Allogeneic bone marrow transplantation for refractory mantle cell lymphoma

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.

Mantle cell lymphoma: state-of-the-art management and future perspective

Mantle cell lymphoma (MCL) is a unique subtype of B-cell non-Hodgkin lymphomas (NHL) characterized in almost all cases by the chromosomal translocation t(11;14)(q13;q32) and nuclear cyclin D1 overexpression. Most patients present with advanced stage disease, often with extranodal dissemination, and typically pursue an aggressive clinical course. Recent improvement has been achieved by the successful introduction of monoclonal antibodies and dose-intensified approaches including autologous stem cell transplantation strategies. However, with the exception of allogeneic hematopoietic stem cell transplantation, current treatment approaches are not curative and the corresponding survival curve is characterized by a relatively steep and continuous decline, with a median survival of about 4 years and <15% long-term survivors. Despite its rarity, MCL is of particular clinical and scientific interest by providing a paradigm for neoplasms with dysregulated control of cell cycle machinery and impaired apoptotic pathways. Recently gained insights into underlying pathobiology unravel numerous promising molecular targeting strategies, however their introduction into clinical practice and current treatment algorithms remains a challenge. This article will provide relevant information for decision making in clinical practice and give a perspective on upcoming management strategies.

Allogeneic stem cell transplantation for mantle cell lymphoma--does it deserve a better look?

Mantle cell lymphoma is a subtype of non-Hodgkin's lymphoma. Mantle cell is generally considered incurable with a median overall survival of about 3 years. It is most common in 50 - 70 year old individuals and for this reason transplantation is not a common therapeutic option. Autologous stem cell transplantation does not appear to improve survival with most patients relapsing after transplant and no disease-free plateau. We present 6 mantle cell patients that had a mean of 3 different types of therapy prior to allogeneic transplantation. Allogeneic transplantation is associated with substantial mortality post-transplant from acute toxicity and GVHD. Despite the extensive amount of pretransplant therapy in our patient population, there was no transplant related mortality. All patients are alive and in remission a median of 4.3 plus years after transplantation. Survival from the date of diagnosis is a median of 6.5 plus years. The results of this series would suggest that in a selected group of patients allogeneic stem cell transplantation may be the treatment of choice for lymphomas not curable by standard therapy or autotransplant.

Hematopoietic stem cell transplantation in mantle cell lymphoma

BACKGROUND

Patients with mantle cell lymphoma (MCL) have in general, lower response rates and overall survival (OS) than those with other B-cell non-Hodgkin's lymphomas. The role of hematopoietic stem cell transplantation (HSCT) in MCL is unclear. Hence we decided to study the clinical course of patients who received autologous and allogeneic HSCT for MCL.

METHODS

Ninety-seven patients, (80 patients-autologous; 17 patients-allogeneic) who received a HSCT for mantle cell lymphoma were included in the study.

RESULTS

The complete response rates at day 100 between the two groups were similar (73% vs. 62%). Day-100 mortality was higher in the allogeneic HSCT group (19% vs. 0%) (P < 0.01). The estimated 5-year relapse rates, 5-year event-free survival (EFS) and 5-year OS among the allogeneic HSCT patients were 21%, 44% and 49%, respectively, similar to 56%, 39% and 47% in the autologous group. Ten patients received HyperCVAD (hyperfractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone + high-dose methotrexate and cytarabine) +/- rituximab prior to transplant. There have been no relapses or deaths amongst these patients at a median follow-up of 16 months.

CONCLUSIONS

Patients treated with allogeneic HSCT had a lower relapse rate, but similar EFS and OS to autologous HSCT. Treatment of MCL with HyperCVAD +/- rituximab followed by HSCT seems promising.

The role of allogeneic transplantation in non-Hodgkin's lymphoma

The evolution of combination chemotherapy regimens, combined with improvements in supportive care, has incrementally improved survival outcomes for patients with non-Hodgkin's lymphomas (NHL). Although 40-60% of younger patients with diffuse large cell lymphoma can now expect to be cured, significant numbers will either fail to achieve a remission or relapse after attaining a remission. In addition, certain histological subtypes are associated with particularly poor prognoses with combination chemotherapy alone (e.g. mantle cell lymphoma, B-cell prolymphocytic leukaemia). Relatively few of these patients can achieve long-term responses. Other NHL subtypes, whilst associated with more favourable prognoses in terms of overall survival, are rarely, if ever, cured (e.g. most low grade NHL including follicular lymphoma, chronic lymphocytic leukaemia and small lymphocytic lymphoma). For these reasons dose escalation and allogeneic transplantation have been investigated as potential ways of improving outcome, although this has mainly been in the setting of advanced disease. Any possible benefits have frequently been out-weighed by procedural morbidity and mortality. The parallel development of transplantation approaches that limit procedural toxicity along with advances in supportive care require that the role of allogeneic haematopoietic stem cell transplantation in the management of lymphoma be re-evaluated.

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

We carried out HLA-matched related (n = 16) and unrelated (n = 17) hematopoietic cell transplantation (HCT) in 33 patients with relapsed and refractory mantle cell lymphoma after nonmyeloablative conditioning with fludarabine and 2 Gy total body irradiation. Postgrafting immunosuppression consisted of cyclosporine and mycophenolate mofetil. Fourteen patients had failed high-dose autologous HCT. Of the 33 patients studied, 31 had stable engraftment, whereas 2 patients experienced nonfatal graft rejections. The incidences of acute grades II, III, and IV, and chronic graft-versus-host disease (GVHD) were 27%, 17%, 13%, and 64%, respectively. The overall response rate in the 20 patients with measurable disease at the time of HCT was 85% (n = 17; 75% complete remissions [CR] and 10% partial remissions [PR]), whereas 3 patients had progressive disease. Only one of the 17 patients who responded and none of the 13 who received transplants in CR had disease relapse with a median follow-up of 24.6 months. Relapse and nonrelapse mortalities were 9% and 24%, respectively, at 2 years. The Kaplan-Meier probabilities of overall and disease-free survivals at 2 years were 65% and 60%, respectively. Allogeneic HCT after nonmyeloablative conditioning is a promising salvage strategy for patients with relapsed and refractory mantle cell lymphoma. The high response and low relapse rates with this approach suggest that mantle cell lymphoma is susceptible to graft-versus-tumor responses.

Allogeneic peripheral blood stem cell transplantation for high-risk non-Hodgkin's lymphoma

A high incidence of nonrelapse mortality (NRM) has limited the use of allogeneic transplantation for poor prognosis non-Hodgkin's lymphoma (NHL). We sought to improve the outcome of allografting by utilizing Filgrastim-mobilized peripheral blood stem cells (PBSC) in combination with either standard ablative or reduced-intensity conditioning. A total of 21 patients with intermediate/high-grade lymphoma and seven patients with low-grade histology were enrolled on protocols using PBSC. All patients were considered high risk for recurrence and/or NRM because of age >50 (n=16), refractory disease (n=17), failed autologous transplant (n=11) and abnormal organ function (n=2). In all, 17 patients received ablative regimens and 11 received modified conditioning including fludarabine, intravenous busulfan and ATG. Tacrolimus and mini-dose methotrexate were used for graft-versus-host-disease (GVHD) prophylaxis. Median follow-up was 38 months. Disease-free and overall survival were 57 and 58%. Seven of the 11 patients who relapsed after a previous transplant remain disease free. Four of the 10 patients with recurrent/persistent disease post transplant responded to additional therapy including withdrawal of immunosuppression+/-DLI. These results support a potent graft-versus-lymphoma effect and suggest that patients who relapse after an autologous transplant can be salvaged with an allogeneic transplant.

Mantle cell lymphoma: therapeutic strategies are different from CLL

In contrast to the typical course of chronic lymphocytic lymphoma and despite an indolent lymphoma-like presentation, the clinical outcome of mantle cell lymphoma (MCL) is dismal, with a median survival time of 3 years and virtually no long-term survivors. Most patients are diagnosed with advanced stage III/IV disease. Although clinical studies did not prove a clear superiority of anthracyclin-containing combinations, CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone)-like regimens represent the standard therapeutic approach in MCL. Recent randomized studies have shown a benefit of a combined immunochemotherapy strategy (chemotherapy plus rituximab) increasing the complete and overall response rates, whereas further follow-up is pending for evaluation of the progression-free and overall survival. In patients younger than 65 years, a dose-intensive consolidation comprising high-dose radiochemotherapy and subsequent autologous stem cell transplantation after a CHOP-like induction results in an improved progression-free survival. However, despite the benefits of this multimodal approach, most patients relapse even after high-dose therapy. The only curative approach is allogeneic stem cell transplantation, which may be adapted to the elderly MCL patient cohort by modified dose-reduced conditioning regimens. Prospective randomized trials remain critical to further improve the clinical course of MCL with the addition of newer treatment modalities, such as radioactively labeled antibodies and targeted therapies (eg, flavopiridol and PS-341).

Autologous and allogeneic transplantation for aggressive NHL

BACKGROUND

Intermediate- and high-grade NHL are generally chemosensitive diseases with high initial response rates to combination chemotherapy. Dose intensification via autologous and allogeneic transplantation provides viable treatment options in specific clinical settings. Currently, autologous transplantation is the standard of care for relapsed but chemosensitive aggressive B-cell NHL. However, tools such as the International Prognostic Index allow risk-adapted analyses, and show that the magnitude of benefit from autologous transplantation differs in lymphoma subsets.

METHODS

Low-risk patients appear to do well regardless of salvage approaches, whereas high-risk patients have suboptimal outcomes with autologous transplantation. In high-risk patients, high-dose chemotherapy with autologous stem-cell transplantation has been examined as part of initial therapy, with long-term data promising but still evolving.

DISCUSSION

A significant concern with autologous transplantation in aggressive and high-grade NHL is the risk of graft contamination with tumor cells. Several investigators have demonstrated the presence of malignant cells in both BM and PBSC, although the clonagenic potential of such cells is unclear. Allogeneic stem-cell transplantation has several potential advantages over autologous transplantation for NHL,including procurement of an uncontaminated stem-cell graft, GvL effects, and the elimination of hematopoietic stem-cell damage and consequent secondary leukemia.

RESULTS

The ideal application of allogeneic transplantation in aggressive and high-grade lymphomas is still unclear; but the lower relapse rates demonstrated in several comparisons of the two approaches make this an exciting area to pursue. Finally, non-myeloablative stem-cell transplantation may broaden the use of allogeneic transplantation by lowering regimen-related mortality while capitalizing on GvL.

Mantle cell lymphoma: a biological and therapeutic paradigm

Recent classifications of non-Hodgkin's lymphomas (NHL) have strictly individualized mantle cell lymphoma (MCL) on the basis of a combination of morphologic, immunophenotypic, and cytogenetic criteria. This clinicopathological entity now appears to be a biological and therapeutic model for the understanding and treatment of hematologic malignancies. The lymphomogenesis of MCL could be explained by a series of genetic abnormalities which occur at different steps of the disease: (1) mutation and/or loss of the ATM gene in centrocytic cells of the follicle mantle of lymph nodes, leading to the loss of ATM function, particularly involved during the V(D)J recombination process; (2) a t(11;14)(q13;q32) translocation which induces a constitutive Bcl-1/PRAD1/CCND1 expression, responsible for cell cycle activation of centrocytic cells characteristic of typical MCL; and (3) secondary additional chromosomal aberrations, such as a p53 mutation, observed in blastic transformation of MCL. Despite the evaluation of a number of treatment modalities, the optimal management of MCL has not yet been defined: (1) conventional and intensified chemotherapy and monoclonal anti-CD20 antibody therapy appear to be effective for the improvement of response rates and event-free or overall survivals; (2) combinations of different treatment modalities must be tested to modify the natural dismal outcome of the disease; and (3) innovative approaches should be developed. From this point of view, all these considerations offer a fine opportunity for extensive medical reflection.

Stem cell transplantation for mantle cell lymphoma: should it ever be used outside clinical trials?

The outlook for patients with mantle cell lymphoma is poor. The reported median survival in most published series is only 3 to 4 years, and even the most favorable prognostic groups have median survival rates of only 5 years, with no evidence of cure. The use of autologous and allogeneic stem cell transplantation in this disease has increased dramatically in recent years. Despite encouraging reports from single centers and registries, the impact of stem cell transplantation on the outcome for mantle cell lymphoma is unclear. Optimal first-line regimens for mantle cell lymphoma have yet to be defined, and it is therefore difficult to place the role of first remission transplantation in an appropriate context. Prospective randomized trials have been difficult to design and conduct in the absence of a well-defined 'standard' treatment. The role of stem cell transplantation as a salvage strategy is also unknown, although available data suggest that it does not improve survival in heavily pre-treated patients. In the absence of clear evidence for a survival advantage for patients receiving stem cell transplants for mantle cell lymphoma, entry into clinical trials should be a priority.

Biology and management of mantle cell lymphoma

Mantle cell lymphoma is a distinct subtype and accounts for approximately 5 to 10% of non-Hodgkin lymphomas. The malignant cells express pan B-cell markers, including CD19, CD20 and CD22, and the T-cell marker CD5, whereas CD10 and CD23 expression are usually absent. By cytogenetic analysis, the t(11;14)(q13;q32) translocation is commonly observed, resulting in overexpression of cyclin D1. This entity often combines some unfavorable clinical features of the indolent and aggressive lymphoma subtypes, as it is generally incurable and relatively aggressive. It is most commonly observed in men 50 to 70 years of age and is characterized by disseminated disease, usually involving lymph nodes, bone marrow, and spleen. Frequently, there is extranodal involvement including the gastrointestinal tract. These tumors are incurable with the currently available therapeutic options, with usual time to progression after chemotherapy of approximately 1 year. Newer chemotherapy regimens (including stem cell transplantation) and monoclonal antibody-based therapies have shown limited evidence of additional benefit. Overall, the prognosis for patients with mantle cell lymphoma remains poor, and novel strategies are needed.