Waldenström's macroglobulinaemia: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Ibrutinib as treatment for Bing-Neel syndrome reclassified as glioblastoma: a case report

BACKGROUND

Glioblastoma is a highly malignant disease with limited treatment options. Ibrutinib, a covalent Bruton tyrosine kinase inhibitor, is an oral agent with manageable side effects used for hematological diseases including Waldenström macroglobulinemia. We present the case of a 69-year-old Caucasian male patient treated with ibrutinib for suspected Bing-Neel syndrome (BNS), which following a biopsy, was reclassified as glioblastoma.

CASE PRESENTATION

In December 2018, a 69-year-old Caucasian male patient was diagnosed with Waldenström macroglobulinemia. As the patient was asymptomatic, without bone marrow failure or high M-component count, watchful waiting was initiated. Due to increasing neurological symptoms, the patient, based on magnetic resonance imaging, was diagnosed with Bing-Neel syndrome in May 2019. The patient received different treatments before starting ibrutinib monotherapy in August 2019 due to disease progression, both on magnetic resonance imaging and clinically. The patient remained clinically stable for 7 months. In March 2020, the patient developed headaches, and both magnetic resonance imaging and a biopsy revealed glioblastoma IDH-wildtype. Treatment was changed in line with the new diagnosis, but the patient died at the end of 2020.

CONCLUSION

We present a case in which a patient with glioblastoma IDH-wildtype remained clinically stable for 7 months when treated with ibrutinib monotherapy, which is similar to what would be expected for the standard treatment for glioblastoma. To our knowledge, this is the first patient receiving ibrutinib for a glioblastoma IDH-wildtype with a meaningful clinical outcome. Our case may therefore support previous nonclinical findings, indicating a therapeutic value of ibrutinib in patients with glioblastoma and support for further investigation of ibrutinib as a possible treatment for glioblastoma.

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.

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.

Bruton Tyrosine Kinase Inhibition: an Effective Strategy to Manage Waldenström Macroglobulinemia

PURPOSE OF REVIEW

The treatment of Waldenström macroglobulinemia (WM) has evolved over the past decade. With the seminal discoveries of MYD88 and CXCR warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) mutations in WM cells, our understanding of the disease biology and treatment has improved. The development of a new class of agents, Bruton tyrosine kinase inhibitors (BTKi), has substantially impacted the treatment paradigm of WM. Herein, we review the current and emerging BTKi and the evidence for their use in WM.

RECENT FINDINGS

Clinical trials have established the role of covalent BTKi in the treatment of WM. Their efficacy is compromised among patients who harbor CXCR4WHIM mutation or MYD88WT genotype. The development of BTKC481 mutation-mediated resistance to covalent BTKi may lead to disease refractoriness. Novel, non-covalent, next-generation BTKi are emerging, and preliminary results of the early phase clinical trials show promising activity in WM, even among patients refractory to a covalent BTKi. Covalent BTK inhibitors have demonstrated meaningful outcomes in treatment-naïve (TN) and relapsed refractory (R/R) WM, particularly among those harboring the MYD88L265P mutation. The next-generation BTKi demonstrate improved selectivity, resulting in a more favorable toxicity profile. In WM, BTKi are administered until progression or the development of intolerable toxicity. Consequently, the potential for acquired resistance, the emergence of cumulative toxicities, and treatment-related financial burden are critical challenges associated with the continuous therapy approach. By circumventing BTK C481 mutations that alter the binding site to covalent BTKi, the non-covalent BTKi serve as alternative agents in the event of acquired resistance. Head-to-head comparative trials with the conventional chemoimmunotherapies are lacking. The findings of the RAINBOW trial (NCT046152), comparing the dexamethasone, rituximab, and cyclophosphamide (DRC) regimen to the first-generation, ibrutinib are awaited, but more studies are needed to draw definitive conclusions on the comparative efficacy of chemoimmunotherapy and BTKi. Complete response is elusive with BTKi, and combination regimens to improve upon the efficacy and limit the treatment duration are also under evaluation in WM.

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.

Long-term outcomes by bone marrow B-cell depletion from the R2W trial of bortezomib with cyclophosphamide and rituximab in Waldenstrőm macroglobulinaemia

There remains a lack of consensus as to the most appropriate primary therapy in Waldenstrőm macroglobulinemia (WM). We evaluated a novel bortezomib-based combination and developed a sensitive WM-specific flow cytometry assay (limit of detection 0.004% of leucocytes) to assess bone marrow (BM) response. Sixty treatment-naïve WM patients were enroled into this phase II trial and randomised (2:1) to receive cyclophosphamide and rituximab with either bortezomib (BRC) or fludarabine (FCR). The primary objective was to assess the overall response rate (ORR) in eligible patients receiving BRC (N = 41). An ORR of 97.6% (95%CI:87.1-99.9) was observed; 27 (65.9%) patients remain alive without progression after 62.6 months median follow-up, with 2-, 3- and 5-year progression-free survival (PFS) rates of 92.7% (95%CI:79.0-97.6), 80.5% (95%CI:64.8-89.7) and 65.5% (95%CI:48.8-77.9). Persistent WM B-cells were demonstrable in 19/38 patients at the end of treatment (median 0.24%, range 0.02-11.2%). PFS was markedly longer in patients with BM B-cell depletion (<0.004%) compared to those who had persistent BM B-cells detectable at end of treatment (HR = 0.06, 95%CI:0.01-0.47, p < 0.001), and remained independently associated after adjusting for baseline risk stratification or investigator-assessed response. BRC is a tolerable, highly efficacious regimen for treatment-naïve WM patients. BM B-cell depletion is independently associated with patient outcomes.

Ibrutinib Efficacy, Safety, and Pharmacokinetics in Chinese Patients with Relapsed or Refractory Waldenström's Macroglobulinemia: A Multicenter, Single-Arm, Phase 4 Study

INTRODUCTION

Waldenström's macroglobulinemia (WM) is a rare malignant B cell lymphoma which occurs in around 1-2% of all hematologic tumors. Ibrutinib was approved in China for WM on the basis of two global pivotal studies which enrolled no Chinese patients. The aim of this study was to determine the efficacy, safety, and pharmacokinetics of ibrutinib in Chinese patients with relapsed or refractory (r/r) WM.

METHODS

This was an open-label, single-arm, multicenter phase 4 study conducted across five sites in China. Enrolled patients with clinicopathological confirmed WM received ibrutinib 420 mg once daily orally until disease progression or unacceptable toxicity. The primary endpoint was major response rate (MRR, partial response [PR], or better) according to the modified consensus criteria from the Sixth International Workshop on WM.

RESULTS

Seventeen patients were enrolled; at data cutoff (March 19, 2022), MRR was 64.7% (90% confidence interval [CI] 42.0-83.4) and overall response rate was 100% (90% CI 83.8-100.0). One (5.9%) patient achieved very good PR, 10 (58.8%) achieved PR, and six (35.3%) achieved minor response. The median duration of response (PR or better) was 14.8 months (95% CI 10.8-not estimable [NE]). Median progression-free survival was 18.4 months (95% CI 12.9-NE). All patients experienced at least one treatment-emergent adverse event (TEAE) related to the study drug, and grade ≥ 3 TEAEs were reported in 13 (76.5%) patients. There were no TEAEs leading to dose reduction or death. The median model estimated maximum plasma concentration and area under the plasma concentration-time curve during 24 h after dosing at steady state were 40.5 ng/mL and 204 ng·h/mL, respectively.

CONCLUSIONS

Ibrutinib demonstrated durable responses in Chinese patients with r/r WM. Treatment was well tolerated with no new safety signals compared with the pivotal global studies. Ibrutinib exposure was also comparable between Chinese and non-Chinese patients.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT04042376.

Unmet clinical needs in the use of zanubrutinib in malignant lymphomas (Waldenström macroglobulinemia, marginal zone lymphoma and mantle cell lymphoma): A consensus-based position paper from an ad hoc expert panel

Zanubrutinib has been approved for the treatment of patients with different lymphoproliferative disorders, and now represents a major breakthrough in the treatment of patients resistant or relapsing after the recommended therapies. Because few systematic studies or comparative randomized clinical trials have been conducted, optimal use of the drug in approved indications is challenging, and questions are emerging on its use in earlier stages of the disorders. This article presents the results of group discussion among an ad hoc constituted panel of experts aimed at identifying and addressing unmet clinical needs (UCNs) in the use of zanubrutinib in the lymphomas which have received the approval of use, specifically Waldenström macroglubulinemia, marginal zone lymphoma and mantle cell lymphoma. Key UCNs were selected according to the criterion of clinical relevance using the Delphi process. The panel produced recommendations and proposals for new studies for the management of the identified UCNs. These recommendations are intended for use not only by expert centers but above all by not experienced hematologists as well as general practitioners.

Advances in Treatment of Waldenström Macroglobulinemia

PURPOSE OF REVIEW

The discovery of recurring somatic mutations, in particular MYD88 and CXCR4 mutations, in Waldenström macroglobulinemia (WM), a rare B-cell lymphoproliferative disorder, led in the last decade to the development of several therapeutic agents with high efficacy. This review aims to provide an overview of available treatments in WM and novel agents, focusing on studies published over recent years.

RECENT FINDINGS

There is no international consensus on the best first-line option in treatment-naïve patients. Randomized clinical trials are rare in WM and there has been no prospective comparison of chemoimmunotherapy and BTK inhibitors in the frontline setting. Chemoimmunotherapy and BTK inhibitors, the two feasible and most widely used treatments in first-line treatment, represent very different options in terms of duration of therapy, route of administration, cost, and adverse effect. In addition to tumor genotype and patient comorbidities, choice of therapy in WM should take into account these parameters. Results of ongoing and future clinical trials evaluating fixed-duration combinations with BTK inhibitors and novel agents are awaited.

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.

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.

Impact of atrial fibrillation in onco-hematological patients in Europe: a targeted literature review

INTRODUCTION

Atrial fibrillation (AF) is a common complication in cancer patients, and the increased risk associated with certain therapies poses a major challenge. The objective was to determine the clinical and economic burden of AF in onco-hematological patients in Europe.

AREAS COVERED

A targeted literature review was completed for observational, retrospective and case studies, and reviews on AF in onco-hematology published between January 2010 and 2022 in PubMed, Science Direct, Medes and IBECS. The search was based on epidemiology, cost, health-related quality of life (HRQoL), disease burden and management, and patient journey. Thirty-one studies fulfilled eligibility criteria. Annual incidence of AF during treatment varies up to 25%, and increased with first-generation Bruton tyrosine kinase inhibitors (BTKi). Risk factors include age ≥65, prior AF or hypertension, hyperlipidemia and ibrutinib use. Complications are managed with anticoagulants and/or antiarrhythmics, and regular monitoring. When AF is no longer controllable, dose reduction or discontinuation is recommended. No data on costs, HRQoL and patient journey were identified.

EXPERT OPINION

There is scarce and heterogeneous information on AF in onco-hematology in Europe. Available evidence reports a higher risk of AF associated with first-generation BTKi. Further studies are needed to understand the burden of AF in these patients.

BeEAM Conditioning including High-Dose Bendamustine before Autologous Stem Cell Transplantation Is Safe and Effective in Patients with Waldenstrom's Macroglobulinemia

High-dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT) is an option to consolidate remission in Waldenstrom's macroglobulinemia (WM), particularly in selected younger patients with chemosensitive disease. BEAM, consisting of BCNU, etoposide, cytarabine, and melphalan, is often used as a conditioning regimen. However, problems with BCNU, including pneumotoxicity, tolerance, and availability, necessitate the search for alternatives. In this pilot study, we investigated high-dose chemotherapy with BeEAM, in which BCNU is replaced with high-dose bendamustine as an alternative conditioning regimen in six subsequent patients with WM. Bendamustine treatment was well tolerated without unexpected toxicities. The overall response rate was 6/6 patients (2 very good partial responses (VGPR) and 4 PR). After a median follow-up of 72 months, two (33%) patients relapsed. Median progression-free and overall survivals were not reached, and no severe late-onset toxicities were observed so far. In this pilot study, BeEAM conditioning before ASCT seems feasible, safe, and effective in patients with WM.

Bendamustine plus rituximab for the treatment of Waldenström Macroglobulinemia: Patient outcomes and impact of bendamustine dosing

Bendamustine and rituximab (BR) therapy is commonly used in the treatment of Waldenström Macroglobulinemia (WM). The impact dose of Bendamustine dose on response and survival outcomes is not well-established, and the impact of its use in different treatment settings is not clear. We aimed to report response rates and survival outcomes following BR, and clarify the impact of depth of response and bendamustine dose on survival. A total of 250 WM patients treated with BR in the frontline or relapsed settings were included in this multicenter, retrospective cohort analysis. Rates of partial response (PR) or better differed significantly between the frontline and relapsed cohorts (91.4% vs 73.9%, respectively; p < 0.001). Depth of response impacted survival outcomes: two-year predicted PFS rates after achieving CR/VGPR vs PR were 96% versus 82%, respectively (p = 0.002). Total bendamustine dose was predictive of PFS: in the frontline setting, PFS was superior in the group receiving ≥1000 mg/m² compared with those receiving 800-999 mg/m² (p = 0.04). In the relapsed cohort, those who received doses of <600 mg/m² had poorer PFS outcomes compared with those who received ≥600 mg/m² (p = 0.02). Attaining CR/VGPR following BR results in superior survival, and total bendamustine dose significantly impacts response and survival outcomes, in both frontline and relapsed settings.

Treatment of relapsed and refractory Waldenstrom Macroglobulinemia

Waldenström's Macroglobulinemia (WM) is a rare type of indolent non-Hodgkin lymphoma (NHL) that remains incurable. Several effective agents such as monoclonal antibodies (in combination with chemotherapy), Bruton's tyrosine kinase inhibitors, proteasome inhibitors, and BCL2 inhibitors are (becoming) available for the treatment of relapsed and refractory WM. There is however no consensus on a preferred treatment in the relapsed setting. Choice of therapy in relapsed WM should be individualized by taking several treatment and patients characteristics into account, such as treatment duration, toxicity, age, comorbidities and MYD88^L265P and CXCR4 mutational status. Due to better understanding of WM biology and the arrival of novel anti-lymphoma agents, the therapeutic options are increasing. Non-cytotoxic and fixed duration regimens, such as those explored in other indolent NHLs should be the focus of future clinical trials in WM.

MYD88 L265P Mutation Detection by ddPCR: Recommendations for Screening and Minimal Residual Disease Monitoring : ddPCR for Highly Sensitive Detection of MYD88 L265P Mutation

MYD88^L265P is a gain-of-function mutation, arising from the missense alteration c.794T>C, that frequently occurs in B-cell malignancies such as Waldenstrom macroglobulinemia and less frequently in IgM monoclonal gammopathy of undetermined significance (IgM-MGUS) or other lymphomas. MYD88^L265P has been recognized as a relevant diagnostic flag, but also as a valid prognostic and predictive biomarker, as well as an investigated therapeutic target. Up until now, allele-specific quantitative PCR (ASqPCR) has been widely used for MYD88^L265P detection providing a higher level of sensitivity than Sanger sequencing. However, the recently developed droplet digital PCR (ddPCR) shows a deeper sensitivity, compared to ASqPCR, that is necessary for screening low infiltrated samples. Actually, ddPCR could represent an improvement in daily laboratory practice since it allows mutation detection in unselected tumor cells, allowing to bypass the time-consuming and costly B-cell selection procedure. ddPCR accuracy has been recently proved to be suitable also for mutation detection in "liquid biopsy" samples that might be used as a noninvasive and patient-friendly alternative to bone marrow aspiration especially during the disease monitoring. The relevance of MYD88^L265P, both in daily management of patients and in prospective clinical trials investigating the efficacy of novel agents, makes crucial to find a sensitive, accurate, and reliable molecular technique for mutation detection. Here, we propose a protocol for MYD88^L265P detection by ddPCR.

Orbital Infiltration in a Patient with Waldenström Macroglobulinemia: Need for Multidisciplinary Approach and Comparison with the Literature

The use of specific inhibitory drugs of intracellular signalling pathways (such as Bruton-Kinase inhibitors) for the treatment of Waldenström's macroglobulinaemia (WM) is a recognised risk factor for Aspergillus spp. infections. The overlapping clinical manifestations of the two diseases may require the involvement of different medical specialities. We describe the clinical course of a patient with pulmonary and encephalic aspergillosis, with concomitant orbital infiltration, which represented a difficult diagnosis: the case required a multidisciplinary approach to define the ocular lesions and an in-depth study of the literature.

Managing Waldenström's macroglobulinemia with BTK inhibitors

Bruton's tyrosine kinase (BTK) inhibition is one of the treatment standards for patients with relapsed/refractory Waldenström's macroglobulinemia (WM) and for patients with WM who are unsuitable for immunochemotherapy (ICT). It offers deep and durable responses with a manageable safety profile that is generally favorable compared with ICT regimens. However, the limitations of the first approved BTK inhibitor (BTKi), ibrutinib, include reduced efficacy in patients lacking the characteristic WM mutation (MYD88L265P) and toxicities related to off-target activity. The risk of atrial fibrillation (AF) and other cardiovascular side effects are a notable feature of ibrutinib therapy. Several next-generation covalent BTKis with greater selectivity for BTK are at various stages of development. In November 2021, zanubrutinib became the first of these agents to be approved by the European Medicines Agency for the treatment of WM. Head-to-head trial data indicate that it has comparable efficacy to ibrutinib for patients with WM overall, although it may be more effective in patients with CXCR4 mutations or wild-type MYD88. In the clinical trial setting, its greater selectivity translates into a reduced risk of cardiovascular side effects, including AF. Acalabrutinib, which is pre-approval in WM, appears to offer similar advantages over ibrutinib in terms of its safety profile. Beyond the next-generation covalent BTKis, non-covalent BTKis are an emerging class with the potential to provide a therapeutic option for patients who relapse on covalent BTKis. In the future, BTKis may be increasingly utilized within combination regimens. Several ongoing trials in WM are investigating the potential for BTKi use in combination with established and novel targeted agents.

Ibrutinib as a treatment of hematologic autoimmune disorders in patients with indolent B-cell lymphoma

BACKGROUND

Autoimmune conditions in B-cell lymphomas are frequent. Steroids are standard of care, but many patients require other immunosuppressive agents. Ibrutinib is a Bruton Tyrosine Kinase inhibitor that is approved for B-cell indolent lymphoma treatment. We evaluated the use of ibrutinib in previously treated hematologic immune manifestations associated with B-cell lymphomas.

RESULTS

We conducted a retrospective multicentric observational study. Patients presenting with active, relapsed/refractory B-cell lymphoma associated hematological immune manifestation (autoimmune cytopenia, acquired immune-mediated bleeding disorders) were included. Twenty-five patients were identified. Median age at ibrutinib introduction was 69 years (range 44-84) and median number of previous treatment lines before ibrutinib was 2 (1-7). Twenty-two patients (88%) were on concomitant stable treatment at inclusion. Within a median exposure of 8 months (2-35), overall response rate to ibrutinib on immune manifestations was 76% (95% CI, 54.9-90.6); complete response rate 44%. Fourteen patients (63%) were able to be weaned from concomitant treatments. Fourteen patients (56%) presented treatment-related adverse events, mostly Grade 1 or 2.

CONCLUSIONS

Ibrutinib in this setting provides good efficacy and safety profile. Clinical trials are needed to define subgroups of patients who will benefit from this strategy and establish its place in the therapeutic arsenal.

Polyneuropathy Associated with IgM Monoclonal Gammopathy; Advances in Genetics and Treatment, Focusing on Anti-MAG Antibodies

With increasing age, the chances of developing either MGUS or polyneuropathy increase as well. In some cases, there is a causative relationship between the IgM M-protein and polyneuropathy. In approximately half of these cases, IgM targets the myelin-associated glycoprotein (MAG). This results in chronic polyneuropathy with slowly progressive, predominantly sensory neurological deficits and distally demyelinating features in nerve conduction studies. Despite the disease being chronic and developing slowly, it can cause considerable impairment. We reviewed English medical publications between 1980 and May 2022 on IgM gammopathy-associated polyneuropathy, with special attention to studies addressing the pathophysiology or treatment of anti-MAG polyneuropathy. Treatment options have been limited to a temporizing effect of intravenous immunoglobulins in some patients and a more sustained effect of rituximab but in only 30 to 55 percent of patients. An increase in our knowledge concerning genetic mutations, particularly the MYD88L265P mutation, led to the development of novel targeted treatment options such as BTK inhibitors. Similarly, due to the increasing knowledge of the pathophysiology of anti-MAG polyneuropathy, new treatment options are emerging. Since anti-MAG polyneuropathy is a rare disease with diverse symptomatology, large trials with good outcome measures are a challenge.

A Canadian Perspective on the Treatment of Waldenström Macroglobulinemia

Waldenström macroglobulinemia (WM) is a slowly progressing B-cell non-Hodgkin lymphoma characterized by monoclonal IgM gammopathy in the blood and infiltration of the bone marrow by clonal lymphoplasmacytic cells. As an incurable disease, the goals for therapy for WM are to relieve symptoms, slow disease progression, prevent organ damage, and maintain quality of life. However, given the rarity of WM, clinical trials comparing treatments for WM are limited and there is no definitive standard of care. The selection of first-line WM therapy is thus based on patient factors, disease characteristics, and drug access, with bendamustine-rituximab and Bruton's tyrosine kinase (BTK) inhibitor therapy considered preferred treatments. Other treatments such as proteasome inhibitor- or purine analogue-based therapy, alternative chemoimmunotherapy, and autologous stem cell transplantation are generally reserved for the relapsed setting but may be used in rare circumstances in earlier lines of therapy. This paper summarizes the efficacy and safety of these WM therapies and discusses considerations for treatment from a Canadian perspective.

STAT3 mutations in “gray-zone” cases of T-cell large granular lymphocytic leukemia associated with autoimmune rheumatic diseases

A persistently increased T-cell large granular lymphocyte (T-LGL) count in the blood of more than 2 × 10⁹/L for at least 6 months is necessary for a reliable diagnosis of T-LGL leukemia. In cases with LGL counts of approximately 0.5–2 × 10⁹/L, a diagnosis of T-LGL leukemia can be made if clonal rearrangement of T-cell receptor (TCR) genes is present and if the patient shows typical manifestations of T-LGL leukemia, such as cytopenia, splenomegaly, or concomitant autoimmune disease. However, in cases with LGL counts of less than 0.5 × 10⁹/L, the diagnosis of T-LGL leukemia is questionable (termed as “gray-zone” cases). Although mutations in signal transducer and activator of transcription 3 (STAT3) gene are the molecular hallmark of T-LGL leukemia, their diagnostic value in the “gray-zone” cases of T-LGL leukemia has not been evaluated – our study has been aimed to examine the prevalence of STAT3 mutations in these cases. Herein, we describe 25 patients with autoimmune rheumatic diseases, neutropenia, clonal rearrangement of TCR genes, and circulating LGL count of less than 0.5 × 10⁹/L. Splenomegaly was observed in 19 (76%) patients. Mutations in the STAT3 were detected in 56% of patients using next-generation sequencing. Importantly, in 3 patients, no involvement of the blood and bone marrow by malignant LGLs was noted, but examination of splenic tissue revealed infiltration by clonal cytotoxic T-lymphocytes within the red pulp, with greater prominence in the cords. We suggest using the term “splenic variant of T-LGL leukemia” for such cases.

Targeting CD38 in Neoplasms and Non-Cancer Diseases

Simple Summary

CD38 remains an interesting target for anticancer therapy. Its relatively high abundance in neoplasms and crucial impact on NAD+/cADPR metabolism and the activity of T cells allows for changing the immune response in autoimmune diseases, neoplasms, and finally the induction of cell death. Antibody-dependent cell cytotoxicity is responsible for cell death induced by targeting the tumor with anti-CD38 antibodies, such as daratumumab. A wide range of laboratory experiments and clinical trials show an especially promising role of anti-CD38 therapy against multiple myeloma, NK cell lymphomas, and CD19- B-cell malignancies. More studies are required to include more diseases in the therapeutic protocols involving the modulation of CD38 activity.

Abstract

CD38 is a myeloid antigen present both on the cell membrane and in the intracellular compartment of the cell. Its occurrence is often enhanced in cancer cells, thus making it a potential target in anticancer therapy. Daratumumab and isatuximab already received FDA approval, and novel agents such as MOR202, TAK079 and TNB-738 undergo clinical trials. Also, novel therapeutics such as SAR442085 aim to outrank the older antibodies against CD38. Multiple myeloma and immunoglobulin light-chain amyloidosis may be effectively treated with anti-CD38 immunotherapy. Its role in other hematological malignancies is also important concerning both diagnostic process and potential treatment in the future. Aside from the hematological malignancies, CD38 remains a potential target in gastrointestinal, neurological and pulmonary system disorders. Due to the strong interaction of CD38 with TCR and CD16 on T cells, it may also serve as the biomarker in transplant rejection in renal transplant patients. Besides, CD38 finds its role outside oncology in systemic lupus erythematosus and collagen-induced arthritis. CD38 plays an important role in viral infections, including AIDS and COVID-19. Most of the undergoing clinical trials focus on the use of anti-CD38 antibodies in the therapy of multiple myeloma, CD19- B-cell malignancies, and NK cell lymphomas. This review focuses on targeting CD38 in cancer and non-cancerous diseases using antibodies, cell-based therapies and CD38 inhibitors. We also provide a summary of current clinical trials targeting CD38.

Waldenstrom Macroglobulinemia/Lymphoplasmacytic Lymphoma Associated with Nephrotic Syndrome during Hemodialysis, Treated Successfully with Tirabrutinib

A 74-year-old woman was diagnosed with Waldenstrom macroglobulinemia/lymphoplasmacytic lymphoma (WM/LPL) in X-18. Fludarabine plus rituximab (FR) was started, and she showed remission. In July X-7, the serum creatinine (Cr) level increased to 1.67 mg/dL, and bendamustine plus rituximab (BR) was started. By November X-7, the Cr level had increased to 8.41 mg/dL, so she was started on hemodialysis (HD). In September X-1, she developed nephrotic syndrome. She was started on tirabrutinib at 480 mg. In July X, her nephrotic syndrome had improved, and a complete response (CR) was achieved. This is the first case of the administration of tirabrutinib in a patient undergoing HD.

Bing-Neel Syndrome, a Rare Presentation of Waldenström Macroglobulinemia—A Multicenter Report by the Polish Lymphoma Research Group

Bing-Neel syndrome (BNS) is a rare presentation of Waldenström macroglobulinemia (WM). BNS is a consequence of the central nervous system (CNS) involvement by lymphoplasmacytic lymphoma (LPL) and, rarely, the peripheral nervous system. The data on BNS are extremely scarce. Therefore, we performed a multicenter retrospective analysis of BNS patients diagnosed and treated in centers aligned with the Polish Lymphoma Research Group. The analysis covers the years 2014–2021. Eleven patients were included, 55% females and the median age at BNS diagnosis was 61 years. The median time from WM to BNS was 3.5 years; 27% of patients did have a diagnosis of WM and BNS made simultaneously or within 30 days from each other. Isolated parenchymal involvement was the least frequent (20%). Patients were treated with different regimens, mostly able to cross the blood-brain barrier, including 18% treated with ibrutinib first line. The cumulative objective response to treatment was 73%. With the median follow-up of 20 months (95% CI, 2–32), the 36-month estimates were: overall survival (OS) 47%, progression-free survival (PFS) 33%, and cumulative incidence of BNS-associated death 41%. The performance status according to ECOG was significant for PFS (HR = 7.79) and the hemoglobin concentration below 11 g/dL was correlated with PFS. To conclude, BNS is a very rare manifestation of WM. It is associated with a poor outcome with most patients succumbing to BNS.

Patient preferences regarding treatment options for Waldenström's macroglobulinemia: A discrete choice experiment

INTRODUCTION

Treatment options for Waldenström's Macroglobulinemia (WM) have expanded rapidly in the last decades. However, there is no consensus on a preferred treatment. Therefore, patient preferences become increasingly important in making individualized treatment plans. Still, WM patients' priorities and perspectives regarding their treatment options are unknown. We evaluated treatment preferences of WM patients using a discrete choice experiment (DCE).

METHODS

A mixed-method approach was utilized for identification and selection of attributes/levels. The DCE questionnaire included five attributes: type of agent (targeted versus chemotherapy); frequency and route of administration; 5-year progression-free survival (PFS); adverse events; and risk of secondary malignancies. An orthogonal design and a mixed logit panel data model were used to construct choice tasks and assess patient preferences, respectively.

RESULTS

Three hundred thirty WM patients participated in the project. In total, 214 (65%) complete questionnaires were included for data analysis. The 5-year PFS, followed by risk of secondary malignancies were the most important attributes for making treatment choices. Regarding side effects, patients chose to avoid neuropathy the most compared to nausea/vomiting and extreme fatigue. Patients preferred a fixed-duration treatment with IV/SC administration at the hospital over a continuous daily oral regimen at home.

CONCLUSION

These are the first systematic data obtained on WM patient preferences for treatment. The results may help discussions with individual patients about their treatment choices. Also, these data can help design clinical trials in WM and inform health-care decision-making regarding outcomes that are most relevant to patients.

Dutch Physician's Perspectives on Diagnosis and Treatment of Waldenström's Macroglobulinemia Before and After the Implementation of a National Guideline

Waldenström's macroglobulinemia (WM), a rare low-grade B-cell non-Hodgkin lymphoma (NHL), has a distinct clinical presentation and different treatment-related side effects compared with other NHL. Currently, a wide variety of therapeutic agents are available for the treatment of WM but there is no consensus on optimal treatment in first line and/or at relapse. The aim of this survey was to evaluate the current knowledge and perspectives of hematologists on diagnosis and treatment of WM. Also, we compare these results to a similar survey done before the publication of the first Dutch national guideline, in order to evaluate the impact of the implementation of a national guideline. A link to an online survey was sent out to all registered hematologists and hemato-oncologists in the Netherlands with the request to participate. The survey contained questions regarding the preferred diagnostic and treatment methods in patients with WM as well as treatment goals. We also compared physicians preferred treatment goals to those of patients (as studied in a recent nationwide patient questionnaire). Ninety-five responses (30% response rate) were obtained, out of which 82 (86%) surveys were complete. The respondents most commonly used dexamethasone-rituximab-cyclophosphamide as first-line treatment. For second-line treatment, bendamustine with rituximab and ibrutinib monotherapy were the most frequently applied. Compared with the initial survey, serum IgM M-protein was determined in all cases, MYD88 mutation analysis was currently widely implemented, prevention of an IgM "flare" was uniformly managed by the respondents and use of rituximab-cyclophosphamide-vincristine-prednisone was entirely abandoned. Physicians differed somewhat from patients with regard to most important treatment goals. The approach to diagnostic methods and treatment options in WM was more consistent with international guidelines and was more homogeneous after implementation of the national guideline. These data indicate an increase in knowledge on WM diagnosis and treatment. This may have resulted from implementation of a local guideline or the global rise in awareness and attention for WM.

Health economic evidence for the use of molecular biomarker tests in hematological malignancies: A systematic review

Objectives

Molecular biomarker tests can inform the clinical management of genomic heterogeneous hematological malignancies, yet their availability in routine care largely depends on the supporting health economic evidence. This study aims to systematically review the economic evidence for recent molecular biomarker tests in hematological malignancies.

Methods

We conducted a systematic search in five electronic databases for studies published between January 2010 and October 2020. Publications were independently screened by two reviewers. Clinical study characteristics, economic methodology, and results were extracted, and reporting quality was assessed.

Results

Fourteen studies were identified, of which half (n = 7; 50%) were full economic evaluations examining both health and economic outcomes. Studies were predominantly conducted in a first‐line treatment setting (n = 7; 50%) and adopted a non‐lifetime time horizon to measure health outcomes and costs (n = 7; 50%). Five studies reported that companion diagnostics for associated therapies were likely cost‐effective for acute myeloid leukemia, chronic myeloid leukemia, diffuse large B‐cell lymphoma, and multiple myeloma. Four studies suggested molecular biomarker tests for treatment monitoring in chronic myeloid leukemia were likely cost‐saving.

Conclusions

Although there is initial confirmation of the promising health economic results, the present research for molecular biomarker tests in hematological malignancies is sparse with many applications of technological advances yet to be evaluated.

An Extended Prognostic Index of the ISSWM Score Based on Thyroid Complications in Waldenström Macroglobulinemia/Lymphoplasmacytoid Lymphoma

Waldenström macroglobulinemia/lymphoplasmacytoid lymphoma (WM/LPL) is a rare lymphoproliferative neoplasm characterized by clonally related lymphocytes, lymphoplasmacytic cells, and plasma cell proliferation. WM/LPL patients commonly present with elevated immunoglobulin, predominantly immunoglobulin M (IgM). Previous studies reported that thyroid dysfunction was associated with the development and progression of solid tumors. However, only limited information is available on the correlation between thyroid complications and lymphoid malignancies. The aim of our study was to explore the prognostic significance of thyroid complications in WM/LPL. Herein, 13.3% of WM/LPL patients were diagnosed with thyroid complications, which were significantly associated with unfavorable progression-free survival (PFS), overall survival (OS), and adverse treatment response. Co-existing thyroid disease was significantly related to alleviated serum IgM levels, providing an answer to practical problems. Furthermore, the presence of thyroid complications was identified as an independent prognostic indicator for PFS in WM/LPL. Incorporating the ISSWM score with thyroid complications was superior to ISSWM alone in risk stratification and prognostic prediction. Furthermore, subgroup analyses of WM/LPL patients revealed that subclinical hypothyroidism predicted undesirable outcomes at the early stage. These results were also supported by independent microarray dataset analyses. In conclusion, the primary strength of this study is that it provides robust real-world evidence on the prognostic role of thyroid complications, highlighting further clinical concerns in the management of WM/LPL patients.

How I manage autoimmune cytopenias in patients with lymphoid cancer

Autoimmune conditions can occur in a temporary relationship with any malignant lymphoma. In many instances, treatment at diagnosis is not required, but symptomatic autoimmune conditions represent an indication for treatment, particularly in chronic lymphoproliferative diseases. Treatment is selected depending on the predominant condition: autoimmune disease (immunosuppression) or lymphoma (antilymphoma therapy). Steroids and anti-CD20 antibodies are effective against both conditions and may suppress the autoimmune complication for a prolonged period. The efficacy of B-cell receptor inhibitors has provided us with novel insights into the pathophysiology of antibody-producing B cells. Screening for underlying autoimmune conditions is part of the lymphoma workup, because other drugs, such as immunomodulators and checkpoint inhibitors, should be avoided or used with caution. In this article, we discuss diagnostic challenges and treatment approaches for different situations involving lymphomas and autoimmune cytopenias.

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.

Preneoplastic somatic mutations including MYD88L265P in lymphoplasmacytic lymphoma

Normal cell counterparts of solid and myeloid tumors accumulate mutations years before disease onset; whether this occurs in B lymphocytes before lymphoma remains uncertain. We sequenced multiple stages of the B lineage in elderly individuals and patients with lymphoplasmacytic lymphoma, a singular disease for studying lymphomagenesis because of the high prevalence of mutated MYD88. We observed similar accumulation of random mutations in B lineages from both cohorts and unexpectedly found MYD88^L265P in normal precursor and mature B lymphocytes from patients with lymphoma. We uncovered genetic and transcriptional pathways driving malignant transformation and leveraged these to model lymphoplasmacytic lymphoma in mice, based on mutated MYD88 in B cell precursors and BCL2 overexpression. Thus, MYD88^L265P is a preneoplastic event, which challenges the current understanding of lymphomagenesis and may have implications for early detection of B cell lymphomas.

A phase-II study of atezolizumab in combination with obinutuzumab or rituximab for relapsed or refractory mantle cell or marginal zone lymphoma or Waldenström's macroglobulinemia

We report efficacy, safety and biomarker data from a phase-II study evaluating atezolizumab (eight 21-day cycle as induction therapy) in combination with obinutuzumab in patients with relapsed/refractory mantle cell lymphoma (MCL, n = 30) or Waldenström's macroglobulinemia (WM, n = 4), and in combination with rituximab in patients with marginal zone lymphoma (MZL, n = 21). All patients received atezolizumab monotherapy as maintenance for ≤10 cycles. Objective response rates at end of induction were 16.7% (MCL) and 42.9% (MZL), with no responses in WM. Median duration of response was 6.8 months (range 5.7-not estimable) for MCL and not reached for MZL. Treatment-emergent adverse events (TEAEs) occurred in 93.3%, 95.2% and 100% of MCL, MZL and WM patients, respectively. One fatal TEAE (pneumonia) occurred in each of the MCL and MZL groups. Biomarker analysis highlighted the importance of characterizing the immune environment to optimize efficacy of immunotherapy regimens.Trial registration details: EudraCT: 2016-003579-22.

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

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

Bruton tyrosine kinase inhibitors for Waldenström macroglobulinemia: A review

OBJECTIVE

The objective of this review is to evaluate the available evidence for the Bruton tyrosine kinase inhibitors in the treatment of Waldenström macroglobulinemia.

DATA SOURCES

A search of the PubMed database was conducted using the following search terms: ibrutinib, PCI-32765, acalabrutinib, ACP-196, zanubrutinib, BGB-3111, and Waldenström macroglobulinemia. Prospective clinical trials evaluating the efficacy and safety of ibrutinib, acalabrutinib, and zanubrutinib in patients with Waldenström macroglobulinemia were evaluated. Abstracts from the American Society of Hematology and American Society of Clinical Oncology annual meetings were reviewed as well as the prescribing information for each drug.

DATA SUMMARY

The first-generation Bruton tyrosine kinase inhibitor ibrutinib received Food and Drug Administration approval for Waldenström macroglobulinemia in 2015; this was the first drug approved for this rare condition. Ibrutinib has been evaluated as monotherapy and in combination with rituximab for the treatment of Waldenström macroglobulinemia. Since then, second-generation Bruton tyrosine kinase inhibitors, acalabrutinib and zanubrutinib, have been evaluated in prospective clinical trials for the treatment of Waldenström macroglobulinemia. All three agents have demonstrated high overall response rates and durable responses.

CONCLUSION

Bruton tyrosine kinase inhibitors have demonstrated significant clinical activity in the treatment of Waldenström macroglobulinemia, both in treatment naïve as well as the relapsed/refractory patient populations.

How to Sequence Therapies in Waldenström Macroglobulinemia

OPINION STATEMENT

There are multiple treatment options in patients with Waldenström macroglobulinemia, including chemotherapy, monoclonal antibodies, proteasome inhibitors, and covalent Bruton tyrosine kinase (BTK) inhibitors. The choice of therapy should take into account the patient's clinical presentation, comorbidities, and preferences. A thorough discussion should take place to outline the administration, safety, and efficacy of the regimens under consideration. The patient's genomic profile can provide insightful information for the treatment selection. In the frontline and relapsed settings, we favor ibrutinib monotherapy over chemoimmunotherapy or proteasome inhibitor-based regimens in patients with MYD88 and without CXCR4 mutations. For patients with MYD88 and CXCR4 mutations or without MYD88 or CXCR4 mutations, chemoimmunotherapy or proteasome inhibitor-based regimens are favored, but efficacy data with ibrutinib in combination with rituximab and with novel covalent BTK inhibitors are emerging. Autologous stem cell transplant should be considered in special cases in the relapsed setting. Participation in clinical trials is positively encouraged in WM patients in frontline and relapsed settings. Agents of interest include the BCL2 antagonist venetoclax, the CXCR4 inhibitor mavorixafor, and the non-covalent BTK inhibitors pirtobrutinib and ARQ-531.

Efficacy and safety assessment of prolonged maintenance with subcutaneous rituximab in patients with relapsed or refractory indolent non-Hodgkin lymphoma: results of the Phase III MabCute study

Rituximab plus chemotherapy induction followed by rituximab maintenance for up to 2 years confers a long-term benefit in terms of progression-free survival in patients with indolent non-Hodgkin lymphoma. It is not known whether further prolonged maintenance with rituximab provides additional benefit. The phase III MabCute study enrolled 692 patients with relapsed or refractory indolent non-Hodgkin lymphoma. Patients who responded to induction with rituximab plus chemotherapy and were still responding after up to 2 years’ initial maintenance with subcutaneous rituximab were randomized to extended maintenance with subcutaneous rituximab (n=138) or observation only (n=138). The primary endpoint of investigator-assessed progression-free survival in the randomized population was un-addressed by the end of study because of an insufficient number of events (129 events were needed for 80% power at 5% significance if approximately 330 patients were randomized). In total, there were 46 progression-free survival events, 19 and 27 in the rituximab and observation arms, respectively (P=0.410 by stratified log-rank test; hazard ratio 0.76 [95% confidence interval: 0.37– 1.53]). The median progression-free survival was not reached in either randomized arm. There were no new safety signals; however, adverse events were seen slightly more frequently with rituximab than with observation during extended maintenance. Maintenance for up to 2 years with rituximab after response to initial induction therefore remains the standard of care in patients with relapsed or refractory indolent non- Hodgkin lymphoma. (Clinicaltrials.gov identifier: NCT01461928)

Obinutuzumab and idelalisib in symptomatic patients with relapsed/refractory Waldenström macroglobulinemia

We present the results of a phase 2 study evaluating the combination of obinutuzumab + idelalisib in relapsed/refractory (R/R) Waldenström macroglobulinemia (WM). The goal was to determine the safety and efficacy of a fixed-duration chemotherapy-free treatment. During the induction phase, patients received idelalisib + obinutuzumab for 6 cycles, followed by a maintenance phase with idelalisib alone for ≤2 years. Forty-eight patients with R/R WM were treated with the induction combination, and 27 patients participated in the maintenance phase. The best responses, reached after a median of 6.5 months (interquartile range, 3.4-7.1; range, 2.6-22.1 months), were very good partial response in 5 patients, partial response in 27 patients, and minor response in 3 patients, leading to overall response rate and major response rate estimates of 71.4% (95% confidence interval [CI], 56.7-83.4) and 65.3% (95% CI, 50.4-78.3), respectively. With a median follow-up of 25.9 months, median progression-free survival was 25.4 months (95% CI, 15.7-29.0). Univariate analysis focusing on molecular screening found no significant impact of CXCR4 genotypes on responses and survivals but a deleterious impact of TP53 mutations on survival. Although there was no grade 5 toxicity, 26 patients were removed from the study because of side effects; the most frequent were neutropenia (9.4%), diarrhea (8.6%), and liver toxicity (9.3%). The combination of idelalisib + obinutuzumab is effective in R/R WM. Nonetheless, the apparent lack of impact of genotype on outcome could give new meaning to targeting of the phosphatidylinositol 3-kinase pathway in WM. This trial was registered at www.clinicaltrials.gov as #NCT02962401.

MYD88L265P Detection in IgM Monoclonal Gammopathies: Methodological Considerations for Routine Implementation

In IgM monoclonal gammopathies MYD88^L265P is a prognostic and predictive biomarker of therapy response. MYD88^L265P detection is mainly performed by allele-specific quantitative PCR (ASqPCR), however recently, droplet digital PCR (ddPCR) has been proved to be suitable for MYD88^L265P screening and minimal residual disease monitoring (MRD). This study compared ASqPCR and ddPCR to define the most sensitive method for MYD88^L265P detection in bone marrow (BM), peripheral blood (PB) sorted or unsorted CD19+ cells, and in plasma cell-free DNA (cfDNA). Overall, the analysis showed a good concordance rate (74%) between the two methods, especially in BM samples, while discordances (26%) were mostly in favor of ddPCR (ddPCR+ vs. ASqPCR-) and were particularly evident in samples with low mutational burden, such as PB and cfDNA. This study highlights ddPCR as a feasible approach for MYD88^L265P detection across different specimen types (including cfDNA). Interestingly, its high sensitivity makes CD19+ selection dispensable. On the other hand, our results showed that MYD88^L265P detection on PB samples, especially with ASqPCR, is suboptimal for screening and MRD analysis. Finally, significantly different MYD88^L265P mutational levels observed between Waldenström Macroglobulinemia and IgM monoclonal gammopathy of undetermined significance patients suggest the need for further studies in order to identify possible correlations between mutational levels and risk of progression to Waldenström.

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

Simple Summary

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

Abstract

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

Clinical application of genomics in Waldenström macroglobulinemia

Waldenström Macroglobulinemia (WM) is an incurable hematologic malignancy characterized by lymphoplasmacytic infiltration of the bone marrow and the presence of monoclonal immunoglobulin (IgM). Although a portion of WM patients may experience a relatively indolent course, patients may experience IgM-related morbidity and/or disease-related mortality. This underscores the need for novel approaches to improve response and survival rates. Significant progress had been made in our understanding of the genomics and biology of WM. The discovery of the highly recurrent somatic mutations in the MYD88 gene detected in 90-95% and the CXCR4 gene detected in 30-40% of WM patients has provided an opportunity to develop novel targeted approaches. Mutational status has important implications in predicting response to therapies such as BTK inhibitors. Treatment of WM should be guided by many factors including performance status, comorbidities, goals of therapy, and toxicities. In this review, we describe how current genomics may be utilized to optimize WM treatment selection. As the therapeutic landscape of WM continues to expand with more targeted approaches, the genomics in WM will likely play a greater role in individualizing treatment.

At the Bedside: Profiling and treating patients with CXCR4-expressing cancers

The chemokine receptor, C-X-C chemokine receptor type 4 (CXCR4) and its ligand, C-X-C motif chemokine 12, are key mediators of hematopoietic cell trafficking. Their roles in the proliferation and metastasis of tumor cells, induction of angiogenesis, and invasive tumor growth have been recognized for over 2 decades. CXCR4 is a promising target for imaging and therapy of both hematologic and solid tumors. To date, Sanofi Genzyme's plerixafor is the only marketed CXCR4 inhibitor (i.e., Food and Drug Administration-approved in 2008 for stem cell mobilization). However, several new CXCR4 inhibitors are now being investigated as potential therapies for a variety of fluid and solid tumors. These small molecules, peptides, and Abs include balixafortide (POL6326, Polyphor), mavorixafor (X4P-001, X4 Pharmaceuticals), motixafortide (BL-8040, BioLineRx), LY2510924 (Eli Lilly), and ulocuplumab (Bristol-Myers Squibb). Early clinical evidence has been encouraging, for example, with motixafortide and balixafortide, and the CXCR4 inhibitors appear to be generally safe and well tolerated. Molecular imaging is increasingly being used for effective patient selection before, or early during CXCR4 inhibitor treatment. The use of radiolabeled theranostics that combine diagnostics and therapeutics is an additional intriguing approach. The current status and future directions for radioimaging and treating patients with CXCR4-expressing hematologic and solid malignancies are reviewed. See related review - At the Bench: Pre-Clinical Evidence for Multiple Functions of CXCR4 in Cancer. J. Leukoc. Biol. xx: xx-xx; 2020.

Immunoglobulin M (IgM) multiple myeloma versus Waldenström macroglobulinemia: diagnostic challenges and therapeutic options: two case reports

Background

Immunoglobulin M multiple myeloma and Waldenström macroglobulinemia are two different hematological diseases with the common finding of an immunoglobulin M monoclonal gammopathy of unknown significance. However, clinical characteristics of the two entities can overlap.

Case presentation

In this report, we describe two cases of immunoglobulin M neoplasm with the same histological bone marrow presentation but with different clinical behavior, cytogenetics, and biological assessment. On the basis of comprehensive diagnostic workup, these patients were considered to have different diseases and treated accordingly with different approaches. Patient 1 (Caucasian man) presented with increased serum protein and immunoglobulin M (7665 mg/L) with an M-spike electrophoresis of 4600 mg/L. His bone marrow biopsy revealed a small-cell immunoglobulin M multiple myeloma. The result of testing for the MYD88 L265P mutation was negative, while fluorescence in situ hybridization analysis showed translocation t(11,14). A diagnosis of immunoglobulin M-κ multiple myeloma was made. Patient 1 was a candidate for bortezomib plus thalidomide and dexamethasone, followed by autologous stem cell transplant consolidation. Patient 2 (Caucasian man) showed an M-spike by protein electrophoresis (300 mg/L, 4.9%), with serum immunoglobulin M level of 327 mg/L. His bone marrow biopsy revealed immunoglobulin M-κ multiple myeloma. Computed tomography showed many enlarged lymph nodes and splenomegaly. Patient 2’s clinical features were suggestive of Waldenström macroglobulinemia, in contrast to the bone marrow biopsy results. The result of testing for the MYD88 L265P mutation was positive. Patient 2 was diagnosed with Waldenström macroglobulinemia and received rituximab, cyclophosphamide, and dexamethasone.

Conclusions

A correct differential diagnosis between immunoglobulin M multiple myeloma and Waldenström macroglobulinemia is a critical point in the setting of a new immunoglobulin M monoclonal gammopathy onset. These patients should undergo a complete diagnostic workup with pathological, radiological, and serological examinations to establish the diagnosis and plan the most appropriate treatment in order to improve the prognosis.