Rituximab-based combination therapy in patients with Waldenström macroglobulinemia: a systematic review and meta-analysis

Efficacy and safety of front-line treatment regimens for Waldenstrom macroglobulinaemia: a systematic review and meta-analysis

Rituximab-based chemo-immunotherapy is currently the standard first-line treatment for Waldenstrom macroglobulinaemia (WM), while ibrutinib has emerged as an alternative. In the absence of randomised trials (RCTs) comparing these regimens, the optimal first-line treatment for WM remains uncertain. In this systematic review and meta-analysis, we sought to assess the efficacy and safety of first-line treatment regimens for WM. We searched key databases from January 2007 to March 2023, including phase II and III trials, including treatment-naïve WM patients treated with rituximab-based regimens or ibrutinib. Response rates, progression-free survival (PFS), overall survival (OS), and toxicities were evaluated. Four phase III and seven phase II trials were included among 736 unique records. Pooled response rates from all comparative and non-comparative trials were 46%, 33% and 26% for bendamustine rituximab (BR), bortezomib-dexamethasone, cyclophosphamide, rituximab (BDRC) and ibrutinib rituximab (IR), respectively. Two-year pooled PFS was 89%, 81% and 82% with BR, BDRC and IR, respectively. Neuropathy was more frequent with bortezomib, while haematologic and cardiac toxicities were more common with chemo-immunotherapy and ibrutinib-based regimens respectively. Our findings suggest that BR yields higher response rates than bortezomib or ibrutinib-based combinations. RCTs comparing BR against emerging therapies, including novel Bruton Tyrosine Kinase Inhibitors, are warranted.

Zanubrutinib in Treating Waldenström Macroglobulinemia, the Last Shall Be the First

In Waldenström macroglobulinemia (WM), a lymphoplasmacytic lymphoma characterized by monoclonal immunoglobulin M (IgM) gammopathy, aberrant Bruton tyrosine kinase (BTK) signaling has been identified as one mechanism of pathogenesis. For this reason, selective BTK inhibiting therapies have emerged as an attractive option for treatment within the therapeutic landscape also comprising chemotherapy, monoclonal antibodies, proteasome inhibitors, and B-cell lymphoma 2 (BCL2) inhibitors. The first BTK inhibiting therapy, ibrutinib, showed great efficacy in treating WM. However, response rates were dependent on whether patients had the CXCR4 mutation, a molecular aberration that may confer resistance to BTK inhibitors. Furthermore, ibrutinib’s toxicities, most notably hypertension and atrial arrhythmia, led to dose reductions or discontinuation. The toxicity profile of ibrutinib can be attributed to the inhibition of additional kinases that are structurally related to BTK. Therefore, the next-generation highly selective zanubrutinib was developed to address the concerns regarding toxicity and tolerance related to ibrutinib therapy. Based on the results of the randomized, open-label Phase 3 ASPEN (NCT03053440) trial, the Food and Drug Administration (FDA) approved zanubrutinib for treating WM. This trial directly compared zanubrutinib to ibrutinib in patients with treatment-naïve or relapsed/refractory WM, and the results showed stronger responses with zanubrutinib. More importantly, patients responded strongly to zanubrutinib therapy regardless of CXCR4 mutation status. Additionally, zanubrutinib was associated with fewer grade 3 or higher toxicities and was generally better tolerated. Another Phase 1/2 study has been conducted with just zanubrutinib in WM showcasing high efficacy with few toxicities as well. Even though zanubrutinib has been the third and last BTK inhibitor to currently penetrate the market for B-cell lymphoproliferative malignancies, we highlight the emergence of zanubrutinib as a key player in the forefront of the therapeutic landscape in WM.

Real-world data on the survival outcome of patients with newly diagnosed Waldenström macroglobulinemia

BACKGROUND/AIMS

Waldenström macroglobulinemia (WM) is a rare lymphoproliferative disorder that usually follows an indolent clinical course. However, some patients show an aggressive clinical course leading to death. We explored the risk factors predicting poor prognosis in WM patients.

METHODS

We retrospectively analyzed 47 patients diagnosed with WM between 2000 and 2018 to explore risk factors predicting poor prognosis using various clinical and laboratory parameters and risk models including the International Prognostic Staging System for WM (IPSS-WM).

RESULTS

Over a median follow-up duration of 80.4 months, 29 patients died. The main causes of death were disease progression, organ failure related to amyloidosis, and infection. The median overall survival (OS) was 55.1 months, and 14 patients, including three with amyloidosis, died within 2 years. Serum β2-microglobulin level higher than 4 mg/dL was significantly associated with poor OS. Accordingly, the IPSS-WM showed a significant association with poor prognosis compared with other risk models, and the low-risk group had better OS than intermediate- and high-risk groups. In the retrospective analysis using the results of targeted sequencing in two cases representing good and bad prognosis, different patterns of mutation profiles were observed, including mutations of MYD88, TP53, ARID1A, and JAK2 in a refractory case.

CONCLUSION

Serum β2-microglobulin could be a single biomarker strongly predictive of poor survival of WM patients, and the low-risk group of the IPSS-WM risk model including serum β2-microglobulin has better prognostic value than other risk models. Mutation analysis also might provide additional information to predict high-risk patients.

Treatment Patterns and Outcomes in a Nationwide Cohort of Older and Younger Veterans with Waldenström Macroglobulinemia, 2006-2019

Simple Summary

Waldenström macroglobulinemia is a rare cancer about which little is known. Evidence from real-world settings provides invaluable information to patients and clinicians, especially for older and/or frailer patients, a demographic often excluded from clinical trials. This study provides information about treatment patterns and outcomes from real-world cohorts of older (>70 years) and younger (≤70 years) patients. We report findings across early (2006–2012) and modern (2013–2019) eras, reflecting a transition during which the number of treatments available for Waldenström macroglobulinemia rapidly increased. We found marked improvements in treatment outcomes among older patients in the modern vs early era, with little or no improvement in outcomes among younger patients. Our findings emphasize the importance of real-world evidence in guiding patient-specific treatment decisions.

Abstract

Little is known about real-world treatment patterns and outcomes in Waldenström macroglobulinemia (WM) following the recent introduction of newer treatments, especially among older adults. We describe patterns of first-line (1 L) WM treatment in early (2006–2012) and modern (2013–2019) eras and report outcomes (overall response rate (ORR), overall survival (OS), progression-free survival (PFS), and adverse event (AE)-related discontinuation) in younger (≤70 years) and older (>70 years) populations. We followed 166 younger and 152 older WM patients who received 1 L treatment between January 2006 and April 2019 in the Veterans Health Administration. Median follow-up was 43.5 months (range: 0.6–147.2 months). Compared to the early era, older patients in the modern era achieved improved ORRs (early: 63.8%, modern: 72.3%) and 41% lower risk of death/progression (hazard ratio (HR) for PFS: 0.59, 95% CI (confidence interval): 0.36–0.95), with little change in AE-related discontinuation between eras (HR: 0.82, 95% CI: 0.4–1.7). In younger patients, the AE-related discontinuation risk increased almost fourfold (HR: 3.9, 95% CI: 1.1–14), whereas treatment effects did not change between eras (HR for OS: 1.4, 95% CI: 0.66–2.8; HR for PFS: 1.1, 95% CI: 0.67–1.7). Marked improvements in survival among older adults accompanied a profound shift in 1 L treatment patterns for WM.

Hyperviscosity Syndrome in Paraprotein Secreting Conditions Including Waldenstrom Macroglobulinemia

Hyperviscosity syndrome is a serious complication associated with high levels of paraproteins in patients with hematological malignancies. Therapeutic advances in disease control may reduce the incidence of hyperviscosity syndrome; however, management of acute cases requires an understanding of key symptoms and prompt treatment to mitigate serious consequences.

Waldenström Macroglobulinemia: Clinical Presentation, Diagnosis, and Management

Waldenström macroglobulinemia is a rare hematologic malignancy characterized by an IgM-associated lymphoplasmacytic lymphoma. Often, it is associated with an indolent disease course, and many patients are candidates for careful monitoring. As many patients present with advanced age and nonspecific constitutional symptoms, careful consideration should be given to treatment decisions, including when and how to treat for maximized clinical benefit with minimal toxicity. This article provides an evidence-based practical approach to appropriate monitoring of the asymptomatic patient and management of symptomatic patients who require treatment for this rare malignancy.