Treatment of Waldenstrom's macroglobulinemia resistant to standard therapy with 2-chlorodeoxyadenosine: identification of prognostic factors

Diagnosis and Management of Waldenström Macroglobulinemia: Mayo Stratification of Macroglobulinemia and Risk-Adapted Therapy (mSMART) Guidelines 2016

Importance

Waldenström macroglobulinemia (WM), an IgM-associated lymphoplasmacytic lymphoma, has witnessed several practice-altering advances in recent years. With availability of a wider array of therapies, the management strategies have become increasingly complex. Our multidisciplinary team appraised studies published or presented up to December 2015 to provide consensus recommendations for a risk-adapted approach to WM, using a grading system.

Observations

Waldenström macroglobulinemia remains a rare, incurable cancer, with a heterogeneous disease course. The major classes of effective agents in WM include monoclonal antibodies, alkylating agents, purine analogs, proteasome inhibitors, immunomodulatory drugs, and mammalian target of rapamycin inhibitors. However, the highest-quality evidence from rigorously conducted randomized clinical trials remains scant.

Conclusions and Relevance

Recognizing the paucity of data, we advocate participation in clinical trials, if available, at every stage of WM. Specific indications exist for initiation of therapy. Outside clinical trials, based on the synthesis of available evidence, we recommend bendamustine-rituximab as primary therapy for bulky disease, profound hematologic compromise, or constitutional symptoms attributable to WM. Dexamethasone-rituximab-cyclophosphamide is an alternative, particularly for nonbulky WM. Routine rituximab maintenance should be avoided. Plasma exchange should be promptly initiated before cytoreduction for hyperviscosity-related symptoms. Stem cell harvest for future use may be considered in first remission for patients 70 years or younger who are potential candidates for autologous stem cell transplantation. At relapse, retreatment with the original therapy is reasonable in patients with prior durable responses (time to next therapy ≥3 years) and good tolerability to previous regimen. Ibrutinib is efficacious in patients with relapsed or refractory disease harboring MYD88 L265P mutation. In the absence of neuropathy, a bortezomib-rituximab-based option is reasonable for relapsed or refractory disease. In select patients with chemosensitive disease, autologous stem cell transplantation should be considered at first or second relapse. Everolimus and purine analogs are suitable options for refractory or multiply relapsed WM. Our recommendations are periodically updated as new, clinically relevant information emerges.

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.

Anti-tumor activities of lipids and lipid analogues and their development as potential anticancer drugs

Lipids have the potential for development as anticancer agents. Endogenous membrane lipids, such as ceramides and certain saturated fatty acids, have been found to modulate the viability of tumor cells. In addition, many tumors over-express cyclooxygenase, lipoxygenase or cytochrome P450 enzymes that mediate the biotransformation of ω-6 polyunsaturated fatty acids (PUFAs) to potent eicosanoid regulators of tumor cell proliferation and cell death. In contrast, several analogous products from the biotransformation of ω-3 PUFAs impair particular tumorigenic pathways. For example, the ω-3 17,18-epoxide of eicosapentaenoic acid activates anti-proliferative and proapoptotic signaling cascades in tumor cells and the lipoxygenase-derived resolvins are effective inhibitors of inflammatory pathways that may drive tumor expansion. However, the development of potential anti-cancer drugs based on these molecules is complex, with in vivo stability a major issue. Nevertheless, recent successes with the antitumor alkyl phospholipids, which are synthetic analogues of naturally-occurring membrane phospholipid esters, have provided the impetus for development of further molecules. The alkyl phospholipids have been tested against a range of cancers and show considerable activity against skin cancers and certain leukemias. Very recently, it has been shown that combination strategies, in which alkyl phospholipids are used in conjunction with established anticancer agents, are promising new therapeutic approaches. In future, the evaluation of new lipid-based molecules in single-agent and combination treatments may also be assessed. This could provide a range of important treatment options in the management of advanced and metastatic cancer.

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.

Novel agents in Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a B-cell disorder characterized by the infiltration of the bone marrow with lymphoplasmacytic cells and the detection of an IgM monoclonal gammopathy in the serum. WM is considered an incurable disease, with a median overall survival of 87 months. The success of targeted therapy in multiple myeloma has led to the development and investigation of more than 30 new compounds in this disease and in other plasma cell dyscrasias, including WM, both in the preclinical settings and as part of clinical trials. Among therapeutic options, first-line therapies have been based on single-agent or combination regimens with alkylator agents, nucleoside analogues and the monoclonal antibody anti-CD20. Based on the understanding of the complex interaction between WM tumor cells and the bone marrow microenvironment, and the signaling pathways that are deregulated in WM pathogenesis, a number of novel therapeutic agents are now available and have demonstrated significant efficacy in WM. The range of the overall response rate for these novel agents is between 25 and 96%. Ongoing and planned future clinical trials include those using protein kinase C inhibitors such as enzastaurin, new proteasome inhibitors such as carfilzomib, histone deacetylase inhibitors such as LBH589, humanized CD20 antibodies such as ofatumumab and additional alkylating agents such as bendamustine. These agents, when compared with traditional chemotherapeutic agents, may lead in the future to higher responses, longer remissions and better quality of life for patients with WM. This article will mainly focus on those novel agents that have entered clinical trials for the treatment of WM.

Phase II trial of weekly bortezomib in combination with rituximab in relapsed or relapsed and refractory Waldenstrom macroglobulinemia

PURPOSE

This study aimed to determine activity and safety of weekly bortezomib and rituximab in patients with relapsed/refractory Waldenström macroglobulinemia (WM).

PATIENTS AND METHODS

Patients who had at least one previous therapy were eligible. All patients received bortezomib intravenously weekly at 1.6 mg/m(2) on days 1, 8, and 15, every 28 days for six cycles and rituximab 375 mg/m(2) weekly on cycles 1 and 4. The primary end point was the percentage of patients with at least a minor response.

RESULTS

Thirty-seven patients were treated. The majority of patients (78%) completed treatment per protocol. At least minimal response (MR) or better was observed in 81% (95% CI, 65% to 92%), with two patients (5%) in complete remission (CR)/near CR, 17 patients (46%) in partial response, and 11 patients (30%) in MR. The median time to progression was 16.4 months (95% CI, 11.4 to 21.1 months). Death occurred in one patient due to viral pneumonia. The most common grade 3 and 4 therapy-related adverse events included reversible neutropenia in 16%, anemia in 11%, and thrombocytopenia in 14%. Grade 3 peripheral neuropathy occurred in only two patients (5%). The median progression-free (PFS) is 15.6 months (95% CI, 11 to 21 months), with estimated 12-month and 18-month PFS of 57% (95% CI, 39% to 75%) and 45% (95% CI, 27% to 63%), respectively. The median overall survival has not been reached.

CONCLUSION

The combination of weekly bortezomib and rituximab showed significant activity and minimal neurologic toxicity in patients with relapsed WM.

Phase II trial of the oral mammalian target of rapamycin inhibitor everolimus in relapsed or refractory Waldenstrom macroglobulinemia

PURPOSE The phosphatidylinositol 3-kinase/mammalian target of rapamycin (mTOR) signal transduction pathway controls cell proliferation and survival. Everolimus is an oral agent targeting raptor mTOR (mTORC1). The trial's goal was to determine the antitumor activity and safety of single-agent everolimus in patients with relapsed/refractory Waldenström macroglobulinemia (WM). PATIENTS AND METHODS Eligible patients had measurable disease (immunoglobulin M monoclonal protein > 1,000 mg/dL with > 10% marrow involvement or nodal masses > 2 cm), a platelet count more than 75,000 x 10(6)/L, a neutrophil count more than 1,000 x 10(6)/L, and a creatinine and bilirubin less than 2 x the laboratory upper limit of normal. Patients received everolimus 10 mg orally daily and were evaluated monthly. Tumor response was assessed after cycles 2 and 6 and then every three cycles until progression. Results Fifty patients were treated. The median age was 63 years (range, 43 to 85 years). The overall response rate (complete response plus partial remission [PR] plus minimal response [MR]) was 70% (95% CI, 55% to 82%), with a PR of 42% and 28% MR. The median duration of response and median progression-free survival (PFS) have not been reached. The estimated PFS at 6 and 12 months is 75% (95% CI, 64% to 89%) and 62% (95% CI, 48% to 80%), respectively. Grade 3 or higher related toxicities were observed in 56% of patients. The most common were hematologic toxicities with cytopenias. Pulmonary toxicity occurred in 10% of patients. Dose reductions due to toxicity occurred in 52% of patients. CONCLUSION Everolimus has high single-agent activity with an overall response rate of 70% and manageable toxicity in patients with relapsed WM and offers a potential new therapeutic strategy for this patient group.

Clinical and translational studies of a phase II trial of the novel oral Akt inhibitor perifosine in relapsed or relapsed/refractory Waldenstrom's macroglobulinemia

BACKGROUND

Waldenström's macroglobulinemia (WM) is a rare, low-grade lymphoproliferative disorder. Based on preclinical studies, we conducted a phase II clinical trial testing the efficacy and safety of the Akt inhibitor perifosine in patients with relapsed/refractory WM.

PATIENTS AND METHODS

Thirty-seven patients were treated with oral perifosine (150 mg daily) for six cycles. Stable or responding patients were allowed to continue therapy until progression.

RESULTS

The median age was 65 years (range, 44-82). The median number of prior therapy lines was two (range, one to five). Of the 37 patients, 4 achieved partial response (11%), 9 minimal response (24%), and 20 showed stable disease (54%). The median progression-free survival was 12.6 months. Additionally, beta2 microglobulin of >3.5 mg/dL was associated with poor event-free survival (P = 0.002). Perifosine was generally well tolerated; adverse events related to therapy were cytopenias (grade 3-4, 13%), gastrointestinal symptoms (grade 1-2, 81%), and arthritis flare (all grades, 11%). Translational studies using gene expression profiling and immunohistochemistry showed that perifosine inhibited pGSK activity downstream of Akt, and inhibited nuclear factor kappaB activity.

CONCLUSION

Perifosine resulted in at least a minimal response in 35% of patients and a median progression-free survival of 12.6 months in patients with relapsed or relapsed/refractory WM, as well as in vivo inhibition of pGSK activity. The results of this study warrant further evaluation of perifosine in combination with rituximab or other active agents in patients with WM.

New Therapeutic Approaches for Waldenstrom Macroglobulinemia

Waldenstrom Macroglobulinemia (WM) is a B-cell disorder characterized by the infiltration of the bone marrow (BM) with lymphoplasmacytic cells, as well as detection of an IgM monoclonal gammopathy in the serum. WM is an incurable disease, with an overall medial survival of only 5-6 years. First-line therapy of WM has been based on single-agent or combination therapy with alkylator agents (e.g. chlorambucil or cyclophasphamide), nucleoside analogues (cladribine or fludarabine), and the monoclonal antibody rituximab. Novel therapeutic agents that have demonstrated efficacy in WM include thalidomide, lenalidomide, bortezomib, everolimus, Atacicept, and perifosine. The range of the ORR to these agents is between 25-80%. Ongoing and planned future clinical trials include those using PKC inhibitors such as enzastaurin, new proteasome inhibitors such as carfilzomib, histone deacetylase inhibitors such as panobinostat, humanized CD20 antibodies such as Ofatumumab, and additional alkylating agents such as bendamustine. These agents, when compared to traditional chemotherapeutic agents, may lead in the future to higher responses, longer remissions and better quality of life for patients with WM.

New Therapeutic Approaches for Waldenstrom Macroglobulinemia

Waldenstrom Macroglobulinemia (WM) is a B-cell disorder characterized by the infiltration of the bone marrow (BM) with lymphoplasmacytic cells, as well as detection of an IgM monoclonal gammopathy in the serum. WM is an incurable disease, with an overall medial survival of only 5-6 years. First-line therapy of WM has been based on single-agent or combination therapy with alkylator agents (e.g. chlorambucil or cyclophasphamide), nucleoside analogues (cladribine or fludarabine), and the monoclonal antibody rituximab. Novel therapeutic agents that have demonstrated efficacy in WM include thalidomide, lenalidomide, bortezomib, everolimus, Atacicept, and perifosine. The range of the ORR to these agents is between 25-80%. Ongoing and planned future clinical trials include those using PKC inhibitors such as enzastaurin, new proteasome inhibitors such as carfilzomib, histone deacetylase inhibitors such as panobinostat, humanized CD20 antibodies such as Ofatumumab, and additional alkylating agents such as bendamustine. These agents, when compared to traditional chemotherapeutic agents, may lead in the future to higher responses, longer remissions and better quality of life for patients with WM.

Phase I/II trial of weekly intravenous 130-nm albumin-bound paclitaxel as initial chemotherapy in patients with stage IV non-small-cell lung cancer

PURPOSE

Nanoparticle albumin-bound paclitaxel (NAB-paclitaxel) is an albumin-bound formulation of paclitaxel that has demonstrated improved efficacy compared with paclitaxel in the treatment of metastatic breast cancer. We undertook this trial to determine the maximum-tolerated dose (MTD) and single-agent activity of NAB-paclitaxel administered on a weekly basis to patients with stage IV non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

This was an open-label, single-arm, phase I/II study. Patients were treated with NAB-paclitaxel intravenously during 30 minutes without corticosteroid or antihistamine premedications on days 1, 8, and 15 of a 28-day cycle. Radiologic tumor assessment was performed every 8 weeks.

RESULTS

Dose levels of 100 and 125 mg/m(2) were tolerated without dose-limiting toxicities (DLTs). At 150 mg/m(2) the MTD was exceeded; two of three patients experienced a DLT (grade 3 sensory neuropathy and febrile neutropenia). The 125 mg/m(2) dose level was expanded and determined to be the MTD. A total of 40 patients were treated at 125 mg/m(2). The objective response rate was 30% (12 of 40 patients; 95% CI, 16% to 44%), median time to progression was 5 months (95% CI, 3 to 8 months), and median overall survival was 11 months (95% CI, 7 months to not reached). The 1-year survival was 41%.

CONCLUSION

NAB-paclitaxel 125 mg/m(2) administered on days 1, 8, and 15 of a 28-day cycle was well tolerated and demonstrated encouraging single-agent activity. No corticosteroid premedication was administered and no hypersensitivity reactions were seen. Additional studies of single-agent NAB-paclitaxel as well as platinum-based combinations are warranted.

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.

Waldenström macroglobulinemia

In the past 36 months, new developments have occurred both in the understanding of the biology of Waldenström macroglobulinemia (WM) and in therapeutic options for WM. Here, we review the classification, clinical features, and diagnostic criteria of the disease. WM is a B-cell neoplasm characterized by lymphoplasmacytic infiltration of the bone marrow and a monoclonal immunoglobulin M (IgM) protein. The symptoms of WM are attributable to the extent of tumor infiltration and to elevated IgM levels. The most common symptom is fatigue attributable to anemia. The prognostic factors predictive of survival include the patient's age, β2-microglobulin level, monoclonal protein level, hemoglobin concentration, and platelet count. Therapy is postponed for asymptomatic patients, and progressive anemia is the most common indication for initiation of treatment. The main therapeutic options include alkylating agents, nucleoside analogues, and rituximab. Studies involving combination chemotherapy are ongoing, and preliminary results are encouraging. No specific agent or regimen has been shown to be superior to another for treatment of WM. Novel agents such as bortezomib, perifosine, atacicept, oblimersen sodium, and tositumomab show promise as rational targeted therapy for 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's macroglobulinemia

The diagnosis of Waldenström's macroglobulinemia (WM) requires evidence of bone-marrow infiltration by lymphoplasmacytoid lymphoma and detection of serum monoclonal protein of IgM type. The normal counterpart of the WM malignant cell is believed to be a postgerminal-center B cell. The clinical manifestations and laboratory abnormalities associated with WM are related to direct tumor infiltration and to the amount and specific properties of IgM. Asymptomatic patients should be followed without treatment. When treatment is indicated, the three main choices for systemic frontline treatment are chlorambucil, the nucleoside analogues fludarabine or cladribine and the monoclonal antibody rituximab. There is evidence that high-dose therapy with autologous stem-cell transplantation is effective even in patients with advanced and resistant disease. Patient's age, hemoglobin and serum beta2-microglobulin before treatment are important prognostic variables which correlate with survival.

Fludarabine Combination Therapy Is Highly Effective in First-Line and Salvage Treatment of Patients with Waldenström's Macroglobulinemia

Alkylating agents or single-agent purine analogues are modestly effective as front-line therapy for Waldenstrom's macroglobulinemia (WM), but response rates of < 50% are exhibited in the salvage therapy setting. Fludarabine combination therapy may be more effective, but no large studies exploring these regimens specifically in WM are available. We report our results of 18 cycles of fludarabine combination therapy: FC (fludarabine 25 mg/m2 for 3 days plus cyclophosphamide 250 mg/m2 for 3 days; n = 9), FM (fludarabine 25 mg/m2 for 3 days plus mitoxantrone 10 mg/m2 for 1 day; n = 3), FCR (FC plus rituximab 375 mg/m2; n = 5), or fludarabine/rituximab (n = 1). Four patients had previously untreated disease, and 14 had pretreated disease; 67% had elevated serum levels of beta2-microglobulin, and 86% had hemoglobin levels < or = 12 g/dL. Patients received a median of 4 cycles (range, 1-6 cycles), with grade > or = 3 neutropenia and infection complicating 25% and 4% of cycles, respectively. Objective responses (all partial) were attained in 13 patients (76%). Response rates did not significantly differ by regimen, previous treatment, age, performance status, beta2-microglobulin level, hemoglobin level, time from diagnosis, previous fludarabine exposure, or alkylator refractoriness. Median remission duration was 38 months; no previously untreated patient had died at a median of 37 months of follow-up, and the actuarial 5-year survival rate was 55% for pretreated patients. No cases of secondary myelodysplasia or leukemia were encountered.

Pentostatin/Cyclophosphamide with or Without Rituximab: An Effective Regimen for Patients with Waldenström's Macroglobulinemia/Lymphoplasmacytic Lymphoma

BACKGROUND

Pentostatin has demonstrated significant activity as a single agent in patients with low-grade B-cell and T-cell lymphomas and is less myelosuppressive than other purine analogues.

PATIENTS AND METHODS

We conducted a phase II trial with the combination regimen of PC-R (pentostatin/cyclophosphamide with or without rituximab) in 14 patients with Waldenstrom's macroglobulinemia (WM) and 3 patients with lymphoplasmacytic lymphoma (LL) without monoclonal serum immunoglobulin M (IgM), followed by a maintenance regimen with rituximab (375 mg/m2 every 3 months) for patients exhibiting a complete response (CR) or a partial response (PR) after 4-6 cycles. Nine patients were untreated, and 8 had been previously treated with 1-3 regimens. The first 9 patients received PC therapy (pentostatin 4 mg/m2 plus cyclophosphamide 600 mg/m2), and 8 patients received the same combination with rituximab 375 mg/m2 on day 1. Cycles were repeated every 3 weeks.

RESULTS

An objective tumor response after PC and PC-R was confirmed in 11 of 17 evaluable patients (64.7%), with 2 CRs (11.7%) and 9 PRs (52.9%). In patients who received rituximab (n = 13) simultaneously or subsequently, the overall response rate was 76.9%. Grade 2/3 nausea and grade 2 vomiting was generally mild based on World Health Organization criteria. Grade 3 hematologic toxicity occurred after 9 of 49 cycles (18.3%), and grade 4 toxicity occurred after 2 cycles (4%). Ten patients were subsequently treated with rituximab every 3 months for 2-9 cycles to date (median, 4 cycles). No patients have had disease relapse to date, and all exhibited stable IgM serum levels. In 3 patients with a PR after completion of chemotherapy, remission has improved further, with normalization of the IgM level in 1 patient and another patient exhibiting a CR.

CONCLUSION

Our data indicate that PC-R is safe and highly effective in patients with WM. Maintenance therapy with rituximab for WM as a single infusion every 3 months can be administered safely and can improve remission status.

Diagnosis and management of Waldenstrom's macroglobulinemia

PURPOSE

To review the diagnostic criteria, prognostic factors, response criteria, and treatment options of patients with Waldenstrom's macroglobulinemia (WM).

METHODS

A review of published reports was facilitated by the use of a MEDLINE computer search and by manual search of the Index Medicus.

RESULTS

WM should be regarded as a distinct clinicopathologic entity and confined to those patients with lymphoplasmacytoid lymphoma who have demonstrable serum immunoglobulin M monoclonal protein. Treatment decisions should rely on specific clinical and laboratory criteria. Initiation of therapy should not be based on serum monoclonal protein levels per se. The three main choices for systemic primary treatment of symptomatic patients with WM include alkylating agents (chlorambucil), nucleoside analogs (fludarabine and cladribine), and the monoclonal antibody rituximab. There are no data from prospective randomized studies to recommend the use of one first-line agent over another, although consideration of a patient's candidacy for autologous stem-cell transplantation (ASCT) should be taken into account to avoid stem cell-damaging agents. There are preliminary data to suggest that combinations of nucleoside analogs and alkylating agents with or without rituximab may improve response rates at the expense of higher toxicity.

CONCLUSION

WM is a distinct low-grade lymphoproliferative disorder. When therapy is indicated, alkylating agents, nucleoside analogs, and rituximab are reasonable choices. Several factors, including the presence of cytopenias, need for rapid disease control, candidacy for ASCT, age, and comorbidities, should be taken into consideration when choosing the most appropriate primary treatment.

Phase III Study of Chlorambucil Versus Fludarabine as Initial Therapy for Waldenström's Macroglobulinemia and Related Disorders

The WM1 study is a prospective randomized open-label study that includes patients with previously untreated Waldenstrom's macroglobulinemia (WM), splenic lymphoma with villous lymphocytes (SLVL), and nonimmunoglobulin (Ig) M lymphoplasmacytic lymphoma (LPL) who have an indication for treatment. At registration, patients are categorized as having WM, SLVL, or LPL, and these cohorts are to be analyzed separately. The aim of the study is to compare the efficacy of oral chlorambucil at a dose of 8 mg/m(2) (6 mg/m(2) for those > 75 years of age) for 10 days every 28 days to a maximum of 12 cycles with oral or intravenous (I.V.) fludarabine at a dose of 40 mg/m(2) orally or 25 mg/m(2) I.V. (30 mg/m(2)orally or 20 mg/m(2)I.V. for those > 75 years of age) for 5 days every 28 days to a maximum of 6 cycles. Primary endpoints are response to therapy and duration of response; secondary endpoints are improvement in hematologic parameters, toxicity of therapy, quality of life, and survival. To detect a difference in response rate of patients with WM of 15%, assuming that the overall response rates will be 50% to chlorambucil and 65% to fludarabine, with a power of 80%, requires the sample size of each group to be 183, indicating the need for collaboration among a number of national investigator groups. As of February 2005, accrual to the study stands at 143. Registration, randomization, and data collection are entirely Internet-based (www.waldenstroms.org), and the study is organized by an international collaboration, with a planned interim analysis and an external data monitoring committee.

Treatment of indolent non-Hodgkin's lymphoma with cladribine as single-agent therapy and in combination with mitoxantrone

The term indolent in describing a non-Hodgkin's lymphoma (NHL) generally refers to a group of B-cell NHLs composed of predominantly small cells that make up several categories, including follicular lymphoma, small lymphocytic lymphoma, and lymphoma of mucosa-associated lymphoid tissue. Most patients with follicular lymphoma respond to therapy, and the average survival time in large series is approximately 10 years. Patients who achieve a complete remission with initial treatment have an approximately 25% chance of remaining free of disease for 10 years. However, this means that more than 80% of patients will require salvage therapy. Cladribine is a newer purine analogue and is of particular interest because it is resistant to deamination by adenosine deaminase. It is cytotoxic to both proliferating and resting lymphocytes, making it an attractive agent for the treatment of indolent NHL. In this review article, we summarize the current treatment approaches for indolent NHL and the results of cladribine monotherapy studies in Japan and cladribine studies in Germany that have focused on a combination therapy with mitoxantrone. Cladribine is a potent inhibitor of DNA repair. The combination of a DNA-damaging agent with an inhibitor of DNA repair constitutes the rationale for combining cladribine with mitoxantrone. A German study has demonstrated that the combination of reduced-dose cladribine and mitoxantrone is a highly active regimen with favorable toxicity profiles. Cladribine is highly effective as a single agent and in combination with mitoxantrone in the treatment of indolent NHL, and its availability broadens the range of therapeutic options for indolent NHL.

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.

Trends in the Aggressiveness of Cancer Care Near the End of Life

Purpose

To characterize the aggressiveness of end-of-life cancer treatment for older adults on Medicare, and its relationship to the availability of healthcare resources.

Patients and Methods

We analyzed Medicare claims of 28,777 patients 65 years and older who died within 1 year of a diagnosis of lung, breast, colorectal, or other gastrointestinal cancer between 1993 and 1996 while living in one of 11 US regions monitored by the Surveillance, Epidemiology, and End Results Program.

Results

Rates of treatment with chemotherapy increased from 27.9% in 1993 to 29.5% in 1996 (P = .02). Among those who received chemotherapy, 15.7% were still receiving treatment within 2 weeks of death, increasing from 13.8% in 1993 to 18.5% in 1996 (P < .001). From 1993 to 1996, increasing proportions of patients had more than one emergency department visit (7.2% v 9.2%; P < .001), hospitalization (7.8% v 9.1%; P = .008), or were admitted to an intensive care unit (7.1% v 9.4%; P = .009) in the last month of life. Although fewer patients died in acute-care hospitals (32.9% v 29.5%; P < .001) and more used hospice services (28.3% v 38.8%; P < .001), an increasing proportion of patients who received hospice care initiated this service only within the last 3 days of life (14.3% v 17.0%; P = .004). Black patients were more likely than white patients to experience aggressive intervention in nonteaching hospitals but not in teaching hospitals. Greater local availability of hospices was associated with less aggressive treatment near death on multivariate analysis.

Conclusion

The treatment of cancer patients near death is becoming increasingly aggressive over time.

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.

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.

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.

Evaluating treatment strategies in advanced Waldenström macroglobulinemia: use of quality-adjusted survival analysis

A randomized phase II multicenter clinical trial comparing the efficacy of fludarabine (FAMP) to that of the association of cyclophosphamide, doxorubicin and prednisone (CAP) in 92 patients with Waldenstrom's macroglobulinemia in first relapse or with primarily resistant disease, was conducted on the behalf of the 'Groupe Coopératif Macroglobulinémie'. The main analysis of this study failed to demonstrate a clear cut benefit of FAMP in terms of overall survival (OS), although a significant benefit in terms of time to disease progression and event-free survival (EFS) was noted. In this rare disorder, where few randomized trials have been conducted, we took advantage of this trial to assess treatment differences while integrating quality of life considerations. We thus performed a quality-adjusted survival analysis, using the quality-adjusted time without symptoms or toxicity (Q-TWiST) approach. Four health states differing in terms of quality of life (QoL) were defined, namely treatment-related toxicity, treatment free of toxicity, no treatment or symptoms, and relapse. The average time spent in these health states (TOX, CT, TWiST and REL, respectively) were then weighted by utility coefficients reflecting relative QoL value according to that of TWiST and summed up giving the so-called Q-TWiST. No difference was found between randomized groups in terms of mean CT. Mean TOX in the two groups were similarly close except when considering alopecia as a relevant toxic event. By contrast, mean TWiST was 5.9 months longer in the FAMP group than in the CAP group (P = 0.006). Unsurprisingly, given the absence of difference in OS but the difference in EFS in favor of the FAMP group, mean REL was increased by 6.8 months in the CAP group (P = 0.047). As a result, benefit of FAMP in terms of average Q-TWiST only relied on the value of the utility coefficient attributed to REL (U(REL)), with a significant benefit when UREL ranged from 0 to 0.28, ie in patients undergoing poor QoL after relapse, which is likely.

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.

Waldenström's macroglobulinemia: clinical features, complications, and management

PURPOSE

To review the clinical features, complications, and treatment of Waldenström's macroglobulinemia, a low-grade lymphoproliferative disorder that produces monoclonal immunoglobulin (Ig) M.

METHODS

A review of published reports was facilitated by the use of a MEDLINE computer search and by manual search of the Index Medicus.

RESULTS

The clinical manifestations associated with Waldenström's macroglobulinemia can be classified according to those related to direct tumor infiltration, to the amount and specific properties of circulating IgM, and to the deposition of IgM in various tissues. Asymptomatic patients should be followed without treatment. For symptomatic patients, standard treatment consists primarily of oral chlorambucil; nucleoside analogs, such as fludarabine and cladribine, are effective in one third of previously treated patients and in up to 80% of previously untreated patients. Preliminary evidence suggests that anti-CD20 monoclonal antibody may be active in about 30% of previously treated patients and that high-dose therapy with autologous stem-cell rescue is effective in most patients, including some with resistance to nucleoside analogs.

CONCLUSION

Waldenström's macroglobulinemia has a wide clinical spectrum that practicing physicians need to recognize early to reach the correct diagnosis. When therapy is indicated, oral chlorambucil is the standard primary treatment, but cladribine or fludarabine can be used when a rapid cytoreduction is desirable. Prospective randomized trials are required to elucidate the impact of nucleoside analogs on patients' survival. A nucleoside analog is the treatment of choice for patients who have been previously treated with an alkylating agent.

Waldenström's macroglobulinemia

Waldenström's macroglobulinemia is an unusual low-grade lymphoplasmacytic lymphoma characterized by the production of monoclonal IgM. The clinical manifestations associated with WM can be classified as those related to direct tumor infiltration, by the amount and specific properties of circulating IgM, and by the deposition of IgM in various tissues. Asymptomatic patients should be followed without treatment. The management of the disease relies on the administration of systemic chemotherapy to reduce tumor load and on the application of plasmapheresis to remove circulating IgM. Standard treatment consists of oral chlorambucil, which induces response in at least 50% of patients, resulting in a median survival of approximately 5 years. Nucleoside analogues (cladribine, fludarabine) are effective in most previously untreated patients. These agents are the treatment of choice for patients with disease resistant to alkylating agents. New treatment approaches include high-dose therapy with stem-cell support and administration of monoclonal anti-CD20 antibodies.

Intermittent 2-hour-infusion of cladribine as first-line therapy or in first relapse of progressive advanced low-grade and mantle cell lymphomas

Aim of this multicenter-study was to evaluate rate and duration of remissions and to examine toxicity of cladribine in low-grade lymphomas as first-line therapy or in first relapse using intermittent 2-hour-infusion of cladribine. A total of 294 courses, median of 5 courses per patient, were administered to 66 evaluable patients (53 previously untreated, 13 relapsed) with 5 mg/m2 cladribine given as intermittent 2-hour-infusion over 5 consecutive days for a maximum of 6 cycles every four weeks. Entities: 26 follicle center, 20 lymphoplasmacytoid, 12 mantle cell, 6 T-cell, 2 marginal zone lymphomas. Fifty of 66 patients responded to cladribine corresponding to an overall response rate of 76% (95% confidence interval (95% CI): 64%-85%) with 38% CR (95% CI: 26%-51%) and a median time of remission duration of 23 months (range 6-45+). The overall survival rate at 48 months was 72%. For 49 previously untreated patients with B-cell lymphomas the overall response rate was 86% (95% CI: 73%-94%) with a high CR rate of 43% (95% CI: 29%-58%). Response rate for the group of 23 previously untreated patients with follicle center lymphomas was high with 96% overall response (95% CI: 78%-100%) and 57% CR rate (95% CI: 34%-77%). Cladribine also showed activity in patients with mantle cell lymphomas achieving a response rate of 58% (95% CI: 28%-85%). Myelosuppression was the major toxicity with 17% neutropenia grade 3 and 4. Thrombocytopenia was rare with only 2% grade 3 and 4. A prolonged CD4-lymphocytopenia was observed in all patients. Life threatening complications were not observed. These results confirm the major single-agent activity of cladribine in a large cohort of patients with untreated low-grade lymphomas using the intermittent 2-hour-infusion dosage-regimen. To improve treatment results furthermore, cladribine should be combined with other agents active in low-grade lymphomas.

Effect of a 2-hour infusion of 2-chlorodeoxyadenosine in the treatment of refractory or previously untreated Waldenström's macroglobulinemia

2-Chlorodeoxyadenosine (2-CdA) is a new purine analogue active in indolent lymphoid malignancies. In this retrospective study 22 patients with Waldenström's macroglobulinemia (MW) were treated with 2-CdA given in 2-h intravenous infusions. Nine of them were untreated and 13 relapsed or were refractory to previous therapeutic modalities with chlorambucil/prednisone (11 patients) or COP (2 patients). The patients were given 1-11 (median 4) courses of 2-CdA at the dose of 0.14 mg/kg daily in 2-h intravenous infusion for 5 consecutive days. The courses were repeated every 28-35 d. If severe myelosuppression or infection developed, 2-CdA therapy was stopped until the haematological parameters increased. The effectiveness of the treatment was evaluated after the 3 cycles and after completion of therapy. None of the patients has achieved complete response (CR) after 3 courses of treatment and only one (4.5%) has obtained CR after 5 courses. Partial response (PR) was achieved in 8 (36.4%) patients, giving an overall response rate of 40.9%. Ten further patients (45.4%) responded to the treatment with less than 50% decrease in monoclonal protein (defined as stabilisation). There was no significant difference between the response rate in previously pretreated (38.5%) and untreated (44.4%) patients (p>0.05). Mean observed decrease in monoclonal protein was 41%. In the group of 9 patients responding to 2-CdA treatment mean duration of response was 12 months (range 3-34). Myelosuppression was the most prominent side-effect. Neutropenia was present in 17 (77.3%) and thrombocytopenia in 7 (31.8%) patients. In 6 patients myelosuppression was the reason for treatment discontinuation after 1 or 2 courses without significant therapeutic effect. Seven patients died, including 4 from the responding group and all three non-responding patients. Treatment-related thrombocytopenia and fatal haemorrhage was the course of death in 1 patient. In conclusion, the results of our study show that 2-CdA given in 2-h infusions is an effective agent in WM and may be given on an outpatient basis. However, myelosuppression is frequent and the drug must be administered with caution.

High-dose therapy with autologous haemopoietic stem cell support for Waldenström's macroglobulinaemia

Standard doses of alkylating agents or purine analogues effect response rates of up to 50% in Waldenström's macroglobulinaemia (WM); however, complete responses are infrequent and there are no cures. We have evaluated the feasibility, safety and efficacy of high-dose chemotherapy with peripheral blood stem cell support in six patients aged 45-69 years (median 51.5) with WM; four patients relapsed after prior therapy inclusive of purine analogues and two patients proceeded with transplant after minimal therapy. Four patients mobilized adequate numbers of stem cells; however, two patients with more extensive fludarabine therapy failed to mobilize and required a second attempt at stem cell collection. Five patients were treated with melphalan 200 mg/m2, including one patient who received tandem transplants and one patient who received melphalan 140 mg/m2 with added total body irradiation (TBI). There was no treatment-related mortality and non-haematological toxicities were manageable. Engraftment was prompt except in one patient with extensive prior use of fludarabine. All the six patients achieved at least partial response (PR), including one who achieved complete response (CR). Five patients are alive and four are event-free at 52+, 15+, 12+ and 2+ months post transplant. This pilot study suggests safety and efficacy of high-dose therapy in WM and suggests that the peripheral blood stem cells should preferably be procured prior to extensive use of purine analogues.

Bolus administration of cladribine in the treatment of Waldenström macroglobulinaemia

This phase II clinical trial evaluated bolus cladribine as a single agent in Waldenstrom macroglobulinaemia (WM). Cladribine was administered to 20 patients at a dose of 0.12 mg/kg/d by 2 h intravenous infusion for 5 consecutive days at monthly intervals for three courses. Partially responding patients were continued on therapy until maximal response and/or prohibitive toxicity, to a maximum of eight courses. Complete responders were treated with one additional course of cladribine. After a median of three courses of cladribine, all 20 patients were evaluable; one achieved a complete response (CR) (5%) and 10 achieved a partial response (PR) (50%). The median duration of response follow-up was 28 months (range 1-37 months). Four of 7 (57%) untreated and 7/13 (54%) previously treated patients responded. The major toxicity encountered was myelosuppression with 60% of patients demonstrating grade 3 or 4 neutropenia. Non-haematological toxicities included two patients with herpes zoster and two patients with non-melanoma skin cancers. At a median follow-up duration of 20 months, 17 patients remain alive and three have died. We confirm that bolus cladribine is an effective and safe method of drug delivery in WM patients. Recommendations regarding the equivalence of the continuous infusion and bolus methods in untreated patients requires further study. Bolus cladribine is more convenient and less costly than infusional cladribine since it obviates the need for central catheters and infusional devices.

2-chloro-2'-deoxyadenosine: clinical applications in hematology

The anticancer drug 2-chloro-2'-deoxyadenosine (CdA) belongs to the family of purine nucleoside analogs. CdA is exquisitely cytotoxic both to the dividing and to the non-dividing lymphocyte, which supports its use in lymphoproliferative disorders of low-grade malignancy. Indeed, the best clinical results with CdA are achieved in hairy-cell leukemia, in chronic lymphocytic leukemia, in Waldenström's macroglobulinemia and in low-grade malignant lymphoma. Most patients with hairy-cell leukemia achieve a complete response with a single course of CdA. However, the disease is not eradicated and a fraction of complete responders will eventually relapse. In chronic lymphocytic leukemia and in malignant lymphoma, complete or partial responses can be achieved in approximately 40% of previously treated patients, even after classical chemotherapy has failed. However, few responses sustain beyond 1 to 2 years, while longer unmaintained responses may be obtained in Waldenström's macroglobulinemia. More responses (70-80%) are achieved in patients with chronic lymphoproliferative disorders treated de novo with CdA but their impact on survival remains to be established. More than 10 years after its first use in clinical practice, late adverse consequences of the severe and sustained immunosuppression induced by CdA have not been reported but should still be closely monitored.