treatment outcomes for patients with CLL and how this line of research is an essential component of modern medicine.

Addition of Rituximab in Reduced Intensity Conditioning Regimens for B-Cell Malignancies Does Not Influence Transplant Outcomes: EBMT Registry Analyses Following Allogeneic Stem Cell Transplantation for B-Cell Malignancies

Rituximab (R) is increasingly incorporated in reduced intensity conditioning (RIC) regimens for allogeneic hematopoietic cell transplantation (alloHCT) in patients with B-cell malignancies, not only to improve disease control, but also to prevent graft-versus-host disease (GVHD). There are no randomized prospective data to validate this practice, although single center data and the CIBMTR analysis have shown promising results. We aimed at validation of these findings in a large registry study. We conducted a retrospective analysis using the EBMT registry of 3,803 adult patients with B-cell malignancies undergoing alloHCT (2001-2013) with either rituximab (R-RIC-9%) or non-rituximab (RIC-91%) reduced intensity regimens respectively. Median age and median follow up were 55 years (range 19.1-77.3) and 43.2 months (range 0.3-179.8), respectively. There was no difference in transplant outcomes (R-RIC vs RIC), including 1-year overall survival (69.9% vs 70.7%), 1-year disease-free survival (64.4% vs 62.2%), 1-year non-relapse mortality (21% vs 22%), and day-100 incidence of acute GVHD 2-4° (12% vs 12%). In summary, we found that addition of rituximab in RIC regimens for B-cell malignancies had no significant impact on major transplant outcome variables. Of note, data on chronic GVHD was not available, limiting the conclusions that can be drawn from the present study.

Alternative donor transplants for severe aplastic anemia

Allogeneic hematopoietic stem-cell transplantation remains the only curative treatment for patients with acquired severe aplastic anemia (SAA). When a matched sibling is not available, one can search for a matched unrelated donor or a cord blood unit (CB) in the international registries or, more recently, for an HLA haploidentical (HAPLO) family member. International guidelines call for a course of antithymocyte globulin (ATG) and cyclosporine before a patient with SAA receives a transplant from a donor other than an HLA identical sibling, but whether this is necessary for patients age <20 years is less clear. Here I will examine the rapid increase in HAPLO transplantations for SAA, showing encouraging early results both in children and young adults. Graft-versus-host disease prophylaxis remains of primary importance in patients with SAA, and in vivo T-cell depletion with either ATG or alemtuzumab offers a significant survival advantage. Finally, I will discuss the strong age effect, which is particularly evident at >40 and 50 years of age for reasons not entirely clear and which should be taken into account when designing a treatment strategy for a given patient.

Fludarabine as a cost-effective adjuvant to enhance engraftment of human normal and malignant hematopoiesis in immunodeficient mice

There is still an unmet need for xenotransplantation models that efficiently recapitulate normal and malignant human hematopoiesis. Indeed, there are a number of strategies to generate humanized mice and specific protocols, including techniques to optimize the cytokine environment of recipient mice and drug alternatives or complementary to the standard conditioning regimens, that can be significantly modulated. Unfortunately, the high costs related to the use of sophisticated mouse models may limit the application of these models to studies that require an extensive experimental design. Here, using an affordable and convenient method, we demonstrate that the administration of fludarabine (Fludara^TM) promotes the extensive and rapid engraftment of human normal hematopoiesis in immunodeficient mice. Quantification of human CD45⁺ cells in bone marrow revealed approximately a 10²-fold increase in mice conditioned with irradiation plus fludarabine. Engrafted cells in the bone marrow included hematopoietic stem cells, as well as myeloid and lymphoid cells. Moreover, this model proved to be sufficient for robust reconstitution of malignant myeloid hematopoiesis, permitting primary acute myeloid leukemia cells to engraft as early as 8 weeks after the transplant. Overall, these results present a novel and affordable model for engraftment of human normal and malignant hematopoiesis in immunodeficient mice.

Recipient and donor cells in the graft-versus-solid tumor effect: It takes two to tango

Allogeneic hematopoietic stem cell transplantation (alloHSCT) produces -similar to the long-established graft-versus-leukemia effect- graft-versus-solid-tumor effects. Clinical trials reported response rates of up to 53%, occurring mostly but not invariably in association with full donor chimerism and/or graft-versus-host disease. Although donor-derived T cells are considered the principal effectors of anti-tumor immunity after alloHSCT or donor leukocyte infusion (DLI), growing evidence indicate that recipient-derived immune cells may also contribute. Whereas the role of recipient-derived antigen-presenting cells in eliciting graft-versus-host reactions and priming donor T cells following DLI is well known, resulting inflammatory responses may also break tolerance of recipient effector cells towards the tumor. Additionally, mouse studies indicated that post-transplant recipient leukocyte infusion produces anti-leukemia and anti-solid-tumor effects that were exclusively mediated by recipient-type effector cells, without graft-versus-host disease. Here, we review current preclinical and clinical evidence on graft-versus-solid-tumor effects and growing evidence on the effector role of recipient-derived immune cells in the anti-tumor effect of alloHSCT.

Checkpoint blockade in Hodgkin and non-Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is characterized by nearly universal genetic alterations in 9p24.1, resulting in constitutive expression of PD-1 ligands. This likely underlies the unique sensitivity of cHL to PD-1 blockade, with response rates of ∼70% in relapsed/refractory disease. There are now numerous clinical trials testing PD-1 inhibitors in earlier stages of treatment and in combination with many other therapies. In general, non-Hodgkin lymphomas (NHLs) do not display a high frequency of 9p24.1 alterations and do not share cHL's vulnerability to PD-1 blockade. However, a few entities have genetic or immunologic features that may predict sensitivity to immune checkpoint blockade. These include primary mediastinal B cell lymphoma, primary central nervous system lymphoma, and primary testicular lymphoma, which harbor frequent alterations in 9p24.1, as well as Epstein Barr virus (EBV)-infected lymphomas, where EBV infection leads to increased PD-L1 expression. Although these subtypes may be specifically vulnerable to PD-1 blockade, the majority of NHLs appear to be minimally sensitive to PD-1 blockade monotherapy. Current investigations in NHL are therefore focusing on targeting other checkpoints or studying PD-1-based combination therapy. Looking forward, additional insight into the most common mechanisms of resistance to immune checkpoint inhibitors will be important to guide rational clinical trial design. In this review, we describe the biological basis for checkpoint blockade in cHL and NHL and summarize the clinical data generated to date. Guided by our rapidly evolving understanding of the pathobiology of various lymphoma subtypes, we are hopeful that the role of checkpoint inhibitors in lymphoma treatment will continue to grow.

The Role of Autologous and Allogeneic Stem Cell Transplantation in Follicular Lymphoma in The New Drugs Era

Follicular lymphoma (FL) is the second most common histotype of non-Hodgkin’s lymphoma, and it is generally characterized by a heterogeneous clinical course. Despite recent therapeutic and diagnostic improvements, a significant fraction of FL patients still relapsed. In younger and/or fit FL relapsed patients bone marrow transplant (BMT) has represented the main salvage therapy for many years. Thanks to the ability of high-dose chemotherapy to overcome the lymphoma resistance and refractoriness, autologous stem cell transplantation (ASCT) can achieve a high complete remission rate (CR) and favorable outcome regarding progression-free survival (PFS) and overall survival (OS). Allogeneic stem cell transplantation (alloSCT) combines the high dose chemotherapy effect together with the immune reaction of the donor immune system against lymphoma, the so-called ‘graft versus lymphoma’ (GVL) effect. Considering the generally higher transplant-related mortality (TRM), alloSCT is mostly indicated for FL relapsed after ASCT. During the last years, there have been a great spread of novel effective and feasible drugs Although these and future novel drugs will probably change our current approach to FL, the OS post-BMT (ASCT and alloSCT) has never been reproduced by any novel combination. In this scenario, it is important to correctly evaluate the disease status, the relapse risk and the comorbidity profile of the relapsed FL patients in order to provide the best salvage therapy and eventually transplant consolidation.

Reduced-Intensity Conditioning with Fludarabine, Cyclophosphamide, and Rituximab Is Associated with Improved Outcomes Compared with Fludarabine and Busulfan after Allogeneic Stem Cell Transplantation for B Cell Malignancies

Reduced-intensity conditioning (RIC) has been used increasingly for allogeneic hematopoietic cell transplantation to minimize transplant-related mortality while maintaining the graft-versus-tumor effect. In B cell lymphoid malignancies, reduced-intensity regimens containing rituximab, an antiCD20 antibody, have been associated with favorable survival; however, the long-term outcomes of rituximab-containing versus nonrituximab-containing regimens for allogeneic hematopoietic cell transplantation in B cell lymphoid malignancies remain to be determined. We retrospectively analyzed 94 patients who received an allogeneic transplant for a B cell lymphoid malignancy. Of these, 33 received RIC with fludarabine, cyclophosphamide, and rituximab (FCR) and graft-versus-host disease (GVHD) prophylaxis with a calcineurin inhibitor and mini-methotrexate, and 61 received RIC with fludarabine and busulfan (FluBu) and GVHD prophylaxis with a calcineurin inhibitor and mycophenolate mofetil. The 2-year overall survival was superior in patients who received FCR versus FluBu (72.7% versus 54.1%, P = .031), and in multivariable analysis adjusted for Disease Risk Index and donor type, only the conditioning regimen (FluBu versus FCR: HR, 2.06; 95% CI, 1.04 to 4.08; P = .037) and Disease Risk Index (low versus intermediate/high: HR, .38; 95% CI, .17 to .86; P = .02) were independent predictors of overall survival. The 2-year cumulative incidence of chronic GVHD was lower in patients who received FCR versus FluBu (24.2% versus 51.7%, P = .01). There was no difference in rate of relapse/progression or acute GVHD. Our results demonstrate that the use of RIC with FCR and GVHD prophylaxis with a calcineurin inhibitor and mini-methotrexate is associated with decreased chronic GVHD and improved overall survival.

Added effects of dexamethasone and mesenchymal stem cells on early Natural Killer cell activation

Graft rejection and graft-versus-host disease are leading causes of transplant related mortality despite advancements in immunosuppressive therapy. Mesenchymal stem cells (MSCs) offer a promising addition to immunosuppressive drugs (ISD), while NK-cells are increasingly used as effector cells in graft-versus-leukemia. Combined therapy of ISD, NK-cells and/or MSCs is used in clinical practice. Here, we examined the effects of MSCs and selected ISD (tacrolimus, cyclosporin A, mycophenolic acid, dexamethasone) treatment on early NK-cell activation. We assessed STAT4 and STAT5 phosphorylation triggered by IL-12 and IL-2, respectively. Furthermore, we determined IFNγ, perforin production and the expression pattern of selected NK-cell receptors. Of all drugs tested, only dexamethasone inhibited NK-cell STAT4 and STAT5 phosphorylation. All ISD, with the exception of MPA, significantly inhibited IFNγ, and only dexamethasone inhibited upregulation of early activation markers CD69 and CD25 (IL-2 condition only). MSCs inhibited IL-2 induced NK cell STAT5 phosphorylation, IFNγ production and CD69 upregulation, and IL-12 induced IFNγ and perforin production. While MSCs mediated inhibition of CD69 expression was cell contact dependent, inhibition of IFNγ and perforin production, as well as STAT5 phosphorylation was cell-contact independent. Importantly, dexamethasone augmented MSCs mediated inhibition of both IL-12 and IL-2 induced CD69 expression and IFNγ production, as well as IL-2 induced STAT5 phosphorylation. Taken together, these novel insights may help the design of future NK-cell and MSCs based immunotherapy.

Therapeutics for Graft-versus-Host Disease: From Conventional Therapies to Novel Virotherapeutic Strategies

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has a curative potential for many hematologic malignancies and blood diseases. However, the success of allo-HSCT is limited by graft-versus-host disease (GVHD), an immunological syndrome that involves inflammation and tissue damage mediated by donor lymphocytes. Despite immune suppression, GVHD is highly incident even after allo-HSCT using human leukocyte antigen (HLA)-matched donors. Therefore, alternative and more effective therapies are needed to prevent or control GVHD while preserving the beneficial graft-versus-cancer (GVC) effects against residual disease. Among novel therapeutics for GVHD, oncolytic viruses such as myxoma virus (MYXV) are receiving increased attention due to their dual role in controlling GVHD while preserving or augmenting GVC. This review focuses on the molecular basis of GVHD, as well as state-of-the-art advances in developing novel therapies to prevent or control GVHD while minimizing impact on GVC. Recent literature regarding conventional and the emerging therapies are summarized, with special emphasis on virotherapy to prevent GVHD. Recent advances using preclinical models with oncolytic viruses such as MYXV to ameliorate the deleterious consequences of GVHD, while maintaining or improving the anti-cancer benefits of GVC will be reviewed.

Allogeneic hematopoietic cell transplantation as curative therapy for non-transformed follicular lymphomas

Allogeneic hematopoietic cell transplantation (HCT) offers the chance of cure for patients with non-transformed follicular lymphoma (FL), but is associated with the risk of non-relapse mortality (NRM). The aim of this study was to identify subgroups of FL patients who benefit from HCT. The European Society for Blood and Marrow Transplantation (EBMT) Minimum-Essential-A Data of 146 consecutive patients who received HCT for FL between 1998 and 2008 were extracted from the database of the German Registry 'DRST'. Diagnosis of FL was verified by contact with the reference pathologists. Estimated 1-, 2- and 5-year overall survivals (OS) were 67%, 60% and 53%, respectively. Day 100 NRM was 15%. Thirteen out of 33 patients (40%) with treatment-refractory disease (RD) at the time of transplantation survived long term. Univariate statistical analysis suggested limited chronic GvHD, donor age ⩽42 years and TBI-based conditioning in treatment refractory patients to correlate with favorable OS. Independent prognostic factors for OS were treatment-sensitive disease and limited chronic GvHD for the whole cohort, and additionally TBI-based conditioning for the treatment refractory subgroup. In contrast, patient age ⩾55 years had no impact on outcome. Thus, HCT for FL is associated with acceptable NRM, and offers a substantial chance of cure for patients with RD or advanced age. Donors ⩽42 years should be preferred if available.

Alternative donor transplants for severe aplastic anemia: current experience

Patients with acquired severe aplastic anemia (SAA), who lack a human leukocyte antigen (HLA) identical sibling donor (SIB), have two therapeutic options: immunosuppressive therapy with anti-thymocyte globulin (ATG) and cyclosporine (CsA), or a transplant from an alternative donor. In these patients, the current guidelines of the European Group for Blood and Marrow Transplantation (EBMT) call for a course of ATG + CsA first and transplantation in case of no response. The alternative donor source can be an unrelated donor (UD), a cord blood (CB) unit, or a family mismatched member, in most instances genetically HLA haplo-mismatched (HAPLO). In the present review, we will discuss recent results of transplants from matched UD and SIB donors, with significantly improved outcome, especially with UD in the past decade. We will also be looking at CB transplants, and the problems of limited stem cell dose. Finally HAPLO grafts have been explored in patients lacking or having rejected an unrelated or CB graft: early results seem encouraging, though the procedure should still be considered experimental.

Haplotype counting by next-generation sequencing for ultrasensitive human DNA detection

Human identity testing is critical to the fields of forensics, paternity, and hematopoietic stem cell transplantation. Most bone marrow (BM) engraftment testing currently uses microsatellites or short tandem repeats that are resolved by capillary electrophoresis. Single-nucleotide polymorphisms (SNPs) are theoretically a better choice among polymorphic DNA; however, ultrasensitive detection of SNPs using next-generation sequencing is currently not possible because of its inherently high error rate. We circumvent this problem by analyzing blocks of closely spaced SNPs, or haplotypes. As proof-of-principle, we chose the HLA-A locus because it is highly polymorphic and is already genotyped to select proper donors for BM transplant recipients. We aligned common HLA-A alleles and identified a region containing 18 closely spaced SNPs, flanked by nonpolymorphic DNA for primer placement. Analysis of cell line mixtures shows that the assay is accurate and precise, and has a lower limit of detection of approximately 0.01%. The BM from a series of hematopoietic stem cell transplantation patients who tested as all donor by short tandem repeat analysis demonstrated 0% to 1.5% patient DNA. Comprehensive analysis of the human genome using the 1000 Genomes database identified many additional loci that could be used for this purpose. This assay may prove useful to identify hematopoietic stem cell transplantation patients destined to relapse, microchimerism associated with solid organ transplantation, forensic applications, and possibly patient identification.

Rituximab for indolent lymphomas before and after allogeneic hematopoietic stem cell transplantation

PURPOSE OF REVIEW

The most substantial advancement in the treatment of indolent B-cell non-Hodgkin lymphoma (NHL), since the advent of combination chemotherapy, has been the introduction of the monoclonal anti-CD20 antibody rituximab. However, the optimal schedule, timing, and duration of rituximab therapy remain controversial.

RECENT FINDINGS

Since its initially reported single-agent activity in 1997, the role of rituximab has greatly expanded and it is now ubiquitously integrated in all treatment phases of indolent NHL. Yet, several questions remain to be addressed: should asymptomatic patients be treated at diagnosis with single-agent rituximab or still kept in watchful waiting, what are the optimal first-line treatments to combine with rituximab, what is the role of maintenance therapy, and is there a benefit in incorporating rituximab in autologous and allogeneic stem cell transplantation schemes for these diseases? Recent and ongoing clinical trials tackling these relevant issues will be presented and critically discussed in this article.

SUMMARY

Excellent outcomes are reported with rituximab therapy in indolent NHL, both early and late in the disease course. Continued study of this most valuable therapeutic agent is warranted to set the optimal treatment approach leading to cure the majority of patients.

Allogeneic hematopoietic cell transplantation after failed autologous transplant for lymphoma using TLI and anti-thymocyte globulin conditioning

We describe 47 patients with lymphoma and failed prior autologous hematopoietic cell transplantation (HCT) who received TLI-ATG conditioning followed by allogeneic HCT. Thirty-two patients had non-Hodgkin lymphoma (NHL; diffuse large B cell lymphoma [n=19], T-cell NHL [n=6], mantle cell lymphoma [n= 4], or other B-cell subtypes [n=3]), and 15 had Hodgkin lymphoma. The median follow-up was 4.9 (range, 2.1–11.9) years. The cumulative incidence of grade II–IV acute GVHD at day +100 was 12%, and the cumulative incidence of extensive chronic GVHD at 1 year was 36%. The 3-year cumulative incidences of overall survival, progression-free survival (PFS), and non-relapse mortality (NRM) were 81%, 44%, and 7%, respectively. Fifteen patients died (relapse, n=10; NRM, n=5). Among the 25 patients with relapse after allogeneic HCT, 11 (44%) achieved durable (>1 year) complete remissions following donor lymphocyte infusion or chemoradiotherapy. The majority of surviving patients (75%; n=24) were able to discontinue all immunosuppression. For patients with relapsed lymphoma after autologous HCT, allogeneic HCT using TLI-ATG conditioning is a well-tolerated, predominantly outpatient therapy with low NRM (7% at 3 years), a low incidence of GVHD, durable disease control, and excellent overall survival (81% at 3 years).

Non-myeloablative allogeneic hematopoietic stem cell transplantation for adults with relapsed and refractory mantle cell lymphoma: a single-center analysis in the rituximab era

Relapsed and refractory (rel/ref) mantle cell lymphoma (MCL) portends a dismal prognosis. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) represents the only potentially curative therapy in this setting. We analyzed survival outcomes of 29 recipients of non-myeloablative allo-HSCT for rel/ref MCL, and studied possible prognostic factors in this setting. The cumulative incidence of disease progression and non-relapse mortality at 3 years were 28% (95% confidence interval [CI]: 13-46%) and 29% (95%CI: 13-47%), respectively. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) at days +100 and +180 were 34% (95%CI: 18-52%) and 45% (95%CI: 26-62%), respectively. With a median follow-up in survivors of 53 (range 24-83) months, the 3-year overall survival (OS) and progression-free survival (PFS) were 54% (95%CI: 38-76%) and 41% (95%CI: 26-64%), respectively. In vivo T-cell depletion with alemtuzumab (n=6) was associated with inferior 3-year PFS (0% vs. 51%, p=0.007) and OS (17% vs. 64%, p=0.014). Conversely, a second line international prognostic index (sIPI) at transplantation equal to 0 (no risk factors) was associated with an improved 3-year PFS (52% vs. 22%, p=0.020) and OS (71% vs. 22%, p=0.006) compared to sIPI ≥1. Performing an allo-HSCT before 2007 was associated with a decreased 3-year OS (25% vs. 76%, p=0.015) but not with a significantly inferior PFS (17% vs. 59%, p=0.058). In this single center series, we report encouraging results with allo-HSCT for patients with rel/ref MCL. High alemtuzumab doses should probably be avoided in this context.

Therapeutic benefits targeting B-cells in chronic graft-versus-host disease

Allogeneic hematopoietic cell transplantation (allo-HCT) can be a curative strategy for hematological diseases, and the indications for allo-HCT have broadened widely due to recent progress in supportive strategies. However, patients must overcome various complications and chronic graft-versus-host disease (cGVHD) remains the most common allo-HCT cause of long-term morbidity and mortality. cGVHD is difficult to biologically assess due to the heterogeneity of cGVHD symptoms, and the pathogenesis of cGVHD has yet to be established. Recent experimental model progress has suggested that B-cells play a critical role in cGVHD development. Consistent with these experimental results, some clinical studies investigating B-cell depletion and modulation of B-cell signaling pathways have decreased cGVHD incidence and provided some therapeutic benefit. However, randomized control studies are necessary to confirm the efficacy of B-cell targeting drugs for cGVHD. Here, we review the pathophysiology of cGVHD, especially focusing on the role of B-cell immunity, and discuss the efficacy of both B-cell depletion and modulation of B-cell signaling pathways in human cGVHD prevention, initial treatment, and salvage treatment.

Alternative donors extend transplantation for patients with lymphoma who lack an HLA matched donor

Alternative donor transplantation is increasingly used for high risk lymphoma patients. We analyzed 1593 transplant recipients (2000 to 2010) and compared transplant outcomes in recipients of 8/8 allele human leukocyte antigen (HLA)-A, -B, -C, and DRB1 matched unrelated donors (MUD; n=1176), 7/8 allele HLA-matched unrelated donors (MMUD; n=275) and umbilical cord blood donors (1 or 2 units UCB; n=142). Adjusted 3-year non-relapse mortality of MMUD (44%) was higher as compared to MUD (35%; p=0.004), but similar to UCB recipients (37%; p=0.19), although UCB had lower rates of neutrophil and platelet recovery compared to unrelated donor groups. With a median follow-up of 55 months, 3-year adjusted cumulative incidence of relapse was lower after MMUD compared with MUD (25% vs 33%, p=0.003) but similar between UCB and MUD (30% vs 33%; p=0.48). In multivariate analysis UCB recipients had lower risks of acute and chronic graft versus host disease compared with adult donor groups (UCB vs MUD: HR=0.68, p=0.05; HR=0.35; p<0.001). Adjusted 3-year overall survival was comparable (43% MUD, 37% MMUD and 41% UCB). Data highlight that patients with lymphoma have acceptable survival after alternative donor transplantation. MMUD and UCB can expand the curative potential of allotransplant to patients who lack suitable HLA-matched sibling or MUD.

Conditioning with treosulfan and fludarabine for patients with refractory or relapsed non-Hodgkin lymphoma

The treatment of refractory or relapsed non-Hodgkin lymphoma (NHL) remains challenging. In this retrospective study, 88 patients with refractory or relapsed NHL received treosulfan and fludarabine as a reduced-intensity conditioning for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Of the 88 intensely pre-treated patients, 73 experienced a relapse, with 18 of the 88 patients experiencing an early relapse (ER; <6 months from the last chemotherapy). At the time of allo-HSCT, 26 patients were in complete remission (CR) and 43 in partial remission (PR), 12 patients had progressive disease (PD) and 7 had stable disease (SD). A total of 47 patients received an autologous graft followed by allo-HSCT. Following allo-HSCT, 69 of the 88 patients were in CR and 7 were in PR, resulting in an overall response rate of 86.4% (76/88). A total of 33 patients achieved a CR from PR, as did 6 patients from PD and 5 from SD. Of the 88 patients, 43 (49%) were alive at the end of the follow-up period. The patients who directly underwent allo-HSCT without prior auto-HSCT exhibited a better disease-free survival (DFS; P=0.038) with a tendency (P=0.077) for a better overall survival (OS). The patients with ER exhibited a probability of OS of 0.35±0.12 after 3 and 7 years. Chronic graft-versus-host disease (cGvHD) exerted a positive effect on OS and DFS (for limited cGvHD vs. no cGvHD, P=0.002 and 0.004, respectively). In conclusion, allogeneic stem cell transplantation following conditioning with treosufan and fludarabine constitutes a viable therapeutic option for patients with refractory or relapsed NHL and should be considered early during the course of salvage treatment.

Allogeneic transplantation after reduced-intensity conditioning with fludarabine-CY for both indolent and aggressive lymphoid malignancies

We studied the outcome of allo-SCT after reduced-intensity conditioning in relapsed or refractory indolent and aggressive lymphoid malignancies. All 54 patients (diagnosis: B-CLL n=13, indolent lymphoma n=12, aggressive lymphoma n=13, transformed lymphoma n=16) received conditioning with fludarabine and CY between July 2001 and November 2010. They underwent allo-SCT because of relapse after auto-SCT or because no other therapy could lead to a meaningful remission. Patients received an unmanipulated peripheral blood stem-cell graft. Median follow-up was 67 months. Thirty-two patients had received rituximab. Immediately after transplantation, remission status had improved in 21 patients, all without DLI. During the follow-up six additional patients achieved CR without further therapy. Four-year OS (EFS) was 46% (46%) for B-CLL, 83% (75%) for indolent lymphoma, 69% (55%) for aggressive lymphoma and 74% (67%) for transformed lymphoma (P=0.28 (P=0.54)). Forty two percent developed acute GVHD, 68% chronic GVHD (16% limited, 52% extensive). Previous auto-SCT did not influence OS, while acute GVHD did. Two-year non-relapse mortality was 16%. In conclusion, reduced-intensity conditioning with fludarabine-CY is feasible and effective for both indolent and aggressive lymphoid malignancies, even after previous auto-SCT. Because of the excellent anti-B-cell/lymphoma activity fludarabine-CY decreases tumor load, gaining time for the development of a graft versus lymphoma effect.

Radioimmunotherapy for hematopoietic cell transplantation

Radioimmunotherapy (RIT) represents an attractive strategy to deliver radiation selectively to tumor and other target organs while minimizing toxicity to normal tissues. RIT with β-particle-emitting isotopes targeting CD33, CD45 and CD66 can potentially allow intensification of conditioning before hematopoietic cell transplantation (HCT) in leukemia. Similarly, RIT directed against CD20 has shown promise in the setting of autologous and allogeneic HCT for B-cell lymphomas. α-particle immunotherapy with isotopes such as bismuth-213, actinium-225 and astatinine-211 offers the possibility of more selective and efficient killing of target cells while sparing the surrounding normal cells. Pretargeting strategies may further improve target:normal organ dose ratios. While RIT has demonstrated significant antitumor activity, ultimately, randomized studies will be required to determine if conditioning regimens that include this therapeutic modality can improve patient outcomes after HCT.

Clinical outcomes of allogeneic stem cell transplantation for relapsed or refractory follicular lymphoma: a retrospective analysis by the Fukuoka Blood and Marrow Transplantation Group

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is considered the only curative treatment for relapsed or refractory follicular lymphoma (FL), but it has a high treatment-related mortality rate. Only a few reports, however, have described the efficacy of allo-SCT for FL in the Japanese population. We retrospectively analyzed the outcome of allo-SCT in 30 patients with FL. Seventeen (56.7 %) patients were chemorefractory, whereas 13 (43.3 %) were chemosensitive. An estimated 2-year overall survival rate (OS) and relapse rate of all patients was 46.7 and 20.0 %, respectively. There were no significant differences in the estimated 2-year OS rate between patients who received myeloablative conditioning and those who received reduced-intensity conditioning (P = 0.98), and among the recipients of related bone marrow (BM)/peripheral blood stem cell, unrelated BM and umbilical cord blood (P = 0.20). In patients who were either chemosensitive or chemorefractory at allo-SCT, the 2-year OS rate was 69.2 and 29.4 % (P = 0.06). Patients with mild-to-moderate acute GVHD had better 2-year PFS rate compared with patients who had severe acute GVHD (P = 0.01), but not better PFS compared with patients who had no acute GVHD (P = 0.12). Our results suggest that the graft-versus-lymphoma effects of allo-SCT may provide survival benefits even in patients with chemorefractory FL.

Host lymphocyte depletion as a strategy to facilitate early full donor chimerism after reduced-intensity allogeneic stem cell transplantation

Reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (RIC-alloHSCT) is associated with lower toxicity but higher rates of prolonged mixed chimerism than myeloablative conditioning. Decreased pretransplantation host T cell numbers are associated with less graft rejection and early full donor chimerism. To compensate for variability in pretransplantation host lymphocyte numbers and facilitate the achievement of rapid full donor chimerism, we tested a strategy of targeted lymphocyte depletion (TLD) using chemotherapy at conventional doses to provide cytoreduction and lymphocyte depletion before RIC-alloHSCT. In our study, 111 patients with advanced hematologic malignancies received 1 to 3 cycles of conventional-dose chemotherapy to reduce circulating lymphocytes to a predetermined level. Patients then underwent RIC-alloHSCT from HLA-matched siblings. Patients received a median of 2 cycles of TLD chemotherapy, resulting in a median 71% decline in CD4(+) count. All patients engrafted; there were no late graft failures. By day +14, median CD3(+) chimerism was 99% donor and was significantly associated with lower post-TLD CD4(+) counts (P = .012). One- and 5-year treatment-related mortality were 15% and 21%, respectively. At 1-year follow-up, 66% of patients had achieved complete remission (CR) of which 92% were not in CR at the time of transplantation. Overall survival at 1 and 5 years post transplantation were 66% and 47%, respectively.

Alternative donor hematopoietic stem cell transplantation for mature lymphoid malignancies after reduced-intensity conditioning regimen: similar outcomes with umbilical cord blood and unrelated donor peripheral blood

We have reported encouraging results of unrelated cord blood transplantation for patients with lymphoid malignancies. Whether those outcomes are comparable to matched unrelated donor transplants remains to be defined. We studied 645 adult patients with mature lymphoid malignancies who received an allogeneic unrelated donor transplant using umbilical cord blood (n=104) or mobilized peripheral blood stem cells (n=541) after a reduced-intensity conditioning regimen. Unrelated cord blood recipients had more refractory disease. Median follow-up time was 30 months. Neutrophil engraftment (81% vs. 97%, respectively; P<0.0001) and chronic graft-versus-host disease (26% vs. 52%; P=0.0005) were less frequent after unrelated cord blood than after matched unrelated donor, whereas no differences were observed in grade II-IV acute graft-versus-host disease (29% vs. 32%), non-relapse mortality (29% vs. 28%), and relapse or progression (28% vs. 35%) at 36 months. There were also no significant differences in 2-year progression-free survival (43% vs. 58%, respectively) and overall survival (36% vs. 51%) at 36 months. In a multivariate analysis, no differences were observed in the outcomes between the two stem cell sources except for a higher risk of neutrophil engraftment (hazard ratio=2.12; P<0.0001) and chronic graft-versus-host disease (hazard ratio 2.10; P=0.0002) after matched unrelated donor transplant. In conclusion, there was no difference in final outcomes after transplantation between umbilical cord blood and matched unrelated donor transplant. Umbilical cord blood is a valuable alternative for patients with lymphoid malignancies lacking an HLA-matched donor, being associated with lower risk of chronic graft-versus-host disease.

Apoptotic cells in allogeneic hematopoietic stem cell transplantations: "turning trash into gold"

Allogeneic hematopoietic stem cell transplantation (HST) is an important therapeutic option for various malignant and non-malignant conditions. HST during first remission offers the best cure for patients for whom conventional chemotherapy alone is not sufficient. Yet, in spite of the high curative potential and recent advances in this treatment modality, it remains limited by transplant related toxicity and grant-versus-host disease (GVHD). Apoptotic cells, which used to be regarded as immunologically "bland," are now recognized as important modulators of immune responses. Taking into account the immunological properties of apoptotic cells and the nature of the side effects of HST, they have been administered simultaneously with hematopoietic stem cells in experimental transplantation models, in anticipation of improved outcome. Under these conditions, engraftment and full-donor chimerism are facilitated without significant generation of anti-apoptotic cell auto-antibodies. In addition they prevent alloimmunization, up-regulate T regulatory cells and reduce both the frequency and the severity of GVHD. These favorable effects require host macrophages and donor bone marrow plasmatoid dendritic cells, and are associated with tumor growth factor-β (TGF-β) production. To summarize, apoptotic cells can play a crucial role in the setting of transplantations, and may be viewed as "turning trash into gold." Clinical studies are underway.

Recent progress in managing graft-versus-host disease and viral infections following allogeneic stem cell transplantation

Despite recent reductions in transplant-related mortality, post-transplant complications such as graft-versus-host disease (GvHD) remain major obstacles to the successful application of allogeneic hematopoietic transplantation. Steroid-refractory GvHD has a poor outcome. Although there are a variety of new approaches to the treatment of refractory GvHD, many have limited evidence of efficacy. Other approaches appear to be unacceptably toxic. It would be preferable to improve GvHD prophylaxis. There is good evidence that rates of GvHD can be reduced without unacceptable reduction of the graft-versus-leukemia effect or compromising overall survival. However, prophylactic measures aimed at reducing T-cell numbers or functions are associated with high rates of reactivation of latent viruses. New technologies that allow rapid generation of virus-specific T-cells show promise to reduce the frequency and severity of such reactivations and have the potential to revolutionize the approach to post-transplant infectious complications.

Promising role of reduced-toxicity hematopoietic stem cell transplantation (PART-I)

Allogeneic hematopoietic stem cell transplantation (HSCT) remains a potential curative option for many patients with hematological malignancies (HM). However, the high rate of transplantation-related mortality (TRM) restricted the use of standard myeloablative HSCT to a minority of young and fit patients. Over the past few years, it has become evident that the alloreactivity of the immunocompetent donor cells mediated anti-malignancy effects independent of the action of high dose chemoradiotherapy. The use of reduced intensity conditioning (RIC) regimens has allowed a graft-versus-malignancy (GvM) effect to be exploited in patients who were previously ineligible for HSCT on the grounds of age and comorbidity. Retrospective analysis showed that RIC has been associated with lower TRM but a higher relapse rate leading to similar intermediate term overall and progression-free survivals when compared to standard myeloablative HSCT. However, the long term antitumor effect of this approach is less well established. Prospective studies are ongoing to define which patients might most benefit from reduced toxicity stem cell transplant (RT-SCT) and which transplant protocols are suitable for the different types of HM. The advent of RT-SCT permits the delivery of a potentially curative GvM effect to the majority of patients with HM whose outcome with conventional chemotherapy would be dismal. Remaining challenges include development of effective strategies to reduce relapse rates by augmenting GvM effects without increasing toxicity.

Monoclonal antibodies in conditioning regimens for hematopoietic cell transplantation

Monoclonal antibodies are increasingly being incorporated in conditioning regimens for autologous or allogeneic hematopoietic cell transplantation (HCT). The benefit of adding rituximab to autologous HCT regimens is purportedly related to in vivo purging of clonal B cells. Randomized trials comparing the addition (or not) of rituximab to high-dose therapy regimens are lacking. No benefit of standard-dose radioimmunotherapy-based regimens for autografting in aggressive lymphomas was seen in a randomized controlled study. The incorporation of rituximab into allogeneic HCT regimens aims to improve responses while reducing nonrelapse mortality resulting from acute graft-versus-host disease. The optimal dose and administration schedule of rituximab in this setting are unknown, and potentially serious complications from increased infections owing to prolonged (and profound) cytopenias or persistent hypogammaglobulinemia are of concern. Radioimmunotherapy-based conditioning for allografting holds promise as a modality to optimize tumor control and synergize adoptive immunotherapy effects, but it remains experimental at this time. The addition of alemtuzumab to allogeneic HCT regimens is associated with prolonged lymphopenia and impaired immune reconstitution, high relapse rates, and serious infections. The optimal dose and schedule of alemtuzumab to avoid prolonged immune paresis remain elusive. It is anticipated that additional monoclonal antibodies will soon become available that can be incorporated into HCT regimens after safety and clinical efficacy are demonstrated.

Long-Term Results of Fludarabine/Melphalan as a Reduced-Intensity Conditioning Regimen in Mantle Cell Lymphoma: The GELTAMO Experience

BACKGROUND

We herein report the long-term results of an allogeneic reduced-intensity conditioning (allo-RIC) protocol used in 21 consecutive patients (16 males, median age 56 years, 71% in complete remission) diagnosed with mantle cell lymphoma (MCL).

METHODS

The allo-RIC consisted of fludarabine plus melphalan and peripheral blood hematopoietic stem cells (PBSCs) from human leukocyte antigen (HLA)-identical siblings were used in all cases. Median CD34+ infused cells was 5.8 times 10(6)/kg. All patients engrafted promptly.

RESULTS

Early toxicity included mild/moderate mucositis (43%), febrile neutropenia (33%) and bacterial infections (19%). With a median follow up of 48 months, four deaths were reported, all due to infections and/or graft-versus-host disease (GVHD), yielding a 3-year cumulative incidence of nonrelapse mortality of 19.5%. Grade III-IV acute GVHD occurred in 15% and chronic GVHD in 78%, being extensive in 39%. The 5-year progression-free survival (PFS) and overall survival (OS) were both 80% (95% CI: 63-97%). Age was the only possible prognostic factor for OS, which was 43% for those aged more than 60 years and 100% for those younger (p < 0.001).

CONCLUSIONS

Our data confirm that allo-RIC offers a low toxicity profile and a chance for prolonged long-term disease-free survival in MCL, particularly in younger patients.

Management of indolent lymphoma: where are we now and where are we going

Indolent lymphoma comprises a unique and challenging subset of non-Hodgkin lymphoma (NHL). While definitions of indolence will vary, the most common indolent NHL subtypes include follicular lymphoma, marginal zone lymphoma, and small lymphocytic lymphoma. Patients with indolent NHL (iNHL) excluding those with rare localized presentations are often met with an incurable but highly treatable NHL. In the rituximab era, response rates are approaching 90% with rituximab plus chemotherapy and time to next treatment are beginning to be measured in years. As a result of a prolonged natural history, we are encountering a gridlock of novel regimens and agents that appropriately fill peer-reviewed journals. In this review, we tackle a spectrum of topics in the management of indolent lymphoma including the initial approach to the newly diagnosed patient, approaches to first cytotoxic chemotherapy, maintenance and consolidation techniques, as well as highlight promising treatments on the horizon in iNHL. Clinicians continue to face tough choices in the management of iNHL. Through well-thought out clinical trials and peer-reviewed vetting of data we will continue to determine how to best manage the clinical continuum that is iNHL.

Rituximab, fludarabine, and total body irradiation as conditioning regimen before allogeneic hematopoietic stem cell transplantation for advanced chronic lymphocytic leukemia: long-term prospective multicenter study

To evaluate the efficacy and toxicity of reduced-intensity conditioning (RIC) combining fludarabine, low-dose total body irradiation (TBI) and rituximab before allogeneic hematopoietic stem cell transplantation (allo-HSCT) from human leucocyte antigen (HLA) identical siblings, we conducted a prospective study in patients ≤65 years old with advanced chronic lymphocytic leukemia (CLL) stage B or C in response after a salvage treatment. Conditioning included rituximab (375 mg/m² on day 5), fludarabine (30 mg/m² from day 4 to day 2), TBI (2 Gy on day 0), and rituximab (500 mg/m² on days 1 and 8). Forty patients were included, 34 (85%) were male with a median age of 54 years (range, 35-65 years), 38 (95%) were in B stage, and 2 were in stage C; only 7 patients (17%) were in complete response. Seven (17%) patients did not receive rituximab. Thirty-nine (98%) patients engrafted, 17 patients developed acute graft-versus-host disease (GVHD) grade ≥II with a cumulative incidence at 3 months of 44% (36-52) with a significant protective effect of rituximab (p = 0.02). The cumulative incidence of chronic GVHD was 29% (21-36) at 12 months for both limited and extensive forms. The median overall survival was not reached with 5-years probability of 55% (41-74). The multivariate analysis showed a positive effect of rituximab on overall survival and event-free survival (hazard ratio [HR] = 0.1 [0-0.6], p = 0.02; and HR = 0.1 [0-0.4], p = 0.035, respectively). The association of fludarabine, TBI, and rituximab is feasible, well tolerated, and allows better outcomes in advanced CLL.

Dose-adjusted EPOCH-rituximab combined with fludarabine provides an effective bridge to reduced-intensity allogeneic hematopoietic stem-cell transplantation in patients with lymphoid malignancies

PURPOSE

There is currently no standard chemotherapy regimen for patients with lymphoid malignancies being considered for reduced-intensity conditioning allogeneic hematopoietic stem-cell transplantation (RIC-alloHSCT). The ideal regimen would provide disease control and result in lymphocyte depletion to facilitate engraftment. To this end, we developed a novel regimen by adding fludarabine to dose-adjusted continuous-infusion etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin plus with or without rituximab (DA-EPOCH-F/R).

PATIENTS AND METHODS

One hundred forty-seven patients with lymphoid malignancy (median age, 50 years) who had heavily pretreated (median prior regimens, three) and chemo-refractory (47%) disease were treated with DA-EPOCH-F/R before RIC-alloHSCT. Patients received one to three consecutive cycles until achieving lymphocyte depletion (CD4(+) count < 200/μL) or progressive disease.

RESULTS

Overall response rate was 41%; 39% of patients had stable disease. Toxicity included grade 4 neutropenia in 65% and thrombocytopenia in 25% of patients. DA-EPOCH-F/R resulted in lymphocyte depletion (P < .001), which was inversely associated with serum interleukin (IL) 7 and IL-15 levels. Of 147 patients, 143 patients proceeded to RIC-alloHSCT. Patients with lower CD3(+) (P < .001), CD4(+) (P < .001), and CD8(+) (P < .001) T-cell counts after DA-EPOCH-F/R were more likely to achieve full donor lymphoid chimerism by day +14 after transplant. Relative to nonresponders to DA-EPOCH-F/R, patients with complete and partial response had increased event-free survival (77.4 v 4.8 months; P < .001) and overall survival (98.5 v 16.2 months; P < .001).

CONCLUSION

DA-EPOCH-F/R safely provides tumor cytoreduction and lymphocyte depletion, thereby offering a bridge to RIC-alloHSCT in patients with aggressive lymphoid malignancies.

Allogeneic hematopoietic stem cell transplantation in patients with diffuse large B cell lymphoma relapsed after autologous stem cell transplantation: a GITMO study

Patients who relapse after an autologous hematopoietic stem cell transplantation (SCT) have a very poor prognosis. We have retrospectively analyzed diffuse large B cell lymphoma patients who underwent an allo-SCT after an auto-SCT relapse reported in the Gruppo Italiano Trapianto di Midollo Osseo (GITMO) database. From 1995 to 2008, 3449 autologous transplants were reported in the GITMO database. Eight hundred eighty-four patients relapsed or progressed after transplant; 165 patients, 19% of the relapsed patients, were treated with allo-transplant. The stem cell donor was related to the patient in 108 cases. A reduced intensity conditioning regimen was used in 116. After allo-SCT, 72 patients (43%) obtained a complete response and 9 obtained a partial response with an overall response rate of 49%; 84 patients (51%) experienced rapid progression of disease. Ninety-one patients died, 45 due to disease and 46 due to treatment-related mortality. Acute graft-versus-host disease was recorded in 57 patients and a chronic GvHD in 38 patients. With a median follow-up of 24 months (2-144) after allo, overall survival (OS) was 39%, and after a median of 21 months (2-138) after allo, progression-free survival (PFS) was 32%. Multivariate analysis indicated that the only factors affecting OS were status at allo-SCT, and those affecting PFS were status at allo-SCT and stem cell donor. This retrospective analysis shows that about one-fifth of patients with diffuse large B cell lymphoma who experience relapse after autologous transplantation may be treated with allogeneic transplantation. Moreover, the only parameter affecting either OS or PFS was the response status at the time of allo-SCT.

Hematopoietic Stem Cell Allografting for Chronic Lymphocytic Leukemia: A Focus on Reduced-Intensity Conditioning Regimens

Background

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only known treatment modality that currently offers a potential cure to patients with chronic lymphocytic leukemia (CLL). A better understanding of the role of adoptive immunotherapy and its consequent bona fide graft-vs-leukemia (GVL) effect has resulted in a reduction of the ablative intensity and toxicity of preparative allo-HCT regimens.

Methods

The authors review the published data of reduced-intensity conditioning (RIC) allo-HCT in patients with CLL.

Results

RIC allo-HCT has reduced the transplant associated morbidity and mortality of the procedure and has consequently broadened applicability of allo-HCT to patients with CLL who are generally of more advanced age (> 60 years) and who often have associated comorbidities.

Conclusions

Published literature supports the use of RIC allo-HCT for these patients once a suitable donor is identified, provided they fulfill acceptable consensus criteria for hematopoietic stem cell allografting. Several studies have shown that T-cell-replete RIC allo-HCT is also capable of overcoming the adverse effect of poor prognostic factors in CLL such as del(17p), unmutated IgVH, or ZAP-70 expression. Continued clinical trials to identify the optimal regimen for RIC allo-HCT for patients with CLL are warranted.

Transplantation with bone marrow stromal cells promotes wound healing under chemotherapy through altering phenotypes

Stem cell transplantation is a promising strategy for delayed wound healing caused by chemotherapy. However, the fate of stem cells under chemotherapy has not been fully elucidated. Herein we characterized human fetal bone marrow stromal cells (hBMSCs) during wound healing in mice treated with cyclophosphamide (CTX). The isolated hBMSCs expressed the phenotype of CD11b^low/CD14^low/CD34^low/CD45^low/CD29^high/CD44^high/CD90^high/CD105^high/CD146^high/STRO-1^low. Following in vitro exposure to CTX, hBMSCs showed decreased cell growth in a dose- and time-dependent manner, accompanied by increased expressions of collagen-I/III, and CD31. After transplantation, wounds closed as early as 8 days and were positive for α-smooth muscle actin (α-SMA), implicating the enhanced re-epithelialization and wound contraction. Moreover, proliferating cell nuclear antigen (PCNA) and CD31 showed co-localization with α-SMA, suggesting the differentiation of hBMSCs into epithelial cells and myofibroblasts/fibroblasts. Taken together, our results indicate hBMSCs can accelerate wound healing under chemotherapy through altering their phenotypes.

Rituximab for prevention and treatment of graft-versus-host disease

Growing understanding of the important role of B lymphocytes in alloreactivity has paved the way for evaluating anti-B cell therapy with rituximab in patients undergoing allogeneic hematopoietic cell transplantation. Data suggesting a beneficial reduction in incidence and severity of acute graft-versus-host disease (GVHD) are limited to non-randomized studies from single institutions using higher than conventional doses of rituximab. Additionally, rituximab is used as an effective treatment of corticosteroid-refractory chronic GVHD with good responses, particularly in cases of dermatologic and mucosal involvement. Post-transplant administration of rituximab appears to reduce the rate of chronic GVHD in preliminary studies.

(90)Y-ibritumomab tiuxetan followed by reduced-intensity conditioning and allo-SCT in patients with advanced follicular lymphoma

RIC HSCT is a potentially curative therapeutic option for patients with advanced FL but disease relapse remains the most common cause of failure. Radioimmunoconjugates administered prior to RIC allogeneic HSCT may enhance cytoreduction and allow more time for graft versus lymphoma effect to develop without the associated toxicity of a myeloablative HSCT. We performed a retrospective study to describe the outcomes of patients with relapsed, refractory or transformed FL who received ⁹⁰Y ibritumomab tiuxetan followed by fludarabine and low-dose busulfan RIC allogeneic HSCT at the Dana-Farber Cancer Institute between 2006 and 2009, inclusively. Twelve patients were identified with a median age of 55 (40–66) years and a median number of lines of therapy of 5 (2–10). Two patients (17%) had transformed to a more aggressive histology and 5 (42%) had chemorefractory FL. Cumulative incidences of grade II–IV acute GVHD at 100 days were 17% (± 11%) and chronic GVHD at 12 months were 63% (±19%). Two-year non-relapse mortality was 18% (± 12%). Two-year OS and progression-free survival (PFS) were 83% (± 11%) and 74% (± 13%), respectively. This treatment is associated with favorable outcomes including acceptable rates of GVHD and relapse in advanced FL patients and warrants prospective studies.

Targeted IV busulfan and fludarabine followed by post-allogeneic hematopoietic cell transplantation rituximab demonstrate encouraging activity in CD20+ lymphoid malignancies without increased risk of infectious complications

We examined pharmacokinetic-targeted IV busulfan (75-170 mg/m(2), with target AUC of 3500-6000 μmol min) and fludarabine (40 mg/m(2)) × 4 days with rituximab (t-IV Bu/Flu + rituximab) 375 mg/m(2) on days +1 and +8 followed by allogeneic hematopoietic cell transplantation in 19 patients (median age 56, range 35-68 years) with CD20+ lymphoid malignancies. Median time to neutrophil and platelet engraftment was 15 and 12 days. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 58% (95% confidence interval, CI 39-85%), and chronic GVHD was 50% (95% CI 28-88%). With a median follow up of 7 (range 1-31) months, overall response was observed in 15, and stable or progressive disease in 4. Overall survival at 1 year was 67%. Engraftment, chimerism, and infectious complications did not differ significantly from a contemporaneous non-rituximab containing comparator group. The addition of rituximab 375 mg/m(2) to t-IV Bu/Flu does not appear to adversely affect engraftment, donor chimerism, or increase the risk of infectious complications.

Stem cell transplantation in chronic lymphocytic leukaemia - steering a safe course over shifting sands

There is no clear consensus regarding the optimal management of chronic lymphocytic leukaemia. Many patients are diagnosed at an advanced age and will die with chronic lymphocytic leukaemia, but of other unrelated causes. A significant minority are diagnosed at an earlier age, or with more aggressive disease, and despite chemotherapy, are likely to die of chronic lymphocytic leukaemia. The infusion of autologous or allogeneic haemopoietic stem cells, following a variety of conditioning regimes, offers the possibility of longer remissions or even cure. We explore the key questions facing clinicians in this field: Who is it best to transplant? When is it best to transplant? How is it best to transplant?

Immunotherapy following hematopoietic stem cell transplantation: potential for synergistic effects

Hematopoietic stem cell transplantation (HSCT) is a particularly important treatment for hematologic malignancies. Unfortunately, following allogeneic HSCT, graft-versus-host disease, immunosuppression and susceptibility to opportunistic infections remain among the most substantial problems restricting the efficacy and use of this procedure, particularly for cancer. Adoptive immunotherapy and/or manipulation of the graft offer ways to attack residual cancer as well as other transplant-related complications. Recent exciting discoveries have demonstrated that HSCT could be expanded to solid tissue cancers with profound effects on the effectiveness of adoptive immunotherapy. This review will provide a background regarding HSCT, discuss the complications that make it such a complex treatment procedure following up with current immunotherapeutic strategies and discuss emerging approaches in applying immunotherapy in HSCT for cancer.

Allogeneic stem-cell transplantation in patients with Waldenström macroglobulinemia: report from the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation

PURPOSE

Allogeneic stem-cell transplantation (alloSCT) is a curative therapeutic option for patients with low-grade lymphoid malignancies. Information regarding alloSCT in Waldenström macroglobulinemia (WM) is limited. This study presents the long-term outcome of a large series of patients with WM treated with alloSCT.

PATIENTS AND METHODS

A total of 86 patients received allograft by using either myeloablative (MAC; n = 37) or reduced-intensity conditioning (RIC; n = 49) regimens and were retrospectively studied. The median age was 49 years (range, 23 to 64 years); 47 patients had received three or more previous lines of therapy, and eight patients had experienced failure on a prior autologous stem-cell transplantation. A total of 59 patients (68.6%) had chemotherapy-sensitive disease at the time of alloSCT. Median follow-up of the surviving patients was 50 months (7 to 142 months).

RESULTS

Nonrelapse mortality (NRM) at 3 years was 33% for MAC and 23% for RIC. The overall response rate was 75.6%. The relapse rates (RRs) at 3 years were 11% for MAC and 25% for RIC. Fourteen patients received donor lymphocyte infusions (DLIs) for disease relapse. PFS and OS at 5 years were 56% and 62% for MAC and 49% and 64% for RIC, respectively. The occurrence of chronic graft-versus-host disease (cGVHD) was associated with a higher NRM and a lower RR, leading to an improvement in PFS.

CONCLUSION

alloSCT can induce durable remissions in a selected population of young and heavily pretreated patients with WM. The low RR, the achievement of additional disease responses after DLIs, and the lower RR in patients developing cGVHD suggest the existence of a clinically relevant graft-versus-WM effect.

Tackling mantle cell lymphoma (MCL): Potential benefit of allogeneic stem cell transplantation

Mantle cell lymphoma (MCL) is a type of non-Hodgkins lymphoma (NHL) associated with poor progression-free and overall survival. There is a high relapse rate with conventional cytotoxic chemotherapy. Intensive combination chemotherapy including rituximab, dose intense CHOP- (cyclophosphamide-doxorubicin-vincristine-prednisone) like regimens, high dose cytarabine, and/or consolidation with autologous stem cell transplant (autoSCT) have shown promise in significantly prolonging remissions. Data from phase II studies show that even in patients with chemotherapy refractory MCL, allogeneic stem cell transplant (alloSCT) can lead to long term disease control. Most patients with MCL are not candidates for myeloablative alloSCT due to their age, comorbidities, and performance status. The advent of less toxic reduced intensity conditioning (RIC) regimens, which rely more on the graft-versus-lymphoma (GVL) effect, have expanded the population of patients who would be eligible for alloSCT. RIC regimens alter the balance of toxicity and efficacy favoring its use. Treatment decisions are complicated by introduction of novel agents which are attractive options for older, frail patients. Further studies are needed to determine the role and timing of alloSCT in MCL. Currently, for selected fit patients with chemotherapy resistant MCL or those who progress after autoSCT, alloSCT may provide long term survival.