Waldenström macroglobulinemia: 2019 update on diagnosis, risk stratification, and management

Waldenström macroglobulinemia presenting as bilateral bloody pleural effusion: A case report

RATIONALE

Pleural effusion, especially bilateral bloody pleural effusion, is a rare complication of Waldenström macroglobulinemia (WM). Pleural effusion in patients with WM has many causes, such as infection, tumor invasion of the pleura, and rupture of the thoracic duct or its branches. Patients with WM presenting to the respiratory department with chest tightness and shortness of breath need more differential diagnosis by respiratory physicians, which is helpful for effective treatment. Herein, we present a case of MV diagnosis in a patient with bilateral bloody pleural effusion.

PATIENT CONCERN

Our patient is a 59-year-old man with WM presenting as having bilateral bloody pleural effusion.

INTERVENTIONS

The patient was treated with pleural effusion drainage. After confirming the diagnosis, the patient was treated with rituximab, cyclophosphamide, and dexamethasone.

OUTCOMES

Following these treatments, the patient's symptoms improved, and ultrasound showed a decrease in pleural effusion.

LESSONS

Despite its favorable prognosis, the cause of pleural effusion in a patient with WM can be challenging to diagnose. The cause of pleural effusion should be considered a differential diagnosis when diagnosing patients diagnosed with WM.

Residential proximity to dioxin-emitting facilities and risk of non-Hodgkin lymphoma in the NIH-AARP Diet and Health Study

BACKGROUND

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are persistent organic pollutants emitted from industrial sources. Residential proximity to these emissions has been associated with risk of non-Hodgkin lymphoma (NHL) in a limited number of studies.

METHODS

We evaluated associations between residential proximity to PCDD/F-emitting facilities and NHL in the NIH-AARP Diet and Health Study (N = 451,410), a prospective cohort enrolled in 1995-1996 in 6 states and 2 U.S. cities. We linked enrollment addresses with a U.S. Environmental Protection Agency database of 4,478 historical PCDD/F sources with estimated toxic equivalency quotient (TEQ) emissions. We evaluated associations between NHL and exposures during a historical period prior to enrollment (1980-1995) using an average emissions index, weighted by toxicity, distance, and wind direction (AEI-W [g TEQ/km2]) within 3-, 5- and 10 km of residences. We also evaluated proximity-only metrics indicating the presence/absence of one or more facilities within each distance, and metrics calculated separately for each facility type. We used Cox regression to estimate associations (hazard ratio, HR; 95 % confidence interval, 95 %CI) with NHL and major subtypes, adjusting for demographic, lifestyle, and dietary factors.

RESULTS

A total of 6,467 incident cases of NHL were diagnosed through 2011. Participants with an AEI-W ≥ 95th percentile had elevated risk of NHL compared to those unexposed at 3 km (HR = 1.16; 95 %CI = 0.89-1.52; p-trend = 0.24), 5 km (HR = 1.20;95 %CI = 0.99-1.46;p-trend = 0.05) and 10 km (HR = 1.15; 95 %CI = 0.99-1.34; p-trend = 0.04). We found a positive association at 5 km with follicular lymphoma (HR≥95vs.0 = 1.62; 95 %CI = 0.98-2.67; p-trend = 0.05) and a suggestive association for diffuse large B-cell lymphoma (HR≥95vs.0 = 1.40; 95 %CI = 0.91-2.14; p-trend = 0.11). NHL risk was also associated with high emissions from coal-fired power plants within 10 km (HR≥95vs.0 = 1.42; 95 %CI = 1.09-1.84; p-trend = 0.05).

CONCLUSIONS

Residential proximity to relatively high dioxin emissions from industrial sources may increase the risk of NHL and specific subtypes.

Biomarker analysis of the ASPEN study comparing zanubrutinib with ibrutinib for patients with Waldenström macroglobulinemia

ABSTRACT

The phase 3 ASPEN trial (NCT03053440) compared Bruton tyrosine kinase inhibitors (BTKis), zanubrutinib and ibrutinib, in patients with Waldenström macroglobulinemia (WM). Post-hoc biomarker analysis was performed using next-generation sequencing on pretreatment bone marrow samples from 98 patients treated with zanubrutinib and 92 patients treated with ibrutinib with mutated (MUT) MYD88 and 20 patients with wild-type (WT) MYD88 treated with zanubrutinib. Of 329 mutations in 52 genes, mutations in CXCR4 (25.7%), TP53 (24.8%), ARID1A (15.7%), and TERT (9.0%) were most common. TP53MUT, ARID1AMUT, and TERTMUT were associated with higher rates of CXCR4MUT (P < .05). Patients with CXCR4MUT (frameshift or nonsense [NS] mutations) had lower very good partial response (VGPR) and complete response rates (CR; 17.0% vs 37.2%, P = .020) and longer time to response (11.1 vs 8.4 months) than patients with CXCR4WT treated with BTKis. CXCR4NS was associated with inferior progression-free survival (PFS; hazard ratio [HR], 3.39; P = .017) in patients treated with ibrutinib but not in those treated with zanubrutinib (HR, 0.67; P = .598), but VGPR + CR rates were similar between treatment groups (14.3% vs 15.4%). Compared with ibrutinib, patients with CXCR4NS treated with zanubrutinib had a favorable major response rate (MRR; 85.7% vs 53.8%; P = .09) and PFS (HR, 0.30; P = .093). In patients with TP53MUT, significantly lower MRRs were observed for patients treated with ibrutinib (63.6% vs 85.7%; P = .04) but not for those treated with zanubrutinib (80.8% vs 81.9%; P = .978). In TP53MUT, compared with ibrutinib, patients treated with zanubrutinib had higher VGPR and CR (34.6% vs 13.6%; P < .05), numerically improved MRR (80.8% vs 63.6%; P = .11), and longer PFS (not reached vs 44.2 months; HR, 0.66; P = .37). Collectively, patients with WM with CXCR4MUT or TP53MUT had worse prognosis compared with patients with WT alleles, and zanubrutinib led to better clinical outcomes.

A review of clinical guidelines, laboratory recommendations and external quality assurance programs for monoclonal gammopathy testing

Monoclonal gammopathy (MG) is a spectrum of diseases ranging from the benign asymptomatic monoclonal gammopathy of undetermined significance to the malignant multiple myeloma. Clinical guidelines and laboratory recommendations have been developed to inform best practices in the diagnosis, monitoring, and management of MG. In this review, the pathophysiology, relevant laboratory testing recommended in clinical practice guidelines and laboratory recommendations related to MG testing and reporting are examined. The clinical guidelines recommend serum protein electrophoresis, serum immunofixation and serum free light chain measurement as initial screening. The laboratory recommendations omit serum immunofixation as it offers limited additional diagnostic value. The laboratory recommendations offer guidance on reporting findings beyond monoclonal protein, which was not required by the clinical guidelines. The clinical guidelines suggested monitoring total IgA concentration by turbidimetry or nephelometry method if the monoclonal protein migrates in the non-gamma region, whereas the laboratory recommendations make allowance for involved IgM and IgG. Additionally, several external quality assurance programs for MG protein electrophoresis and free light chain testing are also appraised. The external quality assurance programs show varied assessment criteria for protein electrophoresis reporting and unit of measurement. There is also significant disparity in reported monoclonal protein concentrations with wide inter-method analytical variation noted for both monoclonal protein quantification and serum free light chain measurement, however this variation appears smaller when the same method was used. Greater harmonization among laboratory recommendations and reporting format may improve clinical interpretation of MG testing.

Paraproteinemic Neuropathies

OBJECTIVE

Coexistence of polyneuropathy and gammopathy is a common but potentially challenging situation in clinical practice. This article reviews the clinical, electrophysiologic, and hematologic phenotypes of the paraproteinemic neuropathies and the diagnostic and treatment strategies for each.

LATEST DEVELOPMENTS

Advances in our understanding of the underlying pathophysiology of various paraproteinemic neuropathies and their corresponding phenotypes have identified potential new therapeutic targets. Therapeutic strategies to diminish anti-myelin-associated glycoprotein (MAG) IgM antibodies have shown partial and inconsistent efficacy; however, antigen-specific immune therapy is being investigated as a novel treatment to remove the presumably pathogenic anti-MAG antibody. Advances in genetic and cell signaling studies have resulted in the approval of Bruton tyrosine kinase inhibitors for Waldenström macroglobulinemia. Monoclonal antibodies are being investigated for the treatment of light chain amyloidosis.

ESSENTIAL POINTS

Early recognition and treatment of underlying plasma cell disorders improves clinical outcomes in patients with paraproteinemic neuropathy. Despite significant progress, our knowledge regarding underlying mechanisms for paraproteinemic neuropathy is still limited. Clinicians' awareness of clinical phenotypes, electrophysiologic hallmarks, and hematologic findings of the different paraproteinemic neuropathies is crucial to promptly identify and treat patients and to avert misdiagnosis. Multidisciplinary collaboration among specialists, including neurologists and hematologists, is paramount for the optimal treatment of these patients with overlapping conditions.

Pleural effusion and Waldenström macroglobulinemia: if cytology and flow cytometric findings do not match. A case report

Pleural effusion is a rare complication of lymphoplasmacytic lymphoma. When it occurs, traditional investigation techniques may not always be successful. The flow cytometry is a fast and precise diagnostic technique, which can be helpful in the diagnosis of pleural localization of hematological diseases. We present a case report of a pleural localization of Waldenström macroglobulinaemia detected by flow cytometry.

Risk of a second cancer and infection in patients with indolent B-cell lymphoma exposed to first-line bendamustine plus rituximab: A retrospective analysis of an administrative claims database

Bendamustine has a potent immunosuppressive effect because it causes T-cell lymphopenia, which might lead to a second primary malignancy (SPM) and would increase the risk of infection. Using the Medical Data Vision administrative claims database, we compared the cumulative incidence of SPM, infections within 6 months, and overall survival (OS) among untreated patients with indolent B-cell lymphomas (iBCL) who received rituximab-based chemotherapy between 2009 and 2020. Patients with grade 3b follicular lymphoma or a previous history of malignancy were excluded. Eligible 5234 patients were assigned to three cohorts: rituximab monotherapy (N = 780), RCHOP/RCVP/RTHPCOP (doxorubicin replaced with pirarubicin) (N = 2298), or bendamustine/rituximab (BR) (N = 2156). There were 589 recorded SPMs, of which myelodysplastic syndromes were the most common (1.7%). The cumulative incidence of SPM was significantly higher in patients treated with BR than in those treated with rituximab monotherapy (p < 0.01) or RCHOP/RCVP/RTHPCOP (p < 0.0001): the 5-year cumulative incidence function was 18.1%, 12.5%, and 12.9%, respectively. In the Fine-Gray subdistribution hazards model, BR showed a significantly higher cumulative incidence of SPM than RCHOP/RCVP/RTHPCOP (subhazard ratio, 1.33; 95% confidence interval [CI], 1.10-1.61). Furthermore, in sensitivity analysis, a nested case-control study using an entire cohort showed consistent results: the SPM odds ratios (95% CI) of first-line bendamustine, bendamustine after first-line, and any-line bendamustine were 1.43 (1.14-1.78), 1.26 (0.96-1.64), and 1.33 (1.09-1.62), respectively. Regarding infections, adjusted odds ratios (95% CI) of BR compared to RCHOP/RCVP/RTHPCOP were as follows: cytomegalovirus infection, 13.7 (4.88-38.4); bacterial pneumonia, 0.63 (0.50-0.78); and pneumocystis pneumonia, 0.24 (0.11-0.53). There was no significant difference in OS between RCHOP/RCVP/RTHPCOP and BR in patients with follicular, mantle cell, marginal zone, or lymphoplasmacytic lymphomas. In conclusion, treatment strategies that consider the risk of SPM and infections after chemotherapy are warranted in patients with iBCL.

Rare presentation of double-clonal Waldenström macroglobulinemia with pulmonary embolism: A case report

Waldenström macroglobulinemia (WM) rarely leads to pulmonary embolism. Due to its low incidence, the underlying pathophysiology, prognosis, and optimal treatment remain largely unexplored and uninvestigated. In this study, a patient with a double-clonal WM, a rare subtype, presented with pulmonary embolism. The patient had a small number of plasma cells without morphological abnormalities, and an effective therapeutic response was observed. Nonetheless, the clinical prognosis requires a long-term follow-up.

Insurance-based disparities impact survival outcomes in Waldenström macroglobulinemia within the United States

Considerable healthcare resource utilization and financial burden have been associated with the treatment of WM; however, the impact of health insurance status on outcomes has not been previously reported. We conducted a National Cancer Database analysis of newly diagnosed cases of active WM between 2004 and 2017 to evaluate the impact of insurance status on outcomes. For patients <65 years old (n = 1249, male sex: 62.4%, median age: 58 years), significant insurance-based survival differences were observed on multivariable analysis; patients who were uninsured [n = 63; HR 3.11 (95%CI, 1.77-5.45), p < 0.001], on Medicaid [n = 87; HR 1.88 (95% CI, 1.01-3.48), p = 0.045], or on Medicare [n = 122; HR 2.78 (95%CI, 1.76-4.38), p < 0.001], had inferior survival compared to patients with private insurance (n = 977; reference). In patients ≥65 years, no insurance-based survival differences were found (p = 0.10). Overall, significant insurance-based outcome disparities exist in WM. Further work is desperately needed to systematically uncover and address these disparities.

Current and future applications of biomarkers in samples collected through minimally invasive methods for cancer medicine and population-based research

Despite advances in cancer medicine and research, invasive and potentially risky procedures such as biopsies, venous blood tests, imaging, colonoscopy, and pap smear tests are still primarily used for screening, staging, and assessing response to therapy. The development and interdisciplinary use of biomarkers from urine, feces, saliva, scent, and capillary blood collected with minimally invasive methods represents a potential opportunity for integration with biomarker analysis for cancers, both in clinical practice (e.g., in screening, treatment, and disease monitoring, and improved quality of life for patients) and population-based research (e.g., in epidemiology/public health, studies of social and environmental determinants, and evolutionary medicine). In this article, we review the scientific rationale, benefits, challenges, and potential opportunities for measuring cancer-related biomarkers in samples collected through minimally invasive methods.

Battling BTK mutants with noncovalent inhibitors that overcome Cys481 and Thr474 mutations in Waldenström macroglobulinemia therapy: structural mechanistic insights on the role of fenebrutinib

Recently, the non-covalent Bruton tyrosine kinase (BTK) inhibitor fenebrutinib was presented as a therapeutic option with strong inhibitory efficacy against a single (C481S) and double (T474S/C481S) BTK variant in the treatment of Waldenström macroglobulinemia (WM). However, the molecular events surrounding its inhibition mechanism towards this variant remain unresolved. Herein, we employed in silico methods such as molecular dynamic simulation coupled with binding free energy estimations to explore the mechanistic activity of the fenebrutinib on (C481S) and (T474S/C481S) BTK variant, at a molecular level. Our investigations reveal that amino acid arginine contributed immensely to the total binding energy, this establishing the cruciality of amino acid residues, Arg132 and Arg156 in (C481S) and Arg99, Arg137, and Arg132 in (T474S/C481S) in the binding of fenebrutinib towards both BTK variants. The structural orientations of fenebrutinib within the respective hydrophobic pockets allowed favorable interactions with binding site residues, accounting for its superior binding affinity by 24.5% and relative high hydrogen bond formation towards (T474S/C481S) when compared with (C481S) BTK variants. Structurally, fenebrutinib impacted the stability, flexibility, and solvent accessible surface area of both BTK variants, characterized by various alterations observed in the bound and unbound structures, which proved enough to disrupt their biological function. Findings from this study, therefore, provide insights into the inhibitory mechanism of fenebrutinib at the atomistic level and reveal its high selectivity towards BTK variants. These insights could be key in designing and developing BTK mutants' inhibitors to treat Waldenström macroglobulinemia (WM).

The landscape of immunoglobulin heavy chain gene repertoire and its clinical relevance in LPL/WM

We unveil the distinct patterns of IGHV repertoire and discuss the correlation between IGHV and other genetic abnormalities in LPL/WM.

IGHV4 usage was a predictive marker of shorter progression-free survival in patients with LPL/WM.

Lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) is a heterogeneous disease in which the role of immunoglobulin heavy-chain genes (IGHs) remains unknown. To determine the clinical relevance of the IGH repertoire in patients with LPL/WM, we performed immunoglobulin gene rearrangement and complementarity determining region 3 (CDR3) analysis. The IGH variable gene (IGHV) repertoire was remarkably biased in LPL/WM. IGHV3-23, IGHV4-34, IGHV3-30, IGHV3-7, and IGHV3-74 accounted for one-half of the cohort’s repertoire. Most cases (97.1%) were found to carry mutated IGHV genes, based on a 98% IGHV germline homology cutoff. IGHV3-30 was associated with long heavy chain CDR3, indicating there was specific antigen selection in LPL/WM. Patients with IGHV3-7 were significantly more likely to harbor the 6q deletion (P < .001) and an abnormal karyotype (P = .004). The IGHV hypermutation rate in patients with the MYD88 L265P mutation was significantly higher than that of wild-type patients (P = .050). IGHV3-23 and IGHV3-74 segments were more frequently detected in patients with MYD88-mutated LPL/WM (P = .050), whereas IGHV3-7 presented more frequently in MYD88 wild-type patients (P = .042). Patients with IGHV4, especially IGHV4-34, had higher levels of lactate dehydrogenase, and IGHV4 was a predictive marker of shorter progression-free survival. These results showed for the first time that the IGHV repertoire has clinical relevance in LPL/WM.

Does Waldenstrom's macroglobulinemia also cause bone destruction? A rare case report

Waldenstrom’s macroglobulinemia (WM) is a rare type of malignant B-cell lymphoma. The main feature of WM is elevated serum monoclonal immunoglobulin M, similar to multiple myeloma (MM). Unlike in MM, the rarity of destructive bone lesions in WM has been repeatedly emphasized. We report a unique case of WM with a vertebral compression fracture as the first symptom. This case highlights that the presence or absence of bone destruction may not clearly distinguish between WM and MM. The possibility of WM should be considered in patients with vertebral fracture and destruction as the first presentation. Performing vertebral bone marrow aspiration biopsy during percutaneous vertebroplasty is a convenient and effective method to assist in the diagnosis of WM.

Simple headache revealed a rare lymphoma: Waldenstrom macroglobulinemia with unique markers: a case report and review of the literature

BACKGROUND

Waldenstrom macroglobulinemia (WM) is a rare lymphoma with an incidence rate of 3 per million people per year, with approximately 1000 to 1500 new cases diagnosed each year in the USA. It is primarily seen in Caucasian males with a median age of 70 years old. Patients are most often asymptomatic, but WM can manifest itself with constitutional symptoms such as lethargy, bleeding, organomegaly, and neurological or fundoscopic abnormalities. WM is characterized by immunoglobulin M (IgM) monoclonal gammopathy, lymphocytic infiltration of bone marrow, and normocytic anemia due to bone marrow replacement.

CASE PRESENTATION

Our patient is a Hispanic 67-year-old female that presents with one month of intermittent band-like bilateral headache accompanied by dizziness, light-headedness, nausea, and blurred vision. A thorough diagnostic workup was performed, including serum protein electrophoresis (SPEP) with serum immunofixation (SIFE) showing an M spike and IgM kappa. Bone marrow biopsy was significant for lymphoplasmacytic infiltration with nodular B cells (CD19+, CD20+, CD22+). Computerized Tomography (CT) imaging showed splenomegaly in the patient. Treatment was provided for hyperviscosity syndrome with plasmapheresis twice. The patient reported improvement of her symptoms and was then scheduled for chemotherapy. Throughout 7 months, our patient received multiple cycles of bortezomib, dexamethasone, and rituximab. While her symptoms improved her psychiatric status got progressively worse.

CONCLUSION

It is important not to neglect symptoms such as a headache, which may seem small, but could serve as a clue in the diagnosis of Waldenstrom's macroglobulinemia.

A rare clinical presentation of Waldenström Macroglobulinemia mimicking lung cancer

Waldenström macroglobulinemia rarely presents as pulmonary symptoms, and even rarer as chylothorax. We present a patient who presented with bilateral pleural effusion and a 30 mm solid lesion in the lung. Biochemical analysis of the pleural fluid revealed chylothorax. The 18-fluorodeoxygenase positron emission tomography, bronchoscopy, endobronchial ultrasound, and cytological examination of the pleural fluid, showed no apparent cause of the chylothorax. The diagnostic breakthrough was made with flow cytometry of the pleural fluid, which revealed a small group of clonal B-cells. Biopsy from the parietal pleura and bone marrow led to the diagnosis Waldenström macroglobulinemia. This demonstrates that flow cytometry should be considered when routine diagnostics do not lead to a reach a specific diagnosis.

CD5-Negative, CD10-Negative Low-Grade B-Cell Lymphoproliferative Disorders of the Spleen

CD5-negative, CD10-negative low-grade B-cell lymphoproliferative disorders (CD5-CD10-LPD) of the spleen comprise a fascinating group of indolent, neoplastic, mature B-cell proliferations that are essential to accurately identify but can be difficult to diagnose. They comprise the majority of B-cell LPDs primary to the spleen, commonly presenting with splenomegaly and co-involvement of peripheral blood and bone marrow, but with little to no involvement of lymph nodes. Splenic marginal zone lymphoma is one of the prototypical, best studied, and most frequently encountered CD5-CD10-LPD of the spleen and typically involves white pulp. In contrast, hairy cell leukemia, another well-studied CD5-CD10-LPD of the spleen, involves red pulp, as do the two less common entities comprising so-called splenic B-cell lymphoma/leukemia unclassifiable: splenic diffuse red pulp small B-cell lymphoma and hairy cell leukemia variant. Although not always encountered in the spleen, lymphoplasmacytic lymphoma, a B-cell lymphoproliferative disorder consisting of a dual population of both clonal B-cells and plasma cells and the frequent presence of the MYD88 L265P mutation, is another CD5-CD10-LPD that can be seen in the spleen. Distinction of these different entities is possible through careful evaluation of morphologic, immunophenotypic, cytogenetic, and molecular features, as well as peripheral blood and bone marrow specimens. A firm understanding of this group of low-grade B-cell lymphoproliferative disorders is necessary for accurate diagnosis leading to optimal patient management.

Post-relapse survival in Waldenstrom macroglobulinemia patients experiencing therapy failure following autologous transplantation

Waldenström macroglobulinemia (WM) is a rare B-cell lymphoproliferative malignancy. Autologous hematopoietic cell transplantation (auto-HCT) is considered in a subset of WM patients with relapsed disease. While registry data has shown a benefit for auto-HCT in relapsed WM, there is a paucity of data on outcomes of patients relapsing after auto-HCT. Eligibility criteria included adult patients with relapsed/refractory WM who underwent auto-HCT between 2007 and 2017. The primary endpoint was post-relapse overall survival (PR-OS). Secondary endpoints were to identify factors prognostic of PR-OS. Of the 48 patients with WM who underwent auto-HCT, 22 (46%) experienced relapse following auto-HCT. Median PR-OS of relapsed WM patients after auto-HCT (n = 22) was not reached (NR) (95% confidence interval [CI]: 17.5 months-NR). Among patients who relapsed <1 year versus ≥1 year from auto-HCT, the median PR-OS was 18.4 months (95%CI: 0.8-NR) months and NR (95%CI: 17.5-NR), respectively (p = 0.06). Of note, disease status at the time of transplant, CR/VGPR versus partial remission did not appear to impact PR-OS. The median PR-OS was significantly longer in patients who received ibrutinib in the post-transplant setting compared to those who did not (NR vs. 18.4 months, 95%CI: 9.1-NR, p = 0.02). On univariable analysis, the presence of complex karyotype (RR = 4.87, 95% CI = 1.22-19.53) and a higher number of prior lines of therapy (RR = 1.81, 95% CI = 1.23-2.67) were associated with a significantly higher risk of relapse. This is the only study to date that evaluated outcomes of WM patients who relapsed following auto-HCT and provides a benchmark for future trials evaluating survival following auto-HCT relapse.

A Phase II Trial of the Bruton Tyrosine-Kinase Inhibitor Zanubrutinib (BGB-3111) in Patients with Relapsed/Refractory Waldenström Macroglobulinemia

PURPOSE

Although Bruton tyrosine kinase (BTK) inhibitors have demonstrated promising efficacy in patients with Waldenström macroglobulinemia (WM), data in Asian populations are scarce. This trial is the first to investigate the effect of a BTK inhibitor in Chinese patients with relapsed/refractory (R/R) WM.

PATIENTS AND METHODS

Patients with R/R WM with at least one prior regimen were enrolled into this single-arm, multicenter, phase II study (NCT03332173) and received zanubrutinib 160 mg twice daily until disease progression or unacceptable toxicity. The primary endpoint was major response rate (MRR), as assessed by an independent review committee. Secondary endpoints included progression-free survival, overall response rate, duration of major response, and safety.

RESULTS

Forty-four patients were enrolled. After a median follow-up of 33.0 (range, 3.2-36.5) months, MRR in all patients was 69.8%, with very good partial response or better in 32.6% of patients. All mutation groups benefited from zanubrutinib treatment (MRR in patients with MYD88 ^L265P mutation, 73%; MRR in patients with MYD88 wild type mutation, 50%). A higher response rate was seen in the MYD88 ^L265P/CXCR4 ^WT population, compared with the other populations. Median progression-free survival and median duration of major response were not reached. The most frequently reported grade ≥3 treatment-emergent adverse events (AEs) were neutrophil count decreased (31.8%), and platelet count decreased and pneumonia (20.5% each). No case of atrial fibrillation/flutter occurred.

CONCLUSIONS

Zanubrutinib achieved a high rate of response that was durable and deep in patients with R/R WM across all subgroups, and potentially confers a positive benefit-risk profile for WM.

Treatment of Patients with Monoclonal Gammopathy of Clinical Significance

Simple Summary

Monoclonal gammopathy of clinical significance (MGCS) is a recently recognized clinical-pathological entity. Symptoms are caused by the presence of a monoclonal protein leading to high comorbidity. The affected organs vary according to the target antigen However, as most of the knowledge relies on case reports or short series; there is a lack of consensus regarding treatment approach. Here, we discuss MGCS other than renal (skin, ocular, neurologic, and bleeding disorders). We provide insights into the pathophysiology, diagnosis, treatment, and follow-up based on clinical cases. Finally, we discuss future directions in this field, such as potential novel therapeutic targets and prognosis of patients with MGCS.

Abstract

Monoclonal gammopathy of undetermined significance (MGUS) is defined as the presence of a monoclonal protein (M-protein) produced by a small amount of plasma cells. The majority of patients remain asymptomatic; however, a fraction of them develop clinical manifestations related to the monoclonal gammopathy despite not fulfilling criteria of multiple myeloma or other lymphoproliferative disorder. These patients constitute an emerging clinical issue coined as monoclonal gammopathy of clinical significance (MGCS). The mechanisms involved are poorly understood, and literature is scarce regarding management. The clinical spectrum involves symptoms related to renal, neurologic, skin, ocular, or bleeding manifestations, requiring a multidisciplinary approach. Treatment strategies rely on the basis of symptomatic disease and the M-protein isotype. In this review, we focus on MGCS other than renal, as the latter was earliest recognized and better known. We review the literature and discuss management from diagnosis to treatment based on illustrative cases from daily practice.

Ibrutinib effect in acquired von Willebrand syndrome secondary to Waldenström macroglobulinemia

The pathological increase of clonal IgM in Waldenström macroglobulinemia can be associated with acquired von Willebrand syndrome and can be a major risk of bleeding symptoms in this subgroup of patients with Waldenström macroglobulinemia. The Bruton tyrosine kinase inhibitor ibrutinib is one of the approved treatments for symptomatic Waldenström macroglobulinemia. However, some controversy exists regarding the use of ibrutinib in these patients with high risk of bleeding because of its antiaggregant effect that could increase the risk of bleeding. Here, we present the case of a patient with Waldenström macroglobulinemia with associated acquired von Willebrand syndrome and progressively significant bleeding symptoms, who experienced a rapid increase in von Willebrand factor with ibrutinib treatment, despite only reaching a partial response in IgM levels similar to those reached with other previous treatments. We suggest that the control over the monoclonal protein is not the only mechanism that explains the good response, improvement in the bleeding symptoms and von Willebrand factor levels. This fact could be explained by the reduced glycoprotein Ib receptor expression induced by ibrutinib and the consequent von Willebrand factor increase in peripheral blood.

Ibrutinib plus rituximab for the treatment of adult patients with Waldenström's macroglobulinemia: a safety evaluation

Introduction: Waldenström's macroglobulinemia (WM), an orphan disease, is a rare low-grade B-cell lymphoplasmacytic lymphoma with unique clinical features and monoclonal IgM production. Rituximab remains to this date the backbone of most commonly used treatment combinations. The FDA/EMA approval of Ibrutinib, the first-in-class BTK inhibitor, either as monotherapy or in combination with rituximab, changed the treatment landscape of the disease.Areas covered: Clinical trial data that demonstrate mode of action, efficacy, and the safety profile of each agent will be covered. A safety analysis of the combination treatment will also be performed to point out its high efficacy and overall favorable toxicity profile. The disadvantages and treatment gaps that still exist in the treatment of WM which relate to the need for long-term ibrutinib administration and the lack of deep remissions and subsequent disease relapse, will also be reviewed.Expert opinion: The ibrutinib-rituximab combination is both effective and safe, in the newly-diagnosed and relapsed-refractory disease setting. The optimal therapeutic approach for WM patients remains however to be established. The question of which combinatory (or synergistic) regimen can allow for a fixed-treatment duration, deep and durable responses with a safe toxicity profile is being addressed in ongoing clinical trials.

Waldenstrom Macroglobulinemia Manifesting as Acute Kidney Injury and Bing-Neel Syndrome With Excellent Response to Ibrutinib

Waldenstrom macroglobulinemia (WM) is a lymphoplasmacytic lymphoma associated with a monoclonal immunoglobulin M protein. Extranodal involvement in WM is not very common. In this article, we present a rare case of WM with kidney and central nervous system involvement. Bing-Neel syndrome is a distinct complication of WM where lymphoplasmacytic cells involve the central nervous system (CNS). Our patient was initially treated with dialysis and steroids with improvement in his kidney function. He was then started on systemic treatment with rituximab, cyclophosphamide, and dexamethasone with stable kidney function but persistent CNS symptoms. Due to rarity of cases, there is no standard treatment for Bing-Neel syndrome. His treatment was switched to ibrutinib with dramatic improvement in his CNS symptoms as well as radiological findings on magnetic resonance imaging.

Zanubrutinib-induced liver injury: a case report and literature review

BACKGROUND

Zanubrutinib is a Bruton's tyrosine kinase inhibitor that has been recently licensed in refractory mantle cell lymphoma and under assessment in phase 3 clinical trials for other B cell malignancies. To date, there are no reported cases of hepatotoxicity secondary to zanubrutinib. We report the first case of severe liver injury due to zanubrutinib.

CASE PRESENTATION

A 56-year-old Caucasian male with a history of relapsed lymphoplasmacytic lymphoma was admitted to the hospital with new-onset jaundice, choluria, and pruritus for 10 days. He had been on zanubrutinib as part of a clinical trial for 30 months. His blood profile showed a severe hepatocellular injury with jaundice (alanine transaminase 2474 IU/L and total bilirubin 141 umol/L with mild coagulopathy). He had an extensive work-up including virology, autoimmune, and metabolic profiles in addition to abdominal ultrasound with no alternative explanation found for his liver injury. Zanubrutinib-induced liver injury was suspected, and causality assessment by the updated Roussel Uclaf Causality Assessment Method score showed a probable causal relationship with zanubrutinib. His liver histology was also consistent with drug-induced liver injury. His liver biochemistry improved following cessation of zanubrutinib and normalised after 8 weeks.

CONCLUSION

We report the first case of severe liver injury secondary to zanubrutinib after 30 months of treatment. This case raises clinical awareness regarding zanubrutinib-induced liver toxicity and the importance of drug withdrawal in the event of liver injury.

Zanubrutinib for the treatment of MYD88 wild-type Waldenström macroglobulinemia: a substudy of the phase 3 ASPEN trial

Patients with Waldenström macroglobulinemia (WM) lacking activating mutations in the MYD88 gene (MYD88WT) have demonstrated relatively poor outcomes to ibrutinib monotherapy, with no major responses reported in a phase 2 pivotal study. Zanubrutinib is a novel, selective Bruton tyrosine kinase (BTK) inhibitor designed to maximize BTK occupancy and minimize off-target activity. The ASPEN study consisted of a randomized comparison of zanubrutinib and ibrutinib efficacy and safety in patients with WM who have the MYD88 mutation, as well as a separate cohort of patients without MYD88 mutation (MYD88WT) or with unknown mutational status who received zanubrutinib. Results from the latter single-arm cohort are reported herein. Efficacy endpoints included overall, major and complete (CR) or very good partial response (VGPR) rates, progression-free survival (PFS), duration of response (DOR), and overall survival (OS). Twenty-eight patients (23 relapsed/refractory; 5 treatment-naïve) were enrolled, including 26 with centrally confirmed MYD88WT disease and 2 with unknown MYD88 mutational status. At a median follow-up of 17.9 months, 7 of 26 MYD88WT patients (27%) had achieved a VGPR and 50% a major response (partial response or better); there were no CRs. At 18 months, the estimated PFS and OS rates were 68% and 88%, respectively, while the median DOR had not been reached. Two patients discontinued zanubrutinib due to adverse events. Treatment-emergent hypertension, atrial fibrillation, and major hemorrhages were reported in 3, 1 and 2 patients (including 1 concurrent with enoxaparin therapy), respectively. Results of this substudy demonstrate that zanubrutinib monotherapy can induce high quality responses in patients with MYD88WT WM. This trial is registered on www.clinicaltrials.gov as NCT #03053440.

Defining an Ultra-Low Risk Group in Asymptomatic IgM Monoclonal Gammopathy

Simple Summary

Patients with asymptomatic IgM monoclonal gammopathies include IgM monoclonal gammopathy of undetermined significance (IgM MGUS) and smoldering Waldenström macroglobulinemia (SWM), all with some risk of progression to symptomatic Waldenström macroglobulinemia, amyloidosis, or other lymphoproliferative disorder. Due to their low incidence, few studies have focused on the risk of progression, with SWM being the most studied. As both are recognized clinical-pathological entities that share similar clonal and phenotypical features, we focus on defining new biomarkers of progression in this population with long follow-up.

Abstract

We analyzed 171 patients with asymptomatic IgM monoclonal gammopathies (64 with IgM monoclonal gammopathy of undetermined significance—MGUS and 107 with smoldering Waldenström macroglobulinemia - SWM) who had a bone marrow (BM) evaluation performed at diagnosis. Abnormal free-light chain ratio (53% vs. 31%) and MYD88 mutation prevalence (66% vs. 30%) were higher in patients with SWM. No other differences were found among groups. With a median follow-up of 4.3 years, 14 patients progressed to Waldenström macroglobulinemia, 1 to amyloidosis, and 28 died without progression. The MYD88 mutation was found in 53% of patients (available in 160 patients). Multivariate analysis showed that immunoparesis (subhazard ratio—SHR 10.2, 95% confidence interval—CI: 4.2–24.8; p < 0.001) and BM lymphoplasmacytic infiltration ≥ 20% (SHR: 6, 95% CI: 1.6–22.1; p = 0.007) were associated with higher risk of progression. We developed a risk model based on these two risk factors. In the absence of both variables, an ultra-low risk group was identified (SHR 0.1, 95% CI 0.02–0.5; p = 0.004), with 3% and 6% of cumulative incidence of progression at 10 and 20 years, respectively. Bootstrap analysis confirmed the reproducibility of these results. This study finds immunoparesis and BM infiltration as biomarkers of progression as well as a low-risk group of progression in asymptomatic IgM monoclonal gammopathies.

Identification of a Candidate Gene Set Signature for the Risk of Progression in IgM MGUS to Smoldering/Symptomatic Waldenström Macroglobulinemia (WM) by a Comparative Transcriptome Analysis of B Cells and Plasma Cells

Waldenström Macroglobulinemia (WM) is a B-cell lymphoma characterized by the precursor condition IgM monoclonal gammopathies of undetermined significance (IgM MGUS). We performed a gene expression profiling study to compare the transcriptome signatures of bone marrow (BM) B-cells and plasma cells of 36 WM patients, 13 IgM MGUS cases, and 7 healthy subjects used as controls (CTRLs) by Affymetrix microarray. We determined 2038 differentially expressed genes (DEGs) in CD19+ cells and 29 DEGs genes in CD138+ cells, respectively. The DEGs identified in B-cells were associated with KEGG pathways, mainly involved in hematopoietic cell lineage antigens, cell adhesion/focal adhesion/transmembrane proteins, adherens junctions, Wnt-signaling pathway, BCR-signaling pathway, calcium signaling pathway, complement/coagulation cascade, platelet activation, cytokine-cytokine receptor interactions, and signaling pathways responsible for cell cycle, apoptosis, proliferation and survival. In conclusion, we showed the deregulation of groups of genes belonging to KEGG pathways in the comparison among WM vs. IgM MGUS vs. CTRLs in B-cells. Interestingly, a small set of genes in B-cells displayed a common transcriptome expression profile between WM and IgM MGUS compared to CTRLs, suggesting its possible role in the risk of transformation of IgM MGUS to WM.

Zanubrutinib for the treatment of patients with Waldenström macroglobulinemia: 3 years of follow-up

Inhibitors of Bruton's tyrosine kinase (BTK) have established therapeutic activity in patients with Waldenström macroglobulinemia (WM). Zanubrutinib, a potent and selective BTK inhibitor, was evaluated in a phase 1/2 study in patients with WM who were either treatment-naïve (TN) or had relapsed/refractory (R/R) disease. Patients had disease requiring treatment per International Workshop on Waldenström Macroglobulinemia (IWWM) criteria. Treatment was 160 mg of oral zanubrutinib twice daily (n = 50) or 320 mg once daily (n = 23). Efficacy endpoints included overall response rate (ORR) and very good partial response/complete response (VGPR/CR) rates per IWWM-6 criteria (with modification of VGPR definition published previously). Between September 2014 and March 2018, 77 patients (24 TN and 53 R/R) began treatment. At a median follow-up of 36.0 months for patients with R/R disease and 23.5 months for TN, 72.7% remained on treatment. Reasons for treatment discontinuation included any adverse events in 13.0% of patients (1 treatment related), disease progression (10.4%), and other (3.9%). The ORR was 95.9%, and the VGPR/CR rate was 45.2%, which increased over time: 20.5% at 6 months, 32.9% at 12 months, and 43.8% at 24 months. Estimated 3-year progression-free survival rate was 80.5%, and overall survival rate was 84.8%. Adverse events of interest included contusion (32.5%, all grade 1), neutropenia (18.2%), major hemorrhage (3.9%), atrial fibrillation/flutter (5.2%), and grade 3 diarrhea (2.6%). Long-term treatment with single-agent zanubrutinib resulted in deep and durable responses in some patients with WM. The safety profile of long-term zanubrutinib therapy in these patients was acceptable. This trial was registered at www.clinicaltrials.gov as #NCT02343120.

A randomized phase 3 trial of zanubrutinib vs ibrutinib in symptomatic Waldenström macroglobulinemia: the ASPEN study

Bruton tyrosine kinase (BTK) inhibition is an effective treatment approach for patients with Waldenström macroglobulinemia (WM). The phase 3 ASPEN study compared the efficacy and safety of ibrutinib, a first-generation BTK inhibitor, with zanubrutinib, a novel highly selective BTK inhibitor, in patients with WM. Patients with MYD88L265P disease were randomly assigned 1:1 to treatment with ibrutinib or zanubrutinib. The primary end point was the proportion of patients achieving a complete response (CR) or a very good partial response (VGPR) by independent review. Key secondary end points included major response rate (MRR), progression-free survival (PFS), duration of response (DOR), disease burden, and safety. A total of 201 patients were randomized, and 199 received ≥1 dose of study treatment. No patient achieved a CR. Twenty-nine (28%) zanubrutinib patients and 19 (19%) ibrutinib patients achieved a VGPR, a nonstatistically significant difference (P = .09). MRRs were 77% and 78%, respectively. Median DOR and PFS were not reached; 84% and 85% of ibrutinib and zanubrutinib patients were progression free at 18 months. Atrial fibrillation, contusion, diarrhea, peripheral edema, hemorrhage, muscle spasms, and pneumonia, as well as adverse events leading to treatment discontinuation, were less common among zanubrutinib recipients. Incidence of neutropenia was higher with zanubrutinib, although grade ≥3 infection rates were similar in both arms (1.2 and 1.1 events per 100 person-months). These results demonstrate that zanubrutinib and ibrutinib are highly effective in the treatment of WM, but zanubrutinib treatment was associated with a trend toward better response quality and less toxicity, particularly cardiovascular toxicity.

Optical coherence tomography angiography characteristics in Waldenström macroglobulinemia retinopathy: A case report

BACKGROUND

Waldenström macroglobulinemia (WM) is a distinct clinicopathologic entity characterized by the infiltration of the bone marrow by clonal lymphoplasmacytic cells that produce monoclonal immunoglobulin M (IgM) in the blood, and patients may present with symptoms related to the infiltration of the hematopoietic tissues or the effects of monoclonal IgM in the blood. Funduscopic abnormalities were noted in some of the patients due to hyperviscosity or other retinal lesions. Optical coherence tomography angiography (OCTA) as a non-invasive imaging tool can give qualitative and quantitative information about the status of retinal and choroidal vessels, which might be useful for diagnosing patients with WM-associated retinopathy.

CASE SUMMARY

The patient was a 67-year-old man who presented with sudden visual disturbance in both eyes. Ophthalmic tests showed that best corrected visual acuity (BCVA) for this patient was 20/100 in the right eye and 20/1000 in the left eye. Fundus examination, optical coherence tomography (OCT), and OCTA revealed substantial bilateral optic disc edema, dilated and tortuous retinal veins, and diffuse intraretinal blot hemorrhages and edema which were consistent with bilateral central retinal vein occlusion (CRVO). Meanwhile, remarkable bilateral serous macular detachments (SMD) were noticed on OCT. Systemic examinations showed that the patient had anemia and extremely high level of monoclonal IgM and infiltration of clonal lymphoplasmacytic cells in bone marrow. The diagnosis of WM with hyperviscosity and retinopathy was made based on the clinical manifestation and laboratory findings. He was subsequently treated with intravitreal ranibizumab injection, plasmapheresis, and bortezomib plus rituximab with dexamethasone. Six months after treatments, the central macular volume decreased by 16.1% in the right eye and 28.6% in the left eye on OCT, and the patient’s BCVA was improved to 20/60 in the right eye and 20/400 in the left eye. Very good partial response was obtained after systemic treatment.

CONCLUSION

WM may affect visual function and present as bilateral CRVO. OCTA can show characteristic changes in both retina and choroid vasculatures, which might be of great value for diagnosing or following patients with WM retinopathy. Intravitreal anti-vascular endothelial growth factor treatment combined with systemic therapy might be beneficial for WM patients with retinopathy (SMD and CRVO).

B-Cell-Specific Myd88 L252P Expression Causes a Premalignant Gammopathy Resembling IgM MGUS

A highly recurrent somatic L265P mutation in the TIR domain of the signaling adapter MYD88 constitutively activates NF-κB. It occurs in nearly all human patients with Waldenström’s macroglobulinemia (WM), a B cell malignancy caused by IgM-expressing cells. Here, we introduced an inducible leucine to proline point mutation into the mouse Myd88 locus, at the orthologous position L252P. When the mutation was introduced early during B cell development, B cells developed normally. However, IgM-expressing plasma cells accumulated with age in spleen and bone, leading to more than 20-fold elevated serum IgM titers. When introduced into germinal center B cells in the context of an immunization, the Myd88^L252P mutation caused prolonged persistence of antigen-specific serum IgM and elevated numbers of antigen-specific IgM plasma cells. Myd88^L252P-expressing B cells switched normally, but plasma cells expressing other immunoglobulin isotypes did not increase in numbers, implying that IgM expression may be required for the observed cellular expansion. In order to test whether the Myd88^L252P mutation can cause clonal expansions, we introduced it into a small fraction of CD19-positive B cells. In this scenario, five out of five mice developed monoclonal IgM serum paraproteins accompanied by an expansion of clonally related plasma cells that expressed mostly hypermutated VDJ regions. Taken together, our data suggest that the Myd88^L252P mutation is sufficient to promote aberrant survival and expansion of IgM-expressing plasma cells which in turn can cause IgM monoclonal gammopathy of undetermined significance (MGUS), the premalignant condition that precedes WM.

Lymphoplasmacytic lymphoma involving the mediastinum and the lung, followed by amyloidosis: A surgically and genetically proven case

A 60-year-old man was admitted for ground glass opacity in the lower lung field and mediastinal lymphadenopathy. Blood tests revealed elevated serum IgM levels, and the urine test detected Bence-Jones protein. Surgical biopsy from the mediastinal lymph node and lung showed small lymphocytes and plasma cells between follicles, and AL kappa amyloid deposition. Genetic examination detected MYD88 L265P mutation. Our diagnosis was lymphoplasmacytic lymphoma (LPL), involving the mediastinum and the lung, followed by amyloidosis. Mutation analysis, in addition to conventional histological evaluation, was useful for a precise diagnosis.

Waldenström Macroglobulinemia: Clinico-pathological Profile and Treatment Outcomes of Patients from a Tertiary Care Centre of North India

Waldenstorms Macroglobulinemia (WM) is a rare mature B cell neoplasm characterized by a lymphoplasmacytic lymphoma and an IgM monoclonal protein. It is managed by Rituximab based chemotherapy. A single-centre retrospective study was carried out to analyse the clinical presentation, laboratory features, and treatment outcomes of all consecutive patients of WM, diagnosed over a period of 86 months. First-line treatment regimens included RCD (Rituximab/Cyclophosphamide/Dexamethasone), BDR (Bortezomib /Dexamethasone/ Rituximab) and (Lenalidomide/Dexamethasone). A total of 26 patients of WM were diagnosed during this period, with a median age of 65 years. Majority (89%) of these patients were of intermediate (47%) to high risk (42%). An overall response rate of 76.4% was achieved. RCD was found superior to BDR in terms of treatment response. For those who required 2nd line chemotherapy, the median time to next treatment was 22 months. To conclude, a late presentation and higher risk categories were common in our cohort of patients. Treatment outcome was comparable to those reported in western literature. RCD regimen was found to be a better treatment option in terms of overall survival.

The Spectrum of Monoclonal Immunoglobulin-Associated Diseases

The spectrum of immunoglobulin paraprotein-associated diseases requiring therapy extends beyond multiple myeloma and AL amyloidosis. Awareness of these is essential in ensuring timely accurate diagnosis and appropriate treatment. As most paraprotein-associated diseases are fairly uncommon, therapeutic decisions must often be made in the absence of data from randomized controlled trials. Treatment is generally directed at the underlying clonal cell population. This review focuses on the spectrum of the less common paraprotein-associated disorders. In most instances, the monoclonal immunoglobulin plays a direct role in the pathophysiology of the disease course; in a select few, the paraprotein may be a disease marker.

[Monoclonal gammopathy of renal significance: consensus of hematologists and nephrologists of Russia on the establishment of nosology, diagnostic approach and rationale for clone specific treatment]

Monoclonal gammopathy of renal significance (MGRS) is a new nosology in modern nephrology and oncohematology. MGRS is defined as kidney injury due to nephrotoxic monoclonal immunoglobulin produced by the B-cell line clone which does not reach the hematological criteria for specific treatment initiation. Monoclonal proteins pathological effects on kidney parenchyma result in irreversible decline of kidney function till the end stage renal disease that in line with the position of International Consensus of hematologists and nephrologists determinates critical necessity for clone specific treatment in patients with MGRS despite the absence of hematological indications for treatment initiation. Main challenge of MGRS in Russian Federation is an inaccessibility of an in-time diagnostic and appropriate treatment for the great majority of patients due to the following reasons: 1) limited knowledge about the MGRS among hematologists and nephrologists; 2) lack of necessary diagnostic resources in most health-care facilities; 3) lack of approved clinical recommendations and medical economic standards for treatment of this pathological entity. Consensus document comprises the opinion of experts leading nephrologists and hematologists of Russian Federation on the problem of MGRS including the incoherence in nosology classification, diagnostics approach and rationale for clone specific treatment. Consensus document is based on conclusions and agreements reached during the conference of leading nephrologists and hematologists of Russia which was held in the framework of symposia Plasma cell dyscrasias and lymphoproliferative diseases: modern approaches to therapy, 1516 of March 2019, Pavlov First Saint Petersburg State Medical University. The present Consensus is intended to define the principal practical steps to resolve the problem of MGRS in Russian Federation that are summarized as final clauses.

Current and Emerging Treatments for Waldenström Macroglobulinemia

Waldenström macroglobulinemia (WM) is a rare lymphoplasmacytic lymphoma. The primary goal of therapy is to reduce symptoms related to direct infiltration of the bone marrow and decrease monoclonal IgM-associated complications. Active agents in the management of WM can be broadly classified as rituximab-alkylator combination therapy, proteasome inhibitor-based therapy, and Bruton's tyrosine kinase inhibitor-based therapy. MYD88L265P and CXCR4 genetic status are pivotal for tailoring treatment options. Ibrutinib is a suitable treatment option for both treatment-naïve and relapsing WM patients. Recent advances in the intracellular B cell and cytokine signaling pathways have contributed to the development of novel therapeutic strategies. Current clinical trials are promising and may further advance WM-directed therapy.

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.

Spectral-domain optical coherence tomography of retinal vessels in Waldenström's macroglobulinemia

PURPOSE

To image retinal blood vessels in patients with Waldenström's macroglobulinemia using optical coherence tomography (OCT).

METHODS

Retrospective case series examining fundus photographs and OCT scans of 16 eyes in eight patients with Waldenström's macroglobulinemia. Analyses included intravascular OCT reflectivity profiles and vessel diameters, and their relation to total immunoglobulin M (IgM) levels.

RESULTS

In six out of eight patients, cross-sectional OCT scans of larger retinal vessels (diameter > 100 μm) showed normal intravascular reflectivity and retrovascular shadowing. In two patients with the highest total IgM > 60 g/l, altered intravascular reflectivity, distinct anterior and posterior vessel wall reflexes, and retrovascular hyposhadowing were seen. Normalization of the OCT reflectivity in these patients occurred after reduction of total IgM to < 17 g/l and was accompanied by decreasing venous tortuosity and disappearance of retinal haemorrhages and cotton wool spots.

CONCLUSION

This study found that Waldenström's macroglobulinemia and total IgM > 60 g/l were associated with abnormal intravascular reflectivity and retrovascular shadowing on OCT. Awareness of these signs of hyperviscosity could potentially enable earlier detection of critical conditions in patients with Waldenström's macroglobulinemia and improve the assessment of severity and treatment effect.

Good Profile of Efficacy/Tolerance of Bortezomib or Idelalisib in Waldenström Macroglobulinemia Associated with Acquired Von Willebrand Syndrome

Acquired von Willebrand syndrome (AVWS) in the setting of Waldenström macroglobulinemia (WM) is a challenging condition. No real standard of care is recommended for these patients, although the therapeutic strategy should include a rapid approach to the emergency bleeding events and to the underlying malignant lymphoid disorder. We report here our experience treating three elderly patients with these concomitant hematologic entities. The use of a bortezomib-based chemotherapy regimen showed a good profile of tolerance and efficacy even in a long-term follow-up period. These patients were treated for several years before switching their therapy to idelalisib, a targeted oral therapy that inhibits phosphatidylinositol 3-kinase isoform-delta (PI3KD), which is part of the signaling pathway downstream B-cell receptor. This approach was well tolerated and efficacious, although some adverse effects were observed, particularly at hepatic levels, but were all reversible. The same profile of tolerance/efficacy was observed in one very old patient who received idelalisib as a first-line therapy. We think that bortezomib-based therapy could be considered in refractory patients with AVWS associated with WM.

Severe nephritis as initial sign of Waldenström's macroglobulinemia

Waldenström's macroglobulinemia (WM), characterized with monoclonal immunoglobulins of type M and lymphoplasmacytic lymphoma, is a rare clonal Bcell disorder. WM usually present as an indolent lymphoma, and renal involvement is, in contrast to multiple myeloma, very rarely seen. We present a patient presenting with severe nephritis and nephrotic range proteinuria of more than 9 g/day as initial manifestations of WM. Furthermore, we discuss diagnostic and therapeutic approaches for this rare manifestation of the disease, in the light of recent research and treatment recommendations.

MYD88 in the driver's seat of B-cell lymphomagenesis: from molecular mechanisms to clinical implications

More than 50 subtypes of B-cell non-Hodgkin lymphoma (B-NHL) are recognized in the most recent World Health Organization classification of 2016. The current treatment paradigm, however, is largely based on 'one-size-fits-all' immune-chemotherapy. Unfortunately, this therapeutic strategy is inadequate for a significant number of patients. As such, there is an indisputable need for novel, preferably targeted, therapies based on a biologically driven classification and risk stratification. Sequencing studies identified mutations in the MYD88 gene as an important oncogenic driver in B-cell lymphomas. MYD88 mutations constitutively activate NF-κB and its associated signaling pathways, thereby promoting B-cell proliferation and survival. High frequencies of the hotspot MYD88(L265P) mutation are observed in extranodal diffuse large B-cell lymphoma and Waldenström macroglobulinemia, thereby demonstrating this mutation's potential as a disease marker. In addition, the presence of mutant MYD88 predicts survival outcome in B-NHL subtypes and it provides a therapeutic target. Early clinical trials targeting MYD88 have shown encouraging results in relapsed/refractory B-NHL. Patients with these disorders can benefit from analysis for the MYD88 hotspot mutation in liquid biopsies, as a minimally invasive method to demonstrate treatment response or resistance. Given these clear clinical implications and the crucial role of MYD88 in lymphomagenesis, we expect that analysis of this gene will increasingly be used in routine clinical practice, not only as a diagnostic classifier, but also as a prognostic and therapeutic biomarker directing precision medicine. This review focuses on the pivotal mechanistic role of mutated MYD88 and its clinical implications in B-NHL.

Development of Central Nervous System Vasculitis in a Patient with Waldenstrom Macroglobulinemia: A Rare Presentation with Poor Prognosis

Waldenstrom macroglobulinemia (WM) is a rare lymphoproliferative disorder characterized by the presence of monoclonal immunoglobulin M in serum. WM may present with neurologic complications involving the peripheral and central nervous systems (CNS) though CNS complications associated with WM are rare. We present a case of a 72-year-old male with an 18-month history of WM who experienced neurologic and constitutional symptoms indicative of WM progression over a three-week period while on rituximab maintenance therapy. The patient’s symptoms were initially attributed to rituximab-induced asthenia though his clinical condition did not improve with rituximab discontinuation. Due to progressively worsening neurologic symptoms, the patient was re-evaluated and found to have multiple cerebral infarcts and increased serum cryoglobulin levels indicative of cryoglobulinema. The patient was promptly initiated on a combination regimen of high dose steroids, intravenous immunoglobulin (IVIG), and plasmapheresis but had a poor response. Brain biopsy revealed necrotizing vasculitis with dense intra- and peri-vascular CD3 positive T-cell infiltrates with mural necrosis. This is a unique case of WM complicated by type 1 cryoglobulinemia associated with CNS vasculitis that was unresponsive to active rituximab therapy; this case illustrates a poor prognosis of patients with CNS involvement in WM.

Diagnosis of Waldenström macroglobulinemia

Waldenström macroglobulinemia is a rare disorder affecting about 1400 people annually in the United States. This case report reviews from a primary care provider's perspective the initial presentation of a patient who complained of fatigue and dizziness that ultimately led to hospital admission with a diagnosis of Waldenström macroglobulinemia. The referral to hematology/oncology prompting the bone marrow biopsy that led to the diagnosis highlights the important role of the primary care provider in the initial workup, coordination among specialists, and overall management of patients with rare disorders.

KIDNEY DISEASE ASSOCIATED WITH MONOCLONAL GAMMOPATHIES: SINGLE-CENTER STUDY

INTRODUCTION:Renal injury associated with monoclonal gammopathies (MG) is an area of interest of practical onconephrology. Prevalence, spectrum and renal outcome as far as approaches to treatment in this pathological entity, particularly in Russian population, still remain unclear and need refinement. AIM: Analysis of the prevalence, spectrum, treatment approaches and renal outcome in kidney injury associated with monoclonal gammopathies (MG).

PATIENTS AND METHODS:Patients with MG and renal injury proven by kidney biopsies from 01.01.2011 till 01.05.2018 were enrolled into this one-center prospective study (n=119). Cases of MG of undetermined significance and non-amyloid kidney lesions were estimated as MG of renal significance (MGRS). Treatment approaches, haematological and renal responses were analysed. Worsening of kidney function was estimated as eGFR decrease >25 % from initial value or initiation of renal replacement treatment (RRT), improving – as eGFR increase >25 % from the initial value or the discontinuation of RRT. Other cases were determined as stable kidney function. Kidney outcome was determined in RRT initiation or eGFR<15 ml/min/1,73m2 at the end of follow-up. Long-term kidney outcome was estimated by Kaplan-Meier survival analysis. The median follow-up period was 12 (2; 27) months.

RESULTS.Prevalence of kidney injury associated with MG among all performed kidney biopsies was 7,5 %, MGRS – 0,94 %. Multiple myeloma (MM), AL-amyloidosis and lymphoproliferative disorder (LPD) were diagnosed in 39, 55 and 10 patients, respectively. Prevalence of kidney injury types was the following: Al-amyloidosis (53 %); cast nephropathy (12 %); light chain deposition disease (12 %); C3-glomerulopathy (3 %); proliferative glomerulonephritis (GN) with monoclonal immunoglobulin deposits (3 %); cryoglobulinemic GN (2 %); thrombotic microangiopathy (2 %); podocytopathy (2 %); acute tubular necrosis – 2 %; immunotactoid GN (1 %); fibrillary GN (1 %); proximal tubulopathy (1 %), combination of different types (6 %). Patients mostly were treated with bortezomib and dexamethasone. Autologous stem cell transplantation was performed in 13 patients. Haematological response was achieved in 48,8 %, 45,4 % and 46,7 % of patients with MM, AL-amyloidosis and MGRS, respectively. Worsening of kidney function was registered in 11,1 % of MM and in 37,2 % of AL-amyloidosis; improving or stable kidney function was in 88,9 % and 62,7 % MM and AL-amyloidosis patients, respectively. In MGRS improving (20 %) and stable kidney function (80 %) were detected. Four-years cumulative renal survival in MM, AL-amyloidosis, MGRS and LPD groups was 63 %, 54 %, 80 % and 39 %, respectively, and does not differ between 4 groups.

CONCLUSION:MG-associated kidney disease represented by diverse clinical and morphological patterns is standard problem in routine clinical practice. It is associated with inferior renal outcome and requires a practical implementation of highly-specialized interdisciplinary approach to diagnostics and treatment.