The pretransplant Follicular Lymphoma International Prognostic Index is associated with survival of follicular lymphoma patients undergoing autologous hematopoietic stem cell transplantation

Where does transplant fit in the age of targeted therapies?

The role of hematopoietic cell transplantation (HCT) for indolent lymphoma has evolved over the last 5 years with the availability of novel low-toxicity therapies and a better understanding of the prognosis of these entities. However, despite numerous treatment options for patients with follicular lymphoma, none are thought to be curative, and many require ongoing therapy with chronic toxicity. Historical trials indicate that autologous HCT as initial consolidation leads to improved progression-free survival, but not overall survival (OS) and, thus, is not typically recommended. However, autologous HCT for chemosensitive relapse can be carried out with ∼1% early mortality risk, affording disease control lasting a median of 3 to 5 years and the potential to improve OS. These results may compare favorably in efficacy, toxicity, and cost vs multiple sequential novel therapies with shorter durations of benefit. Recent data indicate that autologous HCT in follicular lymphoma patients with early initial progression will result in more than one third being alive and without relapse at 5 years, leading to improved OS when used within a year of the first recurrence. Unlike other available therapies, allogeneic HCT has the potential to cure up to one half of those transplanted with indolent B-cell non-Hodgkin lymphoma, although the risks need to be recognized and appropriate patient and donor selection is critical to ensure the best outcomes. HCT continues to remain a viable option in the current era of multiple targeted agents.

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.

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.

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.

Hematopoietic stem cell transplantation for follicular lymphoma: optimal timing and indication

The definitive management of advanced follicular lymphoma (FL) remains controversial due to various treatment options, including watchful waiting, single-agent or combination chemotherapy, monoclonal antibody, and radioimmunotherapy. These options can provide prolonged progression-free survival. However, they cannot cure advanced FL. Allogeneic hematopoietic stem cell transplantation (allo-SCT) remains the sole curative therapy for FL. Allo-SCT has had a major impact with the use of reduced-intensity conditioning regimens because of its lower associated nonrelapse mortality compared with myeloablative regimens. Autologous SCT (auto-SCT) shows high response rates and extends progression-free survival in patients with chemosensitive relapse. In the rituximab era, however, associated comorbidities, risk of secondary cancers, and presence of refractory disease have become problematic in the auto-SCT population. On the basis of results from large-scale randomized trials, upfront auto-SCT is not recommended. Novel conditioning regimens including radioimmunotherapy followed by either auto-SCT or allo-SCT are likely to show efficacy even in chemorefractory disease. Consequently, the optimal timing for SCT remains a matter of opinion, except for patients in first remission. However, the outcomes of allo-SCT and auto-SCT keep on improving. Physicians should note that there is no therapy with a track record equivalent to that of SCT for relapsed or refractory FL.

Autologous transplant for relapsed follicular lymphoma: impact of pre-transplant rituximab sensitivity

Patients with rituximab-refractory follicular lymphoma (FL) have limited options. Before the rituximab era, autologous stem cell transplant (ASCT) was shown to improve outcomes in chemotherapy-sensitive, relapsed FL, but the impact of rituximab-sensitivity on these results is unknown. We analyzed 194 consecutive relapsed patients with FL who underwent ASCT at out center and categorized them as rituximab-sensitive (RS, n = 35), rituximab-refractory (RR, n = 65) or no rituximab (NoR, n = 94) if transplanted before rituximab was used. Progression-free survival at 3 years was 85% in RS and 35% in RR patients (p = 0.0004). Only rituximab-sensitivity was significant on multivariate analysis with improved overall survival (OS) (hazard ratio [HR] 0.24, p = 0.01) and progression-free survival (PFS) (HR 0.35, p = 0.006) in RS patients and increased relapse in RR patients (HR 2.11, p = 0.01). Pre-transplant rituximab-sensitivity is a strong independent predictor of post-transplant outcomes in relapsed FL, although one-third of RR patients achieved a PFS of over 3 years with ASCT.

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.

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.

Phase II study of autologous stem cell transplant using busulfan-melphalan chemotherapy-only conditioning followed by interferon for relapsed poor prognosis follicular non-Hodgkin lymphoma

Alpha interferon has proven efficacy in prolonging remissions in patients with follicular non-Hodgkin lymphoma (NHL) when given concurrently with or after conventional-dose anthracycline-based chemotherapy, but there are limited data on its use after myeloablative conditioning. We prospectively evaluated the toxicity and efficacy of interferon given thrice weekly for up to 5 years post-engraftment in patients with relapsed follicular NHL undergoing autologous stem cell transplant using busulfan-melphalan conditioning. Thirty-seven patients were enrolled in this Australasian Leukaemia & Lymphoma Group study and transplanted between 1995 and 1999. Only one patient had received prior rituximab. Two patients died of transplant-related toxicity; 28 of the remainder commenced interferon, but it was discontinued prematurely in most patients due to toxicity (mainly fatigue and depression) or relapse. While the majority of patients (29/36 evaluable: 81%) achieved a complete remission based on clinical and CT scan criteria post-transplant, most relapsed relatively early, with a median progression-free survival of 2.4 years. The overall survival at 7 years was 49%. Eight patients (22%), however, remain alive a median of 9.3 years post-transplant, having never relapsed, and another six patients (16%) remain alive in durable remission after salvage therapy. These results demonstrate that interferon is poorly tolerated post-autograft and hence is unlikely to positively contribute to patient outcome. Long-term follow-up demonstrates that autografting may result in durable remissions in a meaningful minority of patients with relapsed follicular NHL.

The role of cytotoxic therapy with hematopoietic stem cell transplantation in the treatment of follicular lymphoma: an evidence-based review

Clinical research examining the role of hematopoietic stem cell transplantation (SCT) in the therapy of follicular non-Hodgkin lymphoma in adults is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations reached unanimously by a panel of follicular lymphoma experts are: (1) autologous SCT is recommended as salvage therapy based on pre-rituximab data, with a significant improvement in overall survival (OS) and progression-free (PFS) survival; (2) autologous SCT is not recommended as first-line treatment for most patients because of no significant improvement in OS; (3) autologous SCT is recommended for transformed follicular lymphoma patients; (4) reduced intensity conditioning before allogeneic SCT appears to be an acceptable alternative to myeloablative regimens; (5) an HLA-matched unrelated donor appears to be as effective an HLA-matched related donor for reduced intensity conditioning allogeneic SCT. There are insufficient data to make a recommendation on the use of autologous SCT after rituximab-based salvage therapy. Eleven areas of needed research in the treatment of follicular lymphoma with SCT were identified and are presented in the review.

Follicular non-Hodgkin lymphoma: long-term results of stem-cell transplantation

PURPOSE OF REVIEW

Hematopoietic stem-cell transplantation is an effective treatment option for follicular lymphoma. This review summarizes recent updates of the literature focusing on the available long-term follow-up of high-dose therapeutic approaches.

RECENT FINDINGS

Autologous transplantation can prolong overall survival in relapsed disease and can extend progression-free survival in first remission. With more than 10 years of follow-up, the survival curves demonstrate a plateau indicating a potential cure in certain patients. Use of allogeneic transplantation may result in cure as well, but has been plagued by high treatment-related mortality rates when myeloablative conditioning is used. The decreased toxicity of reduced-intensity conditioning is more applicable to the older follicular lymphoma population, but long-term follow-up data are lacking.

SUMMARY

For selected patients, both autologous and allogeneic transplantation offer the possibility of prolonged survival and can result in a cure in up to 25-45% of cases. It is unclear whether to incorporate monoclonal antibody or radioimmunoconjugate therapy. Stem-cell transplantation should at least be considered in patients younger than 60 years, possibly early in the disease course. Late consequences such as an increased risk of second malignancy may compromise this approach and close patient follow-up is essential.