Allogeneic hematopoietic cell transplantation after fludarabine and 2 Gy total body irradiation for relapsed and refractory mantle cell lymphoma

Mantle cell lymphoma: 2013 Update on diagnosis, risk-stratification, and clinical management

DISEASE OVERVIEW

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood, and bone marrow with a short remission duration to standard therapies and a median overall survival of 4-5 years.

DIAGNOSIS

Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t(11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma.

RISK STRATIFICATION

The Mantle Cell Lymphoma International Prognostic Index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median overall survival (OS) for the low risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 months and 29 months for the high risk group.

RISK-ADAPTED THERAPY

For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytarabine containing regimen ± autologous stem cell transplantation should be considered. For older MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor) or lenalidamide (anti-angiogenesis) are approved agents. Clinical trials with Ibruitinib (Bruton's Tyrosine Kinase inhibitor) or Idelalisib (PI3K inhibitor) have demonstrated excellent clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients.

Hematopoietic cell transplantation for mantle cell lymphoma: predictive value of pretransplant positron emission tomography/computed tomography and bone marrow evaluations for outcomes

BACKGROUND

The prognostic roles of 18F-fludeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging and marrow involvement evaluation on outcomes following autologous and allogeneic hematopoietic cell transplantation (HCT) for mantle cell lymphoma (MCL) are uncertain and require more data.

PATIENTS AND METHODS

We categorized 66 patients with MCL who received HCT (38 autologous and 28 allogeneic) on the basis of pre-HCT residual disease (RD) status as assessed by marrow MCL morphology and flow/molecular analysis and PET/CT imaging to RD positive (RD(+)) (either or both measures positive) and RD(-) (both negative). We analyzed the predictive value of these RD detection methods on transplant outcomes.

RESULTS

The 2-year relapse rate after autograft was significantly higher in pre-HCT RD(+) patients (46% [95% CI 16-77%]) than in patients who were RD(-) (19% [95% CI 0-42%]; P = .02), leading to worse 5-year disease-free survival (DFS) in RD(+) patients (46% [95% CI 14%-73%] vs. 68% [95% CI 33-87%], P = .04). In multivariate analysis, RD(+) status was associated with a reduction in DFS (hazard ratio, 5.6; P = .02). Most allogeneic HCT recipients had advanced disease and most were RD(+) (12 PET/CT(+); 5 marrow-positive). The 5-year DFS and relapse rates after allogeneic HCT were 34% and 25% for all patients and 40% and 33% for RD(+) recipients, suggesting that active disease at the time of allograft does not preclude long-term remissions in advanced MCL.

CONCLUSION

Both autologous and allogeneic HCT lead to promising long-term survival. RD detected prior to autograft was associated with increased relapse and worse 5 year DFS. Allograft recipients had favorable long-term outcomes even in presence of pre-HCT detectable disease.

Management of relapsed/refractory mantle cell lymphoma: a review of current therapeutic strategies

Abstract Despite recent advances in therapeutic strategies, a large proportion of patients with mantle cell lymphoma (MCL) experience progression after first-line treatment. Several attempts have been made to assess the role of different therapies for the treatment of patients with relapsed/refractory mantle cell lymphoma; however, a consensus on the optimal therapeutic strategy for each individual patient has not been reached. Overall, clinical evidence from phase II studies shows that high-dose cytarabine containing regimens, stem cell transplant and different biological agents all have promising activity with acceptable safety profiles. Therefore, these therapies can represent suitable treatment options for patients with relapsed/refractory MCL. Among different biological agents, at present only temsirolimus has been tested in a phase III study. This review considers available evidence on the management of relapsed/refractory MCL as discussed during a consensus meeting on the current treatment strategies for MCL.

Clinical practice guidelines for diagnosis, treatment, and follow-up of patients with mantle cell lymphoma. Recommendations from the GEL/TAMO Spanish Cooperative Group

Mantle cell lymphoma (MCL) is considered a distinct type of B-cell lymphoma genetically characterized by the t(11;14) translocation and cyclin D1 overexpression. There is also a small subset of tumors negative for cyclin D1 expression that are morphologically and immunophenotypically indistinguishable from conventional MCL. Although in the last decades, the median overall survival of patients with MCL has improved significantly, it is still considered as one of the poorest prognoses diseases among B-cell lymphomas. Election of treatment for patients with MCL is complex due to the scarcity of solid evidence. Current available data shows that conventional chemotherapy does not yield satisfactory results as in other types of B-cell lymphomas. However, the role of other approaches such as autologous or allogenic stem cell transplantation, immunotherapy, the administration of consolidation or maintenance schedules, or the use of targeted therapies still lack clear indications. In view of this situation, the Spanish Group of Lymphomas/Autologous Bone Marrow Transplantation has conducted a series of reviews on different aspects of MCL, namely its diagnosis, prognosis, first-line and salvage treatment (both in young and elderly patients), new targeted therapies, and detection of minimal residual disease. On the basis of the available evidence, a series of recommendations have been issued with the intention of providing guidance to clinicians on the diagnosis, treatment, and monitoring of patients with MCL.

Allogeneic hematopoietic cell transplantation for diffuse large B cell lymphoma: who, when and how?

Despite overall improvements in outcomes of patients with diffuse large B cell lymphoma (DLBCL), ∼30-40% of patients develop relapsed or refractory disease. For patients with chemo refractory disease, or recurrent disease following autologous hematopoietic SCT (auto-HCT), the prognosis is poor, with no consensus on the optimal therapy. Currently, owing to the graft vs lymphoma effect, hematopoietic allogeneic hematopoietic cell transplantation (allo-HCT) is the only potentially curative option for such patients. In addition, many patients who are considered today for auto-HCT actually have a low likelihood of benefit. For example, a patient with prior rituximab exposure who relapses within 1 year of diagnosis and has a second-line age-adjusted International Prognosis Index of 2 or 3 at relapse has a <25% chance of being cured by auto-HCT. It is possible that such patients may be better served with an allo-HCT. Unfortunately, in many cases, allo-HCT applicability is limited by patient age, comorbidities, performance status and treatment-related toxicities. Recent attempts to improve the efficacy of auto-HCT, such as incorporating radio-immunotherapy into the conditioning regimen, have not resulted in improved outcomes. However, incorporation of novel agents such as anti-programmed death-1 antibodies as maintenance therapy after auto-HCT show promise. Allo-HCT in relapsed/refractory DLBCL patients can result in a 30-40% PFS rate at 3 years, in part due to a graft vs DLBCL effect. While reduced-intensity/non-myeloablative conditioning is increasingly being used, certain patients may benefit from myeloablative conditioning. We present an algorithm intended to discriminate which relapsed and refractory DLBCL patients are most likely to benefit from auto-HCT vs allo-HCT. New approaches, using novel agents that target the molecular heterogeneity in DLBCL, will be an essential component of moving the field forward. Lastly, we propose a prospective registry-based study as the only feasible mechanism to define the optimal position of allo-HCT in the overall treatment strategy for DLBCL. It is hoped that this review will promote the development of prospective multicenter efforts to determine whether such patients do, in fact, benefit from earlier and/or more effective implementation of allo-HCT.

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.

Indications and outcomes of reduced-toxicity hematopoietic stem cell transplantation in adult patients with hematological malignancies

Hematopoietic stem cell transplantation (HCT) utilizing non-myeloablative (NMA) and reduced-intensity conditioning (RIC) regimens (collectively referred to as reduced-toxicity HCT, RT-HCT) has become a viable therapeutic option for patients with hematological malignancies who are ineligible for standard myeloablative conditioning transplantation (MA-HCT). RT-HCT has been shown to induce stable engraftment with low toxicity, and to produce similar overall and progression-free survival (PFS) when compared to MA-HCT in acute myeloid leukemia and myelodysplastic syndrome. The best results for RT-HCT have been reported for patients with disease that is in remission, indolent and chemosensitive, and with a strong graft-versus-malignancy effect. Chronic graft-versus-host disease seems to correlate with a lower relapse rate and better PFS. RT-HCT is inferior when performed in poor risk or advanced disease, due to high relapse rates. A search for novel strategies that includes the most appropriate conditioning regimens and post-transplant immunomodulation protocols with more intensive anti-malignancy activity but limited toxicity is in progress. This review provides an update on the results of clinical studies of RT-HCT, and discusses possible indications and investigative strategies for improving the clinical outcomes of RT-HCT for the major hematological malignancies.

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.

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.

Allogeneic hematopoietic cell transplantation for chemotherapy-unresponsive mantle cell lymphoma: a cohort analysis from the center for international blood and marrow transplant research

Patients with chemorefractory mantle cell lymphoma (MCL) have a poor prognosis. We used the Center for International Blood and Marrow Transplant Research database to study the outcome of 202 patients with refractory MCL who underwent allogeneic hematopoietic cell transplantation (allo-HCT) using either myeloablative (MA) or reduced-intensity/nonmyeloablative conditioning (RIC/NST), during 1998-2010. We analyzed nonrelapse mortality (NRM), progression/relapse, progression-free survival (PFS), and overall survival (OS). Seventy-four patients (median age, 54 years) received MA, and 128 patients (median age, 59 years) received RIC/NST. Median follow-up after allo-HCT was 35 months in the MA group and 43 months in the RIC/NST group. At 3 years post-transplantation, no significant between-group differences were seen in terms of NRM (47% in MA versus 43% in RIC/NST; P = .68), relapse/progression (33% versus 32%; P = .89), PFS (20% versus 25%; P = .53), or OS (25% versus 30%; P = .45). Multivariate analysis also revealed no significant between-group differences in NRM, relapse, PFS, or OS; however, receipt of a bone marrow or T cell-depleted allograft was associated with an increased risk of NRM and inferior PFS and OS. Our data suggest that despite a refractory disease state, approximately 25% of patients with MCL can attain durable remission after allo-HCT, and conditioning regimen intensity does not influence outcome of allo-HCT.

Low-dose alemtuzumab vs. standard policy for prevention of graft-versus-host disease in unrelated and related allogeneic stem cell transplantation-a matched pair analysis

Antibody-mediated in vivo T cell depletion is common prior to unrelated (URD) or mismatched allogeneic stem cell transplantation (alloSCT) and optional in HLA-identical sibling (FAM) alloSCT. While anti-thymocyte globulin (ATG) is the current standard, alemtuzumab is an alternative. The optimal dose of alemtuzumab has not been defined. This retrospective analysis compares low-dose alemtuzumab with ATG in URD alloSCT and with no antibody in FAM alloSCT. Twenty-eight patients treated with alemtuzumab (10 mg; HLA mismatch, 20 mg) were matched to 28 patients who have either received ATG (URD) or no antibody (noAB) according to disease, disease stage, age, transplant type and risk state. Both groups were compared for engraftment, outcome, disease-free (DFS) and overall survival (OS), graft-versus-host disease (GvHD), freedom from GvHD (ffGvHD) and transplant-related mortality (TRM). No significant differences were found between the groups for leukocyte engraftment, GvHD, ffGvHD, TRM, DFS and OS. There was a trend for reduction of cGvHD by alemtuzumab (p = 0.05). A transplant-type stratified subanalysis consolidated equivalency of alemtuzumab and ATG in URD-SCT and indicates possible superiority of low-dose alemtuzumab compared to noAB in FAM-SCT. Low-dose alemtuzumab, as part of conditioning regimen prior to alloSCT, is safe and comparable to standard ATG. Prospective trials, particularly comparing alemtuzumab vs. noAB in FAM alloSCT, should be conducted.

ESMO Consensus conferences: guidelines on malignant lymphoma. part 2: marginal zone lymphoma, mantle cell lymphoma, peripheral T-cell lymphoma

To complement the existing treatment guidelines for all tumour types, ESMO organizes consensus conferences to focus on specific issues in each type of tumour. In this setting, a consensus conference on the management of lymphoma was held on 18 June 2011 in Lugano, next to the 11th International Conference on Malignant Lymphoma. The conference convened ∼30 experts from all around Europe, and selected six lymphoma entities to be addressed; for each of them, three to five open questions were to be addressed by the experts. For each question, a recommendation should be given by the panel, referring to the strength of the recommendation based on the level of evidence. This consensus report focuses on the three less common lymphoproliferative malignancies: marginal zone lymphoma, mantle cell lymphoma, and peripheral T-cell lymphomas. A first report had focused on diffuse large B-cell lymphoma, follicular lymphoma, and chronic lymphocytic leukaemia.

Hematopoietic cell transplantation for B-cell lymphoma: an update

BACKGROUND

B-cell lymphoma comprises the majority of non-Hodgkin lymphomas worldwide. Hematopoietic cell transplantation (HCT) is used for patients with high-risk, relapsed, or refractory B-cell lymphoma.

METHODS

The current medical literature and the results of recently published trials were reviewed to provide an update on the most common indications for HCT in B-cell lymphoma.

RESULTS

Autologous HCT has evolving and new roles in the treatment of patients with high-risk diffuse large B-cell cell lymphoma, mantle cell lymphoma, and HIV-related lymphoma. Reduced-intensity conditioning has largely replaced older myeloablative conditioning regimens, making allogeneic transplantation safer for more patients with lymphoma.

CONCLUSIONS

The indication and timing of HCT depend on the patient's histology, age, and response to previous therapies. HCT is an essential component in the armamentarium to treat B-cell lymphoma.

Mantle cell lymphoma: 2012 update on diagnosis, risk-stratification, and clinical management

DISEASE OVERVIEW

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood, and bone marrow with a short remission duration to standard therapies and a median overall survival of 4-5 years.

DIAGNOSIS

Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t(11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma.

RISK STRATIFICATION

The mantle cell lymphoma international prognostic index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median overall survival (OS) for the low-risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 and 29 months for the high-risk group.

RISK-ADAPTED THERAPY

For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytarabine containing regimen ± autologous stem cell transplantation should be considered. For older MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor), BTK inhibitors or CAL-101 (B-cell receptor inhibitors) or lenalidamide (antiangiogenesis) have clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients.

Prophylactic rituximab after allogeneic transplantation decreases B-cell alloimmunity with low chronic GVHD incidence

B cells are involved in the pathogenesis of chronic GVHD (cGVHD). We hypothesized that prophylactic anti-B-cell therapy delivered 2 months after transplantation would decrease allogeneic donor B-cell immunity and possibly the incidence of cGVHD. Therefore, in the present study, patients with high-risk chronic lymphocytic leukemia (n = 22) and mantle-cell lymphoma (n = 13) received a total lymphoid irradiation of 80 cGy for 10 days and antithymocyte globulin 1.5 mg/kg/d for 5 days. Rituximab (375 mg/m(2)) was infused weekly on days 56, 63, 70, and 77 after transplantation. The incidence of acute GVHD was 6%. The cumulative incidence of cGVHD was 20%. Nonrelapse mortality was 3%. Rituximab treatment after allogeneic transplantation significantly reduced B-cell allogeneic immunity, with complete prevention of alloreactive H-Y Ab development in male patients with female donors (P = .01). Overall survival and freedom from progression at 4 years for chronic lymphocytic leukemia patients were 73% and 47%, respectively; for mantle-cell lymphoma patients, they were 69% and 53%, respectively.

Allogeneic hematopoietic cell transplantation in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a high-risk non-Hodgkin lymphoma that is considered incurable with standard chemotherapy. While autologous hematopoietic cell transplantation (autoHCT) can provide lengthy disease-free survival in select patients, cure generally is not an expected outcome with this approach. Allogeneic hematopoietic cell transplantation (alloHCT), which can exploit the potential benefits of graft-versus-lymphoma (GVL) effect, has been shown in multiple studies to yield a small but reproducible portion of patients with long-term remission more suggestive of cure. Historically, alloHCT for MCL was administered after myeloablative conditioning, but this approach was limited by early non-relapse mortality. Development of reduced-intensity (RI)-alloHCT has abrogated some of the early post-transplant risks, allowing this potentially effective therapy to be offered to a larger number of affected individuals. The trends in published data reflect a preference toward using RI-alloHCT for MCL, often because patients in whom alloHCT is being considered have relapsed disease following myeloablative autoHCT. Further efforts to spare the effects of graft-versus-host disease (GVHD) while still evoking GVL remain a focus of investigation in this area. In this review, we will discuss the application of alloHCT in the management of MCL, the factors associated with outcome, the different methods in which it can be performed, and the strategies that can be employed in post-alloHCT relapse.

Ultra-short course sirolimus contributes to effective GVHD prophylaxis after reduced-intensity allogeneic hematopoietic cell transplantation

Reduced-intensity conditioning (RIC) allo-SCT is a potentially curative treatment approach for patients with relapsed Hodgkin's or non-Hodgkin's lymphoma. In the present study, 37 patients underwent RIC allo-SCT after induction treatment with EPOCH-F(R) using a novel form of dual-agent immunosuppression for GVHD prophylaxis with CsA and sirolimus. With a median follow-up of 28 months among survivors, the probability for OS at 3 and 5 years was 56%. Treatment-related mortality was 16% at day +100 and 30% after 1 year of transplant. Acute GVHD grades II-IV developed in 38% of patients, suggesting that the regimen consisting of CsA and an ultra-short course of sirolimus is effective in the prevention of acute GVHD.

Multicenter experience using total lymphoid irradiation and antithymocyte globulin as conditioning for allografting in hematological malignancies

A non myeloablative conditioning with total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) was shown to protect against graft-versus-host disease (GVHD). To evaluate the effects of TLI-ATG in a multicenter study, 45 heavily pretreated patients, median age 51, with lymphoid (n = 38) and myeloid (n = 7) malignancies were enrolled at 9 centers. Twenty-eight patients (62%) received at least 3 lines of treatment before allografting, and 13 (29%) had refractory/relapsed disease at the time of transplantation. Peripheral blood hematopoietic cells were from HLA identical sibling (n = 30), HLA-matched (n = 9), or 1 antigen HLA-mismatched (n = 6) unrelated donors. A cumulative TLI dose of 8 Gy was administered from day -11 through -1 with ATG at the dose of 1.5 mg/kg/day (from day -11 through -7). GVHD prophylaxis consisted of cyclosporine and mycophenolate mofetil. Donor engraftment was reached in 95% of patients. Grade II to IV acute GVHD (aGVHD) developed in 6 patients (13.3%), and in 2 of these patients, it developed beyond day 100. Incidence of chronic GVHD (cGVHD) was 35.8%. One-year nonrelapse mortality was 9.1%. After a median follow-up of 28 months (range, 3-57 months) from transplantation, median overall survival was not reached, whereas median event-free survival was 20 months. This multicenter experience confirms that TLI-ATG protects against GVHD and maintains graft-vs-tumor effects.

Reduced-intensity conditioning allogeneic stem cell transplantation for relapsed/refractory mantle cell lymphoma: a multicenter experience

BACKGROUND

Despite therapeutic approach that combines rituximab-containing chemotherapy, followed or not by autologous stem cell transplantation (auto-SCT), mantle cell lymphoma (MCL) patients experience relapses. Reduced-intensity conditioning allogeneic stem cell transplantation (RIC-allo-SCT) at time of relapse may represent an attractive strategy.

PATIENTS AND METHODS

We report a multicenter retrospective analysis. Seventy MCL patients underwent RIC-allo-SCT in 12 centers.

RESULTS

Median age at transplantation was 56 years and median time from diagnosis to transplantation was 44 months. The median number of previous therapies was 2 (range, 1-5) including autologous transplantation in 47 cases. At time of transplantation, 35 patients were in complete remission, 20 were in partial response and 15 in stable disease or progressive disease. The median follow-up for living patients was 24 months. The 2-year event-free survival (EFS) and overall survival (OS) rates were 50% and 53%, respectively. The 1- and 2-year transplant-related mortality rates were 22% and 32%, respectively. The statistical analysis demonstrated that disease status at transplantation was the only parameter influencing EFS and OS.

CONCLUSIONS

These results suggest that RIC-allo-SCT may be an effective therapy in MCL patients with a chemo-sensitive disease at time of transplantation, irrespective of the number of lines of prior therapy. Studies are warranted to investigate the best type of RIC regimen.

CD20-specific adoptive immunotherapy for lymphoma using a chimeric antigen receptor with both CD28 and 4-1BB domains: pilot clinical trial results

Cellular immune responses have the potential to elicit dramatic and sustained clinical remissions in lymphoma patients. Recent clinical trial data demonstrate that modification of T cells with chimeric antigen receptors (CARs) is a promising strategy. T cells containing CARs with costimulatory domains exhibit improved activity against tumors. We conducted a pilot clinical trial testing a "third-generation" CD20-specific CAR with CD28 and 4-1BB costimulatory domains in patients with relapsed indolent B-cell and mantle cell lymphomas. Four patients were enrolled, and 3 received T-cell infusions after cyclophosphamide lymphodepletion. Treatment was well tolerated, although one patient developed transient infusional symptoms. Two patients without evaluable disease remained progression-free for 12 and 24 months. The third patient had an objective partial remission and relapsed at 12 months after infusions. Modified T cells were detected by quantitative PCR at tumor sites and up to 1 year in peripheral blood, albeit at low levels. No evidence of host immune responses against infused cells was detected. In conclusion, adoptive immunotherapy with CD20-specific T cells was well tolerated and was associated with antitumor activity. We will pursue alternative gene transfer technologies and culture conditions in future studies to improve CAR expression and cell production efficiency.

Hematopoietic Cell Transplantation for Lymphomas

Background

The heterogeneity of lymphomas results in numerous treatment options, including both autologous and allogeneic hematopoietic cell transplantation. However, the type of transplantation, the timing the procedure, and the selection of suitable patients for transplant continue to evolve.

Methods

We reviewed the current medical literature to provide a succinct synthesis for the most common types of lymphoma and the indications for transplantation.

Results

This review discusses the outcomes of autologous and allogeneic transplantation for patients with diffuse large B-cell lymphoma, follicular lymphoma, HIV-associated lymphomas, mantle cell lymphoma, T-cell lymphoma, and Hodgkin lymphoma.

Conclusions

Each of these histologies differs in the indications and timing for transplantation. However, ongoing clinical trials support the continuing role of both autologous and allogeneic transplantation for lymphoma management.

The evolving role of stem cell transplants in lymphomas

Autologous stem cell transplantation (ASCT) is an established therapeutic modality in the treatment of lymphomas, especially in the relapse setting. It is also under investigation after first-line therapy, for example, in patients with mantle cell or T cell lymphomas. Each year more than 6000 autotransplants for lymphomas are reported to the European Blood and Marrow Transplantation (EBMT) registry. The number of allogeneic stem cell transplantations (alloSCT) in lymphoma patients has increased over the last decade, with about 1200 transplanted lymphoma patients annually reported to the registry. Optimal timing and indications for alloSCT are not well defined because of absence of randomized trials. Developments in the treatment of lymphomas including immunotherapy have changed the clinical scenarios in regard to ASCT, and many published studies are now outdated. On the other hand, patients relapsing after immunochemotherapy may derive less benefit from ASCT. Consequently, there is an increasing interest in using alloSCT not only in lymphoma patients relapsing after ASCT but also in earlier phases in specific circumstances. Although curative potential is higher with alloSCT compared with ASCT, its wider use has been hindered by excessive nonrelapse mortality (NRM). Along with decreasing NRM figures, popularity of alloSCT may increase in the near future, possibly with the expense of ASCT. Prospective, randomized studies are needed to evaluate feasibility and efficacy of alloSCT in several clinical settings, as most published evidence is based on retrospective registry data or single-center experiences.

Selective resistance of CD44hi T cells to p53-dependent cell death results in persistence of immunologic memory after total body irradiation

Our previous studies showed that treatment of mice with total body irradiation (TBI) or total lymphoid tissue irradiation markedly changes the balance of residual T cell subsets to favor CD4(+)CD44(hi) NKT cells because of the differential resistance of the latter subset to cell death. The object of the current study was to further elucidate the changed balance and mechanisms of differential radioresistance of T cell subsets after graded doses of TBI. The experimental results showed that CD4(+) T cells were markedly more resistant than CD8(+) T cells, and CD44(hi) T cells, including NKT cells and memory T cells, were markedly more resistant than CD44(lo) (naive) T cells. The memory T cells immunized to alloantigens persisted even after myeloablative (1000 cGy) TBI and were able to prevent engraftment of bone marrow transplants. Although T cell death after 1000 cGy was prevented in p53(-/-) mice, there was progressive T cell death in p53(-/-) mice at higher doses. Although p53-dependent T cell death changed the balance of subsets, p53-independent T cell death did not. In conclusion, resistance of CD44(hi) T cells to p53-dependent cell death results in the persistence of immunological memory after TBI and can explain the immune-mediated rejection of marrow transplants in sensitized recipients.

Mucositis after reduced intensity conditioning and allogeneic stem cell transplantation

BACKGROUND

Therapyrelated mucositis is associated with considerable morbidity. This complication following allogeneic stem cell therapy (alloSCT) is less severe after reduced intense conditioning (RIC); however, even here it may be serious.

METHODS

52 patients (male: n = 35 (67%), female: n = 17 (33%)) at a median age of 62 years (35-73 years) underwent alloSCT after RIC. Conditioning was either total body irradiation (TBI)(2Gy)/±fludarabine (n = 33, 63.5%) or chemotherapy based. Graftversushost disease (GvHD) prophylaxis was carried out with cyclosporine A ± mycophenolate mofetil (MMF). 45 patients (87%) received shortcourse methotrexate (MTX). Mucositis was graded according to the Bearman and the World Health Organisation (WHO) scale. A variety of parameters were correlated with mucositis.

RESULTS

The Bearman and WHO scales showed excellent correlation. Mucositis was significantly more severe after chemotherapybased conditioning compared to conditioning with TBI(2Gy)/±fludarabine (p < 0.002) as well as in cases with an increase in creatinine levels above the upper normal value (UNV) on day +1 after SCT (p < 0.05). Furthermore, the severity correlated with time to engraftment of leucocytes (correlation coefficient (cc) = 0.26, p < 0.02) and thrombocytes (cc = 0.38, p < 0.001).

CONCLUSIONS

The conditioning regimen and increased creatinine levels at day +1 were identified as factors predicting the severity of mucositis after RICSCT. Creatinine levels on day +1 after SCT may help identify patients at risk for severe mucositis in the further course of transplantation.

Cytopenias after day 28 in allogeneic hematopoietic cell transplantation: impact of recipient/donor factors, transplant conditions and myelotoxic drugs

BACKGROUND

Secondary cytopenias are serious complications following hematopoietic cell transplantation. Etiologies include myelotoxic agents, viral infections, and possibly transplant-related factors such as the intensity of the conditioning regimen and the source of stem cells.

DESIGN AND METHODS

We retrospectively analyzed data from 2162 hematopoietic cell transplant recipients to examine the effect of these factors on overall cytopenias occurring after 28 days in hematopoietic cell transplantation.

RESULTS

Advanced age of the patient, recipient cytomegalovirus seropositivity, unrelated donor status, human leukocyte antigen mismatch and lower doses of transplanted CD34(+) cells (≤ 6.4×10(6)/kg) significantly increased the risk of cytopenias after day 28. Non-myeloablative hematopoietic cell transplantation had protective effects on anemia and thrombocytopenia after day 28 (adjusted odds ratio 0.76, probability value of 0.05 and adjusted odds ratio 0.31, probability value of <0.0001, respectively) but not on overall or ganciclovir-related neutropenia. This lack of protection appeared to be due to the use of mycophenolate mofetil in the majority of recipients of non-myeloablative hematopoietic cell transplants. Peripheral blood stem cells did not confer protection from cytopenias when compared to bone marrow.

CONCLUSIONS

Elderly patients appear to be more prone to cumulative toxicities of post-transplant drug regimens, but non-myeloablative conditioning, optimized human leukocyte antigen matching, and higher doses of CD34(+) cell infusions may reduce the risk of cytopenia after day 28.

Case report: blastic Mantle Cell Leukemia

The patient, who was being followed up for Mantle Cell Lymphoma, was diagnosed with Mast Cell Leukemia 2 years after receiving R-CHOP treatment. The results of flow cytometry, which was performed upon determining leucocytosis and detecting blasts in the peripheral smear following the patient's presentation due to his poor general condition, was consistent with Mantle Cell Leukemia. This case is being presented since there are a very limited number of previously published cases on this topic.

Mantle cell lymphoma

MCL is a well-characterized clinically aggressive lymphoma with a poor prognosis. Recent research findings have slightly improved the outcome of this neoplasm. The addition of rituximab to conventional chemotherapy has increased overall response rates, but it does not improve overall survival with respect to chemotherapy alone. The use of intensive frontline therapies including rituximab and consolidated by ASCT ameliorates response rate and prolongs progression-free survival, but any impact on survival remains to be proven. Furthermore, the optimal timing, cytoreductive regimen and conditioning regimen, and the clinical implications of achieving a disease remission even at molecular level remain to be elucidated. The development of targeted therapies as the consequence of better dissection of pathogenetic pathways in MCL might improve the outcome of conventional chemotherapy in most patients and spare the toxicity of intense therapy in a minority of MCL patients characterized by a relatively indolent disease. Patients not eligible for intensive regimens, such as hyperC-VAD, may be considered for less demanding therapies, such as the combination of rituximab either with CHOP or with purine analogues, or bendamustine. Allogeneic SCT can be an effective option for relapsed disease in patients who are fit enough and have a compatible donor. Maintenance rituximab may be considered after response to immunochemotherapy for relapsed disease, although there are currently no data to recommend this approach as the first-line strategy. As the optimal approach to the management of MCL is still evolving, it is critical that these patients be enrolled in clinical trials to identify better treatment options.

Pretransplant CSF-1 therapy expands recipient macrophages and ameliorates GVHD after allogeneic hematopoietic cell transplantation

Host macrophages protect against graft-versus-host disease in part by engulfing donor T cells and inhibiting their proliferation.

Acute graft-versus-host disease (GVHD) results from the attack of host tissues by donor allogeneic T cells and is the most serious limitation of allogeneic hematopoietic cell transplantation (allo-HCT). Host antigen-presenting cells are thought to control the priming of alloreactive T cells and the induction of acute GVHD after allo-HCT. However, whereas the role of host DC in GVHD has been established, the contribution of host macrophages to GVHD has not been clearly addressed. We show that, in contrast to DC, reducing of the host macrophage pool in recipient mice increased donor T cell expansion and aggravated GVHD mortality after allo-HCT. We also show that host macrophages that persist after allo-HCT engulf donor allogeneic T cells and inhibit their proliferation. Conversely, administration of the cytokine CSF-1 before transplant expanded the host macrophage pool, reduced donor T cell expansion, and improved GVHD morbidity and mortality after allo-HCT. This study establishes the unexpected key role of host macrophages in inhibiting GVHD and identifies CSF-1 as a potential prophylactic therapy to limit acute GVHD after allo-HCT in the clinic.

⁹⁰Y-Ibritumomab tiuxetan, fludarabine, and TBI-based nonmyeloablative allogeneic transplantation conditioning for patients with persistent high-risk B-cell lymphoma

Nonmyeloablative allogeneic transplantation (NMAT) infrequently cures active chemoresistant, bulky, or aggressive B-cell lymphoma (B-cell non-Hodgkin lymphoma [B-NHL]). We hypothesized that ⁹⁰Y-ibritumomab tiuxetan-based NMAT would facilitate early cytoreduction in such patients promoting improved long-term disease control by the allogeneic graft. Forty high-risk B-NHL patients with persistent disease received 0.4 mCi/kg (maximum, 32 mCi/kg) ⁹⁰Y-ibritumomab tiuxetan, fludarabine, and 2 Gy total body irradiation and matched-related (15) or unrelated (25) transplantation. Baseline features included: median age, 58 years (range, 29-69 years); median prior regimens, 6 (range, 3-12); chemosensitive disease, 6 (15%); bulk > 5 cm, 17 (range, 5.2-18.6 cm, 43%); diffuse large B-cell lymphoma, 14 (35%); and comorbidity score > zero, 34 (85%). Early responses were observed in 24 (60%, 14 complete remission/complete remission unconfirmed, 10 partial response) patients, including 17 of 29 (59%) with chemotherapy-resistant disease and 10 (59%) with bulk > 5 cm. The estimated 30-month survival, progression-free survival, and nonrelapse mortality were 54.1%, 31.1%, and 15.9%, respectively. Early response, baseline platelet counts over 25 000/μL, indolent histology, and related donors were associated with improved survival. The addition of ⁹⁰Y-ibritumomab tiuxetan to NMAT is safe and yields early responses and prolonged disease control in some of the highest-risk B-NHL patients. This trial was registered at www.clinicaltrials.gov as #NCT00119392.

Transplantation for non-Hodgkin lymphoma

High-dose therapy followed by autologous hematopoietic stem cell transplantation (auto-HCT) has become the treatment of choice for patients with relapsed aggressive non-Hodgkin lymphoma (NHL). However, relapse remains the most common cause of treatment failure after auto-HCT. More intensive regimens incorporating radioimmunotherapy into high-dose regimens have been developed to prevent relapse. The role of auto-HCT for follicular lymphoma and mantle cell lymphoma remain inconclusive. Since prognosis of patients with peripheral T-cell lymphoma, not otherwise specified are very poor with conventional chemotherapy, auto-HCT during first remission is being explored in peripheral T-cell lymphoma. Given the lower risk of relapse after allogeneic HCT (allo-HCT) in NHL, allo-HCT has been performed in patients with refractory or relapsed NHL, especially after auto-HCT failure. However, the transplant-related mortality remains high after myeloablative allo-HCT. Reduced-intensity conditioning followed by allo-HCT has been shown to reduce transplant-related mortality but graft-versus-host disease continues to be the major problem, thus the role of allo-HCT in NHL remains an investigational approach for NHL. The outcomes of auto-HCT and allo-HCT for various lymphomas are reviewed.

Allogeneic transplantation for lymphoma

Historically, high levels of treatment-related mortality restricted the use of standard myeloablative allogeneic stem-cell transplantation to a minority of young and fit patients with lymphoma. Over the last decade, increasing numbers of patients with lymphoma have undergone allogeneic stem-cell transplantation using reduced-intensity protocols that are associated with lower toxicity and reduced transplantation-related mortality. Graft-versus-lymphoma effects contribute to the therapeutic effect in patients with indolent or Hodgkin's lymphoma. However, definitive evidence for efficacy of this strategy is lacking because most patients undergoing transplantation do so after failure of several lines of treatment, leaving no obvious comparator arm for randomized controlled studies. Nevertheless, encouraging results have been reported for selected patients for most lymphoma subtypes, with pretransplantation disease status emerging as the most important predictor of outcome. The major long-term toxicity is chronic graft-versus-host disease that contributes to ill health in a significant minority of survivors. In the future, risk-adapted trials that evaluate reduced-intensity allogeneic transplantation in patients with predicted poor outcomes with immunochemotherapy or autologous transplantation will be important in determining the role of this treatment.

Should there be a standard therapy for mantle cell lymphoma?

Mantle cell lymphoma (MCL) is an uncommon subtype of B-cell lymphomathat is characterized by monoclonal B cells that express CD5 on their surface, but not CD23, and harbor the t(11:14) chromosomal translocation that leads to dysregulated expression of cyclin D1. MCL is a biologically and clinically heterogeneous disease. It has the unfavorable characteristics of both aggressive and indolent lymphoma in that MCL is not curable with current standard therapy, yet patients have a shorter survival compared with other indolent histology. MCL is incurable, yet more intensive therapy does lead to longer disease-free intervals; therefore, treatment must be designed to optimize survival while maintaining quality of life. Thus, therapy should be individualized based on both the clinical behavior of the lymphoma and the patient’s status. While there is no clear standard therapy that can be recommended for all patients, there may be an optimal choice for each patient. Knowledge of the expected clinical benefits and toxicities of various approaches will allow the physician and patient to appropriately select the therapy.

Use of matched unrelated donors compared with matched related donors is associated with lower relapse and superior progression-free survival after reduced-intensity conditioning hematopoietic stem cell transplantation

As success of reduced-intensity conditioning (RIC) hematopoietic stem cell transplantation (HSCT) relies primarily on graft-versus-leukemia (GVL) activity, increased minor HLA disparity in unrelated compared to related donors could have a significant impact on transplant outcomes. To assess whether use of unrelated donors (URD) engenders more potent GVL in RIC HSCT compared to matched related donors (MRD), we retrospectively studied 433 consecutive T-replete 6/6 HLA matched URD (n = 246) and MRD (n = 187) RIC HSCT for hematologic malignancies at our institution. Diseases included: acute myelogenous leukemia (AML) (127), non-Hodgkin lymphoma (NHL) (71), chronic lymphocytic leukemia (CLL) (68), myelodysplastic syndrome (MDS) (64), Hodgkin disease (HD) (40), chronic myeloid leukemia (CML) (25), multiple myeloma (MM) (23), myeloproliferative disorder (MPD) (12), acute lymphoblastic leukemia (ALL) (7), and other leukemia (1). All received uniform fludarabine and intravenous busulfan conditioning, and GVHD prophylaxis with tacrolimus/mini-methroxate (mini-MTX) or tacrolimus/sirolimus ± mini-MTX. Unrelated donors were younger compared to MRD (median donor age: 33 years versus 52 years, P < .0001), and provided larger CD34(+) products (median CD34(+) cells infused: 8.7 × 10(6)/kg versus 7.5 × 10(6)/kg, P = .002). Distribution of diseases, disease risk, prior transplant, and cytomegalovirus (CMV) status was similar in both cohorts. Cumulative incidence of grade II-IV acute GVHD (at day +180), 2-year chronic GVHD, and 2-year nonrelapse mortality (NRM) were 20% versus 16%, 55% versus 50%, and 8% versus 6% in URD and MRD, respectively (P = NS). Cumulative incidence of relapse at 2 years was lower in URD, 52% versus 65% (P = .005). With median follow-up of 26.5 and 35.8 months, 2-year progression-free survival (PFS) was significantly better in unrelated donor transplants, 39.5% for URD, and 29% for MRD (P = .01). Overall survival (OS) at 2 years were 56% for URD versus 50% for MRD (P = .53). In multivariable analysis, URD was associated with a lower risk of relapse (hazard ratio [HR] 0.67, P = .002) and superior PFS (HR 0.69, P = .002). These results suggest that URD is associated with greater GVL activity than MRD, and could have practice changing impact on future donor selection in RIC HSCT.

Role of comorbidities in optimizing decision-making for allogeneic hematopoietic cell transplantation

Allogeneic conventional hematopoietic cell transplantation (HCT) following high-dose, myeloablative conditioning regimens has been used since the 1970’s as potentially curative treatment for patients with malignant, hematological disorders. The toxicities of conditioning regimens have limited conventional HCT to relatively young patients in otherwise good medical condition. With the development of less toxic nonmyeloablative regimens and improvements in supportive care, increasing numbers of older and medically infirm patients have been treated by allogeneic HCT. Until recently, there has been almost no effort to evaluate the prevalence of comorbidities among HCT recipients and their impact on outcomes. We first evaluated the Charlson Comorbidity Index (CCI) developed for patients with solid malignancies, for this purpose. While useful, it lacked sensitivity and specificity for the HCT setting. We next introduced the HCT-specific comorbidity index (HCT-CI) which was based on objective laboratory data to better define comorbidities. Here, we describe this development and illustrate the usefulness of the HCT-CI in predicting HCT outcomes in patients with myeloid and lymphoid malignancies undergoing allogeneic transplantation.

Patterns and outcome of relapse after autologous stem cell transplantation for mantle cell lymphoma

BACKGROUND

Autologous stem cell transplantation (autoSCT) has improved the outcome of patients with mantle cell lymphoma (MCL) considerably. However, little is known about the patterns and outcome of MCL recurrence after autoSCT.

METHODS

The authors conducted a retrospective study of 118 patients with MCL who underwent autoSCT from August 1992 to August 2008 at 3 different referral centers in Germany.

RESULTS

Fifty-two relapses occurred for a cumulative incidence of 46% after 5 years. Only 3 patients relapsed after 5 years (at 90 months, 91 months, and 171 months) after undergoing autoSCT. A Cox regression analysis of the incidence of relapse identified not receiving rituximab before autoSCT and undergoing salvage autoSCT as predictive factors for relapse, whereas cytosine arabinoside intensification; a total body irradiation-based, high-dose regimen; patient age; and year of transplantation had no influence. The median overall survival (OS) after relapse was 23 months. Twenty patients (39%) underwent allogeneic stem cell transplantation (alloSCT) for relapse, and 11 of those patients remained in ongoing complete remission at the time of the current report. It is noteworthy that there were 4 long-term survivors who lived for >5 years after relapse even without undergoing alloSCT. A Cox regression analysis of OS after relapse revealed that the response duration after autoSCT was an adverse predictor of OS, whereas alloSCT was associated with a significantly longer OS after relapse.

CONCLUSIONS

The current results indicated that autoSCT was capable of inducing long-term remission up to 16 years after treatment, but the outcome of patients with MCL who relapsed after autoSCT was poor, especially if their response duration after autoSCT was short. However, for a subset of patients with relapsed MCL, alloSCT may offer the possibility of durable survival, and individual patients can enjoy long-term survival after relapse even without undergoing alloSCT.

NKT cells, Treg, and their interactions in bone marrow transplantation

Bone marrow transplantation (BMT) is a potentially curative treatment for patients with leukemia and lymphoma. Tumor eradication is promoted by the anti-tumor activity of donor T cells contained in the transplant; however, donor T cells also mediate the serious side effect of graft-versus-host disease (GVHD). Separation of GVHD from graft anti-tumor activity is an important goal of research in improving transplant outcome. One approach is to take advantage of the immunomodulatory activity of regulatory NKT cells and CD4(+)CD25(+) Treg of host and/or donor origin. Both host and donor NKT cells and donor Treg are able to prevent GVHD in murine models. In this review, we summarize the mechanisms of NKT cell- and Treg-mediated protection against GVHD in mice while maintaining graft anti-tumor activity. In addition, we also examine the interactions between NKT cells and Treg in the context of BMT, and integrate the data from murine experimental models with the observations made in humans.

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 Allogeneic Stem Cell Transplantation in Relapsed/Refractory Hodgkin's Lymphoma Patients

Despite the favorable prognosis of most patients with Hodgkin's Lymphoma (HL), 15-20% of patients remain refractory to chemoradiotherapy, and 20-40% experience relapses following autologous stem cell transplantation (SCT) being used as salvage approach in this situation. Long-term survival of only 20% was reported for patients who failed this option. As some authors suggested the presence of a graft versus HL effect, allogeneic SCT was introduced as a further option. Myeloablative strategies were reported to be able to achieve cure in some younger patients, but high nonrelapse mortality remains a problem. Reduced intensity conditioning, in turn, was found to be associated with high posttransplant relapse rates. As there is currently no standard in the management of HL patients who failed autologous SCT, we here review the literature on allogeneic stem cell transplantation in HL patients with a special focus on the outcomes and risk factors being reported in the largest studies.