Reduced-intensity rituximab-BEAM-CAMPATH allogeneic haematopoietic stem cell transplantation for follicular lymphoma is feasible and induces durable molecular remissions

BEAM-Campath Allogeneic Stem Cell Transplant for Patients with Relapsed/Refractory Lymphoma: High Incidence of Long-Term Mixed Donor-Recipient Chimerism and the Response to Donor Lymphocyte Infusions

BiCNU (carmustine), etoposide, Ara-C, melphalan (BEAM) and Campath conditioning was developed to reduce the high transplant-related mortality in patients with lymphoma while delivering intensive antilymphoma immunotherapy, as well as to some extent a platform for allogeneic stem cell engraftment. Significant numbers of patients appeared to have persistent recipient-derived hematopoiesis, and therefore we retrospectively analyzed patients with lymphoma undergoing BEAM-Campath conditioned allogeneic stem cell transplantation at our center (2003 to 2017) to characterize the patterns of chimerism and patient outcomes. Chimerism was analyzed with short tandem repeat PCR. Mixed donor-recipient chimerism (MDRC) was defined as 5% to 94.9% donor. Fifty-two patients (n = 30 male), with a median age of 45 years, were identified with histologic diagnoses of Hodgkin lymphoma (n = 13), diffuse large B cell lymphoma (n = 7), low-grade non-Hodgkin lymphoma (n = 16), mantle cell lymphoma (n = 10), and T cell lymphoma (n = 6). Pretransplant, 93% achieved complete response (52%) or partial response (41%) with a median of 3 prior therapies (n = 3 prior autologous stem cell transplantation). Donors were Matched sibling donors (MSD) (n = 21), matched unrelated donors (MUD) (n = 24), miss-matched unrelated donors (MMUD) (n = 6), and syngeneic (n = 1). Acute graft-versus host disease (GVHD) developed in 52% (81% grade I to II) and chronic GVHD (83% extensive) in 12%. MDRC of T cells (MDRCt) developed in 62% (n = 32), and 29% (n = 15) developed MDRC of myeloid cells (MDRCm) at a median onset of 100 days. Donor lymphocyte infusion (DLI) was given to 17 patients, with a median starting dose of 1 × 10⁶/kg. The first DLI was given at a median of 225 days post-transplant (range, 99 days to 5.3 years). Of these, 9 developed acute post-DLI GVHD and 2 limited chronic GVHD. Conversion to full donor occurred in 47% MDRCt and 50% MDRCm. Multivariate analysis identified sibling donor type as associated with increased MDRCt (P = .035; hazard ratio [HR], 0.17) and reduced total nucleated cell dose with increased MDRCm (P = .021; HR, 0.76). The median follow-up was 6 years, and 2-year NRM cumulative incidence was 16% (95% confidence interval [CI], 7% to 27%). Ten-year progression and extensive GVHD-free survival was 45% (95% CI, 28% to 61%), and overall survival was 66% (95% CI, 50% to 78%). One-year landmark analysis identified no increased GVHD or relapse risk with MDRCt or MDRCm but reduced nonrelapse mortality (NRM) risk with MDRCt (P = .001). BEAM-Campath allografts for high-risk lymphoma achieve long-term disease-free survival with low rates of GVHD and transplant-related mortality. The frequent development of myeloid MDRC demonstrates that BEAM-Campath is a nonmyeloablative conditioning regimen in almost a third of patients. MDRCt is associated with reduced NRM, but neither MDRCt or MDRCm is associated with increased GVHD or relapse.

Allogeneic stem cell transplantation for relapsed or refractory lymphoma after conditioning with BEAM/fludarabine/TBI

Allogeneic stem cell transplant (SCT) after high-dose conditioning with BEAM/fludarabine/total body irradiation (TBI) in patients with relapsed or refractory lymphoma has shown promising results in a pilot study. In this trial, we treated 50 consecutive patients with refractory or relapsed lymphoma or chronic lymphocytic leukemia (CLL). The patients included were considered to have poor-prognosis disease (eg, one-third was chemo-refractory at transplantation and more than one-half had failed previous autologous or allogeneic SCT). All patients engrafted and achieved full donor chimerism. Grade II-IV acute graft-versus-host disease (aGVHD) occurred in 64% of patients (95% confidence interval [CI], 52% to 79%), and chronic GVHD (cGVHD) in 51% (95% CI, 36% to 66%). At 3 years, overall survival was 61% (95% CI, 46% to 75%). Progression-free survival was 55% (95% CI, 40% to 70%), with 30% (95% CI, 19% to 47%) transplantation-related mortality and a relapse incidence of 15% (95% CI, 7% to 32%). Disease classification and stage as well as remission status at transplantation and type of previous treatment (including previous SCT) had no significant impact on transplantation outcome. In conclusion, allogeneic SCT after BEAM/fludarabine/TBI provides excellent tumor control with complete and durable remissions in patients with poor-prognosis lymphoma and CLL. High rates of GVHD and GVHD-related mortality associated with this regimen are a major concern and warrant modification of the regimen in the future.

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

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

Emerging role of CD20 blockade in allogeneic hematopoietic cell transplantation

There is growing evidence incriminating B lymphocytes in the pathogenesis of graft-versus-host disease (GVHD). Better understanding of the role of B lymphocytes has uncovered new therapeutic approaches, such as CD20 blockade, which appear to be improving outcomes in allogeneic hematopoietic cell transplant recipients. Administration of the chimeric murine/human anti-CD20 monoclonal antibody, rituximab, prior to hematopoietic cell allografting or as part of preparative regimens appears to reduce treatment-related mortality and to improve posttransplant outcomes mainly by decreasing the incidence and severity of acute GVHD. This beneficial effect of rituximab has not had an impact, to the same extent on the incidence of chronic GVHD, which remains a significant cause of morbidity and mortality following hematopoietic cell allografting. Alternatively, rituximab has been shown to be effective for treatment of cGVHD, but data is limited because of the lack of randomized controlled clinical trials and the small sample size in most of the published series. Incorporation of rituximab into the therapeutic armamentarium of Epstein-Barr virus-associated posttransplant lymphoproliferative disorder has clearly improved the overall prognosis of this dreadful disease. This review highlights the evolving role of CD20 blockade in allogeneic hematopoietic cell transplantation and the need to continue to refine B cell depletion strategies in this setting.

Advanced-stage follicular lymphoma in the rituximab era: when should patients receive anthracycline-based chemotherapy?

Follicular lymphoma (FL), the most common subtype of indolent lymphoma, is usually diagnosed at an advanced stage (III-IV), although patients are often asymptomatic. Traditionally, a palliative approach to management has been taken, cycling through watchful waiting, radiotherapy, oral alkylating agents and, eventually, combination chemotherapy, as deemed necessary. However, accumulating evidence suggests that in patients requiring treatment, early initiation of an anthracycline-based regimen may achieve better response rates and progression-free survival compared with reserving such options until late in the course of disease. Delivery of myelosuppressive chemotherapy has been facilitated by the availability of granulocyte colony-stimulating factors. Incorporation of the anti-CD20 monoclonal antibody rituximab into upfront chemotherapy regimens further improves outcomes. With a trend towards early use of rituximab chemotherapy combinations, median survival appears to have increased in patients with FL. A number of issues remain to be addressed by ongoing research. These include identification of the most effective rituximab chemotherapy regimen, the impact of treatment on responsiveness to future treatment, the need for rituximab maintenance therapy and the place of newer treatments. Clearly, there are arguments in favour of considering early aggressive rituximab and chemotherapy regimens in patients with FL requiring treatment, and it is hoped that new prognostic tools will help us to more accurately identify which patients are most likely to benefit.

The role of purine analogues in low-intensity regimens with allogeneic hematopoietic stem cell transplantation

Host conditioning prior to allogeneic bone marrow transplantation (BMT) has traditionally involved the use of high-dose, myeloablative chemotherapy and irradiation, focusing on maximal tumor cytoreduction as well as adequate immunosuppression to allow engraftment of allogeneic stem cells. High-dose chemoradiation conditioning regimens have been associated with a significant incidence of organ toxicity and acute and chronic graft-versus-host disease (GVHD). Recent efforts to diminish the acute transplant-associated toxicities have focused on the development of relatively nontoxic, nonmyeloablative, or less myeloablative conditioning regimens, with the emphasis being predominantly on induction of immunosuppression to enable engraftment. Without ablative chemotherapy, disease control in these regimens is largely relegated to the graft-versus-leukemia/lymphoma (GVL) effect. While the evolution these regimens has resulted in successful engraftment of allogeneic stem cells with minimal toxicity, acute and chronic GVHD occurs in 20% to 50% of patients and remains a major cause of transplant-associated morbidity. Strategies to lower the incidence of acute GVHD have primarily focused on more precise molecular donor/recipient matching, alternative stem cell sources, and T-cell depletion of the graft. While successful in lowering the frequency and severity of GVHD, T-cell-depleted grafts have been associated with compromised the graft-versus-disease effect. Recent studies have suggested that, in addition to T-effector cells within the graft, donor and host dendritic cells may play a role in GVHD. Purine analogues have been evaluated as part of these regimens. While fludarabine and cladribine have been shown to be effective, these agents have been associated with an increased incidence of serious infection and severe acute GVHD. Pentostatin has a different mechanism of action and was also investigated as part of these preparative regimens. Regimens using pentostatin/extracorporeal photopheresis (ECP)/total body irradiation (TBI) have been shown to be well tolerated and associated with early full donor engraftment with a predominance of donor dendritic cell (DC)2 cells and a low incidence of acute GVHD. Further investigation evaluating this preparative regimen is warranted.

The graft-versus-lymphoma effect: clinical review and future opportunities

Numerous lines of preclinical and clinical evidence support the existence of a graft-versus-leukemia effect, but less evidence supporting a comparable graft-versus-lymphoma effect exists. We review here current clinical data addressing the graft-versus-lymphoma effect, including comparisons of autologous, syngeneic, and allogeneic transplantation; responses to immunomodulation; and responses to nonmyeloablative stem cell transplantation. Despite several limitations of the data, we believe that there is sufficient evidence suggesting a significant graft-versus-lymphoma effect. In addition, we discuss approaches for clinical management of lymphoma patients, opportunities for mechanistic studies afforded by donor leukocyte infusions and nonmyeloablative transplantation, and suggestions for clinical studies to further define the magnitude and applicability of the graft-versus-lymphoma effect.

The influence of the conditions of hematopoietic cell transplantation on infectious complications

PURPOSE OF REVIEW

The multitude of factors that influence the risk of infection after hematopoietic cell transplantation has been further complicated by the rapid evolution of this therapy in the past 5 years. The degree to which functional immune reconstitution has been achieved reflects the equilibrium reached by the immune systems of the recipient and donor in the context of host non-hematopoietic tissue. Thus immunomodulatory influences on the recipient and the transplanted graft, both before and after hematopoietic cell transplantation, have a profound influence on the incidence and severity of infection. This review of the recent literature contributes to our understanding of how the conditions of hematopoietic cell transplantation influence the timing and nature of infectious complications.

RECENT FINDINGS

The main themes of published primary research from 2004 to the present focus on non-myeloablative conditioning regimens and their effects on immune reconstitution after hematopoietic cell transplantation.

SUMMARY

A plethora of clinical trials are ongoing, focused on the outcome after conditioning regimens designed to result in less regimen-related toxicity while preserving or enhancing the graft-versus-tumor effect. Given the infancy of these new approaches, it is not possible to make definitive statements regarding the relative risk of serious infection with each therapy. It is clear that a reduction in regimen-related non-infectious complications or mortality does not necessarily ensure a reduction in clinically significant infections. Improvements in early diagnostic and therapeutic options for these infections now bring us to an era of understanding pathogens as probes of the functional reconstitution of immunity.

Detection and monitoring of minimal residual disease by quantitative real-time PCR

BACKGROUND

The detection of malignant cells by quantitative real-time PCR has become state of the art for diagnosis, monitoring response to treatment and detection of minimal residual disease (MRD) in patients with leukemia or lymphoma. In order to be used in high-throughput analyses technical details have to be standardized to improve reproducibility and comparability of quantitative results obtained in different laboratories.

METHODS

Molecular monitoring of disease activity during and after treatment based on the detection of malignant cells in circulation or bone marrow by quantitative real-time PCR will be helpful to develop individualized treatment strategies for every patient.

CONCLUSIONS

The effectiveness of any kind of innovative treatment with specific antibodies, cellular immunotherapy or molecules designed for specific targets of tumor cells can be controlled at a very high level of sensitivity and accuracy. Based on quantitative results indicative for success or treatment failure, therapeutic changes upon the detection of progressive disease at the molecular level can be made even before symptoms or signs of clinical relapse occur. Hopefully, this will lead to higher cure rates and improved long-term survival.

LightCyclerR-based quantitative real-time PCR monitoring of patients with follicular lymphoma receiving rituximab in combination with conventional or high-dose cytotoxic chemotherapy

OBJECTIVES

Quantitative real-time polymerase chain reaction (qPCR) is a suitable method to measure residual disease in hematological malignancies. Our objective was to assess a LightCycler-based qPCR for t(14;18)(q32;q21)(IgH/bcl-2)-positive cells quantification in the context of clinical and morphopathological characteristics of patients with follicular lymphoma treated with rituximab (R) in combination with conventional or high-dose chemotherapy.

METHODS

A total of 270 bone marrow (BM) and peripheral blood (PB) samples collected from 52 patients with follicular lymphoma at diagnosis or at relapse before or sequentially during therapy were examined by qPCR and nested-PCR.

RESULTS

A greater amount of t(14;18)-positive cells was observed in BM in comparison with PB in 76% of paired samples. The presence and number of t(14;18)-positive cells in BM and PB correlated with lymphoma activity. Significantly higher numbers of lymphoma cells were found in patients under non-remission compared with patients in clinical remission. During non-remission, 10-fold higher numbers were measured at relapse than at diagnosis. During remission, significantly higher levels were found in partial compared with complete remission. During first-line therapy, R/cyclophosphamide/adriamycin/vincristine/prednisone (CHOP) had higher in vivo purging ability than R/fludarabine/mitoxantrone (FM). After R/high-dose cytosine-arabinoside and mitoxantrone (HAM) or R/carmustine/etoposide/cytarabine/melphalan (BEAM), the level of t(14;18)-positive cells dropped below the detection limit in 80% of patients.

CONCLUSIONS

LightCycler qPCR is a reliable method for quantitative molecular monitoring of t(14;18)-positive cells in BM and PB of patients with follicular lymphoma. It reflects the clinical characteristics of patients and allows assessment of response to different treatment regimens on a molecular level.