Timing of high-dose methotrexate CNS prophylaxis in DLBCL: a multicenter international analysis of 1384 patients.

Prophylactic high-dose methotrexate (HD-MTX) is often used for diffuse large B-cell lymphoma (DLBCL) patients at high risk of central nervous system (CNS) relapse, despite limited evidence demonstrating efficacy or the optimal delivery method. We conducted a retrospective, international analysis of 1384 patients receiving HD-MTX CNS prophylaxis either intercalated (i-HD-MTX) (n = 749) or at the end (n = 635) of R-CHOP/R-CHOP-like therapy (EOT). There were 78 CNS relapses (3-year rate 5.7%), with no difference between i-HD-MTX and EOT: 5.7% vs 5.8%, P = .98; 3-year difference: 0.04% (-2.0% to 3.1%). Conclusions were unchanged on adjusting for baseline prognostic factors or on 6-month landmark analysis (n = 1253). In patients with a high CNS international prognostic index (n = 600), the 3-year CNS relapse rate was 9.1%, with no difference between i-HD-MTX and EOT. On multivariable analysis, increasing age and renal/adrenal involvement were the only independent risk factors for CNS relapse. Concurrent intrathecal prophylaxis was not associated with a reduction in CNS relapse. R-CHOP delays of ≥7 days were significantly increased with i-HD-MTX vs EOT, with 308 of 1573 (19.6%) i-HD-MTX treatments resulting in a delay to subsequent R-CHOP (median 8 days). Increased risk of delay occurred in older patients when delivery was later than day 10 in the R-CHOP cycle. In summary, we found no evidence that EOT delivery increases CNS relapse risk vs i-HD-MTX. Findings in high-risk subgroups were unchanged. Rates of CNS relapse in this HD-MTX-treated cohort were similar to comparable cohorts receiving infrequent CNS prophylaxis. If HD-MTX is still considered for certain high-risk patients, delivery could be deferred until R-CHOP completion.

Rituximab-Lenalidomide-Ibrutinib Combination for Relapsed/Refractory Primary CNS Lymphoma: A Case Series of the LOC Network.

BACKGROUND AND OBJECTIVES: To evaluate the efficacy and tolerance of the association rituximab-lenalidomide-ibrutinib (R2I) in relapsed/refractory (R/R) primary CNS lymphoma (PCNSL). METHODS: R/R PCNSL patients treated with R2I were retrospectively selected and analyzed from the French LOC database. RESULTS: Fourteen patients (median age: 63 years, median Karnofsky Performance Status: 75%) received R2I, administered after a median of 2 previous lines of chemotherapy, including autologous stem cell transplantation (ASCT) in 5 cases. The best response was complete response in 4/14 patients and partial response in 4/14 patients, achieved in a median of 2.5 months. Three responder patients received consolidation treatment (WBRT: N = 2, ASCT: N = 1) after R2I, and R2I served as a bridge before CAR-T cell therapy for one patient. R2I was discontinued due to toxicity in 3/14 patients. There were no toxicity-related deaths. DISCUSSION: The R2I combination resulted in a high rate of response of rapid-onset in heavily pretreated patients with poor prognosis, with manageable toxicity, and allowed 3 patients to proceed to consolidation. Although preliminary, these results support the use of R2I for R/R PCNSL failing conventional chemotherapies. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that combination of rituximab-lenalidomide-ibrutinib induces a high rate of response in heavily pretreated R/R PCNSL.

Outcomes after first-line immunochemotherapy for primary mediastinal B-cell lymphoma: a LYSA study.

Primary mediastinal B-cell lymphoma (PMBL) is a rare type of aggressive lymphoma typically affecting young female patients. The first-line standard of care remains debated. We performed a large multicenter retrospective study in 25 centers in France and Belgium to describe PMBL patient outcomes after first-line treatment in real-life settings. A total of 313 patients were enrolled and received rituximab (R) plus ACVBP (doxorubicin, cyclophosphamide, vindesine, bleomycin, and prednisone) (n = 180) or CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) delivered every 14 days (R-CHOP14, n = 76) or 21 days (R-CHOP21, n = 57) and consolidation strategies in modalities that varied according to time and institution, mainly guided by positron emission tomography. Consolidation autologous stem cell transplantation was performed for 46 (25.6%), 24 (31.6%), and 1 (1.8%) patient in the R-ACVBP, R-CHOP14, and R-CHOP21 groups, respectively (P < .001); only 17 (5.4%) patients received mediastinal radiotherapy. The end-of-treatment complete metabolic response rates were 86.3%, 86.8%, and 76.6% (P = .23) in the R-ACVBP, R-CHOP14, and R-CHOP21 groups. The median follow-up was 44 months, and the R-ACVBP, R-CHOP14, and R-CHOP21 three-year progression-free survival probabilities were 89.4% (95% confidence interval [CI], 84.8-94.2), 89.4% (95% CI, 82.7-96.6), and 74.7% (95% CI, 64-87.1) (P = .018). A baseline total metabolic tumor volume (TMTV) ≥360 cm3 was associated with a lower progression-free survival (hazard ratio, 2.18; 95% CI, 1.05-4.53). Excess febrile neutropenia (24.4% vs 5.3% vs 5.3%; P < .001) and mucositis (22.8% vs 3.9% vs 1.8%; P < .001) were observed with R-ACVBP compared with the R-CHOP regimens. Patients with PMBL treated with dose-dense immunochemotherapy without radiotherapy have excellent outcomes. R-ACVBP acute toxicity was higher than that of R-CHOP14. Our data confirmed the prognostic importance of baseline TMTV.

Impact of High-Dose Methotrexate on the Outcome of Patients with Diffuse Large B-Cell Lymphoma and Skeletal Involvement.

Diffuse large B-cell lymphoma (DLBCL) with extra nodal skeletal involvement is rare. It is currently unclear whether these lymphomas should be treated in the same manner as those without skeletal involvement. We retrospectively analyzed the impact of combining high-dose methotrexate (HD-MTX) with an anthracycline-based regimen and rituximab as first-line treatment in a cohort of 93 patients with DLBCL and skeletal involvement with long follow-up. Fifty patients (54%) received upfront HD-MTX for prophylaxis of CNS recurrence (high IPI score and/or epidural involvement) or because of skeletal involvement. After adjusting for age, ECOG, high LDH levels, and type of skeletal involvement, HD-MTX was associated with an improved PFS and OS (HR: 0.2, 95% CI: 0.1-0.3, p < 0.001 and HR: 0.1, 95% CI: 0.04-0.3, p < 0.001, respectively). Patients who received HD-MTX had significantly better 5-year PFS and OS (77% vs. 39%, p <0.001 and 83 vs. 58%, p < 0.001). Radiotherapy was associated with an improved 5-year PFS (74 vs. 48%, p = 0.02), whereas 5-year OS was not significantly different (79% vs. 66%, p = 0.09). A landmark analysis showed that autologous stem cell transplantation was not associated with improved PFS or OS. The combination of high-dose methotrexate and an anthracycline-based immunochemotherapy is associated with an improved outcome in patients with DLBCL and skeletal involvement and should be confirmed in prospective trials.

Allogeneic transplantation after PD-1 blockade for classic Hodgkin lymphoma.

Anti-PD-1 monoclonal antibodies yield high response rates in patients with relapsed/refractory classic Hodgkin lymphoma (cHL), but most patients will eventually progress. Allogeneic hematopoietic cell transplantation (alloHCT) after PD-1 blockade may be associated with increased toxicity, raising challenging questions about the role, timing, and optimal method of transplantation in this setting. To address these questions, we assembled a retrospective cohort of 209 cHL patients who underwent alloHCT after PD-1 blockade. With a median follow-up among survivors of 24 months, the 2-year cumulative incidences (CIs) of non-relapse mortality and relapse were 14 and 18%, respectively; the 2-year graft-versus-host disease (GVHD) and relapse-free survival (GRFS), progression-free survival (PFS), and overall survival were 47%, 69%, and 82%, respectively. The 180-day CI of grade 3-4 acute GVHD was 15%, while the 2-year CI of chronic GVHD was 34%. In multivariable analyses, a longer interval from PD-1 to alloHCT was associated with less frequent severe acute GVHD, while additional treatment between PD-1 and alloHCT was associated with a higher risk of relapse. Notably, post-transplant cyclophosphamide (PTCy)-based GVHD prophylaxis was associated with significant improvements in PFS and GRFS. While awaiting prospective clinical trials, PTCy-based GVHD prophylaxis may be considered the optimal transplantation strategy for this patient population.

Integrative analysis of a phase 2 trial combining lenalidomide with CHOP in angioimmunoblastic T-cell lymphoma.

Angioimmunoblastic T-cell lymphoma (AITL) is a frequent T-cell lymphoma in the elderly population that has a poor prognosis when treated with cyclophosphamide, doxorubicin, vincristine, and prednisone  (CHOP) therapy. Lenalidomide, which has been safely combined with CHOP to treat B-cell lymphoma, has shown efficacy as a single agent in AITL treatment. We performed a multicentric phase 2 trial combining 25 mg lenalidomide daily for 14 days per cycle with 8 cycles of CHOP21 in previously untreated AITL patients aged 60 to 80 years. The primary objective was the complete metabolic response (CMR) rate at the end of treatment. Seventy-eight of the 80 patients enrolled were included in the efficacy and safety analysis. CMR was achieved in 32 (41%; 95% confidence interval [CI], 30%-52.7%) patients, which was below the prespecified CMR rate of 55% defined as success in the study. The 2-year progression-free survival (PFS) was 42.1% (95% CI, 30.9%-52.8%), and the 2-year overall survival was 59.2% (95% CI, 47.3%-69.3%). The most common toxicities were hematologic and led to treatment discontinuation in 15% of patients. This large prospective and uniform series of AITL treatment data was used to perform an integrative analysis of clinical, pathologic, biologic, and molecular data. TET2, RHOA, DNMT3A, and IDH2 mutations were present in 78%, 54%, 32%, and 22% of patients, respectively. IDH2 mutations were associated with distinct pathologic and clinical features and DNMT3A was associated with shorter PFS. In conclusion, the combination of lenalidomide and CHOP did not improve the CMR in AITL patients. This trial clarified the clinical impact of recurrent mutations in AITL. This trial was registered at www.clincialtrials.gov as #NCT01553786.

Performance of CT Compared with 18F-FDG PET in Predicting the Efficacy of Nivolumab in Relapsed or Refractory Hodgkin Lymphoma.

Background CT and fluorine 18 (18F) fluorodeoxyglucose (FDG) PET/CT performances following immune therapy are not well known in patients with relapsed or refractory Hodgkin lymphoma (RRHL). Purpose To compare CT and PET/CT for prognostic value of early response evaluation following nivolumab therapy. Materials and Methods This retrospective study included patients from 34 institutions who underwent early imaging response evaluation from July 2013 to April 2017. Three experienced readers classified imaging response by using Cheson et al and 2016 Lymphoma Response to Immunomodulatory Therapy Criteria as follows: complete (metabolic) response, partial (metabolic) response, stable disease or no metabolic response, or progressive (metabolic) disease. Primary CT and PET assessments were performed at a median of 2.0 months (interquartile range, 1.7-3.7 months) after nivolumab initiation. Kaplan-Meier analysis was used to determine the relationship of primary CT and PET assessment response categories to overall survival (OS). Agreements between primary and secondary imaging assessments were assessed by using κ analysis. Results A total of 45 patients (median age, 37 years; range, 18-77 years; 25 men) underwent a primary assessment using CT and PET/CT; 36 patients also underwent a subsequent assessment. Eleven patients (24%) died after a median follow-up of 21.2 months. CT and PET response categories were associated with OS (P = .03 for primary CT assessment; P = .02 for primary PET assessment). There was no pseudoprogression at primary CT and PET assessments. At the primary assessment, response categories by using CT were reclassified by using PET in 44% (20 of 45) of patients. Among these, 55% (11 of 20) were reclassified to complete metabolic response (complete metabolic response rate: 29% [13 of 45 patients] vs complete response rate: 4% [two of 45 patients]), with a 2-year OS probability of 100%. At the secondary assessment, complete response rate using CT increased to 17% (six of 36 patients), hence a better agreement with PET (κ = 0.78; P < .001). Conclusion Early CT and PET/CT at a median of 2 months after initiation of nivolumab predicted overall survival in relapsed or refractory Hodgkin lymphoma. Early PET detected additional patients with complete metabolic response. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Scott and Wang in this issue.

Management and outcome of primary CNS lymphoma in the modern era: An LOC network study.

OBJECTIVE: Real-life studies on patients with primary CNS lymphoma (PCNSL) are scarce. Our objective was to analyze, in a nationwide population-based study, the current medical practice in the management of PCNSL. METHODS: The French oculo-cerebral lymphoma network (LOC) database prospectively records all newly diagnosed PCNSL cases from 32 French centers. Data of patients diagnosed between 2011 and 2016 were retrospectively analyzed. RESULTS: We identified 1,002 immunocompetent patients (43% aged >70 years, median Karnofsky Performance Status [KPS] 60). First-line treatment was high-dose methotrexate-based chemotherapy in 92% of cases, with an increasing use of rituximab over time (66%). Patients <60 years of age received consolidation treatment in 77% of cases, consisting of whole-brain radiotherapy (WBRT) (54%) or high-dose chemotherapy with autologous stem cell transplantation (HCT-ASCT) (23%). Among patients >60 years of age, WBRT and HCT-ASCT consolidation were administered in only 9% and 2%, respectively. The complete response rate to initial chemotherapy was 50%. Median progression-free survival was 10.5 months. For relapse, second-line chemotherapy, HCT-ASCT, WBRT, and palliative care were offered to 55%, 17%, 10%, and 18% of patients, respectively. The median, 2-year, and 5-year overall survival was 25.3 months, 51%, and 38%, respectively (<60 years: not reached [NR], 70%, and 61%; >60 years: 15.4 months, 44%, and 28%). Age, KPS, sex, and response to induction CT were independent prognostic factors in multivariate analysis. CONCLUSIONS: Our study confirms the increasing proportion of elderly within the PCNSL population and shows comparable outcome in this population-based study with those reported by clinical trials, reflecting a notable application of recent PCNSL advances in treatment.

Early 18F-FDG PET/CT Response Predicts Survival in Relapsed or Refractory Hodgkin Lymphoma Treated with Nivolumab.

Monoclonal antibodies (mAbs) against programmed cell death 1 (PD-1), such as nivolumab and pembrolizumab, are associated with high response rates in patients with relapsed or refractory classic Hodgkin lymphoma (HL). To date, no prognostic factor for overall survival (OS) has been established with these agents in HL. We examined whether the first early response assessment evaluated using 18F-FDG PET/CT may be associated with OS in this setting. Methods: This retrospective study included 45 patients from 34 institutions. In a masked, centralized review, 3 independent radiologists classified PET/CT scans obtained at a median of 2.0 mo (interquartile range, 1.7-3.7 mo) after nivolumab initiation using existing criteria (i.e., 2014 Lugano classification and 2016 LYRIC). Patients were classified according to 4 possible response categories: complete metabolic response (CMR), partial metabolic response (PMR), no metabolic response (NMR), or progressive metabolic disease (PMD). Because the OS of patients with NMR and PMR was similar, they were grouped together. OS was estimated using the Kaplan-Meier method and compared between groups using log-rank testing. Results: Eleven patients (24%) died after a median follow-up of 21.2 mo. The classification was identical between Lugano and LYRIC because all 16 progression events classified as indeterminate response per LYRIC were confirmed on subsequent evaluations. Both Lugano and LYRIC classified patients as CMR in 13 cases (29%), PMD in 16 (36%), NMR in 4 (9%), and PMR in 12 (27%). The 2-y OS probability was significantly different in patients with PMD (0.53; 95% confidence interval [95%CI], 0.32-0.87), NMR or PMR (0.80; 95%CI, 0.63-1.00), and CMR (1.00; 95%CI, 1.00-1.00) in the overall population (P = 0.02, 45 patients), as well as according to a landmark analysis at 3 mo (P = 0.05, 32 patients). Conclusion: In relapsed or refractory HL patients treated with anti-PD-1 mAbs, the first early PET/CT assessment using either Lugano or LYRIC predicted OS and allowed early risk stratification, suggesting that PET/CT might be used to develop risk-adapted strategies.

Long-term efficacy of anti-PD1 therapy in Hodgkin lymphoma with and without allogenic stem cell transplantation.

INTRODUCTION: Long-term efficacy of anti-PD1 therapy and the need for a consolidation with allogenic haematopoietic stem cell transplantation (allo-HSCT) remain unclear in patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL). METHODS: We retrospectively analysed 78 patients with R/R HL treated with nivolumab in the French Early Access Program and compared their outcomes according to subsequent allo-HSCT. RESULTS: After a median follow-up of 34.3 months, the best overall response rate was 65.8%, including 38.2% complete responses (CRs). The median progression-free survival (PFS) was 12.1 months. Patients reaching a CR upon nivolumab had a significantly longer PFS than those reaching a partial response (PR) (median = not reached vs 9.3 months, p < 0.001). In our cohort, 13 patients who responded (i.e. in CR or PR) to nivolumab monotherapy underwent consolidation with allo-HSCT. Among responding patients, none of those who underwent subsequent allo-HSCT (N = 13) relapsed, whereas 62.2% of those who were not consolidated with allo-HSCT (N = 37) relapsed (p < 0.001). There was no difference in overall survival (OS) between the two groups. Five of 6 patients who were not in CR at the time of transplantation (4 PRs and 1 progressive disease) converted into a CR after allo-HSCT. CONCLUSION: Most patients with R/R HL treated with anti-PD1 monotherapy eventually progressed, notably those who did not achieve a CR. Patients undergoing consolidation with allo-HSCT after anti-PD1 therapy experienced prolonged disease-free survival compared with non-transplanted patients, but this difference did not translate into a benefit in OS. This information should be considered when evaluating the risk/benefit ratio of allo-HSCT after anti-PD1 therapy.

Impact of front line relative dose intensity for methotrexate and comorbidities in immunocompetent elderly patients with primary central nervous system lymphoma.

Primary central nervous system lymphomas (PCNSL) are non-Hodgkin lymphomas strictly localized to the CNS, occurring mainly in elderly patients with comorbidities. Current treatment in fit patients relies on high-dose methotrexate and high-dose cytarabine. The aim of this study was to evaluate the efficacy and feasibility of this treatment in elderly patients and to assess potential prognostic factors associated with survival. We conducted a retrospective study in two centers between January 2008 and September 2015 including 35 elderly immunocompetent patients who received first-line treatment with high-dose methotrexate. With a median follow-up of 19.8 months (range: 1.7-73.4 months), median overall survival (OS) was 39.5 months (95% confidence interval (95% CI): 18.3-60.7) and median progression-free survival (PFS) was 25.8 months (95% CI: 5.2-46.4). In univariate analysis, administration of high-dose cytarabine and achieving a relative dose intensity for methotrexate > 75% were associated with increased OS (p = 0.006 and p = 0.003, respectively) and PFS (p = 0.003 and p = 0.04, respectively) whereas comorbidities, defined by a CIRS-G score ≥ 8, were associated with decreased OS and PFS (p = 0.02 and p = 0.04, respectively). A high MSKCC score was associated with decreased OS (p = 0.02). In multivariate analysis, administration of high-dose cytarabine was associated with increased OS and PFS (p = 0.02 and p = 0.007, respectively). Comorbidities and relative dose intensity for methotrexate are important for the prognosis of elderly patients with PCNSL. These results must be confirmed in prospective trials.

Primary CNS lymphoma at first relapse/progression: characteristics, management, and outcome of 256 patients from the French LOC network.

BACKGROUND: Treatment of relapsed/refractory (R/R) primary CNS lymphoma (PCNSL) is poorly defined, because randomized trials and large studies are lacking. The aim of this study was to analyze the characteristics, management, and outcome of R/R PCNSL patients after first-line therapy in a nationwide cohort. METHODS: We analyzed R/R PCNSL patients following first-line treatment who had been prospectively registered in the database of the French network for oculocerebral lymphoma (LOC) between 2011 and 2014. RESULTS: Among 563 PCNSL patients treated with first-line therapy, we identified 256 with relapsed (n = 93, 16.5%) or refractory (n = 163, 29.0%) disease. Patients who were asymptomatic at relapse/progression (25.5%), mostly diagnosed on routine follow-up neuroimaging, tended to have a better outcome. Patients who received salvage therapy followed by consolidation (mostly intensive chemotherapy plus autologous hematopoietic stem cell transplantation [ICT + AHSCT]) experienced prolonged survival compared with those who did not receive salvage or consolidation therapy. Independent prognostic factors at first relapse/progression were: KPS ≥ 70 vs KPS < 70), sensitivity to first-line therapy (relapsed vs refractory disease), duration of first remission (progression-free survival [PFS] ≥1 y vs <1 y), and management at relapse/progression (palliative care vs salvage therapy). Patients who relapsed early after first-line therapy (ie, PFS < 1 y) had a poor outcome, comparable to that of refractory patients. Conversely, patients experiencing late relapses (PFS ≥ 1 y) and/or undergoing consolidation with ICT + AHSCT experienced prolonged survival. CONCLUSIONS: About a third of PCNSL patients are primary refractory to first line treatment. We identified several independent prognostic factors that can guide the management of R/R PCNSL patients.

Intermediate stage Hodgkin lymphoma in partial remission after three or four courses of doxorubicin, bleomycin, vinblastine dacarbazine: no benefit of one course of intensive chemotherapy before irradiation.

The H97-I trial (1997-2004) for Hodgkin lymphoma at intermediate stage (HL-I) included 269 patients who were randomized to receive three or four cycles of doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD). The 197 patients who reached complete remission (CR) (73.2%, p = 0.41 between arms) received radiotherapy (RT); their 10-year progression-free survival (PFS) rate was 87.7 ± 3.0%, similar to that of the 180 patients of a historical control group (HCG) in CR after three ABVD cycles before RT. The 59 patients who reached post-ABVD partial remission (PR) received one course of intensive chemotherapy (i.v., mg/m(2), vindesine 5, adriamycin 90, BCNU 140, etoposide 600, methylprednisolone 600) before RT. In spite of this additional intensive chemotherapy, their PFS rate (78.4 ± 6.3%) remained significantly lower (p = 0.03) than that of the 197 patients who reached post-ABVD CR, and was similar to that of the 60 patients of the HCG in PR after three ABVD cycles who did not receive additional chemotherapy before RT.

Reduced versus full doses of irradiation after 3 cycles of combined doxorubicin, bleomycin, vinblastine, and dacarbazine in early stage Hodgkin lymphomas: results of a randomized trial.

BACKGROUND: The combination of 3 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) and a tailored, extended irradiation schedule has been used to treat patients with early Hodgkin lymphoma (HL) in the authors' group since 1981. The randomized H97-E trial (1997-2004) was designed to assess the impact of a slightly reduced irradiation dose on the freedom from treatment failure (FFTF) rate. METHODS: Patients with supradiaphragmatic HL at clinical stages I and II who had

Allogeneic hematopoietic stem cell transplantation allows long-term complete remission and curability in high-risk Waldenström's macroglobulinemia. Results of a retrospective analysis of the Société Française de Greffe de Moelle et de Thérapie Cellulaire.

BACKGROUND: Patients with poor-risk Waldenström's macroglobulinemia have suboptimal response and early post-treatment relapse with conventional therapies. Hence, new therapeutic approaches such as allogeneic stem cell transplantation should be evaluated in these patients. DESIGN AND METHODS: We examined the long-term outcome of allogeneic stem cell transplantation in Waldenström's macroglobulinemia by studying the records of 24 patients reported in the SFGM-TC database and one transplanted in the bone marrow unit in Hamburg. RESULTS: Median age at the time of transplant was 48 years (range, 24-64). The patients had previously received a median of 3 lines of therapy (range, 1-6) and 44% of them had refractory disease at time of transplant. Allogeneic stem cell transplantation after myeloablative (n=12) or reduced-intensity (n=13) conditioning yielded an overall response rate of 92% and immunofixation-negative complete remission in 50% of evaluable patients. With a median follow-up of 64 months among survivors (range, 11-149 months), 5-year overall survival and progression-free survival rates were respectively, 67% (95% CI: 46-81) and 58% (95% CI: 38-75). The 5-year estimated risk of progression was 25% (95% CI: 10-36%), with only one relapse among the 12 patients who entered complete remission, versus 5 in the 12 patients who did not. Only one of the 6 relapses occurred more than three years post-transplant. CONCLUSIONS: Allogeneic stem cell transplantation yields a high rate of complete remissions and is potentially curative in poor-risk Waldenström's macroglobulinemia.