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

Six-year follow-up of phase II study exploring chemo-free treatment association with idelalisib and obinutuzumab in symptomatic relapsed/ refractory patients with Waldenström's macroglobulinemia

We present the 6-year update of a phase 2 study evaluating the combination of obinutuzumab and idelalisib in relapse/refractory Waldenstrom macroglobulinemia. The results of the REMODEL trial demonstrated interesting efficacy in a high-risk genotype profile population. The primary endpoint was achieved with a median PFS of 25.4 months (95% CI, 15.7 to 29.0). However, a major limitation of idelalisib is its toxicity. With a median follow-up of 70.9 months, median OS was still not reached, and 5-year OS was 72.9% (95% CI, 61.3 to 86.6). We confirm that CXCR4 mutations had no impact on PFS or OS. However, TP53 mutated patients had shorter OS. At the time of analysis, six patients are alive without relapse and 40 had progressive disease. Among the 38 patients who received a new treatment, the median time to second progression was not reached in ibrutinib treated patients (n = 17) versus 30.8 months in patients treated with other options (95% CI, 16.9 to NA), p = 0.005. With longer follow-up our prospective study is the first to show an impact of TP53 mutations in patients treated with fixed duration chemo-free regimen leading to a significant shorter OS in this population. Moreover, ibrutinib remains an effective treatment after this combination. This study was registered on the clinicaltrial.gov web (NCT02962401, November 9, 2016).

Novel Approaches to Managing Patients with Relapsed and Refractory Waldenström Macroglobulinemia

PURPOSE OF REVIEW

Waldenström macroglobulinemia is a rare non-Hodgkin lymphoma (NHL) characterized by lymphoplasmacytic bone marrow infiltration associated with an immunoglobulin M (IgM) monoclonal gammopathy. Over the past two decades, a number of important novel therapies have emerged for the treatment of relapsed and refractory (R/R) WM. The purpose of this review is to discuss these novel agents.

RECENT FINDINGS

Chemoimmunotherapy which formed the basis treatment for R/R WM is slowly being replaced by novel targeted agents. These therapies, including Bruton's tyrosine kinase inhibitors, proteasome inhibitors, and B-cell lymphoma 2 inhibitors, have widened the landscape of management. Emerging therapies currently under investigation, such as bispecific T-cell engagers, chimeric antigen T-cell receptor therapy, and novel small molecule inhibitors, have additionally shown the potential to improve response and survival. The treatment of R/R WM has greatly evolved, in large part due to a greater understanding of the biology of WM, and the evaluation of novel targeted agents in the basket trials of NHL, showing early activity in the small WM cohorts. Combination regimens with these established and emerging novel therapies have the potential to further improve disease control and induce higher rates of deep responses. Strategies aimed at altering the disease trajectory would require randomized controlled trials to provide relevant data on optimal integration and sequencing of more effective and tolerable regimens earlier in the disease course.

MicroRNA and long non-coding RNA analysis in IgM-monoclonal gammopathies reveals epigenetic influence on cellular functions and oncogenesis

Not available.

Development and Clinical Applications of PI3K/AKT/mTOR Pathway Inhibitors as a Therapeutic Option for Leukemias

Leukemias are hematological neoplasms characterized by dysregulations in several cellular signaling pathways, prominently including the PI3K/AKT/mTOR pathway. Since this pathway is associated with several important cellular mechanisms, such as proliferation, metabolism, survival, and cell death, its hyperactivation significantly contributes to the development of leukemias. In addition, it is a crucial prognostic factor, often correlated with therapeutic resistance. Changes in the PI3K/AKT/mTOR pathway are identified in more than 50% of cases of acute leukemia, especially in myeloid lineages. Furthermore, these changes are highly frequent in cases of chronic lymphocytic leukemia, especially those with a B cell phenotype, due to the correlation between the hyperactivation of B cell receptors and the abnormal activation of PI3Kδ. Thus, the search for new therapies that inhibit the activity of the PI3K/AKT/mTOR pathway has become the objective of several clinical studies that aim to replace conventional oncological treatments that have high rates of toxicities and low specificity with target-specific therapies offering improved patient quality of life. In this review we describe the PI3K/AKT/mTOR signal transduction pathway and its implications in leukemogenesis. Furthermore, we provide an overview of clinical trials that employed PI3K/AKT/mTOR inhibitors either as monotherapy or in combination with other cytotoxic agents for treating patients with various types of leukemias. The varying degrees of treatment efficacy are also reported.

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.

PI3K/AKT/mTOR signaling transduction pathway and targeted therapies in cancer

The PI3K/AKT/mTOR (PAM) signaling pathway is a highly conserved signal transduction network in eukaryotic cells that promotes cell survival, cell growth, and cell cycle progression. Growth factor signalling to transcription factors in the PAM axis is highly regulated by multiple cross-interactions with several other signaling pathways, and dysregulation of signal transduction can predispose to cancer development. The PAM axis is the most frequently activated signaling pathway in human cancer and is often implicated in resistance to anticancer therapies. Dysfunction of components of this pathway such as hyperactivity of PI3K, loss of function of PTEN, and gain-of-function of AKT, are notorious drivers of treatment resistance and disease progression in cancer. In this review we highlight the major dysregulations in the PAM signaling pathway in cancer, and discuss the results of PI3K, AKT and mTOR inhibitors as monotherapy and in co-administation with other antineoplastic agents in clinical trials as a strategy for overcoming treatment resistance. Finally, the major mechanisms of resistance to PAM signaling targeted therapies, including PAM signaling in immunology and immunotherapies are also discussed.

The Management of Relapsed or Refractory Waldenström's Macroglobulinemia

Waldenström's macroglobulinemia (WM) is an immunoglobulin M monoclonal gammopathy produced by a bone marrow lymphoplasmacytic lymphoma, an indolent non-Hodgkin lymphoma in which the cure is still an unmet challenge. Combinations with alkylating agents, purine analogs, and monoclonal antibodies, Bruton tyrosine kinase, and proteasome inhibitors are used for the treatment of relapsed and refractory patients. Moreover, new additional agents can be seen on the horizon as potential effective therapies. No consensus on a preferred treatment in the relapsed setting is available yet.

Clinical Implications of Genomic Profile in Waldenström Macroglobulinemia

With the increasing availability of sequencing techniques and new polymerase chain reaction-based methods, data regarding the genomic profile of Waldenström macroglobulinemia (WM) are being continuously analyzed and reproduced. MYD88 and CXCR4 mutations are highly prevalent in all the stages of WM, including the early IgM monoclonal gammopathy of undetermined significance or a more advanced stage, such as smoldering WM. Thus, there is a need to define genotypes before starting either standard treatment regimens or clinical trials. Here, we review the genomic profile of WM and its clinical implications while focusing on recent advances.

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.

Development and safety of PI3K inhibitors in cancer

The phosphatidylinositol 3-kinase (PI3K) signalling pathway regulates cell survival, proliferation, migration, metabolism and other vital cellular life processes. In addition, activation of the PI3K signalling pathway is important for cancer development. As a result, a variety of PI3K inhibitors have been clinically developed to treat malignancies. Although several PI3K inhibitors have received approval from the Food and Drug Administration (FDA) for significant antitumour activity, frequent and severe adverse effects have greatly limited their clinical application. These toxicities are mostly on-target and immune-mediated; nevertheless, the underlying mechanisms are still unclear. Current management usually involves intervention through symptomatic treatment, with discontinuation if toxicity persists. Therefore, it is necessary to comprehensively understand these adverse events and ensure the clinical safety application of PI3K inhibitors by establishing the most effective management guidelines, appropriate intermittent dosing regimens and new combination administration. Here, the focus is on the development of PI3K inhibitors in cancer therapy, with particular emphasis on isoform-specific PI3K inhibitors. The most common adverse effects of PI3K inhibitors are also covered, as well as potential mechanisms and management approaches.

Report of consensus Panel 4 from the 11th International Workshop on Waldenstrom's macroglobulinemia on diagnostic and response criteria

Consensus Panel 4 (CP4) of the 11th International Workshop on Waldenstrom's Macroglobulinemia (IWWM-11) was tasked with reviewing the current criteria for diagnosis and response assessment. Since the initial consensus reports of the 2nd International Workshop, there have been updates in the understanding of the mutational landscape of IgM related diseases, including the discovery and prevalence of MYD88 and CXCR4 mutations; an improved recognition of disease related morbidities attributed to monoclonal IgM and tumor infiltration; and a better understanding of response assessment based on multiple, prospective trials that have evaluated diverse agents in Waldenstrom's macroglobulinemia. The key recommendations from IWWM-11 CP4 included: (1) reaffirmation of IWWM-2 consensus panel recommendations that arbitrary values for laboratory parameters such as minimal IgM level or bone marrow infiltration should not be used to distinguish Waldenstrom's macroglobulinemia from IgM MGUS; (2) delineation of IgM MGUS into 2 subclasses including a subtype characterized by clonal plasma cells and MYD88 wild-type, and the other by presence of monotypic or monoclonal B cells which may carry the MYD88 mutation; and (3) recognition of "simplified" response assessments that use serum IgM only for determining partial and very good partial responses (simplified IWWM-6/new IWWM-11 response criteria). Guidance on response determination for suspected IgM flare and IgM rebound related to treatment, as well as extramedullary disease assessment was also updated and included in this report.

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.

Prognostic impact of MYD88 and CXCR4 mutations assessed by droplet digital polymerase chain reaction in IgM monoclonal gammopathy of undetermined significance and smouldering Waldenström macroglobulinaemia

Waldenström macroglobulinaemia (WM) is characterized by recurrent somatic mutations in MYD88 and CXCR4 genes. However, limitations arise when analysing these mutations in IgM monoclonal gammopathy of undetermined significance (MGUS) or smouldering WM (SWM) given the lower tumour load. Here, we used droplet digital polymerase chain reaction (ddPCR) to analyse MYD88 L265P and CXCR4 S338* mutations (C1013G and C1013A) in unsorted bone marrow (BM) or cell-free DNA (cfDNA) samples from 101 IgM MGUS and 69 SWM patients. ddPCR was more sensitive to assess MYD88 L265P compared to allele-specific PCR, especially in IgM MGUS (64% vs 39%). MYD88 mutation burden correlated with other laboratory biomarkers, particularly BM infiltration (r = 0.8; p < 0.001). CXCR4 C1013G was analysed in MYD88-mutated samples with available genomic DNA and was detected in 19/54 (35%) and 18/42 (43%) IgM MGUS and SWM cases respectively, also showing correlation with BM involvement (r = 0.9; p < 0.001). ddPCR also detected 8 (38%) and 10 (63%) MYD88-mutated cfDNA samples in IgM MGUS and SWM respectively. Moreover, high BM mutation burden (≥8% MYD88 and ≥2% CXCR4) was associated with an increased risk of progression to symptomatic WM. We show the clinical applicability of ddPCR to assess MYD88 and CXCR4 in IgM MGUS and SWM and provide a molecular-based risk classification.

[Waldenström disease: News and perspectives in 2022]

Waldenström's disease is a B-cell neoplasm characterized by the accumulation of lymphoplasmacytic cells (LPCs) in the bone marrow, and more rarely in the lymph nodes and the spleen, which produce a monoclonal immunoglobulin M (IgM) protein. The diagnosis requires the identification of LPCs in the bone marrow, using specific markers in flow cytometry. The MYD88L265P mutation is found in 95% of cases and the CXCR4 mutation in 30-40% of cases. These markers must be sought because they have a diagnostic and prognostic role, and they might become predictive in the future. The clinical presentation is very variable, and includes anomalies related to the bone marrow infiltration of the LPCs (such as anemia), but also anomalies of the physico-chemical and/or immunological activity of the overproduced IgM (hyperviscosity, AL amyloidosis, cryoglobulinemia, anti-MAG neuropathies, etc.). Prognostic scores (IPSSWM) now make it possible to understand the prognosis of symptomatic WM requiring appropriate treatment. The therapeutic management depends on many parameters, such as the specific clinical presentation, the speed of evolution and of course the age and comorbidities. Immuno-chemotherapy is often the 1st line treatment (rituximab-cyclophosphamide-dexamethasone (RCD) or bendamustine-rituximab (BR)) but the role of targeted therapies is becoming preponderant. Bruton tyrosine kinase inhibitors (BTKi) are used today in first relapse. Other therapeutic perspectives will certainly allow us tomorrow to better understand this incurable chronic disease, such as new generations of BTKi, BCL2 inhibitors, anti-CXCR4, bi-specific antibodies, and CAR-T cells.

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.

SOHO State of the Art Updates and Next Questions: Targeted therapies and emerging novel treatment approaches for Waldenström Macroglobulinemia

Waldenström Macroglobulinemia (WM) is a rare hematologic malignancy characterized by the presence of lymphoplasmacytic lymphoma cells involving the bone marrow and production of a monoclonal IgM paraprotein. Recurrent somatic mutations in MYD88^L265P and CXCR4 have been reported in 90% to 95% and 30% to 40% of patients with WM, respectively. Standard treatment regimens combine the anti-CD20 antibody rituximab with alkylating agents (eg, bendamustine, cyclophosphamide), nucleoside analogs (eg, fludarabine, cladribine), or proteasome inhibitors (eg, bortezomib, carfilzomib, and ixazomib). Covalent BTK inhibitors (eg, ibrutinib, acalabrutinib, zanubrutinib) have shown to be safe and highly effective in patients with WM. Novel and promising agents in this disease include next-generation covalent BTK inhibitors (eg, tirabrutinib, orelabrutinib), non-covalent BTK inhibitors (eg, pirtobrutinib, ARQ531), BCL-2 antagonists (eg, venetoclax), and CXCR4-targeted agents (eg, mavorixafor, ulocuplumab), among others. Future studies will focus on developing fixed-duration combinations regimens with these novel agents aimed at increasing durable responses while minimizing toxicity and cost.

Identification of CXCR4 Upregulation in Diffuse Large B-Cell Lymphoma Associated with Prognostic Significance and Clinicopathological Characteristics

Background

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous malignant lymphoma with distinct characteristics. Patients with treatment failure after the standard immunochemotherapy have worse prognosis, which implies the necessity to uncover novel targets. The C-X-C chemokine receptor 4 (CXCR4) overexpression has been identified in several hematopoietic malignancies. However, the expression signatures and prognostic significance of CXCR4 in DLBCL associated with clinicopathological features remain unclear.

Methods

Gene expression profiles of DLBCL were obtained from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Then, a meta-analysis with an integrated bioinformatic analysis was performed to assess the relationship between CXCR4 expression and clinicopathological features of DLBCL. Finally, experimental verification including immunohistochemical (IHC) staining and real-time quantitative PCR (qPCR) was carried out using patient samples. In vitro cell line viability tests were conducted using CXCR4 inhibitor WZ811.

Results

DLBCL patients with activated B-cell-like (ABC) subtype have higher expression level of CXCR4 with worse survival. Differential expressed genes in the CXCR4-upregulation group were enriched in canonical pathways associated with oncogenesis. DLBCL with CXCR4 upregulation had lower degree of CD8⁺ T cell infiltration. TIMER analysis demonstrated that the CXCR4 expression was positively correlated with the expression of CD5, MYC, NOTCH1, PDCD1, CD274, mTOR, FOXO1, and hnRNPA2B1 in DLBCL. IHC study in patient samples showed the positive correlation between CXCR4 and nongerminal center B-cell (non-GCB) subtype and mTOR expression. Meanwhile, quantitative polymerase chain reaction results revealed that high CXCR4 mRNA level was correlated to double-hit DLBCL. Finally, cell viability test showed that WZ811 exerted antiproliferation effect in DLBCL cell lines in a dose-dependent manner.

Conclusion

CXCR4 was upregulated in ABC-DLBCL associated with worse prognosis. Our analysis predicted CXCR4 as a potential target for DLBCL treatment, which may serve as an inhibitor both on BCR signaling and nuclear export warranting further investigation in clinical trials.

Treatment paradigm in Waldenström macroglobulinemia: frontline therapy and beyond

Waldenström macroglobulinemia (WM) is an indolent lymphoplasmacytic lymphoma. Recent strides made in the genomic profiling of patients with WM have led to the identification of many novel therapeutic targets. Patients with WM can present with asymptomatic disease and not all patients require treatment. When criteria for initiating systemic therapy are met, the choice of therapy depends on the tumor genotype (MYD88 and CXCR4 mutation status), patient preference (fixed versus continuous duration therapy, oral versus intravenous route, cost), associated medical comorbidities, and adverse effect profile of the treatment. In the absence of head-to-head comparison between chemoimmunotherapy and Bruton’s tyrosine kinase inhibitors in otherwise fit patients with a MYD88^L265P mutation, our preference is fixed duration therapy with four to six cycles of chemoimmunotherapy with bendamustine–rituximab. In this review, we discuss the role of MYD88 and CXCR4 mutation in treatment selection, and current data for frontline and salvage treatment options in patients with WM.

Targeted Agents in the Treatment of Indolent B-Cell Non-Hodgkin Lymphomas

Targeted therapies continue to change the landscape of lymphoma treatment, resulting in improved therapy options and patient outcomes. Numerous agents are now approved for use in the indolent lymphomas and many others under development demonstrate significant promise. In this article, we review the landscape of targeted agents that apply to the indolent lymphomas, predominantly follicular lymphoma, lymphoplasmacytic lymphoma/Waldenstrom macroglobulinaemia and marginal zone lymphoma. The review covers small molecule inhibitors, immunomodulators and targeted immunotherapies, as well as presenting emerging and promising combination therapies.

Cytogenetic and molecular abnormalities in Waldenström's macroglobulinemia patients: Correlations and prognostic impact

While Waldenström macroglobulinemia (WM) is characterized by an almost unifying mutation in MYD88, clinical presentation at diagnosis and response to therapy can be widely different among WM patients. Current prognostic tools only partially address this clinical heterogeneity. Limited data compiling both molecular and cytogenetic information have been used in risk prognostication in WM. To investigate the clinical impact of genetic alterations in WM, we evaluated cytogenetic and molecular abnormalities by chromosome banding analyses, FISH and targeted NGS in a retrospective cohort of 239 WM patients, including 187 patients treated by first-line chemotherapy or immunochemotherapy. Most frequent mutations were identified in MYD88 (93%), CXCR4 (29%), MLL2 (11%), ARID1A (8%), TP53 (8%), CD79A/B (6%), TBL1XR1 (4%) and SPI1 (4%). The median number of cytogenetic abnormalities was two (range, 0-22). Main cytogenetic abnormalities were 6q deletion (del6q) (27%), trisomy 4 (tri4) (12%), tri18 (11%), del13q (11%), tri12 (7.5%) and del17p (7%). Complex karyotype (CK) was observed in 15% (n = 31) of cases, including 5% (n = 12) of highly CK (high-CK). TP53 abnormalities (TP53abn) were present in 15% of evaluable patients. TP53abn and del6q were associated with CK/high-CK (p < .05). Fifty-three percent of patients with hyperviscosity harbored CXCR4 mutations. Cytogenetic and molecular abnormalities did not significantly impact time to first treatment and response to therapy. Prognostic factors associated with shorter PFS were del6q (p = .01), TP53abn (p = .002) and high-CK (p = .01). These same factors as well as IPSSWM, tri4, CXCR4 frameshift and SPI1 mutations were significantly associated with lower OS (p < .05). These results argue for integration of both cytogenetic and molecular screening in evaluation of first-line WM patients.