Myeloablative radiochemotherapy followed by reinfusion of purged autologous stem cells for Waldenström's macroglobulinaemia

Efficacy of Autologous and Allogeneic Hematopoietic Cell Transplantation in Waldenström Macroglobulinemia: A Systematic Review and Meta-analysis

INTRODUCTION

Waldenström macroglobulinemia (WM) is an IgM-producing lymphoproliferative disorder that remains incurable. Patients with high-risk disease have an overall survival (OS) of less than 3 years. Both autologous (AHCT) and allogeneic (allo-HCT) hematopoietic cell transplantation (HCT) are prescribed for treatment of WM despite a lack of randomized controlled studies.

MATERIALS AND METHODS

We performed a comprehensive literature search using PubMed/Medline and EMBASE on September 10, 2019. Data on clinical outcomes related to benefits and harms was extracted independently by 3 authors. Fifteen studies (8 AHCT [n = 278 patients], 7 allo-HCT [n = 311 patients]) were included in this systematic review/meta-analysis.

RESULTS

Pooled OS, progression-free survival (PFS), and nonrelapse mortality (NRM) rates post AHCT were 76% (95% confidence interval [CI], 65%-86%), 55% (95% CI, 42%-68%), and 4% (95% CI, 1%-7%), respectively. Pooled OS, PFS, and NRM rates post allografting were 57% (95% CI, 50%-65%), 49% (95% CI, 42%-56%), and 29% (95% CI, 23%-34%), respectively. OS and PFS rates were reported at 3 to 5 years, and NRM was reported at 1 year in most studies. Pooled ORR (at day 100) post AHCT and allo-HCT were 85% (95% CI, 72%-94%) and 81% (95% CI, 69%-91%), respectively. Pooled complete response rates post AHCT and allo-HCT were 22% (95% CI, 17%-28%) and 26% (95% CI, 7%-50%), respectively. Relapse rates post AHCT and allo-HCT were 42% (95% CI, 30%-55%) and 23% (95% CI, 18%-28%), respectively.

CONCLUSIONS

Our results show that both AHCT and allo-HCT are effective in the treatment of WM. A 2-fold lower relapse rate but a 7-fold higher NRM was noted for allo-HCT compared with AHCT. The role of transplant in WM needs to be addressed in the era of novel agents.

Waldenstrom Macroglobulinemia: Genomic Aberrations and Treatment

Waldenström macroglobulinemia (WM) is a rare, indolent, and monoclonal immunoglobulin M-associated lymphoplasmacytic disorder with unique clinicopathologic characteristics. Over the past decade, remarkable progress has occurred on both the diagnostic and therapeutic fronts in WM. A deeper understanding of the disease biology emanates from the seminal discoveries of myeloid differentiation primary response 88 (MYD88) L265P somatic mutation in the vast majority of cases and C-X-C chemokine receptor, type 4, mutations in about a third of patients. Although WM remains an incurable malignancy, and the indications to initiate treatment are largely unchanged, the therapeutic armamentarium continues to expand. Acknowledging the paucity of high-level evidence from large randomized controlled trials, herein, we evaluate the genomic aberrations and provide a strategic framework for the management in the frontline as well as the relapsed/refractory settings of symptomatic WM.

Waldenström macroglobulinemia: What a hematologist needs to know

Waldenström macroglobulinemia (WM) is a distinct hematologic malignancy characterized by a lymphoplasmacytic bone marrow infiltration and the presence of immunoglobulin (Ig)M monoclonal protein. Patients typically present at an advanced age, and a substantial proportion are asymptomatic at diagnosis. A unifying diagnosis of WM may be missed by an unsuspecting hematologist, as symptomatic patients present with a multitude of non-specific manifestations. Although constitutional and neuropathy-related symptoms predominate, concomitant IgM-induced hyperviscosity-associated features can provide useful diagnostic clues. There are specific indications for initiation of therapy. This review focuses on the most up-to-date management strategies of WM, in addition to highlighting the recent discoveries of MYD88 and CXCR4 mutations that have shed unprecedented light on the complex signaling pathways, and opened avenues for novel therapeutic targeting. Although WM remains incurable, with the rapid emergence and integration of effective novel therapies, its clinical course appears poised to improve in the foreseeable future.

Advances in the treatment of Waldenström’s macroglobulinemia

Waldenström's macroglobulinemia is a distinct disorder characterized by a monoclonal immunoglobulin M paraprotein and morphological evidence of lymphoplasmacytic lymphoma. It is relatively rare, accounting for approximately 2% of all hematological malignancies. The aim of treatment for patients with Waldenström's macroglobulinemia should be to improve the quality and duration of life with minimal side effects in the most cost-effective manner. It is not yet clear if achievement of a complete remission confers clinical benefit and it is possible that prolonging therapy to maximal response may increase toxicity without extra benefit. Plasma exchange is indicated for the acute management of patients with severe problems due to a circulating paraprotein. There are no comparative data but alkylating agent-based treatments, combination therapy or purine analogs are all suitable choices for the initial therapy of patients requiring treatment. In younger patients, in whom high-dose treatment is contemplated, there is a role for the use of rituximab; however, it should be administered with caution in patients with high levels of immunoglobulin M paraprotein or signs of hyperviscosity because of the risk of 'flare' in the paraprotein level and consequent adverse clinical events.

Update on therapeutic options in Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a B-cell disorder characterized primarily by bone marrow infiltration with lymphoplasmacytic cells (LPCs), along with demonstration of an IgM monoclonal gammopathy in the blood. WM remains incurable, with 5-6 yr median overall survival for patients with symptomatic WM. The main therapeutic options include alkylating agents, nucleoside analogues, and rituximab, either in monotherapy or in combination. Studies involving combination chemotherapy are ongoing, and preliminary results are encouraging. However, there are several limitations to these approaches. The complete response rate is low and the treatment free survival are short in many patients, no specific agent or regimen has been shown to be superior to another, and no treatment has been specifically approved for WM. As such, novel therapeutic agents are needed for the treatment of WM. In ongoing efforts, we and others have sought to exploit advances made in the understanding of the biology of WM so as to develop new targeted therapeutics for this malignancy. These efforts have led to the development of proteasome inhibitors, of them bortezomib, several Akt/mTor inhibitors, such as perifosine and Rad001, and immunomodulatory agents such as thalidomide and lenalidomide. Many agents and monoclonal antibodies are currently being tested in clinical trials and seem promising. This report provides an update of the current preclinical studies and clinical efforts for the development of novel agents in the treatment of WM.

The outcome of haemopoietic stem cell transplantation in the treatment of lymphoplasmacytic lymphoma in the UK: a British Society Bone Marrow Transplantation study

Lymphoplasmacytic lymphoma (LL) is incurable by standard therapy (median survival: 60 months). UK transplant registry data 1984-2003 identified 18 cases of histologically verified LL (median age: 50 years, range: 38-58 years). Nine patients received high dose chemotherapy [plus total body irradiation (TBI) in 1/9] and autologous peripheral blood stem cells (PBSC). Disease status at transplant was complete remission (2), partial remission (5), primary refractory (1) or relapse (1). Transplant related mortality (TRM) at 12 months was 0%. Median follow-up is 44 months with 4 year disease free survival 43% and overall survival 73%. Karnofsky performance status (KPS) is 80-100%. The nine allografted patients (median age: 49 years, range: 39-56 years) were conditioned with standard TBI (2), BEAM (2) or FLU-MEL (5) and received PBSC from HLA-matched sibling (8) or unrelated (1) donors. Disease status at transplant was partial remission (7) or primary refractory (2). TRM at 12 months was 44%. Complications included graft failure (2), grades I-II acute graft versus host disease (aGVHD) (2), grades III-IV aGVHD (3) and chronic GVHD (4). Median follow-up is 32 months with 4 year disease free survival 44% and overall survival 56%. KPS is 70-100%.

Waldenström macroglobulinaemia

Over time, Waldenström macroglobulinaemia (WM) has evolved conceptually from a clinical syndrome to a distinct clinicopathological entity. Progress is being made in standardization of the disease definition and treatment response criteria, although nosologic controversies persist. According to the Second International Workshop on WM, the disease is defined as a B-cell neoplasm characterized by a lymphoplasmacytic infiltrate in the bone marrow, with an associated immunoglobulin (Ig) M paraprotein. Disease symptoms are often divided into those related to tumour infiltration and those related to the rheological effects of the monoclonal IgM. As with other low-grade lymphomas, asymptomatic patients are observed only, with treatment reserved for symptomatic patients. There is no standard treatment for WM and choices include rituximab, alkylating agents, purine nucleoside analogues, alone or in combination, as well as autologous peripheral blood stem cell transplant in eligible patients. Novel treatments, such as bortezomib, oblimersen sodium, perifosine and others are being evaluated.

Primary Treatment of Waldenström Macroglobulinemia With Dexamethasone, Rituximab, and Cyclophosphamide

Purpose

Alkylating agents and the anti-CD20 monoclonal antibody rituximab are among appropriate choices for the primary treatment of symptomatic patients with Waldenström macroglobulinemia (WM), and they induce at least a partial response in 30% to 50% of patients. To improve these results, we designed a phase II study that included previously untreated symptomatic patients with WM who received a combination of dexamethasone, rituximab, and cyclophosphamide (DRC).

Patients and Methods

Seventy-two patients were treated with dexamethasone 20 mg intravenously followed by rituximab 375 mg/m2intravenously on day 1 and cyclophosphamide 100 mg/m2orally bid on days 1 to 5 (total dose, 1,000 mg/m2). This regimen was repeated every 21 days for 6 months. Patients' median age was 69 years and many had features of advanced disease such as anemia (57%), hypoalbuminemia (40%), and elevated serum beta2-microglobulin (43%).

Results

On an intent-to-treat basis, 83% of patients (95% CI, 73% to 91%) achieved a response, including 7% complete, 67% partial, and 9% minor responses. The median time to response was 4.1 months. The 2-year progression-free survival rate for all patients was 67%; for patients who responded to DRC, it was 80%. The 2-year disease-specific survival rate was 90%. Treatment with DRC was well tolerated, with 9% of patients experiencing grade 3 or 4 neutropenia and approximately 20% of patients experiencing some form of toxicity related to rituximab.

Conclusion

Our large, multicenter trial showed that the non–stem-cell toxic DRC regimen is an active, well-tolerated treatment for symptomatic patients with WM.

Evidence of graft-versus-Waldenstrom's macroglobulinaemia effect after allogeneic stem cell transplantation: a single centre experience

The role of allogeneic stem cell transplantation (SCT) in Waldenstrom's macroglobulinaemia (WM) is not yet clear, as published data on allogeneic SCT in WM are limited. We present a retrospective study of allogeneic SCT in five patients with WM. Median age was 56 years (range 40-60 years). All patients were heavily pretreated. Conditioning therapy with busulphan and cyclophosphamide was used for all patients and all were given cyclosporine and methotrexate for graft-versus-host disease prophylaxis. With a median follow-up of 32 months (range 2-43), all except one are alive and disease free. Progressive, delayed decline in serum IgM levels were noted in all the patients, suggesting an active graft-versus-Waldenstrom's effect. With the limited available data, it appears that allogeneic SCT is a useful treatment option for advanced WM.

Treatment of Waldenstrom’s Macroglobulinemia

Waldenstrom's macroglobulinemia is defined by bone marrow lymphoplasmacytic infiltration and by production of monoclonal IgM. Treatment is employed only to symptomatic patients. Alkylating agents (chlorambucil), nucleoside analogues and rituximab are reasonable choices for primary therapy. Combination therapy either with nucleoside analogues with alkylating agents and/or rituximab or rituximab with chemotherapy such as CHOP or cyclophosphamide are also reasonable frontline treatment options for WM patients. Several factors should be taken into account when choosing the most appropriate primary treatment. These factors include the age of the patient and possible co-morbidities, the presence of cytopenias and especially thrombocytopenia, the presence of symptoms and signs indicative of hyperviscosity, the need for rapid disease control due to severe symptoms, significant splenomegaly or lymphadenopathy, symptomatic peripheral neuropathy and whether the patient is candidate for autologous stem cell transplantation. For patients with refractory or relapsing disease, the use of an alternate first-line agent is reasonable. Outside the setting of a clinical trial, the administration of high-dose therapy should be reserved only for patients refractory to alkylating agents, purine nucleoside and rituximab. For patients who develop resistance to all three classes of agents, alemtuzumab, thalidomide with or without dexamethasone or bortezomib could be tried.

Waldenström macroglobulinemia: a review of therapy

Waldenström macroglobulinemia is a rare monoclonal gammopathy-associated lymphoplasmacytic lymphoma. Its incidence is only 4 per million per year. This review contains the known published literature specifically on the available management tools for Waldenström macroglobulinemia and is designed to assist clinicians in making management decisions for patients with this uncommon disorder.

Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a low-grade lymphoproliferative disorder characterized by the presence of an immunoglobulin M monoclonal protein in the blood and monoclonal small lymphocytes and lymphoplasmacytoid cells in the marrow. The disease is uncommon and there is a lack of clear diagnostic criteria. WM is treatable but not curable and long-term survival is possible. Therefore, the treating physician needs to carefully balance the risks and benefits of treatment. Treatments are aimed at relieving symptoms resulting from marrow infiltration and the hyperviscosity syndrome. Therapies available for initiation of treatment include alkylating agents, purine nucleoside analogs, and rituximab. Chlorambucil has been the mainstay of treatment for many years and remains useful, especially in older patients. Rituximab has become an important new therapy for this disease because of its positive treatment responses, acceptable toxicity, and lack of therapy-associated myelosuppression and myelodysplasia. Currently, rituximab is being combined with chemotherapy. Other options of treatment include interferon and corticosteroids. Emerging therapies include stem cell transplantation (autologous and allogeneic) for younger patients. Currently, there are few comparative data on which to state an absolute opinion concerning the best available treatment for patients with WM.

Treatment for Waldenstrom’s macroglobulinemia

Waldenstrom's macroglobulinemia is a rare form of indolent lymphoma characterized by the production of a monoclonal immunoglobulin M protein, and complications such as hyperviscosity, cytopenias and peripheral neuropathy. Conventional treatment approaches are based on alkylators or nucleoside analogs, but in the absence of a clearly superior regimen, a broad array of alternative therapies exists. Choices range from biological agents to combination chemotherapy to stem-cell transplantation. A rational approach therefore must be based on careful patient assessment and individualization of therapy.

Waldenström macroglobulinaemia

Waldenström macroglobulinemia (WM) is a lymphoid neoplasm characterised by a monoclonal lymphoplasmacytic expansion accompanied by a serum monoclonal immunoglobulin M (IgM). In some patients, the monoclonal protein will lead to a characteristic hyperviscosity syndrome. Although indolent, WM is incurable and most patients eventually succumb to disease progression. Thus, we need to better understand the natural history and biology of the disease. Recent work has shown that half of patients with WM harbour deletions in the long arm of chromosome 6. Increasing evidence suggests the disease is a defined pathological entity and not purely a clinical syndrome. Current therapeutic modalities include alkylator agents, purine nucleoside analogues, and rituximab. The optimum initial therapeutic strategy is not yet defined, and current clinical trials are addressing the role of combination therapy. In this review, we summarise the current understanding of the pathogenesis, clinical and laboratory features, prognostic factors, and therapeutic options for patients with WM. We also discuss current knowledge of WM and available therapies.

Transplantation in Waldenstrom's macroglobulinemia--the French experience

Published data on transplantation in Waldenstrom's macroglobulinemia (WM) are still limited. We present a retrospective multicentric study of 27 WM patients who underwent 19 autologous (median age, 54 years) and 10 allogeneic (median age, 46 years) transplantations. Median time between diagnosis and transplantation was 36 months; 66% of patients had received three or more treatment lines and 72 % had chemosensitive disease. High-dose therapy (HDT) and autologous transplantation induced a 95% response rate (RR), including 10 major responses. With a median follow-up of 18 months, 12 patients are alive at 10 to 81 months and eight are free of disease progression at 10 to 34 months. The toxic mortality rate (TRM) was 6%. Allogeneic transplantation was preceded by HDT in nine patients and by a nonmyeloablative regimen in one patient. The RR was 80%, including seven major responses. With a median follow-up of 20.5 months, six patients are alive and free of progression at 3 to 76 months. Four patients died, all from toxicity, resulting in a TRM of 40%. HDT followed by autologous transplantation is feasible in WM, even in heavily pretreated patients, with some prolonged responses but a high relapse rate. Conversely, allogeneic transplantation is more toxic, but likely induces a graft-versus-WM effect and may, for some patients, result in long-term disease control.

Role for high-dose therapy with autologous hematopoietic stem cell support in Waldenstrom's macroglobulinemia

Despite effectiveness of standard chemotherapy regimens, complete responses are infrequent in Waldenstrom's macroglobulinemia (WM) and there are no cures. Since WM shares certain biological and clinical features with myeloma, including responsiveness to alkylating agents, evaluation of high-dose therapy (HDT) with transplant, which is effective in myeloma, is an obvious next step in an effort to achieve high response rates and improve survival. Due to the indolent nature of the disease and older patients with comorbidities, such evaluations have been infrequent in the past. We have evaluated the safety and efficacy of high-dose melphalan with peripheral blood stem cell (PBSC) support in eight patients between the ages of 45 and 69 years with WM. Adequate numbers of stem cells were collected in six patients; however, two patients with more extensive prior fludarabine therapy failed to collect adequate cells and required a second attempt at stem cell collection. Seven patients were treated with melphalan 200 mg/m(2), including two patients who received tandem transplants; one patient received melphalan 140 mg/m(2) with total body irradiation (TBI). There was no treatment-related mortality and toxicities were manageable. Recovery of bone marrow after transplant was prompt except in one patient with extensive prior use of fludarabine. All the eight patients achieved at least partial response (PR), including one complete response (CR). Five patients are alive and with out relapse (77+ to 6+ months post-transplant). Other investigators have reported similar experience suggesting safety and efficacy of HDT in WM. However, therapy with purine analogues leads to stem cell damage with decreased ability to collect adequate numbers of stem cells. This suggests that the PBSCs should preferably be procured prior to extensive use of purine analogues. Future strategies in WM will include a plan to evaluate the role of HDT along with biological agents, role of purging using rituximab, post-HDT maintenance strategies (including immunotherapy), and evaluation of nonmyeloablative regimens containing fludarabine to achieve higher response rates and improve survival.

Autologous and allogeneic stem cell transplantation in Waldenstrom's macroglobulinemia: review of the literature and future directions

Waldenstrom's macroglobulinemia (WM) is a chronic lymphoproliferative disorder characterized by lymphoplasmacytic infiltrate and a monoclonal IgM serum peak. Treatment includes cytotoxic chemotherapy with alkylators, or purine nucleoside analogues and monoclonal anti-CD20 antibody. The role of stem cell transplantation (SCT) in WM has not been established. We identified 24 published cases of WM treated with high-dose chemotherapy (HDC) followed by autologous SCT (ASCT). The median age was 50 years; half of the patients had refractory disease and received a variety of preparative regimens. Nine complete and 14 partial responses were observed, with one early death. Fifteen patients were alive and well at follow-ups ranging from 1 to 132 months. Six additional patients, with a median age of 45 years (range, 30 to 62), who received allogeneic SCT have been reported. All were heavily pretreated with refractory or relapsed disease. Median time from diagnosis to transplant was 3.1 years (range, 1.3 to 7). Two patients died of complications of the procedure while one died of disease progression. Three patients were alive and well between 5 and 112 months post-transplant. The small number of reported patients precludes any significant conclusion except that SCT is feasible in WM and long-term disease control can be achieved in selected patients with autologous or allogeneic SCT, even in those with refractory disease.

Waldenström's macroglobulinaemia: current therapy and future approaches

Waldenström's macroglobulinaemia is a rare B-cell malignancy. It is prevalent in the sixth and seventh decades, the median age at diagnosis being 63 years. Conventional treatment has involved alkylator therapy, especially chlorambucil given daily at a low dose or intermittently at a higher dose. Purine analogues, used initially as salvage therapy in refractory disease, are increasingly used for initial therapy. However, purine analogue therapy entails significant complications, including immunosuppression, pancytopenia and autoimmune haemolysis. Moreover, it is unclear whether purine analogues extend survival. All of these need to be considered before initiation of therapy. More recently, anti-CD20 monoclonal antibody and thalidomide have been used with a 30% response in treated patients. High-dose therapy with stem cell support achieves a partial response in a majority of patients receiving this modality of therapy. The median survival of 5 years has not improved considerably since the introduction of purine analogues. Complete response is still uncommon; using all available modalities of therapy may increase the complete response rate and improve survival. Great strides in understanding the malignant cell, the microenvironment and the potential interactions have identified potential targets for therapy in multiple myeloma. These agents may also be useful in Waldenström's macroglobulinaemia. Since this is a rare malignancy, all patients should be treated with well-designed clinical protocols to achieve improvement in outcome.

Waldenström's macroglobulinaemia

Waldenström's macroglobulinaemia (WM) is most usefully defined as a distinct chronic lymphoproliferative disorder with characteristic marrow morphology and phenotype; although nodal morphology if available will reveal a lymphoplasmacytoid lymphoma, the presence of a significant IgM paraprotein defines the clinical features of the disease. The clonal cell is a B-cell expressing IgM, CD19, and CD20 but not IgD, CD5, CD10 or CD23 and has somatic hypermutation of immunoglobulin heavy chain variable regions consistent with a post-germinal centre origin. Treatment of WM has been dependent on alkylating agents with or without coriticosteroids for many years, supplemented by the use of therapeutic plasmapheresis in the initial stages for patients at risk from the clinical consequences of hyperviscosity. This approach to treatment results in response rates of approximately 60% with a median survival of about 60 months. There is increasing evidence to show that the purine analogues fludarabine and cladribine which are active in the treatment of patients who are resistant to alkylating agents such as chlorambucil may be able to achieve higher response rates when used as initial therapy. A prospective trial is being undertaken to compare fludarabine and chlorambucil as initial treatment; because of the effect of subsequent active treatment on patients who do not respond to the first treatment choice, the long-term outcome may be similar for both groups. Recent advances in therapy include the use of therapeutic monoclonal antibodies such as rituximab and the use of autologous or allogeneic transplant procedures for selected patients.

Waldenström's macroglobulinemia: a review of therapy

Waldenstrom's macroglobulinemia is a lymphoplasmacytic disorder characterized by a monoclonal IgM protein, anemia, hepatosplenomegaly, and hyperviscosity. With the increasing use of screening chemistry evaluations, many patients are diagnosed without symptoms and are candidates for observation with no therapeutic intervention until symptoms develop. Plasma exchange can be useful to manage hyperviscosity but does not address the infiltrative process in the bone marrow, which requires cytoreductive therapy. This review covers current regimens that have been used to manage Waldenstrom's macroglobulinemia, including alkylating agents, purine nucleoside analogs, and rituximab. The value of steroids, radiotherapy, stem cell transplantation, and splenectomy is also reviewed. The lack of phase III studies does not permit an algorithm that would be appropriate for all patients. Treatment needs to be individualized based on patient age, the clinical manifestations of Waldenström's, and the patient's potential for developing toxic side effects of the selected treatment regimen.

Stem cell transplantation (SCT) for Waldenstrom's macroglobulinemia (WM)

Waldenstrom's macroglobulinemia (WM) is a low-grade lymphoplasmacytoid malignancy of unknown etiology. It primarily affects elderly patients and is characterized by a monoclonal IgM component, varying degrees of cytopenias, lymphadenopathy and manifestations related to hyperviscosity syndromes. WM is usually treated with single agent nucleoside analogues or alkylating agents that often provide high response rates and durable remissions. Recurrence of the disease after primary therapy is not uncommon, and resistance to both alkylating agents and nucleoside analogs eventually emerges. Small numbers of patients have undergone high-dose chemotherapy (HDC) with either autologous (n = 24) or allogeneic (n = 6) stem cell transplantation (SCT) as treatment for this disease. Most patients in both groups achieved remission. Results are promising and a more in-depth analysis of possible applications of this treatment modality is attempted with this mini-review.

Multicenter, randomized comparative trial of fludarabine and the combination of cyclophosphamide-doxorubicin-prednisone in 92 patients with Waldenström macroglobulinemia in first relapse or with primary refractory disease

Few reports are available on the treatment of patients with Waldenström macroglobulinemia (WM) and primary or secondary resistance to alkylating-agent-based regimens. From December 1993 through December 1997, 92 patients with WM resistant to first-line therapy (42) or with first relapse (50) after alkylating-agent therapy were randomly assigned to receive fludarabine (25 mg/m(2) of body-surface area on days 1-5) or cyclophosphamide, doxorubicin (Adriamycin), and prednisone (CAP; 750 mg/m(2) cyclophosphamide and 25 mg/m(2) doxorubicin on day 1 and 40 mg/m(2) prednisone on days 1-5). The first end point evaluated was the response rate after 6 treatment courses. Forty-five patients received CAP and 45 received fludarabine. Two patients died before the first course of chemotherapy. No statistical differences were observed between the 2 treatment arms with respect to hematologic toxicity or infections. Mucositis and alopecia occurred significantly more often in patients treated with CAP. Partial responses were obtained in 14 patients (30%) treated with fludarabine and 5 patients (11%) treated with CAP (P =.019). Responses were more durable in patients treated with fludarabine (19 months versus 3 months), and the event-free survival rate was significantly higher in this group (P <.01). Forty-four patients died, 22 in the fludarabine group and 22 in the CAP group. There was no statistical difference in the median overall survival time in the 2 study arms. Fludarabine was thus more active than CAP in salvage therapy of WM and should be tested as first-line therapy in a randomized comparison with alkylating agents.

Successful non-myeloablative allogeneic peripheral blood stem cell transplantation (PBSCT) for Waldenström's macroglobulinemia with severe pancytopenia

We report a 62-year-old male who underwent non-myeloablative allogeneic peripheral blood stem cell transplantation (PBSCT) because of his life-threatening severe pancytopenia due to refractory Waldenström's macroglobulinemia. This therapy was performed safely and he made a marked recovery from his cytopenia that had not been improved with any other therapy. Bone marrow aspirates showed post-transplant mixed chimerism during engraftment, and became completely donor-derived after a series of GVHD symptoms, without subsequent donor lymphocyte infusion. Our results suggest that non-myeloablative allogeneic PBSCT could be a good alternative for patients suffering from multi-drug resistant Waldenström's macroglobulinemia.

Treatment options in Waldenström's macroglobulinaemia: the role of the purine analogues

The purine nucleoside analogues, either alone or in combination with other chemotherapeutic agents, are increasingly used in the treatment of patients with indolent B-cell lymphoproliferative disorders. The initial studies in Waldenström's macroglobulinaemia (WM) are very promising. Approximately 40% of patients who have received prior therapy with alkylating agents respond, while response rates of up to 90% have been documented in untreated patients. However, it is not known whether the purine analogues offer any significant advantage over alkylating agents such as chlorambucil. In this review the treatment options in WM and in particular the role of the purine analogues are discussed.

High-dose chemotherapy followed by stem cell transplantation in patients with resistant Waldenstrom's macroglobulinemia

Preliminary evidence suggests that high-dose chemotherapy followed by autologous or allogeneic stem cell transplantation may be effective in some patients with resistant Waldenstrom's macroglobulinemia. During the last 10 years, seven patients with Waldenstrom's macroglobulinemia have received transplants at the MD Anderson Cancer Center, four with autologous and three with allogeneic stem cells. Four patients achieved partial remission, and three patients have remained alive for at least 2 years. Our data confirm the feasibility of high-dose therapy in patients with macroglobulinemia and support the need for prospective studies of this modality in patients with chemosensitive disease.

A prospective study of positive/negative ex vivo B-cell depletion in patients with chronic lymphocytic leukemia

OBJECTIVE

Autologous peripheral blood stem cell (PBSC) transplantation is increasingly being used in patients with chronic lymphocytic leukemia (CLL). As the autografts are frequently contaminated with large numbers of tumor cells, we have prospectively investigated the feasibility and efficacy of ex vivo double purging of PBSC grafts in an open, nonrandomized, single-center phase I/II clinical study.

MATERIALS AND METHODS

Twenty consecutive patients with poor-risk CLL underwent uniform stem cell mobilization with chemotherapy and granulocyte colony-stimulating factor (G-CSF). Double B-cell depletion of the harvested PBSC products was performed using immunomagnetic CD34(+) cell selection (Isolex300i Nexell, Irvine, CA) followed by a negative step with anti-CD19/20/23/37-labeled immunomagnetic beads. The purified PBSC were reinfused after myeloablative treatment with TBI/CY.

RESULTS

A total of 25 separation runs was accomplished using collection products containing 3.4% (1.1-8.1) CD34(+) cells and 1.2% (0.1-42) CD19(+)CD5(+) CLL cells. After double selection, 33% (15-67) CD34(+) cells were recovered with a purity of 98.8% (89.1-99. 8). CLL cells were undetectable by high-resolution flow cytometry in 15 of 25 final products; median purging efficacy was 5 (4.1-6) log. The CD34(+) content of the 20 final grafts was 4.6 (2.2-6.5) x 10(6)/kg. Rapid and durable engraftment developed in all cases. With a median follow-up of 20 (6-29) months, 17 patients live in complete clinical remission, two have recurrent disease, and one patient died due to pulmonary embolism five months after transplant. Persistence of the leukemic clone on the molecular level was demonstrated by dot blotting with clone-specific CDR3 probes in an additional five patients. Serious or unexpected infectious complications did not occur.

CONCLUSIONS

Positive/negative purging with the Isolex system allows preparation of highly purified CD34(+) fractions and up to six log of tumor cell depletion in patients with B-CLL and can be safety reinfused after myeloablative therapy without affecting hematopoietic engraftment.

Waldenström's macroglobulinemia

Waldenström's macroglobulinemia (WM) is a clinical syndrome with diverse prognoses, and not all patients require therapy at diagnosis. Serum beta2 microglobulin is a major prognostic determinant, and asymptomatic patients with low beta2 microglobulin levels and preserved hemoglobin can be observed over long periods without therapy. Low-dose alkylating agents and purine analogs are commonly employed as initial therapy but rarely yield complete remissions. Patients who are refractory to or have relapse after alkylator or purine analogue therapy can be salvaged with purine analogs. Improvement in outcome demands a comprehensive approach aimed at increasing and sustaining complete remissions. Such an approach should probably employ Rituxan (IDEX Pharmaceuticals, La Jolla, CA) in conjunction with induction therapy, peripheral stem cell procurement before purine analog therapy, and high-dose therapy followed by maintenance therapy with interferon.

Waldenström's macroglobulinaemia: a prospective study comparing daily with intermittent oral chlorambucil

This prospective study compared continuous and intermittent chlorambucil therapy of untreated Waldenström's macroglobulinaemia. The diagnosis was established by the presence of an IgM monoclonal (M-) protein in the serum, an infiltrate of lymphocytes and plasma cells in the bone marrow, anaemia or other laboratory abnormalities, physical findings or constitutional symptoms. Patients were randomized to receive chlorambucil 0.1 mg/kg/d or chlorambucil 0.3 mg/kg/d orally for 7 d, repeated every 6 weeks. Criteria for response included 50% or more reduction of serum M-protein, increase in haemoglobin level of 2 g/dl without transfusion, >/= 50% decrease of urine M-protein, or a reduction of 2 cm in the size of the liver, spleen or lymph nodes. Forty-six patients were randomized to continuous chlorambucil (n = 24) or to intermittent chlorambucil (n = 22). Nineteen (79%) (95% CI = 58-93) of the 24 patients given continuous therapy had an objective improvement by either reduction of serum M-protein or increase in haemoglobin. Fifteen (68%) (95% CI = 45-86) of the 22 patients given chlorambucil intermittently had an objective response. The size of the liver decreased by >/= 2 cm in 55% of patients, and the size of the spleen decreased >/= 2 cm in 67%. Lymphadenopathy decreased in 71%. Acute leukaemia or refractory anaemia developed in four patients. The median duration of survival was 5.4 years, and there was no difference between the regimens. Chlorambucil is effective for the treatment of Waldenström's macroglobulinaemia. Patients must be treated for at least 6 months before therapy is abandoned because response is slow. Chlorambucil is an effective agent and should be compared with purine analogues or rituxan (Rituximab) in a prospective study.