Graft-versus-lymphoma effect of donor lymphocyte infusion in indolent lymphomas relapsed after allogeneic stem cell transplantation

Graft versus Leukemia in 2023

Allogeneic hematopoietic stem cell transplantation (HSCT) is commonly utilized in the management of leukemia across multiple subtypes. Graft versus leukemia (GVL) is a critical component of successful transplantation and involves donor cells eradicating residual leukemia within the recipient. Graft versus host disease (GVHD) by contrast is a common complication of the transplantation process in which donor cells identify the recipient's various organ systems as foreign, thereby leading to a multitude of organ toxicities that can be described as autoimmune in nature. As both GVL and GVHD are mediated by a similar mechanism, these processes are felt to occur in tandem with one another. Here, we review the allogeneic HCT process in the context of GVL.

Allogeneic Stem Cell Transplantation in Mantle Cell Lymphoma in the Era of New Drugs and CAR-T Cell Therapy

MCL is an uncommon lymphoproliferative disorder that has been regarded as incurable since its identification as a distinct entity. Allogeneic transplantation for two decades has represented the only option capable of ensuring prolonged remissions and possibly cure. Despite its efficacy, its application has been limited by feasibility limitations and substantial toxicity, particularly in elderly patients. Nevertheless, the experience accumulated over time has been wide though often scattered among retrospective and small prospective studies. In this review, we aimed at critically revise and discuss available evidence on allogeneic transplantation in MCL, trying to put available evidence into the 2020 perspective, characterized by unprecedented development of novel promising therapeutic agents and regimens.

Allogeneic Hematopoietic Transplantation for Multiple Myeloma in the New Drugs Era: A Platform to Cure

Allogeneic hematopoietic cell transplantation (alloHCT) represents a treatment option for multiple myeloma (MM) patients. As shown in several studies, alloHCT is highly effective, but it is hampered by a high toxicity, mainly related to the graft-versus-host disease (GVHD), a complex immunological reaction ascribable to the donor’s immune system. The morbidity and mortality associated with GVHD can weaken the benefits of this procedure. On the other side, the high therapeutic potential of alloHCT is also related to the donor’s immune system, through immunological activity known as the graft-versus-myeloma effect. Clinical research over the past two decades has sought to enhance the favorable part of this balance, along with the reduction in treatment-related toxicity. Frontline alloHCT showed promising results and a potential for a cure in the past. Currently, thanks to the improved results of first-line therapies and the availability of effective second- or third-line salvage therapies, alloHCT is reserved for selected high-risk patients and is considered a clinical option. For donor lymphocyte infusion, bortezomib or lenalidomide have been used as consolidation or maintenance therapies post-transplant—none has become standard of care. For those patients who relapse, the best treatment should be evaluated considering the patient’s clinical status and the previous lines of therapy. The use of newer drugs, such as monoclonal antibodies or other immunotherapies in the post-transplant setting, deserves further investigation. However, acceptable toxicity and a synergic effect with the newer immune system could be hopefully expected.

Cellular Immunotherapy in Lymphoma: Beyond CART Cells

OPINION STATEMENT

Cellular immunotherapy has been rapidly evolving and increasingly utilized in the management of relapsed and refractory lymphoma. CD19-specific chimeric antigen receptor T cells (CARTs) have achieved impressive results in pivotal clinical trials. Although CART development continues, these products have fundamental limitations that may make them less desirable in particular settings. For example, CARTs can only target cell surface antigens and thus are incapable of targeting intracellular tumor-associated proteins. In contrast to CARTs, conventional T cell receptors (TCR) allow T cells to target any cellular antigen, including intracellular proteins, since they interact with peptides presented by MHC I and II molecules. T cells recognizing EBV antigens through native TCRs have been successfully employed for treatment and prophylaxis of EBV-associated lymphomas, including post-transplant lymphoproliferative disorder. Currently, transgenic TCR-transduced T cells targeting nonviral tumor antigens remain experimental but, if successful, could become an invaluable cellular therapy option. Because the manufacturing process of autologous T cell products, including CARTs and other tumor-specific T cells, takes several weeks, patients often need bridging therapy to maintain disease control, which may be challenging. Novel cellular platforms, such as genetically modified NK and NKT cells, may be amenable to allogeneic use and thus may allow production as a readily available, "off-the-shelf" product. As cellular therapies beyond CART continue to grow, available therapeutic options for relapsed and refractory lymphoma patients are expected to expand further.

Hematopoietic-cell transplantation for lymphoma in the era of genetically engineered cellular therapy: it's not quite time to scrap the old vehicle for the new car

PURPOSE OF REVIEW

Second-line platinum-based salvage chemotherapy followed by high-dose chemotherapy and autologous hematopoietic-cell transplantation (AHCT) has remained the standard of care (SOC) for relapsed and primary refractory (r/r) diffuse large B-cell lymphoma (DLBCL) for greater than 2 decades. In the postrituximab era, this strategy has yielded disappointing outcomes for r/r patients with curability in less one-quarter of the patients by intention-to-treat.

RECENT FINDINGS

Given the Food and Drug Administration (FDA) approval of chimeric antigen receptor (CAR) modified T cells directed against CD19 (CD19 CAR T) for DLBCL following two lines of therapy and/or failed AHCT, encouragement with this therapy in the second line for r/r patients has naturally prompted randomized phase III studies against the aforementioned SOC. The predominant hurdle to procession to AHCT is chemotherapy sensitivity after platinum-based salvage therapy.

SUMMARY

In this review, we will discuss recent investigations to improve response rates in r/r DLBCL with the intent of proceeding to potentially curative AHCT, as well as investigations to decrease progression post-AHCT. In addition, data regarding currently FDA approved CD19 CAR T cells will be reviewed. Within 2-3 years, we will know if the multicenter/multinational studies of CD19 CAR T will replace SOC salvage therapy and AHCT in the second-line. The role of allogeneic HCT will also be briefly reviewed in the context of these therapies.

[Allogeneic haematopoietic cell transplantation for indolent lymphomas: Guidelines from the Francophone Society Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

Despite great improvements in the outcome of patients with lymphoma, some may still relapse or present with primary refractory disease. In these situations, allogeneic hematopoietic cell transplantation is a potentially curative option, this is true particularly the case of relapse after autologous stem cell transplantation. Recently, novel agents such as anti-PD1 and BTK inhibitors have started to challenge the use of allogeneic hematopoietic cell transplantation for relapsed or refractory lymphoma. During the 2016 annual workshop of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC), we performed a comprehensive review of the literature published in the last 10 years and established guidelines to clarify the indications and transplant modalities in this setting. This paper specifically reports on our conclusions regarding indolent lymphomas, mainly follicular lymphoma and chronic lymphocytic leukemia.

Milestones of Hematopoietic Stem Cell Transplantation - From First Human Studies to Current Developments

Since the early beginnings, in the 1950s, hematopoietic stem cell transplantation (HSCT) has become an established curative treatment for an increasing number of patients with life-threatening hematological, oncological, hereditary, and immunological diseases. This has become possible due to worldwide efforts of preclinical and clinical research focusing on issues of transplant immunology, reduction of transplant-associated morbidity, and mortality and efficient malignant disease eradication. The latter has been accomplished by potent graft-versus-leukemia (GvL) effector cells contained in the stem cell graft. Exciting insights into the genetics of the human leukocyte antigen (HLA) system allowed improved donor selection, including HLA-identical related and unrelated donors. Besides bone marrow, other stem cell sources like granulocyte-colony stimulating-mobilized peripheral blood stem cells and cord blood stem cells have been established in clinical routine. Use of reduced-intensity or non-myeloablative conditioning regimens has been associated with a marked reduction of non-hematological toxicities and eventually, non-relapse mortality allowing older patients and individuals with comorbidities to undergo allogeneic HSCT and to benefit from GvL or antitumor effects. Whereas in the early years, malignant disease eradication by high-dose chemotherapy or radiotherapy was the ultimate goal; nowadays, allogeneic HSCT has been recognized as cellular immunotherapy relying prominently on immune mechanisms and to a lesser extent on non-specific direct cellular toxicity. This chapter will summarize the key milestones of HSCT and introduce current developments.

Outcome Comparison of Allogeneic versus Autologous Stem Cell Transplantation in Transformed Low-Grade Lymphoid Malignancies: A Systematic Review and Pooled Analysis of Comparative Studies

BACKGROUND

Some patients with low-grade lymphoid malignancies develop transformed disease, requiring stem cell transplantation (SCT). SCT outcomes in transformed low-grade lymphoid malignancies may differ from those of nontransformed disease or other aggressive non-Hodgkin lymphomas. We conducted a pooled analysis of the clinical outcomes of allogeneic versus high-dose therapy (HDT) with autologous SCT in adult patients with transformed low-grade lymphoid malignancies.

METHODS

A PubMed, EMBASE, and Cochrane search yielded 4 comparative studies reporting allogeneic versus HDT with autologous SCT outcomes in adults (age ≥18) with transformed low-grade lymphoid malignancies, including follicular, chronic/small lymphocytic, and marginal zone lymphoma. Risk ratio (RR) and 95% CI were calculated using random-effects models.

RESULTS

Rates for overall survival (OS) were 51.0 versus 69.5% (RR = 1.55, 95% CI 1.19-2.02, p = 0.001), rates of relapse were 37.3 versus 35.3% (RR = 1.04, 95% CI 0.70-1.55, p = 0.84), and rates of transplant-related mortality (TRM) were 33.3 versus 7.2% (RR = 4.52, 95% CI 2.75-7.43, p < 0.00001) for allogeneic versus autologous SCT. Previous rituximab treatment, reduced intensity conditioning regimen prior to SCT, or original pathology had no prognostic impact.

CONCLUSION

HDT followed by autologous SCT was associated with lower TRM and a better OS, but there was no difference in relapse versus allogeneic SCT. Autologous SCT may be the better therapeutic option, considering the second chance of allogeneic SCT in the case of relapse.

Reappraising the timing of transplant for indolent non-Hodgkin lymphomas

INTRODUCTION

Indolent non-Hodgkin lymphomas (iNHL) remain incurable with standard approaches. The timing of autologous stem cell transplant (ASCT) is changing following the introduction of new drugs that can potentially defer the transplant, improved reduced intensity conditioning (RIC) and haploidentical allogeneic SCT (allo-SCT).

AREAS COVERED

The most relevant aspects concerning the role of hematopoietic stem cell transplantation in the management of iNHL are discussed. Literature search methodology included examination of PubMed index and meeting presentations. Expert commentary: ASCT is not currently employed as consolidation in first-line, being reserved to patients with refractory/relapsed disease. The curative potential of graft-versus-lymphoma (GVL) after RIC allo-SCT could be particularly beneficial in patients with iNHL relapsing after ASCT. This scenario could be modified in the near future by better definition of high-risk patients at diagnosis, by the improvement of minimal residual disease (MRD) evaluation and by the introduction of new drugs in the therapeutic algorithm.

Utilizing cell-based therapeutics to overcome immune evasion in hematologic malignancies

Hematologic malignancies provide a suitable testing environment for cell-based immunotherapies, which were pioneered by the development of allogeneic hematopoietic stem cell transplant. All types of cell-based therapies, from donor lymphocyte infusion to dendritic cell vaccines, and adoptive transfer of tumor-specific cytotoxic T cells and natural killer cells, have been clinically translated for hematologic malignancies. The recent success of chimeric antigen receptor-modified T lymphocytes in B-cell malignancies has stimulated the development of this approach toward other hematologic tumors. Similarly, the remarkable activity of checkpoint inhibitors as single agents has created enthusiasm for potential combinations with other cell-based immune therapies. However, tumor cells continuously develop various strategies to evade their immune-mediated elimination. Meanwhile, the recruitment of immunosuppressive cells and the release of inhibitory factors contribute to the development of a tumor microenvironment that hampers the initiation of effective immune responses or blocks the functions of immune effector cells. Understanding how tumor cells escape from immune attack and favor immunosuppression is essential for the improvement of immune cell-based therapies and the development of rational combination approaches.

Donor lymphocyte infusion after allogeneic stem cell transplantation

Allogeneic stem cell transplantation (allo-SCT) is considered the cornerstone in the treatment of several malignant and not malignant hematological diseases. However, relapse of hematological disease after allo-SCT is considered the most challenging point in the field. The risk can be reduced through optimal patients, donor and disease selection before allo-SCT, but harnessing donor immune system is an appealing way to treat or avoid disease relapse. Donor lymphocyte infusion (DLI) is a simple and effective therapy after allo-SCT. In this paper, the efficacy of DLI will be analyzed in different hematological diseases, focusing also on their therapeutic or pre-emptive use.

The role of autologous and allogeneic stem cell transplantation in the management of indolent B-cell lymphoma

Despite improvements over the past decade in the overall survival of patients with indolent non-Hodgkin lymphomas, these lymphomas remain largely incurable with standard therapies. Immunochemotherapy with rituximab-based regimens has become a well-established standard of care in the primary and relapsed disease settings. The role of hematopoietic stem cell transplantation in indolent lymphoma has been defined by the adoption of this therapy largely in the relapse setting because randomized trials in the first-line setting have not shown survival advantages. Allogeneic stem cell transplantation has the possibility for cure because of the potential for immunologic graft-versus-lymphoma effect, but there are significant concerns regarding nonrelapse mortality. Autologous stem cell transplantation offers a safe treatment platform, but relapse remains a significant issue. The role of transplantation in the current treatment landscape of immunochemotherapy has not been conclusively proven, and randomized trials are lacking. This review summarizes the current relevant data regarding transplantation in indolent non-Hodgkin lymphoma and highlights the issues relevant to clinicians in the field.

Long-term survival outcomes of reduced-intensity allogeneic or autologous transplantation in relapsed grade 3 follicular lymphoma

Grade 3 follicular lymphoma (FL) has aggressive clinical behavior. To evaluate the optimal first transplantation approach in relapsed/refractory grade 3 FL patients, we compared the long-term outcomes after allogeneic (allo-) vs autologous hematopoietic cell transplantation (auto-HCT) in the rituximab era. A total of 197 patients undergoing first reduced-intensity conditioning (RIC) allo-HCT or first auto-HCT during 2000-2012 were included. Rituximab-naive patients were excluded. Allo-HCT recipients were younger, more heavily pretreated and had a longer interval between diagnosis and HCT. The 5-year probabilities of non-relapse mortality (NRM), relapse/progression, PFS and overall survival (OS) for auto-HCT vs allo-HCT groups were 4% vs 27% (P<0.001), 61% vs 20% (P<0.001), 36% vs 51% (P=0.07) and 59% vs 54% (P=0.7), respectively. On multivariate analysis, auto-HCT was associated with reduced risk of NRM (relative risk (RR)=0.20; P=0.001). Within the first 11 months post HCT, auto- and allo-HCT had similar risks of relapse/progression and PFS. Beyond 11 months, auto-HCT was associated with higher risk of relapse/progression (RR=21.3; P=0.003) and inferior PFS (RR=3.2; P=0.005). In the first 24 months post HCT, auto-HCT was associated with improved OS (RR=0.42; P=0.005), but in long-time survivors (beyond 24 months) it was associated with inferior OS (RR=3.6; P=0.04). RIC allo-HCT as the first transplant approach can provide improved PFS and OS, in long-term survivors.

High-dose chemotherapy followed by autologous and allogeneic hematopoietic stem cell transplantation in patients with follicular non-Hodgkin’s lymphoma in the rituximab era

High-dose chemotherapy in lymphomas, and mainly non-Hodgkin’s lymphomas, has been advancing since the 1970s. This therapeutic strategy is based on the supposed existence of a dose-response curve for cytotoxic agents. However, the available data are contradictory, so high-dose chemotherapy cannot be guaranteed as consolidation treatment for first-remission follicular lymphoma or diffuse large cell lymphoma. The objective of this paper is to review the current knowledge about high-dose chemotherapy followed by hematopoietic stem cell transplantation in follicular non-Hodgkin’s lymphoma. The published studies on follicular lymphoma after first remission, recurrent follicular lymphoma, and transformed follicular ­lymphoma were assessed together with the data available on diffuse large cell lymphoma. During analysis of the studies, difficulties were encountered in comparing studies due to the heterogeneous nature of the data. High-dose chemotherapy as consolidation treatment after first remission or in recurrent or refractory disease was also analyzed.

Allogeneic hematopoietic cell transplantation for indolent non-Hodgkin lymphoma: indications and outcomes

PURPOSE OF REVIEW

Allogeneic hematopoietic cell transplantation (HCT) can potentially cure indolent non-Hodgkin lymphoma (NHL). However, the optimal timing and indications remain unclear. Here, we review recent published reports on the subject and summarize our approach.

RECENT FINDINGS

Recent prospective clinical trials of allogeneic HCT in indolent NHL are marked by substantial variation in eligibility criteria, patient populations, and transplant approach. Nonetheless, several common themes are apparent. Indolent NHL is highly susceptible to immunologic graft-versus-lymphoma effects and relapse rates after allogeneic HCT are uniformly low. Allogeneic HCT early in the disease course produces the highest overall and progression-free survival, but also increases patient exposure to potential transplant-related complications such as chronic graft-versus-host disease. In contrast, allogeneic HCT can be reserved as a 'last resort' for patients who are refractory to conventional chemotherapy, delaying their exposure to graft-versus-host disease and other transplant-associated risks. No trials have directly addressed the optimal timing of allogeneic HCT in indolent NHL nor prospectively compared different transplant approaches.

SUMMARY

Excellent outcomes have been reported with allogeneic HCT for indolent NHL, both early and late in the disease course. The optimal timing of allogeneic HCT is unknown and depends heavily on patient preferences.

Allogeneic stem cell transplantation in patients with de novo diffuse large B-cell lymphoma who experienced relapse or progression after autologous stem cell transplantation: a Korea-Japan collaborative study

Patients with diffuse large B-cell lymphoma (DLBCL) who failed autologous stem cell transplantation (auto-SCT) generally have a poor prognosis. Allogeneic stem cell transplantation (allo-SCT) has been implemented to overcome this problem. We report clinical outcomes of allo-SCT in patients with de novo DLBCL who failed auto-SCT from four hospitals in Korea and Japan. Thirty patients were included. The median age was 39 (range, 22-59) years. The 5-year event-free survival (EFS) and overall survival (OS) after allo-SCT were 37.9 % and 42.6 %, respectively. There was only a single event beyond 12 months in the Kaplan-Meier curve of EFS. Non-relapse mortality (NRM) was reported in five patients (16.7 %). In the multivariate analysis, the risk factors for EFS were prior chemotherapy lines ≥ 5 (p = 0.010) and chemo-resistant disease (p = 0.007). The risk factors for OS were chemo-resistant disease (p = 0.024) and Eastern Cooperative Oncology Group performance status 2 (p = 0.005). NRM was associated with prior chemotherapy lines ≥ 5 (p = 0.042), chemo-resistant disease (p = 0.009), and poor performance status (p < 0.001). In conclusion, allo-SCT showed considerable efficacy in patients with DLBCL whose disease was relapsed or progressed after auto-SCT. Our data suggest that allo-SCT could be a viable treatment option if patients have fewer lines of prior chemotherapy, chemo-sensitive disease, and/or good PS.

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.

The outcome of reduced intensity allogeneic stem cell transplantation and autologous stem cell transplantation when performed as a first transplant strategy in relapsed follicular lymphoma: an analysis from the Lymphoma Working Party of the EBMT

Both auto-SCT and reduced intensity allo-SCT (RIST) are employed in the treatment of relapsed follicular lymphoma (FL). We have analysed the outcome of these two transplant procedures when used as a first transplant in this setting. We conducted a retrospective comparison of 726 patients who underwent an auto-SCT and 149 who underwent a RIST as a first transplant procedure for relapsed FL as reported to the Lymphoma Working Party of the European Bone Marrow Transplant. The non-relapse mortality (NRM) was significantly worse for patients undergoing a RIST (relative risk (RR) 4.0, P<0.001). The 1-year NRM was 15% for those undergoing a RIST compared with 3% for those undergoing an auto-SCT. Disease relapse or progression were significantly worse for those receiving an auto-SCT (RR 3.1, P<0.001). Patients undergoing a RIST had a 5-year relapse rate of 20% compared with 47% for those undergoing an auto-SCT. The PFS at 5 years was 57% for patients receiving a RIST compared with 48% for those receiving an auto-SCT. There was no significant difference in OS between the two groups. RIST is associated with a higher NRM and lower relapse rate in patients with relapsed FL.

Efficacy of adoptive immunotherapy with donor lymphocyte infusion in relapsed lymphoid malignancies

Aims: There is a perceived benefit associated with the administration of donor lymphocyte infusion (DLI) in patients with lymphoid malignancies relapsing after allogeneic hematopoietic cell transplantation. However, it is unclear if and how this benefit varies according to specific diseases. Because administration of DLI is not universally effective and could be associated with significant toxicities resulting in morbidity and mortality, it is imperative to identify cases where benefits outweigh harms of the procedure. Materials & methods: We conducted a systematic review of the published literature and extracted and pooled data independently for each disease cohort: acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), multiple myeloma (MM), non-Hodgkin’s lymphoma (NHL) and Hodgkin’s lymphoma (HL). Results: In summary, 39 studies met inclusion criteria. The pooled proportion (95% CI) for complete response was 27% (16–40) in ALL, 55% (15–92) in CLL, 26% (19–33) in MM, 52% (33–71) in NHL and 37% (20–56) in HL. Conclusion: Complete response rates appear higher when DLI is used for relapsed CLL and lymphomas (NHL and HL), and less pronounced in ALL or MM. Absence of data pertaining to disease-specific prognostic determinants, such as adverse genetic or molecular abnormalities, or quantitative disease burden when applicable, limit our ability to identify cases in whom benefits from DLI outweigh risks associated with the procedure within a particular disease.

Cellular therapy following allogeneic stem-cell transplantation

Allogeneic hematopoietic stem-cell transplantation (HSCT) is the most effective approach for many patients with hematologic malignancies. Unfortunately, relapse remains the most common cause of death after allogeneic HSCT, and the prognosis of relapsed disease is poor for most patients. Induction of a graft-versus-leukemia (GVL), or graft-versus-tumor, effect through the use of donor leukocyte infusion (DLI), or donor lymphocyte infusion, has been remarkably successful for relapsed chronic myelogenous leukemia. Unfortunately, response to DLI in other hematologic malignancies is much less common and depends on many factors including histology, pace and extent of relapse, and time from HSCT to relapse. Furthermore, graft-versus-host disease (GVHD) is common after DLI and often limits successful immunotherapy. Ultimately, manipulations to minimize GVHD while preserving or enhancing GVL are necessary to improve outcomes for relapse after allogeneic HSCT.

Nonmyeloablative allogeneic stem cell transplantation for non-hodgkin lymphoma

Non-Hodgkin lymphomas constitute a heterogeneous group of hematologic malignancies with varying aggressiveness and many therapeutic options. Nonmyeloablative (NMA) conditioning has been the cornerstone of allogeneic adoptive immunotherapy for these diseases. This approach utilizes a reduced intensity preparative regimen to achieve engraftment with little toxicity. This allows for development of the immune graft-versus-lymphoma effect. Results depend on the histologic type of lymphoma, prognostic factors, patient characteristics, and chemosensitivity. For follicular lymphomas, NMA transplants are highly effective in patients with refractory or recurrent disease after the best chemoimmunotherapy available and who have a matched sibling or unrelated donor. In mantle cell lymphoma, autologous stem cell transplants are generally ineffective for patients with recurrent disease; we reported 6-year actuarial progression-free survival rate of 46%, using NMA allogeneic transplants. The indications of NMA transplants for diffuse large B-cell lymphoma and T-cell lymphomas are controversial; success has been reported in selected high-risk patients and those relapsing after an autologous transplantation who have chemosensitive disease. Considerations for the conditioning regimen, donor source, graft-versus-host disease prophylaxis, donor lymphocyte infusion, and relapse prevention methods are reviewed.

Changing role of stem cell transplantation in follicular lymphoma

Patients with advanced follicular lymphoma (FL) have numerous treatment options, including observation, radiotherapy, single-agent or combination chemotherapy, mAbs, and radioimmunoconjugates. These therapies can extend progression-free survival but none can provide a cure. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curable therapy for FL, with the field shifting more toward the use of reduced-intensity conditioning regimens because of the lower associated nonrelapse mortality compared with myeloablative regimens. However, GVHD and infection are still problematic in the allo-HSCT population. Autologous HSCT (auto-HSCT) confers high response rates and prolongs progression-free survival in relapsed patients who are chemosensitive, and an increasing amount of data suggest that auto-HSCT may be curative if offered to relapsed patients who are not heavily pretreated. Auto-HSCT has no role as consolidation therapy for patients in first remission based on the results from 3 large randomized trials. Novel conditioning regimens with radioimmunoconjugates have been used in both auto-HSCT and allo-HSCT regimens and results have shown efficacy even in chemorefractory patients. Therefore, with the exception of patients in first remission, the optimal timing for HSCT remains controversial. However, the outcomes seen after auto-HSCT and allo-HSCT continue to improve, and HSCT represents a treatment modality that should be considered in all FL patients, especially while their disease remains chemoresponsive.

Controversies and recent advances in hematopoietic cell transplantation for follicular non-hodgkin lymphoma

Commonly designated as an indolent non-Hodgkin lymphoma, follicular lymphoma (FL) presents with striking pathobiological and clinical heterogeneity. Initial management strategies for FL have evolved to involve combination chemoimmunotherapy and/or radio-immunoconjugates. Unfortunately even with the best available nontransplant treatment, which nowadays results in higher frequency of response, FL remains incurable. Although considered a feasible therapeutic option, the use of hematopoietic cell transplantation (HCT) remains controversial. The appropriate timing, graft source, and intensity of HCT conditioning regimens in FL are often matters of debate. Herein we review the available published data pertaining to the use of autologous or allogeneic HCT in patients with FL across different stages of the disease, discuss major recent advances in the field, and highlight avenues for future research. The current literature does not support a role of HCT for FL in first remission, but in the relapsed setting autologous HCT remains appropriate for patients with early chemosensitive relapses, while allogeneic transplantation remains the sole curative modality for this disease, in relatively younger patients without significant comorbidities.

Genetic modification of human T lymphocytes for the treatment of hematologic malignancies

Modern chemotherapy regimens and supportive care have produced remarkable improvements in the overall survival of patients with hematologic malignancies. However, the development of targeted small molecules, monoclonal antibodies, and biological therapies that demonstrate greater efficacy and lower toxicity remains highly desirable in hematology, and oncology in general. In the context of biological therapies, T-lymphocyte based treatments have enormous potential. Donor lymphocyte infusion in patients relapsed after allogeneic hematopoietic stem cell transplant pioneered the concept that T lymphocytes can effectively control tumor growth, and this was then followed by the development of cell culture strategies to generate T lymphocytes with selective activity against tumor cells. Over the past decade, it has become clear that the adoptive transfer of ex vivo expanded antigen-specific cytotoxic T lymphocytes promotes sustained antitumor effects in patients with virus-associated lymphomas, such as Epstein-Barr virus related post-transplant lymphomas and Hodgkin's lymphomas. Because of this compelling clinical evidence and the concomitant development of methodologies for robust gene transfer to human T lymphocytes, the field has rapidly evolved, offering new opportunities to extend T-cell based therapies. This review summarizes the most recent biological and clinical developments using genetically manipulated T cells for the treatment of hematologic malignancies.

T cells raised against allogeneic HLA-A2/CD20 kill primary follicular lymphoma and acute lymphoblastic leukemia cells

T cells mediating a graft-versus-leukemia/lymphoma effects without causing graft-versus-host disease would greatly improve the safety and applicability of hematopoietic stem cell transplantation. We recently demonstrated that highly peptide- and HLA-specific T cells can readily be generated against allogeneic HLA-A*02:01 in complex with a peptide from the B cell-restricted protein CD20. Here, we show that such CD20-specific T cells can easily be induced from naïve precursors in cord blood, demonstrating that they do not represent cross-reactive memory cells. The cells displayed high avidity and mediated potent cytotoxic effects on cells from patients with the CD20(pos) B cell malignancies follicular lymphoma (FL) and acute lymphoblastic leukemia (ALL). However, the cytotoxicity was consistently lower for cells from two of the ALL patients. The ALL cells that were less efficiently killed did not display lower surface expression of CD20 or HLA-A*02:01, or mutations in the CD20 sequence. Peptide pulsing fully restored the levels of cytotoxicity, indicating that they are indeed susceptible to T cell-mediated killing. Adoptive transfer of CD20-specific T cells to an HLA-A*02:01(pos) patient requires an HLA-A*02:01(neg) , but otherwise HLA identical, donor. A search clarified that donors meeting these criteria can be readily identified even for patients with rare haplotypes. The results bear further promise for the clinical utility of CD20-specific T cells in B cell malignancies.

Allogeneic stem cell transplantation in follicular lymphoma

Myeloablative allogeneic transplantation in follicular lymphoma has been found to be particularly effective in patients with relapsed disease and an inadequate bone marrow reserve or massive bone marrow involvement. Allogeneic transplantation carries the promise of long-term disease control by graft-versus-lymphoma immunity but is associated with a 30%-40% risk of transplant-related mortality. Nonmyeloablative stem cell transplantation exploits the graft-versus-lymphoma effect without the attendant toxicity of myeloablative conditioning. The results of several recent reports suggest that it has a high likelihood of resulting in long-term disease-free survival in patients up to 70 years of age with a good performance status, chemotherapy-sensitive disease, and HLA-matched sibling donors. At The University of Texas MD Anderson Cancer Center, the standard NST conditioning regimen for patients with follicular lymphoma is fludarabine, cyclophosphamide, and rituximab. This regimen results in a transplantation-related mortality rate of 10%, and 85% of patients are alive without disease at 8 years. In this article, we discuss the current issues in NST for follicular lymphoma, including chemosensitivity, conditioning intensity, graft-versus-host disease, donor lymphocyte infusion's role, and ongoing strategies to treat refractory disease.

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

This article focuses on the recent evolution of novel conditioning regimens in combination with adoptive cellular therapy in the allogeneic transplant setting for hematologic malignancies. Building on data from animal models, the field of allogeneic transplantation is undergoing a paradigm shift toward immunosuppressive regimens with less toxicity that allow donor hematopoietic engraftment in order to provide a graft-versus-tumor effect as the primary goal of transplantation, rather than chemoablation. In addition, the strategies described in this article, including the use of T-cell subsets as adoptive therapy, will apply to a much broader pool of patients than traditional transplant approaches, thereby allowing more patients with life-limiting illnesses, previously deemed ineligible, to pursue therapy with curative intent.

Allogeneic transplantation for lymphoma: long-term outcome

PURPOSE OF REVIEW

In the last 20 years, allogeneic stem cell transplantation (alloSCT) has been increasingly applied in lymphoma patients, due to the shift towards reduced intensity and nonmyeloablative conditioning. This review reports on the most significant long-term results of allografted lymphoma patients coming from both prospective studies and retrospective analyses.

RECENT FINDINGS

AlloSCT can cure 40-60% of aggressive B-cell lymphomas, but an unfavourable outcome has been observed in case of chemorefractory and active disease at the time of allografting. Indolent lymphoma displays the best outcome, and reduced-intensity alloSCT should be always considered in patients relapsing after an autologous SCT and in cases of chemorefractory disease. Most recent findings in Hodgkin's and T-cell lymphoma are also encouraging.

SUMMARY

Although the nonrelapse mortality has been reduced and survival curves show a plateau, the analysis of the long-term outcome reveals that a significant proportion of patients still experiences disease relapse and delayed morbidity and mortality. At the best of our knowledge, the process of decision-making should be based on lymphoma subtype, chemosensitivity, disease status and patient comorbidities at the time of allografting. To answer some of the still open questions, physicians should try to improve the enrolment of patients in multicentre prospective clinical trials.

Reduced-intensity allogeneic transplantation provides high event-free and overall survival in patients with advanced indolent B cell malignancies: CALGB 109901

Cancer and Leukemia Group B conducted a phase II study to evaluate the safety and efficacy of a reduced-intensity conditioning regimen with allogeneic transplantation to treat patients with recurrent low-grade B cell malignancies. Patients over age 18 with a diagnosis of relapsed, chemotherapy-sensitive disease underwent transplantation with a matched sibling donor, and conditioning with cyclophosphamide (1 g/m(2)/day × 3) and fludarabine phosphate (25 mg/m(2)/day × 5). Graft-versus-host prophylaxis included cyclosporine or tacrolimus plus low-dose methotrexate. Forty-four evaluable patients with a median age of 53 and median of 2 prior regimens were accrued. Sixteen patients had follicular non-Hodgkin lymphoma and 28 had histologies including 7 indolent B cell lymphomas, 4 mantle cell, 15 chronic lymphocytic leukemia (CLL), and 2 prolymphocytic leukemia (PLL) patients. The 6-month treatment-related mortality (TRM) was 2.4% and 3-year TRM was 9%. Three-year event-free and overall survival were 0.75 and 0.81 for the follicular patients, 0.59 and 0.71 for the CLL/PLL patients, and 0.55 and 0.64 for the other histologies. The incidence of grade II-IV acute graft-versus-host disease (GVHD) was 29%, and extensive chronic GVHD was 18%. This report demonstrates that allogeneic sibling transplantation with a reduced-intensity conditioning regimen is safe and efficacious for patients with advanced indolent B cell malignancies enrolled on a Cooperative Group study.

NCI First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation: Report from the Committee on Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation

Relapse is a major cause of treatment failure after allogeneic hematopoietic stem cell transplantation (alloHSCT). Treatment options for relapse have been inadequate, and the majority of patients ultimately die of their disease. There is no standard approach to treating relapse after alloHSCT. Withdrawal of immune suppression and donor lymphocyte infusions are commonly used for all diseases; although these interventions are remarkably effective for relapsed chronic myelogenous leukemia, they have limited efficacy in other hematologic malignancies. Conventional and novel chemotherapy, monoclonal antibody therapy, targeted therapies, and second transplants have been utilized in a variety of relapsed diseases, but reports on these therapies are generally anecdotal and retrospective. As such, there is an immediate need for well-designed, disease-specific trials for treatment of relapse after alloHSCT. This report summarizes current treatment options under investigation for relapse after alloHSCT in a disease-specific manner. In addition, recommendations are provided for specific areas of research necessary in the treatment of relapse after alloHSCT.

The role of rituximab in autologous and allogeneic hematopoietic stem cell transplantation for non-Hodgkin's lymphoma

The addition of rituximab to chemotherapy has substantially changed the treatment strategies for patients with B-cell lymphomas. Rituximab, combined with standard chemotherapy regimens, shows consistently improved results compared with chemotherapy alone and has been extensively employed in both newly diagnosed and relapsed patients with B-cell lymphoma. Because of its low toxicity profile and its potent antilymphoma activity mediated through direct apoptotic and indirect effector mechanisms, rituximab also has been actively incorporated into stem cell transplantation (SCT) protocols to attain a state of minimal disease, provide a safe and effective method for in vivo purging prior to autologous SCT, and promote graft-versus-lymphoma effects in allogeneic SCT. This review compiles the still immature but rapidly growing data on this combined modality.

T-cell-depleted reduced-intensity transplantation followed by donor leukocyte infusions to promote graft-versus-lymphoma activity results in excellent long-term survival in patients with multiply relapsed follicular lymphoma

PURPOSE

Follicular lymphoma (FL) is an indolent disorder that is treatable but considered incurable with chemotherapy alone. The curative potential of allogeneic transplantation using conventional myeloablative conditioning has been demonstrated, but this approach is precluded in the majority of patients with FL because of excessive toxicity. Thus, reduced-intensity conditioning regimens are being explored.

PATIENTS AND METHODS

This study reports the outcome of 82 consecutive patients with FL who underwent transplantation using fludarabine, melphalan, and alemtuzumab for in vivo T-cell depletion. Patients were heavily pretreated, having received a median of four lines of prior therapy, and 26% had experienced treatment failure with previous autologous transplantation. Median patient age was 45 years, and 52% of patients received stem cells from unrelated donors.

RESULTS

With a median follow-up time of 43 months, the nonrelapse mortality was 15% at 4 years (8% for sibling and 22% for unrelated donor transplantations), acute grade 2 or 3 graft-versus-host disease (GVHD) occurred in 13%, and the incidence of extensive chronic GVHD was only 18%. Although relapse risk was 26%, this was significantly reduced where mixed chimerism had been converted to full donor chimerism by the use of donor lymphocyte infusion (DLI; P = .03). In addition, 10 (77%) of 13 patients given DLI for relapse after transplantation experienced remission, with nine of these responses being sustained. Current progression-free survival at 4 years was 76% for the whole cohort (90% for those with sibling donors and 64% for those with unrelated donors).

CONCLUSION

The excellent long-term survival with associated low rates of GVHD and the frequency and durability of DLI responses make this an extremely encouraging strategy for the treatment and potential cure of FL.

Role of donor lymphocyte infusions in relapsed hematological malignancies after stem cell transplantation revisited

BACKGROUND

Treatment of relapsed hematological malignancies after an allogeneic peripheral blood stem cell transplant (SCT) is challenging. Donor lymphocyte infusion (DLI) from the stem cell donor is an attractive clinical option to salvage this group of patients.

METHODS

We reviewed the important studies looking at donor lymphocyte infusion as a therapy for the treatment of hematological disorders that are either refractory to or have relapsed after allogeneic SCT.

RESULTS

The response to DLI is dependent upon type of disease, dose of infused lymphocytes, and the development of graft vs. host disease (GvHD). The best response rates are seen in patients with chronic myeloid leukemia (CML) followed by patients with lymphomas, multiple myeloma and acute leukemias, respectively. The responses in patients with CML are durable whereas durable responses in other diseases are rare.

CONCLUSIONS

Given the development of new drugs to treat some hematological diseases, DLI has taken a backseat. New modalities to target the infused cells to the tumor and new approaches to reduce GvHD that will augment the graft vs. leukemia/lymphoma (GvL) effect and decrease the injury to normal host tissues need to be developed. Understanding the factors and mechanisms that differentiate the GvL effect from GvHD will help in the development of newer treatment modalities.

Multimer technologies for detection and adoptive transfer of antigen-specific T cells

Identification and purification of antigen-specific T cells without altering their functional status are of high scientific and clinical interest. Staining with major histocompatibility complex (MHC)-peptide multimers constitutes a very powerful method to study antigen-specific T-cell subpopulations, allowing their direct visualization and quantification. MHC-peptide multimers, such as dimers, tetramers, pentamers, streptamers, dextramers and octamers have been used to evaluate the frequency of CD8(+) T cells, specific for tumor/leukemia-associated antigens as well as for viral antigens, e.g., CMVpp65 and EBV-EBNA. Moreover, MHC-peptide multimers have been used for rapid and efficient ex vivo isolation and expansion of T cells. A recent development in the field of MHC-peptide multimers led to the purification of CD8(+) T cells specific for leukemia antigens. This might help to select leukemia-specific donor lymphocyte infusions (DLIs), thus allowing dissection of the noxious graft-versus-host disease (GvHD) from beneficial anti-viral and even anti-leukemic effects. This review covers different types of MHC-peptide multimers and their applications, as well as the impact that multimers might have on further development of DLIs.

Treatment of lymphoma with adoptively transferred T cells

BACKGROUND

Chemotherapy-resistant lymphomas can be cured with allogeneic hematopoietic cell transplantation, demonstrating the susceptibility of these tumors to T cell mediated immune responses. However, high rates of transplant-related morbidity and mortality limit this approach. Efforts have, therefore, been made to develop alternative T cell based therapies, and there is growing evidence that adoptive therapy with T cells targeted to lymphoma-associated antigens may be a safe and effective new method for treating this group of diseases.

OBJECTIVE/METHODS

We review publications on adoptive therapy with ex vivo expanded T cells targeting viral antigens, as well as genetically modified autologous T cells, as strategies for the treatment of lymphoma, with the goal of providing an overview of these approaches.

RESULTS/CONCLUSIONS

Epstein-Barr virus specific T cell therapy is an effective and safe method of treating Epstein-Barr virus associated lymphomas; however, most lymphoma subtypes do not express EBV antigens. For these diseases, adoptive immunotherapy with genetically modified T cells expressing chimeric T cell receptors targeting lymphoma-associated antigens such as CD19 and CD20 appears to be a promising alternative. Recent innovations including enhanced co-stimulation, exogenous cytokine administration and use of memory T cells promise to overcome many of the limitations and pitfalls initially encountered with this approach.

Immunotherapy for epstein-barr virus-related lymphomas

Latent EBV infection is associated with several malignancies, including EBV post-transplant lymphoproliferative disorders (LPD), Hodgkin and non-Hodgkin lymphomas, nasopharyngeal carcinoma and Burkitt lymphoma. The range of expression of latent EBV antigens varies in these tumors, which influences how susceptible the tumors are to immunotherapeutic approaches. Tumors expressing type III latency, such as in LPD, express the widest array of EBV antigens making them the most susceptible to immunotherapy. Treatment strategies for EBV-related tumors include restoring normal cellular immunity by adoptive immunotherapy with EBV-specific T cells and targeting the malignant B cells with monoclonal antibodies. We review the current immunotherapies and future studies aimed at targeting EBV antigen expression in these tumors.

Construction and preclinical evaluation of an anti-CD19 chimeric antigen receptor

T cells can be engineered to express the genes of chimeric antigen receptors (CARs) that recognize tumor-associated antigens. We constructed and compared 2 CARs that contained a single chain variable region moiety that recognized CD19. One CAR contained the signaling moiety of the 4-1BB molecule and the other did not. We selected the CAR that did not contain the 4-1BB moiety for further preclinical development. We demonstrated that gammaretroviruses encoding this receptor could transduce human T cells. Anti-CD19-CAR-transduced CD8+ and CD4+ T cells produced interferon-gamma and interleukin-2 specifically in response to CD19+ target cells. The transduced T cells specifically killed primary chronic lymphocytic leukemia (CLL) cells. We transduced T cells from CLL patients that had been previously treated with chemotherapy. We induced these T cells to proliferate sufficiently to provide enough cells for clinical adoptive T cell transfer with a protocol consisting of an initial stimulation with an anti-CD3 monoclonal antibody (OKT3) before transduction followed by a second OKT3 stimulation 7 days after transduction. This protocol was successfully adapted for use in CLL patients with high peripheral blood leukemia cell counts by depleting CD19+ cells before the initial OKT3 stimulation. In preparation for a clinical trial that will enroll patients with advanced B cell malignancies, we generated a producer cell clone that produces retroviruses encoding the anti-CD19 CAR, and we produced sufficient retroviral supernatant for the proposed clinical trial under good manufacturing practice conditions.

Low nonrelapse mortality and prolonged long-term survival after reduced-intensity allogeneic stem cell transplantation for relapsed or refractory diffuse large B cell lymphoma: report of the Société Française de Greffe de Moelle et de Thérapie Cellulaire

Patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) have a very poor prognosis. However, they may achieve long-term survival by undergoing allogeneic stem cell transplantation (SCT). The purpose of this study was to assess the outcome of all adult patients with DLBCL whose treatment included a reduced-intensity conditioning (RIC) regimen for allogeneic SCT and whose data were reported in the French Society of Marrow Transplantation and Cellular Therapy registry. Sixty-eight patients (median age: 48 years) were transplanted from October 1998 to January 2007. They had received a median of 2 regimens of therapy prior to allogeneic SCT, and 54 (79%) had already undergone SCT. Prior to transplantation, 32 patients (47%) were in complete remission (CR). For all patients but 1, conditioning regimens were based on fludarabine (Flu), which was combined with other chemotherapy drugs in 50 cases (74%) and with total body irradiation (TBI) in 17 (25%). For 56 patients (82%), the donor was an HLA-matched sibling, and peripheral blood was the most widely used source of stem cells (57 patients, 84%). With a median follow-up of 49 months, estimated 2-year overall survival (OS), progression-free survival (PFS), and the cumulative incidence of relapse were 49%, 44%, and 41%, respectively. The 1-year cumulative incidence of nonrelapse mortality (NRM) was 23%. According to multivariate analysis, the patients in CR before transplantation had a significantly longer PFS and a lower CI of relapse than patients transplanted during partial remission or stable or progressive disease. These results suggest that reduced-intensity allergenic transplantation is an attractive therapeutic option for patients with high-risk DLBCL.

Role of hematopoietic stem cell transplant in the management of follicular lymphoma

Despite decades of published data regarding the application of autologous and allogeneic stem cell transplant in patients with follicular lymphoma, there remain no uniform indications for its use in this disease. Autologous transplant has been shown to lead to longer progression-free survival times in randomized trials when compared with postremission interferon-based chemoimmunotherapy. However, the development of rituximab and its use in frontline, salvage, and maintenance therapy complicates the decision to pursue autologous transplant, a modality developed prior to the advent of anti-CD20 monoclonal antibodies. Allogeneic transplant offers the advantages of lymphoma-free grafts and the immunologic graft-versus-lymphoma effect. These factors may confer the possibility of long-term remission, though historically they have been accompanied by high rates of upfront morbidity and mortality, especially in heavily pretreated patients with a poor performance status or chemotherapy-refractory disease. Advances in patient selection, human leukocyte antigen (HLA) matching, conditioning regimens, and supportive care have reduced transplant-related mortality and the incidence of graft-versus-host disease. Recently published data focus on the incorporation of rituximab and radioimmunoconjugates prior to, during, and following autologous transplant. Furthermore, reduced-intensity allogeneic stem cell transplantation has increasingly been used for relapsed follicular lymphoma patients with comorbidities or advanced age. Several recent reports suggest that reduced-intensity regimens may provide a high likelihood of long-term disease-free survival for patients up to 70 years of age with a good performance status, chemotherapy-sensitive disease, and HLA-matched sibling donors. Such patients with relapsed disease should be referred to a transplant center that can enroll them in one of the forthcoming clinical trials that aim to confirm these outcomes.

Induction of tumor immunity following allogeneic stem cell transplantation

The curative potential of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for many hematologic malignancies derives in large part from reconstitution of normal donor immunity and the development of a potent graft-versus-leukemia (GVL) immune response capable of rejecting tumor cell in vivo. Elucidation of the mechanisms of GVL by studies of animal models and analysis of clinical data has yielded important insights into how clinically effective tumor immunity is generated following allo-HSCT. These studies have identified NK cells and B cells as well as T cells as important mediators of the GVL response. A variety of antigenic targets of the GVL response have also been identified, and include tumor-associated antigens as well as minor histocompatibility antigens. The principles of effective GVL can now be applied to the development of novel therapies that enhance the therapeutic benefit of allogeneic HSCT while minimizing the toxicities associated with treatment. Moreover, many components of this approach that result in elimination of tumor cells following allogeneic HSCT can potentially be adapted to enhance the effectiveness of tumor immunity in the autologous setting.

Favorable Long-Term Survival After Reduced-Intensity Allogeneic Transplantation for Multiple-Relapse Aggressive Non-Hodgkin's Lymphoma

Purpose

The role of allogeneic transplantation with reduced-intensity conditioning in diffuse large B-cell lymphoma (DLBCL) is currently unclear, with relatively little published data. We report the outcome of reduced-intensity transplantation (RIT) in a cohort of 48 consecutive patients with relapsed/refractory DLBCL (30 patients with de novo disease and 18 patients with transformed follicular lymphoma) who underwent transplantation with an alemtuzumab-containing regimen, with a median follow-up of 52 months.

Patients and Methods

Patients had experienced treatment failure with a median of five lines of prior therapy, including autologous transplantation in 69%, and 17% of patients were chemotherapy refractory at transplantation. Median age was 46 years, and 38% of patients had matched/mismatched unrelated donors. Conditioning was with alemtuzumab, fludarabine, and melphalan, and additional graft-versus-host disease (GVHD) prophylaxis was with cyclosporine.

Results

All patients were successfully engrafted. Only 17% of patients developed grade 2 to 4 acute GVHD, with 13% experiencing extensive chronic GVHD. Four-year estimated nonrelapse mortality was 32%, and relapse risk was 33%. Twelve patients received donor lymphocyte infusions ± chemoimmunotherapy for relapse, and five patients obtained durable remissions, giving current progression-free survival (PFS) and overall survival (OS) rates at 4 years of 48% and 47%, respectively. Patients who had chemotherapy-sensitive disease before RIT had current PFS and OS rates at 4 years of 55% and 54%, respectively. Chemotherapy-refractory patients had a poor outcome.

Conclusion

The encouraging survival rates with extended follow-up suggest a role for RIT in chemotherapy-sensitive relapsed DLBCL, even in patients who have previously experienced treatment failure with autologous transplantation. Future studies will be required to determine whether any subset of patients with relapsed DLBCL should be considered for RIT versus autologous transplantation.

Allogeneic stem cell transplantation in follicular lymphoma: recent progress and controversy

Allogeneic stem cell transplantation (allo HCT) is a curative treatment for follicular lymphoma, but is hampered by a relatively high treatment-related mortality and by difficulties in identifying high-risk groups for whom transplant is warranted. Results with myeloablative conditioning have improved, but the field has shifted largely to reduced-intensity conditioning and non-myeloablative transplantation, though morbidity and mortality are also substantial. Some groups have investigated T cell–depleted transplantation, which results in a low rate of chronic graft-versus-host disease (GVHD) and, in most studies, excellent rates of disease control. Overall, outcome after alloHCT for follicular lymphoma correlates more with disease status, with performance status and with comorbidities than with any particular conditioning regimen used. For patients with chemotherapy-sensitive disease, the treatment-related mortality has stabilized in the 15% to 20% range and, depending on the method of GVHD prophylaxis and the donor type, there is an additional 20% to 60% incidence of chronic GVHD. For patients with chemotherapy-refractory disease, both treatment-related mortality and recurrence rates are much higher, but their prognosis is dismal with other treatments and some may be cured, particularly with myeloablative transplants. Ongoing studies focus on improving conditioning regimens, on prevention of disease recurrence and on decreasing chronic GVHD.

Follicular lymphoma: clinical features and treatment

Follicular lymphoma (FL) is the second most common subtype of non-Hodgkin's lymphoma (NHL) in the Western world, constituting up to 22% of the total cases of NHL. This article describes the clinical characteristics of FL, its prognostic indicators, and its clinical course, including transformation to an aggressive lymphoma. Primary management and therapies for recurrent FL are detailed.

Donor lymphocyte infusions: the long and winding road: how should it be traveled?

Donor lymphocyte infusions (DLI) often are used after allo-SCT to augment the graft-versus-tumor effect. Timing of infusion varies according to indication, for example to treat tumor recurrence, as a planned strategy to prevent disease relapse in the setting of T-cell-depleted grafts or non-myeloablative conditioning regimens, or as a method to convert mixed to full donor chimerism. The optimal strategy of timing, use of cytotoxic conditioning, cell dose and cell product composition, and so on, for DLI administration remains unclear. Despite varied techniques, DLI may lead to 3-year disease-free survivals (DFS) in excess of 60% for all CML patients and approach 90% in patients with only molecular or cytogenetic relapse. Other hematologic malignancies appear much less responsive, as less than 50% of patients respond and provide, at best, 3-year DFS rates of 20-50%. Multiple myeloma patients have overall response rates of 40-45% after DLI, suggesting benefit in relapsed disease, but limited experiences for diseases such as Hodgkin's lymphoma, myelodysplasia and ALL preclude recommendations for use of DLI at this time. Regardless of the indication, treatment-related mortality after DLI is 5-20% and more than one-third of patients will develop acute and/or chronic GVHD after DLI. The risks of these complications appear related, in part, to donor source, cell dose and therapy prior to DLI. Although there are no definitive answers, the information gleaned from published literature suggests that DLI should be administered early after relapse or as a prophylactic strategy in patients receiving T-cell-depleted grafts, and patients with bulky or aggressive disease may benefit from disease reduction prior to DLI.