Diagnostic Next-generation Sequencing Frequently Fails to Detect MYD88L265P in Waldenström Macroglobulinemia

Lymphoplasmacytic lymphoma and Waldenström macroglobulinemia, a decade after the discovery of MYD88L265P

There has been remarkable progress over the past 80 years since Jan Waldenstrom first described patients with a hyperviscosity syndrome related to IgM paraprotein in 1944. The definition of Waldenstrom macroglobulinemia (WM) has evolved from a clinical syndrome to a distinct clinicopathologic entity with characteristic morphology, immunophenotype and molecular features. The landmark discovery of MYD88 mutation among most WM cases in 2012 marked the dawning of an era of molecular genomic exploration that led to a paradigm shift in clinical practice. In the current World Health Organization (WHO) classification of hematologic neoplasms, WM is included in the category of lymphoplasmacytic lymphoma (LPL) of which WM represents over 90% of cases. LPL/WM is also better defined, resolving ambiguity in many cases that would have been classified as "low-grade B-cell lymphoma with plasmacytic differentiation" a decade before. Nevertheless, challenges still face pathologists because criteria for distinguishing LPL/WM from other types of low-grade B-cell lymphoma, particularly marginal zone lymphoma (MZL), remain imperfect. In this review, we highlight the current understanding of LPL and WM brought to light by new discoveries, which in turn are increasingly translated to improved diagnosis and personalized therapy. Key concepts in the diagnosis and their clinical implications are emphasized. Controversies and challenges are also discussed.

PlentiPlex™ MYD88 Waldenström lymphoma qPCR assay: A highly sensitive method for detection of MYD88 L265P mutation

INTRODUCTION

Agarose gel-based conventional and real-time allele-specific polymerase chain reaction (AS-PCR) assays are currently used for sensitive detection and quantification of MYD88 L265P mutation. Visual inspection of an agarose gel can often be ambiguous. We propose a new allele-specific quantification PCR (AS-qPCR) assay, PlentiPlex™ MYD88 Waldenström lymphoma qPCR assay, that uses Intercalating Nucleic Acid (INA®) technology for increased affinity and specificity.

METHODS

This study compares PlentiPlex™ MYD88 Waldenström lymphoma qPCR assay with conventional AS-PCR. We included a total of 102 peripheral and bone marrow blood samples from 94 patients with a lymphoproliferative disorder. Droplet digital PCR (ddPCR) was used as a third method in case of discrepancy.

RESULTS

A positive percent agreement of 100% (95% CI 0.92-1.0) and a negative percent agreement of 98% (95% CI 0.90-1.0) were found between the conventional AS-PCR and the AS-qPCR methods. Including the ddPCR results to validate the discrepant cases, the sensitivity and specificity of PlentiPlex™ MYD88 Waldenström lymphoma qPCR Assay were 1.0 (95% CI 0.97-1.0) and 1.0 (95% CI 0.96-1.0), respectively.

CONCLUSION

Our data demonstrate that PlentiPlex™ MYD88 Waldenström lymphoma qPCR assay is a fast, highly sensitive, and specific method for the detection of MYD88 L265P compared with conventional AS-PCR.

Mutational landscape in Waldenström macroglobulinemia evaluated using a next-generation sequencing lymphoma panel in routine clinical practice

Next-generation sequencing (NGS) affords comprehensive insights into the genomic landscape of lymphomas. We examined the mutational pattern in patients with Waldenström macroglobulinemia (WM) or lymphoplasmacytic lymphoma (LPL) as well as the diagnostic and clinical utility of a tailored NGS lymphoma panel. A consecutive series of 45 patients was reviewed and NGS analysis was performed as part of a routine diagnostic setup. The custom designed NGS panel assayed all coding sequences of 59 genes of known clinical significance in lymphoid neoplasms. The most frequently mutated genes were MYD88, CXCR4, BIRC3, CD79B, and ARID1A. Additional somatic mutations were detected in 17 genes with four mutations categorized as pathogenic or likely pathogenic. BIRC3 and TP53 mutations were associated with adverse clinical phenotypes. NGS performance for the MYD88L265P variant was 96% when compared to qPCR. In conclusion, targeted NGS provided important diagnostic and prognostic information in a routine clinical setting.

How I use genomics and BTK inhibitors in the treatment of Waldenström macroglobulinemia

ABSTRACT

Mutations in MYD88 (95%-97%) and CXCR4 (30%-40%) are common in Waldenström macroglobulinemia (WM). TP53 is altered in 20% to 30% of patients with WM, particularly those previously treated. Mutated MYD88 activates hematopoietic cell kinase that drives Bruton tyrosine kinase (BTK) prosurvival signaling. Both nonsense and frameshift CXCR4 mutations occur in WM. Nonsense variants show greater resistance to BTK inhibitors. Covalent BTK inhibitors (cBTKi) produce major responses in 70% to 80% of patients with WM. MYD88 and CXCR4 mutation status can affect time to major response, depth of response, and/or progression-free survival (PFS) in patients with WM treated with cBTKi. The cBTKi zanubrutinib shows greater response activity and/or improved PFS in patients with WM with wild-type MYD88, mutated CXCR4, or altered TP53. Risks for adverse events, including atrial fibrillation, bleeding diathesis, and neutropenia can differ based on which BTKi is used in WM. Intolerance is also common with cBTKi, and dose reduction or switchover to another cBTKi can be considered. For patients with acquired resistance to cBTKis, newer options include pirtobrutinib or venetoclax. Combinations of BTKis with chemoimmunotherapy, CXCR4, and BCL2 antagonists are discussed. Algorithms for positioning BTKis in treatment naïve or previously treated patients with WM, based on genomics, disease characteristics, and comorbidities, are presented.

BTK Inhibitors in the Frontline Management of Waldenström Macroglobulinemia

The discovery of MYD88 (L265P) mutation led to investigating BTK inhibitors in Waldenström macroglobulinemia (WM). Ibrutinib, the first-in-class agent, was approved based on a phase II trial in relapsed/refractory patients. In the phase III iNNOVATE study, the combination of rituximab and ibrutinib was compared with rituximab and placebo in treatment-naïve and relapsed/refractory patients. Second-generation BTK inhibitor, zanubrutinib, was compared with Ibrutinib in MYD88-mutated WM patients in the phase III ASPEN trial, whereas acalabrutinib was investigated in a phase II trial. Here, we discuss the role of BTK inhibitors in treatment-naïve patients with WM based on currently available evidence.

New developments in the diagnosis and characterization of Waldenström's macroglobulinemia

INTRODUCTION

Waldenström's macroglobulinemia (WM) is defined as a lymphoplasmacytic lymphoma (LPL) with immunoglobulin M (IgM) monoclonal gammopathy and morphologic evidence of bone marrow infiltration by LPL. Immunophenotyping and genotyping provide a firm pathological basis for diagnosis and are particularly valuable in differential diagnosis between WM and related diseases. Emerging technologies in mutational analysis present new opportunities, but challenges remain around standardization of methodologies and reporting of mutational data across centers.

AREAS COVERED

The review provides an overview of the diagnosis of WM, with a particular focus on the role of immunophenotyping and genotyping.

EXPERT OPINION

Demonstration of LPL with a bone marrow biopsy is essential to reach a definitive diagnosis of WM. However, MYD88L265P and a typical WM immunophenotypic profile are valuable for the differential diagnosis of WM and related diseases, such as marginal zone lymphoma, multiple myeloma, and chronic lymphocytic leukemia. These methodologies must be utilized across centers and with appropriate standards followed in the evaluation and reporting of sensitivities and specificities. The diagnostic and/or prognostic value of mutations in genes such as CXCR4 and TP53 that are currently not routinely evaluated in the diagnosis of WM should be explored.

Diagnostic, Prognostic, and Predictive Role of Next-Generation Sequencing in Mature Lymphoid Neoplasms

Lymphoma is a clinically and biologically heterogeneous disease. Next-generation sequencing (NGS) has expanded our understanding of this heterogeneity at the genetic level, refining disease classification, defining new entities, and providing additional information that can be used in diagnosis and management. This review highlights some of the NGS findings in lymphoma and how they can be used as genetic biomarkers to aid diagnosis and prognosis and guide therapy.

Report of Consensus Panel 3 from the 11th International workshop on Waldenström's Macroglobulinemia: Recommendations for molecular diagnosis in Waldenström's Macroglobulinemia

Apart from the MYD88L265P mutation, extensive information exists on the molecular mechanisms in Waldenström's Macroglobulinemia and its potential utility in the diagnosis and treatment tailoring. However, no consensus recommendations are yet available. Consensus Panel 3 (CP3) of the 11th International Workshop on Waldenström's Macroglobulinemia (IWWM-11) was tasked with reviewing the current molecular necessities and best way to access the minimum data required for a correct diagnosis and monitoring. Key recommendations from IWWM-11 CP3 included: (1) molecular studies are warranted for patients in whom therapy is going to be started; such studies should also be done in those whose bone marrow (BM) material is sampled based on clinical issues; (2) molecular studies considered essential for these situations are those that clarify the status of 6q and 17p chromosomes, and MYD88, CXCR4, and TP53 genes. These tests in other situations, and/or other tests, are considered optional; (3) independently of the use of more sensitive and/or specific techniques, the minimum requirements are allele specific polymerase chain reaction for MYD88L265P and CXCR4S338X using whole BM, and fluorescence in situ hybridization for 6q and 17p and sequencing for CXCR4 and TP53 using CD19+ enriched BM; (4) these requirements refer to all patients; therefore, sample should be sent to specialized centers.

Plasma cell neoplasms and related entities-evolution in diagnosis and classification

Plasma cell neoplasms including multiple myeloma (MM) and related terminally differentiated B-cell neoplasms are characterized by secretion of monoclonal immunoglobulin and stepwise development from a preneoplastic clonal B and/or plasma cell proliferation called monoclonal gammopathy of undetermined significance (MGUS). Diagnosis of these disorders requires integration of clinical, laboratory, and morphological features. While their classification mostly remains unchanged compared to the revised 2016 WHO classification and the 2014 International Myeloma Working Group consensus, some changes in criteria and terminology were proposed in the 2022 International Consensus Classification (ICC) of mature lymphoid neoplasms. MGUS of IgM type is now divided into IgM MGUS of plasma cell type, precursor to the rare IgM MM and characterized by MM-type cytogenetics, lack of clonal B-cells and absence of MYD88 mutation, and IgM MGUS, NOS including the remaining cases. Primary cold agglutinin disease is recognized as a new entity. MM is now formally subdivided into cytogenetic groups, recognizing the importance of genetics for clinical features and prognosis. MM with recurrent genetic abnormalities includes MM with CCND family translocations, MM with MAF family translocations, MM with NSD2 translocation, and MM with hyperdiploidy, with the remaining cases classified as MM, NOS. For diagnosis of localized plasma cell tumors, solitary plasmacytoma of bone, and primary extraosseous plasmacytoma, the importance of excluding minimal bone marrow infiltration by flow cytometry is emphasized. Primary systemic amyloidosis is renamed immunoglobulin light chain amyloidosis (AL), and a localized AL amyloidosis is recognized as a distinct entity. This review summarizes the updates on plasma cell neoplasms and related entities proposed in the 2022 ICC. KEY POINTS: • Lymphoplasmacytic lymphoma can be diagnosed with lymphoplasmacytic aggregates in trephine biopsies < 10% of cellularity and evidence of clonal B-cells and plasma cells. • IgM MGUS is subdivided into a plasma cell type and a not otherwise specified (NOS) type. • Primary cold agglutinin disease is recognized as a new entity. • The term "multiple myeloma" replaces the term "plasma cell myeloma" used in the 2016 WHO classification. • Multiple myeloma is subdivided into 4 mutually exclusive cytogenetic groups and MM NOS. • Minimal bone marrow infiltration detected by flow cytometry is of major prognostic importance for solitary plasmacytoma of bone and to a lesser extent for primary extraosseous plasmacytoma. • Localized IG light chain amyloidosis is recognized as a separate entity, distinct from systemic immunoglobulin light chain (AL) amyloidosis.

Genomic profiling for clinical decision making in lymphoid neoplasms

With the introduction of large-scale molecular profiling methods and high-throughput sequencing technologies, the genomic features of most lymphoid neoplasms have been characterized at an unprecedented scale. Although the principles for the classification and diagnosis of these disorders, founded on a multidimensional definition of disease entities, have been consolidated over the past 25 years, novel genomic data have markedly enhanced our understanding of lymphomagenesis and enriched the description of disease entities at the molecular level. Yet, the current diagnosis of lymphoid tumors is largely based on morphological assessment and immunophenotyping, with only few entities being defined by genomic criteria. This paper, which accompanies the International Consensus Classification of mature lymphoid neoplasms, will address how established assays and newly developed technologies for molecular testing already complement clinical diagnoses and provide a novel lens on disease classification. More specifically, their contributions to diagnosis refinement, risk stratification, and therapy prediction will be considered for the main categories of lymphoid neoplasms. The potential of whole-genome sequencing, circulating tumor DNA analyses, single-cell analyses, and epigenetic profiling will be discussed because these will likely become important future tools for implementing precision medicine approaches in clinical decision making for patients with lymphoid malignancies.

[Exploring the detection of MYD88 mutation in patients with Waldenström macroglobulinemia by different methods and specimens]

Objective: To improve the positivity rate and accuracy of MYD88 mutation detection in patients with Waldenström macroglobulinemia (WM) . Methods: MYD88 mutation status was retrospectively evaluated in 66 patients diagnosed with WM in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from June 2017 to June 2021. The positivity rate and accuracy of the different methods and specimens for MYD88 mutation detection were analyzed. Results: MYD88 mutations were detected in 51 of 66 patients with WM, with an overall positivity rate of 77%. The positivity rate of the next-generation sequencing (NGS) or allele-specific polymerase chain reaction (AS-PCR) was significantly higher than that of the first-generation Sanger sequencing (84% vs 71% vs 46%, P<0.05) . For the different specimens, the positivity rate for the lymph nodes or bone marrow was significantly higher than that of peripheral blood (79% vs 84% vs 52%, P<0.05) . The positivity rate of the MYD88 mutation in the lymph nodes, bone marrow, and peripheral blood determined by NGS was 86%, 90%, and 67%, respectively. The positivity rate in the lymph nodes, bone marrow, and peripheral blood detected by AS-PCR was 78%, 81%, and 53%, respectively. Thirty-nine patients with WM underwent ≥ 2 MYD88 mutation detections. The final MYD88 mutational status for each patient was used as the standard to determine the accuracy of the different methods and in different specimens. The accuracy of MYD88 mutation detection in the lymph nodes (n=18) and bone marrow (n=13) by NGS was significantly higher than that in the peripheral blood (n=4) (100% vs 100% vs 75%, P<0.05) . There was no statistically significant difference in the accuracy of MYD88 mutation detection by AS-PCR in the lymph nodes (n=15) , bone marrow (n=11) , or peripheral blood (n=16) (93% vs 91% vs 88%, P>0.05) . Conclusions: In the detection of the MYD88 mutation in patients diagnosed with WM, NGS or AS-PCR is more sensitive than Sanger sequencing. Lymph nodes and bone marrow specimens are better than peripheral blood specimens.

Nucleic Acid Biomarkers in Waldenström Macroglobulinemia and IgM-MGUS: Current Insights and Clinical Relevance

Waldenström Macroglobulinemia (WM) is an indolent lymphoplasmacytic lymphoma, characterized by the production of excess immunoglobulin M monoclonal protein. WM belongs to the spectrum of IgM gammopathies, ranging from asymptomatic IgM monoclonal gammopathy of undetermined significance (IgM-MGUS), through IgM-related disorders and asymptomatic WM to symptomatic WM. In recent years, its complex genomic and transcriptomic landscape has been extensively explored, hereby elucidating the biological mechanisms underlying disease onset, progression and therapy response. An increasing number of mutations, cytogenetic abnormalities, and molecular signatures have been described that have diagnostic, phenotype defining or prognostic implications. Moreover, cell-free nucleic acid biomarkers are increasingly being investigated, benefiting the patient in a minimally invasive way. This review aims to provide an extensive overview of molecular biomarkers in WM and IgM-MGUS, considering current shortcomings, as well as potential future applications in a precision medicine approach.

Zanubrutinib for the treatment of adults with Waldenstrom macroglobulinemia

INTRODUCTION

The development of Bruton tyrosine kinase (BTK) inhibitors has significantly changed the treatment landscape for patients with Waldenström macroglobulinemia (WM). Ibrutinib was the first BTK inhibitor to receive FDA approval for this disease, but in recent years additional more selective BTK inhibitors have become available. Zanubrutinib, the most recently FDA-approved therapy for WM, has demonstrated comparable efficacy regarding hematologic response, but with an improved side effect profile compared to other BTK inhibitors.

AREAS COVERED

In this review, we highlight the pivotal studies that have formed the foundation for the use of zanubrutinib in WM, including safety and efficacy data from prospective clinical trials of the currently available BTK inhibitors.

EXPERT OPINION

BTK inhibitors are very effective in WM and have an overall response rate higher than 90%. The side effect profile of these medications is manageable, but does include a risk of atrial fibrillation, infection, and bleeding. The newer BTK inhibitors, such as acalabrutinib and zanubrutinib, are known to have less off-target effects and are potential treatment options. BTK inhibitors should be considered as a treatment option in treatment-naïve and previously treated disease depending on the individual patient preferences, comorbidities, and molecular profile.

Diagnosis and management of Waldenström macroglobulinaemia-A British Society for Haematology guideline

SCOPE

The objective of this guideline is to provide healthcare professionals with clear guidance on the management of patients with Waldenström macroglobulinaemia. In individual patients, circumstances may dictate an alternative approach.

METHODOLOGY

This guideline was compiled according to the British Society for Haematology (BSH) process at http://www.b-s-h.org.uk/guidelines/proposing-and-writing-a-new-bsh-guideline/. Recommendations are based on a review of the literature using Medline, Pubmed, Embase, Central, Web of Science searches from beginning of 2013 (since the publication of the previous guidelines) up to November 2021. The following search terms were used: Waldenström('s) macroglobulin(a)emia OR lymphoplasmacytic lymphoma, IgM(-related) neuropathy OR cold h(a)emagglutinin disease OR cold agglutinin disease OR cryoglobulin(a)emia AND (for group a only) cytogenetic OR molecular OR mutation OR MYD88 OR CXCR4, management OR treatment OR transfusion OR supportive care OR plasma exchange OR plasmapheresis OR chemotherapy OR bendamustine OR bortezomib OR ibrutinib OR fludarabine OR dexamethasone OR cyclophosphamide OR rituximab OR everolimus, bone marrow transplantation OR stem cell transplantation. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) nomenclature was used to evaluate levels of evidence and to assess the strength of recommendations. The GRADE criteria can be found at http://www.gradeworkinggroup.org. Review of the manuscript was performed by the British Society for Haematology (BSH) Guidelines Committee Haemato-Oncology Task Force, the BSH Guidelines Committee and the Haemato-Oncology sounding board of BSH. It was also on the members section of the BSH website for comment. It has also been reviewed by UK Charity WMUK; these organisations do not necessarily approve or endorse the contents.

Determinants of Drug Resistance in B-Cell Non-Hodgkin Lymphomas: The Case of Lymphoplasmacytic Lymphoma/Waldenström Macroglobulinemia

Lymphoplasmacytic lymphoma (LPL) is a rare subtype of B cell-derived non-Hodgkin lymphoma characterized by the abnormal growth of transformed clonal lymphoplasmacytes and plasma cells. This tumor almost always displays the capability of secreting large amounts of monoclonal immunoglobulins (Ig) of the M class (Waldenström Macroglobulinemia, WM). The clinical manifestations of WM/LPL may range from an asymptomatic condition to a lymphoma-type disease or may be dominated by IgM paraprotein-related symptoms. Despite the substantial progresses achieved over the last years in the therapy of LPL/WM, this lymphoma is still almost invariably incurable and exhibits a propensity towards development of refractoriness to therapy. Patients who have progressive disease are often of difficult clinical management and novel effective treatments are eagerly awaited. In this review, we will describe the essential clinical and pathobiological features of LPL/WM. We will also analyze some key aspects about the current knowledge on the mechanisms of drug resistance in this disease, by concisely focusing on conventional drugs, monoclonal antibodies and novel agents, chiefly Bruton’s Tyrosine Kinase (BTK) inhibitors. The implications of molecular lesions as predictors of response or as a warning for the development of therapy resistance will be highlighted.