A phase 2, open-label study of ibrutinib plus rituximab in Japanese patients with Waldenstrom's macroglobulinemia

Ibrutinib is a first-in-class Bruton kinase inhibitor against B-cell neoplasms including Waldenström macroglobulinemia (WM). This study evaluated the efficacy and safety of ibrutinib-rituximab in Japanese patients with WM. Patients received ibrutinib 420 mg orally once daily plus weekly rituximab 375 mg/m2 IV (8 infusions total). The primary end point was major response rate (MRR; PR or better) by Independent Review Committee assessment. Secondary endpoints were progression-free survival (PFS), safety, pharmacokinetics, and biomarkers. Primary analysis was conducted in 16 patients [baseline, treatment naïve: 8 (50.0%); relapsed/refractory WM: 8 (50.0%)] who received ibrutinib-rituximab, after all patients completed Week 57 or end of treatment. At primary analysis, MRR was 87.5% [14/16 patients; 95% CI: 61.7, 98.4%; p < 0.0001 (null hypothesis: 32% response rate)]. At final analysis (median study intervention duration: 34.4 months, median follow-up: 35.0 months), MRR was unchanged at 87.5%, but VGPR [6/16 (37.5%)] and PR [8/16 (50.0%)] improved. Prior treatment status did not affect response. At final analysis, median PFS was not reached [36-month PFS rate: 86% (95% CI: 55, 96%)]. No critical safety signals were reported. This study demonstrated a positive benefit/risk profile of ibrutinib-rituximab in Japanese patients with WM, consistent with the iNNOVATE study.

Future Directions in the Frontline Management of Waldenström Macroglobulinemia

Despite substantial progress in the clinical management of Waldenström's Macroglobulinemia (WM) and the emergence of chemotherapy-free approaches such as BTK inhibitors, WM is still a disease in which current treatments fail to cure and are in part associated with significant toxicities, compromising treatment outcome and quality of life. Thus, the vision for future front-line therapy should be to develop regimens which combine improved efficacy and excellent applicability with a low toxicity profile. Conventional immunochemotherapy such as bendamustine-rituximab is highly active but limited by hematotoxicity and long-lasting immunosuppression. Thus, further intensification of this treatment concept will most likely not be successful. Chemotherapy-free approaches such as BTK inhibitors have already changed the treatment landscape in WM, but still have major limitations such as the need for non-fixed duration treatment. Most probably, the combination of non-chemotherapy based, targeted approaches with different modes of action will ensure that we at least come closer to our vision of achieving functional cure in WM in the near future.

Management of indolent B-cell Lymphomas: A review of approved and emerging targeted therapies

The indolent B-cell non-Hodgkin lymphomas (B-NHL) comprise a heterogenous group of lymphoproliferative disorders characterized by slow growth kinetics and a relapsing/remitting course. Management has, until recently, been uniform across all indolent B-NHL subtypes. Improving insight into pathophysiological and molecular features of each disease has led to development of several targeted therapies. Consequently, each subtype must now be considered an individual entity. In this review, we consider the three commonest indolent B-NHLs: follicular lymphoma, marginal zone lymphoma and Waldenstrom's macroglobulinemia and review in detail the data on approved and emerging targeted therapeutic agents for each B-NHL subtype.

Low Spike Antibody Levels and Impaired BA.4/5 Neutralization in Patients with Multiple Myeloma or Waldenstrom's Macroglobulinemia after BNT162b2 Booster Vaccination

Patients with symptomatic monoclonal gammopathies have impaired humoral responses to COVID-19 vaccination. Their ability to recognize SARS-CoV-2 Omicron variants is of concern. We compared the response to BNT162b2 mRNA vaccinations of patients with multiple myeloma (MM, n = 60) or Waldenstrom's macroglobulinemia (WM, n = 20) with healthy vaccine recipients (n = 37). Patient cohorts on active therapy affecting B cell development had impaired binding and neutralizing antibody (NAb) response rate and magnitude, including several patients lacking responses, even after a 3rd vaccine dose, whereas non-B cell depleting therapies had a lesser effect. In contrast, MM and WM cohorts off-therapy showed increased NAb with a broad response range. ELISA Spike-Receptor Binding Domain (RBD) Ab titers in healthy vaccine recipients and patient cohorts were good predictors of the ability to neutralize not only the original WA1 but also the most divergent Omicron variants BA.4/5. Compared to WA1, significantly lower NAb responses to BA.4/5 were found in all patient cohorts on-therapy. In contrast, the MM and WM cohorts off-therapy showed a higher probability to neutralize BA.4/5 after the 3rd vaccination. Overall, the boost in NAb after the 3rd dose suggests that repeat vaccination of MM and WM patients is beneficial even under active therapy.

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.

Multiple myeloma: a review of atypical imaging features and other distinct plasma cell disorders that demonstrate similar imaging features

Multiple osteolytic lesions are a well-recognized and typical imaging feature of multiple myeloma as well as several other plasma cell disorders. Given the high volume of imaging studies obtained of multiple myeloma patients, radiologists will likely encounter a subset of multiple myeloma patients with less common or "atypical" findings during their practice. These atypical findings include osteosclerotic lesions, extramedullary lesions, and amyloid deposition. Similar imaging findings that are considered atypical for multiple myeloma can also be detected in other plasma cell disorders that are distinct from multiple myeloma. For instance, POEMS syndrome is a distinct plasma cell disorder from multiple myeloma, but also can present with osteosclerotic lesions. This article reviews the atypical findings associated with multiple myeloma and also reviews other plasma cell disorders that can have a similar spectrum of imaging findings. Special attention is paid to the musculoskeletal imaging findings.

[Complete response with tirabrutinib for relapsed and refractory Bing-Neel syndrome]

A 62-year-old female patient was diagnosed with Waldenstrom's macroglobulinemia/lymphoplasmacytic lymphoma (WM/LPL) 8 years ago, which was resolved with rituximab (R) monotherapy. Five years ago, she experienced numbness of the lower limbs, followed by diminished lower limb muscle strength and hearing disturbance. PET-CT scans showed accumulations along the peripheral nerves of the upper and lower limbs together with clonal B lymphocytes in the cerebrospinal fluid, thus a diagnosis of relapse with Bing-Neel syndrome (BNS). After a temporal remission by high-dose cytarabine or bendamustine plus R regimens as salvage treatments, WM/LPL recurred for the third time accompanied by gait disturbances due to muscle weakness and urinary retention. Thus, tirabrultinib was started as a subsequent therapy, which significantly improved the neurological condition together with abnormal findings of magnetic resonance imaging or cerebrospinal fluids. This case is valuable since few relapsed BNS was reported in the literature with successful tirabrutinib treatment.

Acalabrutinib: A Selective Bruton Tyrosine Kinase Inhibitor for the Treatment of B-Cell Malignancies

Bruton tyrosine kinase (BTK) is a validated target for treatment of B-cell malignancies, and oral inhibitors of BTK have emerged as a standard of care for these diseases. Acalabrutinib is a second generation, highly selective, potent, covalent BTK inhibitor that exhibits minimal off-target activity in in vitro assays, providing the potential to improve tolerability over the first-in-class BTK inhibitor, ibrutinib. Acalabrutinib was approved for the treatment of relapsed/refractory mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) in the US in 2017 and 2019, respectively. Acalabrutinib is also undergoing trials for other B-cell malignancies, both as monotherapy and in combinations. In this review, we discuss results from clinical trials evaluating the efficacy and safety of acalabrutinib in patients with CLL, MCL, and Waldenstrom's macroglobulinemia. Recent phase 3 data showed that acalabrutinib improved progression-free survival (PFS) compared with rituximab plus idelalisib or rituximab plus bendamustine in patients with relapsed/refractory CLL, and acalabrutinib with or without obinutuzumab improved PFS compared with chlorambucil plus obinutuzumab in patients with treatment-naïve CLL. Overall, acalabrutinib had a tolerable safety profile, with most adverse events being grade 1/2 severity (most commonly headache and diarrhea) and a low rate of discontinuation due to adverse events.

Histologic Transformation in an Untreated Waldenstrom's Macroglobulinemia After 14 Years: Case Report and Review of the Literature

Waldenstrom's macroglobulinemia (WM) is an indolent B-cell non-Hodgkin lymphoma characterized by lymphoplasmacytic histology in the bone marrow with monoclonal IgM. Median survival can be in excess of 10 years. The 5-year cumulative incidence of death is low at about 10%. One-third of all-cause specific mortality is due to the lymphoma for which histologic transformation (HT) is rare. Here we present a case of a 60-year-old man with longstanding untreated WM, presenting with minimally symptomatic transformation to diffuse large B-cell lymphoma (DLBCL), with an accompanying review of the literature. Transformed WM, diagnosed greater than 5 years, has a reported survival period of 8 - 9 months. This case highlights that after a decade of continued stability in WM, not requiring treatment, an acute change in laboratory data with minimally progressive IgM levels, in the absence of B symptoms and clinical findings, may be the harbinger of transformation and at the time of diagnosis can have a rapidly deteriorating clinical course. In this case, the tripling of the lactate dehydrogenase (LDH) as the primary drastic change demonstrates the importance of the rapid increase in LDH as a singly reliable marker for HT. Late transformation has been borne out as a negative variable as the generally indolent course of WM is curtailed with the poor outcome in HT. Although MYD88 wildtype is a possible predictive factor for transformation, it is unclear if late transformation is clonally or non-clonally related and further molecular investigation is needed.

Current and novel BTK inhibitors in Waldenström's macroglobulinemia

The current therapeutic approach in Waldenström’s macroglobulinemia (WM) is being driven by insights in disease biology and genomic landscape. Bruton’s tyrosine kinase (BTK) plays a key role in signaling pathways for the survival of WM clone. BTK inhibition has changed the treatment landscape of the disease. Ibrutinib has resulted in deep and durable responses both as an upfront and salvage treatment with a manageable toxicity profile. However, the need for fewer off-target effects and deeper responses has resulted in the clinical development of second-generation BTK inhibitors. Zanubrutinib has resulted in clinically meaningful antitumor activity, including deep and durable responses, with a low discontinuation rate due to treatment-related toxicities. Cardiovascular adverse events seem to be milder compared with ibrutinib. Interestingly, the efficacy of zanubrutinib in WM is significant both for MYD88^L265P and MYD88^WT patients. Although the randomized, phase III ASPEN clinical trial did not meet its primary endpoint in terms of showing a superiority of zanubrutinib in deep responses compared with ibrutinib, secondary efficacy and safety endpoints underscore the potential clinical role of zanubrutinib in the treatment algorithm of WM independent of the MYD88 mutational status. Combination regimens and non-covalent BTK inhibitors are emerging as promising treatment strategies. Long-term data will determine whether next-generation BTK inhibitors are more potent and safer compared with ibrutinib, and whether they are able to overcome resistance to ibrutinib, either alone or in combination with inhibitors of other interrelated molecular pathways.

Pleural fluid MYD88 L265P mutation supporting diagnosis and decision to treat extramedullary Waldenstrom's macroglobulinemia: a case report

Background

Our case of a patient with untreated lymphoplasmacytic lymphoma/Waldenstrom’s macroglobulinemia with extramedullary pleural effusion is the first documented case of pleural fluid MYD88 L265P mutation status in a community hospital setting. Our patient was intolerant to 420 mg ibrutinib, but still achieved a lasting complete remission, as defined by National Comprehensive Cancer Network guidelines, with a dose reduction to 240 mg of ibrutinib.

Case presentation

A 72-year-old Caucasian (white) man diagnosed with monoclonal immunoglobin M kappa lymphoplasmacytic lymphoma/Waldenstrom’s macroglobulinemia monitored without treatment for 2 years, presented with dyspnea and a left pleural effusion. At presentation, computed tomography scans of his chest, abdomen, and pelvis showed layering left pleural effusion and para-aortic lymphadenopathy. Pleural fluid cytology demonstrated B-cell lymphoma of the lymphoplasmacytic subtype, with monoclonal kappa B-cell population on flow and a positive MYD88 L265P mutation. The pleural effusion recurred post-thoracentesis and he achieved a lasting complete remission as defined by National Comprehensive Cancer Network guideline with 240 mg ibrutinib.

Conclusions

Our discussion details a comprehensive literature review of extramedullary pulmonary involvement in Waldenstrom’s macroglobulinemia. Establishing a malignant etiology for pleural effusion in Waldenstrom’s macroglobulinemia can be challenging, as standard techniques may be insensitive. Allele-specific polymerase chain reaction for detecting MYD88 L265P mutations is more sensitive for confirming lymphoplasmacytic lymphoma/Waldenstrom’s macroglobulinemia in pleural fluid. Extramedullary pulmonary involvement usually presents post-diagnosis of Waldenstrom’s macroglobulinemia and responds well to Waldenstrom’s macroglobulinemia-directed treatment regimens. Allele-specific polymerase chain reaction is a sensitive assay for detecting MYD88 L265P mutations in pleural fluid to support the diagnosis of malignant pleural effusion in the setting of Waldenstrom’s macroglobulinemia and helps guide the treatment decision to use ibrutinib. Although intolerant of ibrutinib 420 mg, our patient achieved complete and sustained remission of pleural effusion with a dose of 240 mg with progression free survival of over 30 months.

Evaluating ibrutinib in the treatment of symptomatic Waldenstrom's macroglobulinemia

Waldenstrom's macroglobulinemia (WM) is a rare lymphoplasmacytic lymphoma with indolent course and prolonged disease course. The first-in-class Bruton's tyrosine kinase inhibitor, ibrutinib, has shown significant activity and a distinct adverse event profile among both newly diagnosed and relapsed/refractory WM patients. Interestingly, clinical responses to ibrutinib have been shown to be dependent on patients' MYD88 and CXCR4 mutational status. The recent outcomes of the Phase III iNNOVATE trial showed that the combination of ibrutinib with rituximab resulted in a significantly prolonged progression-free survival compared with rituximab monotherapy, which provides a novel therapeutic option in the clinical practice especially for the rituximab-refractory WM patients. However, the need for continuous drug administration along with the unique toxicity manifestations may render the patient management challenging. Furthermore, our understanding of the underlying resistant mechanisms to ibrutinib is currently being evolved.

A Case of Waldenstrom's Macroglobulinemia Morphologically Resembling Plasma Cell Myeloma

Although both are characterized by the presence of an IgM monoclonal gammopathy, IgM multiple myeloma and Waldenstrom's macroglobulinemia are two distinct hematologic entities. Differentiation of each however, may be challenging, but obviously critical to ensuring appropriate therapeutic decision-making and patient prognostication. Herein we report a case of a patient with Waldenstrom's macroglobulinemia presenting with bone marrow morphology mimicking plasma cell myeloma, highlighting the importance of clinical correlation and ancillary studies to reach an appropriate diagnosis.

The Diagnostic, Prognostic, and Therapeutic Utility of Molecular Testing in a Patient with Waldenstrom's Macroglobulinemia

The application of molecular genomics and our understanding of its clinical implications in the diagnosis, prognostication and treatment of lymphoproliferative disorders has rapidly evolved over the past few years. Of particular importance are indolent B-cell malignancies where tumour cell survival and proliferation are commonly driven by mutations involving the B-cell receptor and downstream signalling pathways. In addition, the increasing number of novel therapies and targeted agents have provided clinicians with new therapeutic options with the aim of exploiting such mutations. In this case report, we highlight one such success story involving the diagnostic impact of the MYD88^L265P mutation in Waldenstrom’s macroglobulinemia (WM), its prognostic implications and effect on choice of therapy in the era of novel therapies.

Waldenstrom Macroglobulinemia: Genomic Aberrations and Treatment

Waldenström macroglobulinemia (WM) is a rare, indolent, and monoclonal immunoglobulin M-associated lymphoplasmacytic disorder with unique clinicopathologic characteristics. Over the past decade, remarkable progress has occurred on both the diagnostic and therapeutic fronts in WM. A deeper understanding of the disease biology emanates from the seminal discoveries of myeloid differentiation primary response 88 (MYD88) L265P somatic mutation in the vast majority of cases and C-X-C chemokine receptor, type 4, mutations in about a third of patients. Although WM remains an incurable malignancy, and the indications to initiate treatment are largely unchanged, the therapeutic armamentarium continues to expand. Acknowledging the paucity of high-level evidence from large randomized controlled trials, herein, we evaluate the genomic aberrations and provide a strategic framework for the management in the frontline as well as the relapsed/refractory settings of symptomatic WM.

Autoimmune thrombocytopenia: a complication of fludarabine therapy in the treatment of Waldenstrom's macroglobulinemia

Fludarabine is an effective purine analogue which has become extensive used in lymph proliferative malignancies. However, an increased incidence of autoimmune disorders including autoimmune hemolytic anemia (AHIA) and idiopathic thrombocytopenia (ITP) is reported with the use of fludarabine. The exact mechanism for fludarabine to exacerbate thrombocytopenia is not distinct. In our report, we describe a patient with WM developed a refractory, life-threatening and fludarabine-associated thrombocytopenia which could not be explained by the cytotoxic effects of fludarabine. Possible mechanisms of fludarabine on autoimmune disorders are discussed.

An unusual case of Waldenstrom's macroglobulinemia presented with nasopharyngeal involvement

We report a rare case of a 68-year-old male who presented with fever, weight loss, nasal blockage, and epistaxis. Examination revealed cervical and axillary lymphadenopathy with no evidence of organomegaly. On evaluation, bone marrow aspiration showed lymphoplasmacytic infiltration. The computed tomography of the neck showed nasopharyngeal mass and the biopsy of this mass and cervical lymph node showed lymphoplasmacytic lymphoma (LPL) with high serum IgM level. Hence, a diagnosis of Waldenstrom’s macroglobulinemia (WM) was made. The patient received six cycles of chemotherapy with a combination of cyclophosphamide, vincristine, and prednisolone (COP regimen). Currently, the patient is under follow-up and in complete remission (CR), one year after completion of therapy. Nasopharyngeal involvement is extremely rare in WM, and hence we report this case.

A Case of Nephrotic Syndrome With Minimal-Change Disease and Waldenstrom's Macroglobulinemia

Kidney disease is a rare complication of Waldenstrom’s macroglobulinemia. We report a case of nephrotic syndrome and minimal change disease in a patient with biopsy proven Waldenstrom’s macroglobulinemia. The patient presented with over 12 grams of proteinuria and was successfully treated with oral prednisone over the course of 4 weeks. Repeat serum protein electrophoresis as well as serum immunoelectrophoresis revealed no paraproteins, urine analysis was negative for protein or blood by dipstick and spot urine protein was 9 mg/dL with creatinine of 101 mg/dL at time of last office visit. This case illustrates the successful treatment with corticosteroids alone with prolonged complete remission.