Evolution of Management and Outcomes in Waldenström Macroglobulinemia: A Population-Based Analysis

Anti-MAG neuropathy: historical aspects, clinical-pathological correlations, and considerations for future therapeutical trials

BACKGROUND

 Patients with anti-MAG neuropathy present with distal demyelinating polyneuropathy, IgM monoclonal gammopathy, and elevated titers of anti-MAG antibodies.

OBJECTIVE

 This paper reviews what is known about the clinical presentation, course, pathophysiology, and treatment of anti-MAG neuropathy, with considerations for the design of therapeutic trials.

METHODS

 A literature review of the medical and scientific literature related to anti-MAG neuropathy, and the design of therapeutic clinical trials in peripheral neuropathy.

RESULTS

 Anti-MAG neuropathy can remain indolent for many years but then enter a progressive phase. Highly elevated antibody titers are diagnostic, but intermediate titers can also occur in chronic inflammatory demyelinating polyneuropathy (CIDP). The peripheral nerves can become inexcitable, thereby masking the demyelinating abnormalities. There is good evidence that the anti-MAG antibodies cause neuropathy. Reduction of the autoantibody concentration by agents that target B-cells was reported to result in clinical improvement in case series and uncontrolled trials, but not in controlled clinical trials, probably due to inadequate trial design.

CONCLUSION

 We propose that therapeutic trials for anti-MAG neuropathy include patients with the typical presentation, some degree of weakness, highly elevated anti-MAG antibody titers, and at least one nerve exhibiting demyelinating range abnormalities. Treatment with one or a combination of anti-B-cell agents would aim at reducing the autoantibody concentration by at least 60%. A trial duration of 2 years may be required to show efficacy. The neuropathy impairment score of the lower extremities (NIS-LL) plus the Lower Limb Function (LLF) score would be a suitable primary outcome measure.

Survival trends in young patients with Waldenström macroglobulinemia: Over five decades of experience

Waldenström macroglobulinemia (WM) is a rare, indolent lymphoma, that predominately affects the elderly. We report the outcomes of young WM patients, evaluated over five decades, compared to their older counterparts, matched for the time of diagnosis. Between January 1, 1960 and October 31, 2013, 140 (11.8%) WM patients were ≤50 years of age at diagnosis in our database, and their estimated 10-year overall survival (OS) was 74%, with death attributable to WM in a higher proportion of patients compared to their older (≥65 years) counterparts (91% vs. 58%, p = .0001). Young patients were grouped into three cohorts based on the timing of the initiation of therapy: Group 1 (1960-1977, n = 12), Group 2 (1978-1995, n = 48), and Group 3 (1996-2013, n = 74). Among young patients, there was no disease-specific survival (DSS) difference across the three periods, [median DSS at 13 years (95% CI 5-23), 16 years (95% CI 14-22), and 15 years (95% CI 10-NR; p = .41), respectively]. However, DSS for the older cohort incrementally improved (Group 1, median 5.2 years, Group 2: 9.6 years, Group 3: 12 years; p = .05) over these periods. The estimated average years-of-life lost for the young cohort was 11.2 years from diagnosis, based on the expected survival for a normal age- and sex-matched population. Despite a protracted disease course, nearly all young patients succumb to their disease. In contrast to the improved survival of the elderly patient population, the evolving treatment strategies in WM have not impacted the outcome of young patients; however, the impact of Bruton tyrosine kinase inhibitors on this unique patient population remains to be determined.

Bilateral central retinal vein occlusion as an initial presentation of Waldenström macroglobulinemia: a case report

BACKGROUND

Waldenström macroglobulinemia is a rare hematological malignancy and is the most common diagnosis in patients with hyperviscosity syndrome. Bilateral central retinal vein occlusion as an initial presentation of hyperviscosity syndrome in Waldenström macroglobulinemia is rare.

CASE PRESENTATION

A 42-year-old Nepalese male presented with sudden-onset bilateral painless blurring of vision. Fundus examination revealed bilateral, diffusely dilated, tortuous retinal veins and intraretinal deep blot hemorrhages in all four quadrants of the retina in both eyes; features of bilateral central retinal vein occlusion. Serum electrophoresis showed hypoalbuminemia with an immunoglobulin M kappa monoclonal spike. Bone marrow picture and immunohistochemistry analysis were suggestive of lymphoplasmacytic lymphoma. The patient received systemic therapy for Waldenström macroglobulinemia, along with intravitreal bevacizumab.

CONCLUSION

Adequate hydration, plasmapheresis, and a combination of bortezomib, dexamethasone, and rituximab regimen as a systemic therapy may represent an ideal choice for patients with hyperviscosity in Waldenström macroglobulinemia.

Treatment and Survival Outcomes of Waldenstrom Macroglobulinemia in Latin American Patients: A Multinational Retrospective Cohort Study

Waldenstrom Macroglobulinemia (WM) is a rare lymphoma with distinct clinical features, and data from Latin American patients are lacking. Therefore, we aim to investigate the clinical, therapy, and outcome patterns of WM in Latin America.

Waldenstrom Macroglobulinemia (WM) is a rare lymphoma with distinct clinical features. Data from Latin American WM patients are lacking. In this article, we report, for the first time, the results of a retrospective analysis focused on the clinical, therapy, and outcome patterns of WM in Latin America. Moreover, we have validated the IPSSWM score as a prognostic factor for mortality and disease progression. Despite the limitations we acknowledge, this is the first study to provide novel real-world data on WM in Latin America.

Multi-catalytic Sites Inhibition of Bcl2 Induces Expanding of Hydrophobic Groove: A New Avenue Towards Waldenström Macroglobulinemia Therapy

B-cell lymphoma 2 (Bcl2) is a key protein regulator of apoptosis. The hydrophobic groove in Bcl2 is a unique structural feature to this class of enzymes and found to have a profound impact on protein overall structure, function, and dynamics. Dynamics of the hydrophobic groove is an essential determinant of the catalytic activity of Bcl2, an implicated protein in Waldenström macroglobulinemia (WM). The mobility of α3-α4 helices around the catalytic site of the protein remains crucial to its activity. The preferential binding mechanisms of the multi-catalytic sites of the Bcl2 enzyme have been a subject of debate in the literature. In addition to our previous report on the same protein, herein, we further investigate the preferential binding modes and the conformational implications of Venetoclax-JQ1 dual drug binding at both catalytic active sites of Bcl2. Structural analysis revealed asymmetric α3-α4 helices movement with the expansion of the distance between the α3 and α4 helix in Venetoclax-JQ1 dual inhibition by 15.2% and 26.3%, respectively when compared to JQ1 and Venetoclax individual drug inhibition-resulting in remarkable widening of hydrophobic groove. Moreso, a reciprocal enhanced binding effect was observed: Venetoclax increased the binding affinity of JQ1 by 11.5%, while the JQ1 fostered the binding affinity of Venetoclax by 16.3% compared with individual inhibition of each drug. This divergence has also resulted in higher protein stability, and prominent correlated motions were observed with the least fluctuations and multiple van der Waals interactions. Findings offer vital conformational dynamics and structural mechanisms of enzyme-single ligand and enzyme-dual ligand interactions, which could potentially shift the current therapeutic protocol of Waldenström macroglobulinemia.

Primary therapy and relative survival in patients with lymphoplasmacytic lymphoma/Waldenström macroglobulinaemia: a population-based study in the Netherlands, 1989-2018

It is unclear how treatment advances impacted the population‐level survival of patients with lymphoplasmacytic lymphoma/Waldenström macroglobulinaemia (LPL/WM). Therefore, we assessed trends in first‐line therapy and relative survival (RS) among patients with LPL/WM diagnosed in the Netherlands between 1989 and 2018 (N = 6232; median age, 70 years; 61% males) using data from the nationwide Netherlands Cancer Registry. Patients were grouped into three age groups (<65, 66–75 and >75 years) and four calendar periods. Overall, treatment with anti‐neoplastic agents within 1 year post‐diagnosis gradually decreased over time, following a broader application of an initial watch‐and‐wait approach. Approximately 40% of patients received anti‐neoplastic therapy during 2011–2018. Furthermore, use of chemotherapy alone decreased over time, following an increased application of chemoimmunotherapy. Detailed data among 1596 patients diagnosed during 2014–2018 revealed that dexamethasone‐rituximab‐cyclophosphamide was the most frequently applied regimen; its use increased from 14% to 39% between 2014 and 2018. The 5‐year RS increased significantly over time, particularly since the introduction of rituximab in the early–mid 2000s. The 5‐year RS during 1989–1995 was 75%, 65%, and 46% across the age groups compared to 93%, 85%, and 79% during 2011–2018. However, the survival improvement was less pronounced after 2011. Collectively, the impressive survival improvement may be accounted for by broader application of rituximab‐containing therapy. The lack of survival improvement in the post‐rituximab era warrants studies across multiple lines of therapy to further improve survival in LPL/WM.

Managing complications secondary to Waldenström's macroglobulinemia

Introduction: Waldenström's macroglobulinemia (WM) is a rare lymphoma characterized by the accumulation of IgM-secreting lymphoplasmacytic cells in the bone marrow and other organs. Clinical sequelae relate to direct tissue infiltration by malignant cells but also to the physicochemical and immunological properties of the monoclonal IgM, resulting in a variety of disease-related complications.Areas covered: This narrative review, following a thorough Pubmed search of pertinent published literature, discusses complications secondary to WM, related to direct tumor infiltration, monoclonal IgM circulation, and deposition, as well as other less common ones. The description and pathophysiology of these complications were described together with their specific management strategies and in the context of available treatment options for WM (anti-CD20 monoclonal antibody-based combinations, proteasome inhibitors, BTK inhibitors, and other emerging ones).Expert opinion: The availability of many novel, active and less toxic regimens for the treatment of WM allows the management of the disease with strategies that depend on clinical presentation and disease-related complications, age, toxicity considerations, and presence of comorbidities.

Ixazomib, dexamethasone, and rituximab in treatment-naive patients with Waldenström macroglobulinemia: long-term follow-up

Proteasome inhibition is a standard of care for the primary treatment of patients with Waldenström macroglobulinemia (WM). We present the long-term follow-up of a prospective, phase II clinical trial that evaluated the combination of ixazomib, dexamethasone, and rituximab (IDR) in 26 treatment-naive patients with WM. IDR was administered as 6 monthly induction cycles followed by 6 every-2-month maintenance cycles. The MYD88 L265P mutation was detected in all patients, and CXCR4 mutations were detected in 15 patients (58%). The median time to response (TTR) and time to major response (TTMR) were 2 and 6 months, respectively. Patients with and without CXCR4 mutations had median TTR of 3 months and 1 month, respectively (P = .003), and median TTMR of 10 months and 3 months, respectively (P = .31). The overall, major, and very good partial response (VGPR) rates were 96%, 77%, and 19%, respectively. The rate of VGPR in patients with and without CXCR4 mutations were 7% and 36%, respectively (P = .06). The median progression-free survival (PFS) was 40 months, the median duration of response (DOR) was 38 months, and the median time to next treatment (TTNT) was 40 months. PFS, DOR, and TTNT were not affected by CXCR4 mutational status. The safety profile was excellent with no grade 4 adverse events or deaths to date. IDR provides a safe and effective frontline treatment option for symptomatic patients with WM. This study was registered at www.clinicaltrials.gov as #NCT02400437.

A multicenter, open-label, phase II study of tirabrutinib (ONO/GS-4059) in patients with Waldenström's macroglobulinemia

Tirabrutinib is a second-generation Bruton's tyrosine kinase inhibitor with greater selectivity than ibrutinib. Here, we conducted a multicenter, phase II study of tirabrutinib in patients with treatment-naïve (Cohort A) or with relapsed/refractory (Cohort B) Waldenström's macroglobulinemia (WM). Patients were treated with tirabrutinib 480 mg once daily. The primary endpoint was major response rate (MRR; ≥ partial response). Secondary endpoints included overall response rate (ORR; ≥ minor response), time to major response (TTMR), progression-free survival (PFS), overall survival (OS), and safety. In total, 27 patients (18 in Cohort A; 9 in Cohort B) were enrolled. The median age was 71 y, and the median serum immunoglobulin M level was 3600 mg/dL. Among the patients, 96.2% had the MYD88^L265P mutation. MRR and ORR were 88.9% and 96.3%, respectively (Cohort A: MRR, 88.9%; ORR, 94.4%; Cohort B: MRR, 88.9%; ORR, 100%). Median TTMR was 1.87 mo. PFS and OS were not reached with a median follow-up of 6.5 and 8.3 mo for Cohorts A and B, respectively. The most common adverse events (AEs) were rash (44.4%), neutropenia (25.9%), and leukopenia (22.2%), with most AEs classified as grade 1 or 2. Grade ≥ 3 AEs included neutropenia (11.1%), lymphopenia (11.1%), and leukopenia (7.4%). No grade 5 AEs were noted. All bleeding events were grade 1; none were associated with drug-related atrial fibrillation or hypertension. Although the follow-up duration was relatively short, the study met the primary endpoint. Therefore, tirabrutinib monotherapy is considered to be highly effective for both untreated and relapsed/refractory WM with a manageable safety profile. (JapicCTI-173646).

Response and Survival Outcomes to Ibrutinib Monotherapy for Patients With Waldenström Macroglobulinemia on and off Clinical Trials

Ibrutinib is the first approved therapy for symptomatic patients with Waldenström macroglobulinemia (WM). The approval was based on a single, multicenter, phase II trial in previously treated WM patients. We sought to evaluate whether there were differences in clinical characteristics, response, and survival outcomes to ibrutinib monotherapy between WM patients treated on and off clinical trials. Treatment naïve and previously treated patients who received ibrutinib monotherapy at our institution and participated in two prospective studies (ON trial; n = 72) or a prospective database (OFF trial; n = 157) were included. The median times from WM diagnosis to ibrutinib initiation were 3.1 and 3.5 years for ON and OFF trial patients, respectively (p = 0.38). Similar rates of categorical response at 6, 12, and 24 months and at best response were also observed between ON trial and OFF trial patients. The 4-year PFS and OS rates for ON trial and OFF trial patients were 72% and 63%, respectively (log-rank p = 0.14) and 83% and 81%, respectively (log-rank p = 0.14). CXCR4 mutations impacted response and survival outcomes to ibrutinib monotherapy. The 4-year rates of ibrutinib discontinuation in ON and OFF trial patients were 36% and 44%, respectively (p = 0.11). Ibrutinib is effective in the routine clinical care of both treatment-naïve and previously treated WM patients. The findings of our study validate the efficacy of ibrutinib monotherapy reported in multiple phase II clinical trials.

Rare lymphomas in routine practice-Treatment and outcome in Waldenström's macroglobulinaemia in the prospective German Tumour Registry Lymphatic Neoplasms

Waldenström's macroglobulinaemia (WM) is a rare indolent B‐cell lymphoma for which only little prospective phase III evidence exists. Thus, real world data are important to provide insight into treatment and survival. We present here data on choice and outcome of systemic treatment of patients with WM treated in German routine practice. In total, 139 patients with WM who had been documented in the prospective clinical cohort study Tumour Registry Lymphatic Neoplasms (NCT00889798) were included into this analysis. We analysed the most frequently used first‐line and second‐line treatments between 2009 and 2017 and examined best response, progression‐free survival (PFS) and overall survival (OS). Bendamustine plus rituximab, with a median of six cycles, was by far the most frequently used first‐line treatment (81%). Second‐line treatment was more heterogenous and mainly based on bendamustine, cyclophosphamide/doxorubicin/vincristine/prednisone (CHOP), fludarabine or ibrutinib, the latter approved in 2014. Three‐year PFS from start of first‐line treatment was 83% (95% confidence interval [CI] 74%‐88%), 3‐year OS was 87% (95% CI 80%‐92%). These prospective data give valuable insights into the management and outcome of non‐selected patients with WM treated in German routine practice. In the lack of prospective phase III clinical trials, real world data can help bridging the gap of evidence.

What is new in the treatment of Waldenstrom macroglobulinemia?

Waldenstrom macroglobulinemia (WM) is a rare type of non-Hodgkin lymphoma. The diagnosis of WM is established by the presence of lymphoplasmacytic lymphoma in the bone marrow or other organs, a monoclonal IgM paraproteinemia and the recurrent MYD88 L265P somatic mutation. Some patients with WM can be asymptomatic, in which case treatment is not indicated. However, most patients with WM will become symptomatic during the course of the disease, due to anemia, hyperviscosity, neuropathy, or other processes, necessitating therapy. Current treatment options for symptomatic WM patients include alkylating agents, proteasome inhibitors and anti-CD20 monoclonal antibodies. The approval of the oral Bruton tyrosine kinase (BTK) inhibitor ibrutinib alone and in combination with rituximab has expanded the treatment options for WM patients. The present Perspective would focus on exciting treatment strategies under development for WM patients, such as proteasome inhibitors (e.g., ixazomib), BTK inhibitors (e.g., acalabrutinib, zanubrutinib, vecabrutinib), BCL2 inhibitors (e.g., venetoclax), and anti-CXCR4 antibodies (e.g., ulocuplumab), among others. It is certainly an exciting time for WM therapy development with novel and promising treatment options in the horizon.

CXCR4 mutation subtypes impact response and survival outcomes in patients with Waldenström macroglobulinaemia treated with ibrutinib

Ibrutinib is associated with response rate of 90% and median progression-free survival (PFS) in excess of 5 years in Waldenström macroglobulinaemia (WM) patients. CXCR4 mutations are detected in 30-40% of patients with WM and associate with lower rates of response and shorter PFS to ibrutinib therapy. Both frameshift (CXCR4^FS ) and nonsense (CXCR4^NS ) CXCR4 mutations have been described. The impact of these mutations on outcomes to ibrutinib have not been evaluated in WM patients. We studied consecutive patients with a diagnosis of WM, on ibrutinib therapy, for the presence of CXCR4^FS and CXCR4^NS mutations and evaluated the differences in response and PFS between groups. Of 180 patients, 68 patients (38%) had CXCR4 mutations; 49 (27%) had CXCR4^NS and 19 (11%) had CXCR4^FS mutations. In multivariate models, patients with CXCR4^NS had lower odds of major response (Odds ratio 0·25, 95% confidence interval [CI] 0·12-0·53; P < 0·001) and worse PFS (Hazard ratio 4·02, 95% CI 1·95-8·26; P < 0·001) than patients without CXCR4 mutations. CXCR4^FS was not associated with worse major response or PFS rates than patients without CXCR4 mutations. Our results suggest different response and PFS rates to ibrutinib for WM patients with CXCR4^NS and CXCR4^FS , and advocate in favour of CXCR4 mutational testing as well as CXCR4-directed therapy.

Prescription Drug Coverage and Outcomes of Myeloma Therapy Among Medicare Beneficiaries

PURPOSE

Novel parenteral (bortezomib) and oral (lenalidomide) therapies have improved survival in myeloma, but the standard Medicare benefit covers only parenteral drugs. We examined the association between prescription drug coverage, receipt of therapy, and survival among Medicare beneficiaries with myeloma.

METHODS

Using SEER-Medicare data, we identified enrollment in a Medicare Part D plan (PDP) or other creditable prescription drug coverage (OCC) among 9,755 beneficiaries who were diagnosed with myeloma in 2006 to 2011. We examined the receipt of active myeloma therapy and that of classic cytotoxic agents or bortezomib as first-line regimen and overall survival. We report relative risk (RR) for binary outcome comparisons and 3-year restricted mean survival time (RMST) ratios, with 95% CI, adjusting for baseline patient- and disease-related characteristics. Beneficiaries with diffuse large B-cell lymphoma, a cancer that is uniformly treated with parenteral chemotherapy, served as a comparison cohort.

RESULTS

Compared with beneficiaries without prescription drug coverage, PDP or OCC enrollees were more likely to receive active myeloma care, and PDP enrollees were less frequently treated with parenteral agents (adjusted RR, 0.86; 95% CI, 0.80 to 0.93) or classic cytotoxic agents in particular (RR, 0.62; 95% CI, 0.51 to 0.76). Overall survival was significantly better for beneficiaries with PDP coverage (adjusted RMST ratio, 1.16; 95% CI, 1.11 to 1.20) or OCC (RMST ratio, 1.16; 95% CI, 1.12 to 1.21). In contrast, we observed no survival differences by prescription drug coverage status in the control cohort with lymphoma.

CONCLUSION

Prescription drug coverage is associated with decreased use of classic cytotoxic chemotherapy and better survival among Medicare beneficiaries with myeloma, which suggests improved access to all existing treatment options. As oral targeted agents increasingly replace parenteral chemotherapy in oncology, adjustments in coverage policy are needed to ensure access to optimal treatment.

Monoclonal Antibodies for Waldenström Macroglobulinemia

For the last 2 decades, anti-CD20 monoclonal antibodies have revolutionized the treatment of patients with B-cell lymphomas. These agents have shown efficacy when used as single agents and also have improved response and survival rates when added to chemotherapy. Monoclonal antibodies are safe and effective as well in patients with Waldenström macroglobulinemia (WM). The purpose of this article is to review the mechanism of action of monoclonal antibodies and to discuss current clinical data supporting their use in patients with WM. This review focuses on retrospective and prospective studies and clinical trials on anti-CD20 antibodies, anti-CD38 antibody, and anti-CXCR4 antibody.

Transfusion dependence, use of hospice services, and quality of end-of-life care in leukemia

Hospice provides high-quality end-of-life care, but patients with leukemias use hospice services less frequently than those with solid tumors. Transfusion dependence (TD) may hinder or delay enrollment, because hospice organizations typically disallow transfusions. We examined the association between TD and end-of-life outcomes among Medicare beneficiaries with leukemia. From the Surveillance, Epidemiology, and End Results-Medicare database, we selected beneficiaries with acute and chronic leukemias who died in 2001-2011. We defined TD as ≥2 transfusions within 30 days before death or hospice enrollment. End points included hospice enrollment and length of stay, reporting relative risk (RR) adjusted for key covariates. Among 21 033 patients with a median age of 79 years, 20% were transfusion dependent before death/hospice enrollment. Use of hospice increased from 35% in 2001 to 49% in 2011. Median time on hospice was 9 days and was shorter for transfusion-dependent patients (6 vs 11 days; P < .001). Adjusting for baseline characteristics, TD was associated with a higher use of hospice services (RR, 1.08; 95% confidence interval [CI], 1.04-1.12) but also with 51% shorter hospice length of stay (RR, 0.49; 95% CI, 0.44-0.54). Hospice enrollees had a lower likelihood of inpatient death and chemotherapy use and lower median Medicare spending at end-of-life, regardless of TD status. In conclusion, relatively increased hospice use combined with a markedly shorter length of stay among transfusion-dependent patients suggests that they have a high and incompletely met need for hospice services and that they experience a barrier to timely referral. Policy solutions supporting palliative transfusions may maximize the benefits of hospice for leukemia patients.

Impact of rituximab and half-dose CHOP as primary therapy for untreated symptomatic Waldenström Macroglobulinemia: review of a combined regimen of rituximab with an alkylating agent

Background

Waldenström Macroglobulinemia (WM) is a rare subtype of indolent B-cell lymphoma, and prospective randomized studies on WM are scarce. The R-CHOP therapy [rituximab (R), cyclophosphamide, hydroxy-doxorubicin, vincristine, and prednisone] is a popular and recommended regimen for primary therapy, prescribed by several treatment guidelines for WM. However, treatment with R-CHOP is accompanied by severe myelosuppression and high rates of peripheral neuropathy. Therefore, we retrospectively evaluated the efficacy and toxicity of half-dose CHOP combined with R as a primary therapy for WM.

Methods

Patients with untreated symptomatic WM, treated at the Disaster Medical Center between April 2011 and September 2016, were retrospectively analyzed after administration of 6 cycles of half-dose R-CHOP for every 3 weeks. The response, median time to response, best response, progression-free survival, overall survival, and toxicities were evaluated.

Results

Of the 20 WM patients analyzed, 16 (80%) received half-dose R-CHOP without vincristine, and 13 (65%) responded to the treatment. With a median follow-up duration of 26.3 months, the 2-year progression-free survival and 2-year overall survival rates were 70 and 93.3%, respectively. The median time to response and best response were 6 and 9.9 weeks, respectively. Grade 3/4 leukocytopenia, neutropenia, febrile neutropenia, and Grade 1 peripheral neuropathy developed in 32, 37, 0, and 21% of patients, respectively.

Conclusion

The half-dose R-CHOP is an effective and well-tolerated primary therapy for WM. To the best of our knowledge, this is the first study reporting the use of a reduced-dose R-CHOP regimen for the primary treatment of WM.

Phase 3 Trial of Ibrutinib plus Rituximab in Waldenström's Macroglobulinemia

BACKGROUND

Single-agent ibrutinib has shown substantial activity in patients with relapsed Waldenström's macroglobulinemia, a rare form of B-cell lymphoma. We evaluated the effect of adding ibrutinib to rituximab in patients with this disease, both in those who had not received previous treatment and in those with disease recurrence.

METHODS

We randomly assigned 150 symptomatic patients to receive ibrutinib plus rituximab or placebo plus rituximab. The primary end point was progression-free survival, as assessed by an independent review committee. Key secondary end points were response rates, sustained hematologic improvement from baseline, and safety. The mutational status of MYD88 and CXCR4 was assessed in bone marrow samples.

RESULTS

At 30 months, the progression-free survival rate was 82% with ibrutinib-rituximab versus 28% with placebo-rituximab (hazard ratio for progression or death, 0.20; P<0.001). The benefit in the ibrutinib-rituximab group over that in the placebo-rituximab group was independent of the MYD88 or CXCR4 genotype. The rate of major response was higher with ibrutinib-rituximab than with placebo-rituximab (72% vs. 32%, P<0.001). More patients had sustained increases in hemoglobin level with ibrutinib-rituximab than with placebo-rituximab (73% vs. 41%, P<0.001). The most common adverse events of any grade with ibrutinib-rituximab included infusion-related reactions, diarrhea, arthralgia, and nausea. Events of grade 3 or higher that occurred more frequently with ibrutinib-rituximab than with placebo-rituximab included atrial fibrillation (12% vs. 1%) and hypertension (13% vs. 4%); those that occurred less frequently included infusion reactions (1% vs. 16%) and any grade of IgM flare (8% vs. 47%). The major hemorrhage rate was the same in the two trial groups (4%).

CONCLUSIONS

Among patients with Waldenström's macroglobulinemia, the use of ibrutinib-rituximab resulted in significantly higher rates of progression-free survival than the use of placebo-rituximab, both among those who had received no previous treatment and among those with disease recurrence. Atrial fibrillation and hypertension were more common with ibrutinib-rituximab, whereas infusion reactions and IgM flare were more common with placebo-rituximab. (Funded by Pharmacyclics and Janssen Research and Development; ClinicalTrials.gov number, NCT02165397 .).

How we manage patients with Waldenström macroglobulinaemia

Waldenström macroglobulinaemia (WM) is a rare, indolent B-cell lymphoproliferative disorder characterized by cellular involvement in bone marrow and monoclonal IgM production. Symptoms can be related to cytopenias, tumoural involvement, or IgM-related disorders. Somatic mutations in the MYD88 gene have been described in the majority of WM cases. The mutation is responsible for a gain-of-function and induces activation of nuclear factor-κB, for DNA transcription and cell survival. It seems that MYD88 mutation is associated with better prognosis and better response to some treatment. Treatments are started when WM is symptomatic, following systematic biological and morphological assessments. Therapeutic choice depends on age, frailty and urgent efficacy need. In first line, the majority of patients are treated with monoclonal anti-CD20 antibody-based regimens combined with cytotoxic chemotherapy. Rituximab, cyclophosphamide and dexamethasone remain the most commonly used regimen with good safety. Nevertheless, increasing numbers of new drugs are becoming available or are in development. Proteasome inhibitors, such as bortezomib or carfilzmib, showed good and rapid responses. Bruton tyrosine kinase (BTK) inhibitor demonstrated excellent results and is now available for relapse/refractory disease or as first line for some patients. This review highlights the diagnostic procedures and therapeutic approaches in WM.

Low-dose bortezomib and dexamethasone as primary therapy in elderly patients with Waldenstrӧm macroglobulinemia

OBJECTIVE

This retrospective study was designed to determine the efficacy and safety of low-dose bortezomib and dexamethasone (lBD) in elderly Chinese patients with Waldenstrӧm macroglobulinemia (WM).

METHODS

Ten patients with WM aged over 60 years received first-line treatment with lBD.

RESULTS

The median age was 70 years (range, 61-77 years). The overall response rate was 80%, including 1 patient who achieved a complete response, 1 patient with very good partial response, and 6 patients with a partial response. Median time to response was 1.8 months after treatment with lBD. Six (60%) patients achieved a partial response, including 2 (20%) patients who had a more than 75% reduction in serum immunoglobulin M levels. A rapid reduction in paraprotein was observed in three patients who received plasmapheresis. After a median follow-up period of 36 months, all patients were still alive and six had no disease progression. The estimated median time to progression was 39 months (range, 15-60 months). The most common adverse events were anemia, thrombocytopenia, neuropathy, and neutropenia. Peripheral neuropathy was the most common non-hematological toxicity in six (60%) patients, but did not result in the discontinuation of bortezomib.

CONCLUSIONS

Our findings show that lBD is an effective and tolerable treatment regimen for elderly patients with WM.

Cost-effectiveness analysis of ibrutinib in patients with Waldenström macroglobulinemia in Italy

Background and Objective: Ibrutinib has recently been approved in Europe for Waldenström Macroglobulinemia (WM) in symptomatic patients who have received at least one prior therapy, or in first-line treatment for patients unsuitable for chemo-immunotherapy. The aim of the study is to estimate the incremental cost-effectiveness ratio (ICER) of ibrutinib in relapse/refractory WM, compared with the Italian current therapeutic pathways (CTP). Methods: A Markov model was adapted for Italy considering the National Health System perspective. Input data from literature as well as global trials were used. The percentage use of therapies, and healthcare resources consumption were estimated according to expert panel advice. Drugs ex-factory prices and national tariffs were used for estimating costs. The model had a 15-year time horizon, with a 3.0% discount rate for both clinical and economic data. Deterministic and probabilistic sensitivity analyses were performed to test the results strength. Results: Ibrutinib resulted in increased Life Years Gained (LYGs) and increased costs compared to CTP, with an ICER of €52,698/LYG. Sensitivity analyses confirmed the results of the BaseCase. Specifically, in the probabilistic analysis, at a willingness to pay threshold of €60,000/LYG ibrutinib was cost-effective in 84% of simulations. Conclusions: Ibrutinib has demonstrated a positive cost-effectiveness profile in Italy.

Subsidies for Oral Chemotherapy and Use of Immunomodulatory Drugs Among Medicare Beneficiaries With Myeloma

Purpose The low-income subsidy (LIS) substantially lowers out-of-pocket costs for qualifying Medicare Part D beneficiaries who receive orally administered chemotherapy. We examined the association of LIS with the use of novel oral immunomodulatory drugs (IMiDs; lenalidomide and thalidomide) among beneficiaries with myeloma, who can receive either orally administered or parenteral (bortezomib-based) therapy. Methods Using SEER-Medicare data, we identified Part D beneficiaries diagnosed with myeloma in 2007 to 2011. In multivariable models adjusted for sociodemographic and clinical characteristics, we analyzed associations between the LIS and use of IMiD-based therapy, delays between IMiD refills, and select health outcomes during the first year of therapy. Results Among 3,038 beneficiaries, 41% received first-line IMiDs. Median out-of-pocket cost for the first IMiD prescription was $3,178 for LIS nonrecipients and $3 for LIS recipients, whereas the respective median costs for the first year of therapy were $5,623 and $6, respectively. Receipt of the LIS was associated with a 32% higher (95% CI, 16% to 47%) probability of receiving IMiDs among beneficiaries age 75 to 84 years and a significantly lower risk of delays between refills in all age groups (adjusted relative risk, 0.54; 95% CI, 0.32 to 0.92). Duration of therapy did not significantly differ between LIS recipients and nonrecipients (median, 7.6 months). Patients treated with IMiDs had significantly fewer emergency department visits and hospitalizations compared with patients receiving bortezomib (without IMiDs), but 1-year overall survival and cumulative Medicare costs were similar. Conclusion Medicare beneficiaries with myeloma who do not receive LISs face a substantial financial barrier to accessing orally administered anticancer therapy, warranting urgent attention from policymakers. Limiting out-of-pocket costs for expensive anticancer drugs like the IMiDs may improve access to oral therapy for patients with myeloma.

Comparative outcomes of immunochemotherapy regimens in Waldenström macroglobulinaemia

Comparative data on immunochemotherapy regimens for Waldenström macroglobulinaemia/lymphoplasmacytic lymphoma (WM/LPL) are lacking. We analysed overall survival (OS), risk of hospitalizations, transfusions and plasmapheresis in a population-based cohort of patients ≥65 years old initiating WM/LPL therapy in 1999-2013. To minimize bias, we applied a propensity score-based causal inference method. We conducted three analyses of: patients treated with or without rituximab, patients treated with rituximab monotherapy or with combination immunochemotherapy, and regimens based on classic purine analogues or alkylators. Among 1310 patients, 78·5% received rituximab. Patients who received rituximab had significantly better OS [hazard ratio (HR) 0·62, 95% confidence interval (CI) 0·55-0·71] and lower risk of transfusions (risk difference -3·3%, 95% CI -6·3 to -0·3) than those who did not, without a significant difference in hospitalizations or plasmapheresis. We observed no significant difference in OS (HR 0·91, 95% CI 0·79-1·04) between rituximab monotherapy and combination immunochemotherapy, but toxicity outcomes were lower with rituximab alone. Neither survival (HR 1·10, 95%CI 0·92-1·32) nor toxicity outcomes differed significantly between regimens based on purine analogues or alkylators. The survival advantage strongly supports rituximab as part of upfront therapy for WM/LPL, whereas regimens with either purine analogues or alkylating agents result in similar outcomes.

[Evaluation of clinical characteristics, MYD88(L265P) mutation, CXCR4(WHIM) mutation and prognosis in Waldenström macroglobulinemia: A single center retrospective study of 93 patients]

Objective: To evaluate the clinical characteristics, MYD88(L265P) mutation, CXCR4(W)HIM mutation and prognosis in patients with Waldenström macroglobulinemia (WM). Methods: The clinical characteristics, International Prognostic Scoring System for symptomatic WM (WPSS) , and overall survival (OS) were retrospectively assayed in 93 patients with newly diagnosed WM at Peking Union Medical College Hospital during January 2000 to August 2016. The MYD88(L265P) mutation and CXCR4(W)HIM mutation were tested among 34 patients. Results: The median age of the 93 patients was 64 years (range, 33-85 years) with a male-to-female ratio of 2.44. According to WPSS, we included 16 (17.2%) low-risk, 44 (47.3%) intermediate-risk and 33 (35.5%) high-risk patients. Eight patients had secondary amyloidosis. With a median follow-up of 44 (1-201) months, the median OS was 84 months. Cox regression multifactor analysis showed WPSS risk group (HR=2.342, 95% CI 1.111-4.950, P=0.025) , whether patients had secondary amyloidosis (HR=5.538, 95% CI 1.958-15.662, P=0.001) and whether patients received new drugs (HR=3.392, 95% CI 1.531-7.513, P=0.003) were independent factors associated with OS. We have investigated the presence of the MYD88(L265P) and CXCR4(WHIM) mutation in 34 patients and found that MYD88(L265P) mutation was occurred in 32 patients (94.1%) and CXCR4(WHIM) mutation was occurred in 8 patients (23.5%). Seven of 8 patients who harbored CXCR4(WHIM)-mutated also exhibited the MYD88(L)265P mutation. Patients with MYD88(L265P)CXCR4(WHIM) vs MYD88(L265P)CXCR4(WT) presented with more severe anemia, lower platelet level, higher M protein level and more hyper-viscosity syndrome. Conclusion: WPSS risk group, whether patients had secondary amyloidosis or received new drugs are independent factors for OS in WM. MYD88(L265P) and CXCR4(WHIM) mutation, the most common somatic variants in WM, often occur together and impact the clinical presentation.

New developments in the management of Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a rare, immunoglobulin M -associated lymphoplasmacytic lymphoma. With the recent discoveries of CXCR warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) and MYD88 mutations, our understanding of the biology of WM has expanded substantially. While WM still remains incurable, the field is rapidly evolving, and a number of promising agents with significant activity in this malignancy are being evaluated currently. In this review, we discuss the new developments that have occurred in WM over the past 15 years, with a focus on the role of ibrutinib, an oral Bruton's tyrosine kinase inhibitor that has recently been approved for WM in the United States, Europe, and Canada.

Long-Term Response and Possible Cure of Patients With B-Cell Malignancies With Dose-Escalated Rituximab

Rituximab (R), a chimeric monoclonal antibody targeting CD20 antigen on B-cells, has become a standard of care in the treatment of B-cell malignancies, most often in conjunction with cytotoxic chemotherapy. Activity has been demonstrated in many subtypes of B-cell lymphoma, including diffuse large cell lymphoma, follicular lymphoma (FL), mantle cell lymphoma (MCL), chronic lymphocytic leukemia (CLL), lymphocyte-predominant Hodgkin lymphoma, and Waldenström macroglobulinemia (WM). Additionally, dose escalation of R as a single agent has demonstrated improved activity in previously treated/poor prognosis CLL. We present 4 cases of B-cell malignancy (2 CLL variants/MCL, 1 FL, 1 WM) who received dose-escalated R as a single agent and achieved complete response (3 patients) and stable disease/partial response (1 patient) of 6.5+ to 15+ years duration. They have been off treatment for 6.5+ to 15+ years. Toxicity was minimal, with initial infusion reactions similar to those observed with standard dose infusions. There were no serious treatment-related adverse events or infections. Dose escalated R as a single agent may possibly be curative for some patients with B-cell malignancies, unlike the standard empiric dose of 375 mg/m², and deserves further study.