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Abstract: Concurrent Bruton tyrosine kinase and BCL2 inhibition has not yet been investigated in Waldenström macroglobulinemia (WM). We performed an investigator-initiated trial of ibrutinib and venetoclax in symptomatic treatment-naïve patients with MYD88-mutated WM. Patients received ibrutinib 420 mg once daily (cycle 1), followed by a ramp-up of venetoclax to 400 mg daily (cycle 2). The combination was then administered for 22 additional 4-week cycles. The attainment of very good partial response (VGPR) was the primary end point. Forty-five patients were enrolled in this study. The median baseline characteristics were as follows: age 67 years, serum IgM 43 g/L, and hemoglobin 102 g/L. Seventeen patients (38%) carried CXCR4 mutations. Nineteen patients (42%) achieved VGPR. Grade 3 or higher adverse events included neutropenia (38%), mucositis (9%), and tumor lysis syndrome (7%). Atrial fibrillation occurred in 3 (9%), and ventricular arrhythmia in 4 (9%) patients that included 2 grade 5 events. With a median follow-up of 24.4 months, the 24-month progression-free survival (PFS) and overall survival (OS) rates were 76% and 96%, respectively, and were not impacted by CXCR4 mutations. The median time on therapy was 10.2 months, and the median time after the end of therapy (EOT) was 13.3 months. Eleven of the 12 progression events occurred after EOT, and the 12-month PFS rates after EOT were 79%; 93% if VGPR was attained, and 69% for other patients (P = .12). Ibrutinib and venetoclax induced high VGPR rates and durable responses after EOT, although they were associated with a higher-than-expected rate of ventricular arrhythmia in patients with WM, leading to early study treatment termination. This trial was registered at www.clinicaltrials.gov as #NCT04273139., (© 2024 American Society of Hematology. Published by Elsevier Inc. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Apart from the MYD88 L265P mutation, extensive information exists on the molecular mechanisms in Waldenström's Macroglobulinemia and its potential utility in the diagnosis and treatment tailoring. However, no consensus recommendations are yet available. Consensus Panel 3 (CP3) of the 11th International Workshop on Waldenström's Macroglobulinemia (IWWM-11) was tasked with reviewing the current molecular necessities and best way to access the minimum data required for a correct diagnosis and monitoring. Key recommendations from IWWM-11 CP3 included: (1) molecular studies are warranted for patients in whom therapy is going to be started; such studies should also be done in those whose bone marrow (BM) material is sampled based on clinical issues; (2) molecular studies considered essential for these situations are those that clarify the status of 6q and 17p chromosomes, and MYD88, CXCR4, and TP53 genes. These tests in other situations, and/or other tests, are considered optional; (3) independently of the use of more sensitive and/or specific techniques, the minimum requirements are allele specific polymerase chain reaction for MYD88 L265P and CXCR4 S338X using whole BM, and fluorescence in situ hybridization for 6q and 17p and sequencing for CXCR4 and TP53 using CD19+ enriched BM; (4) these requirements refer to all patients; therefore, sample should be sent to specialized centers., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Bruton tyrosine kinase (BTK) inhibitors are the only FDA-approved treatments for Waldenström macroglobulinemia (WM). Factors prognostic of survival and predictive of response to BTK inhibitors remained to be clarified. We evaluated 319 patients with WM to identify predictive and prognostic factors on ibrutinib monotherapy. Logistic and Cox proportional-hazard regression models were fitted for response and survival. Multiple imputation analyses were used to address bias associated with missing data. Major (partial response or better) and deep responses (very good partial response or better) were attained in 78% and 28% of patients. CXCR4 mutations were associated with lower odds of major (odds ratio [OR], 0.2; 95% confidence interval [CI], 0.1-0.5; P < .001) and deep response (OR, 0.3; 95% CI, 0.2-0.6; P = .001). CXCR4 mutations (hazard ratio [HR], 2.0; 95% CI, 1.2-3.4; P = .01) and platelet count 100 K/uL or less (HR, 2.5; 95% CI, 1.3-4.9; P = .007) were associated with worse progression-free survival (PFS). We proposed a scoring system using these 2 factors. The median PFS for patients with 0, 1, and 2 risk factors were not reached, 5 years and 3 years (P < .001). Patients with 2 risk factors had HR 2.2 (95% CI, 1.3-3.8; P = .004) compared with 1 factor, and patients with 1 factor had HR 2.3 (95% CI, 1.1-5.1; P = .03) compared with 0 factors. Age ≥65 years was the only factor associated with overall survival (HR, 3.2; 95% CI, 1.4-7.0; P = .005). Multiple imputation analyses did not alter our results. Our study confirms the predictive and prognostic value of CXCR4 mutations in patients with WM treated with ibrutinib monotherapy., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Herein, we present the final report of a single-center, prospective phase II study evaluating ibrutinib 420 mg once daily in 30 treatment-naive patients with Waldenstrom macroglobulinemia (WM). The present study is registered with ClinicalTrials.Gov (NCT02604511). With a median follow-up of 50 months, the overall, major, and VGPR response rates were 100%, 87%, and 30%. The VGPR rate was numerically but not significantly lower in patients with than without CXCR4 mutations (14% vs. 44%; p = 0.09). The median time to a minor response was 0.9 months, and to a major response was 1.9 months, though were longer in those with mutated CXCR4 at 1.7 months (p = 0.07) and 7.3 months (p = 0.01). Six patients had disease progression. The median progression-free survival (PFS) was not reached, and the 4-year PFS rate was 76%. There was also a non-significant lower 4-year PFS rate in patients with than without CXCR4 mutations (59% vs. 92%; p = 0.06). The most common treatment-related adverse events were fatigue, upper respiratory infection, and hematoma. Atrial fibrillation occurred in 20% of patients. Ibrutinib monotherapy induced durable responses in treatment-naive patients with WM. CXCR4 mutations impacted VGPR attainment, time to major response, and 4-year PFS rate., (© 2021. The Author(s).)

Purpose: BCL2 is overexpressed and confers prosurvival signaling in malignant lymphoplasmacytic cells in Waldenström macroglobulinemia (WM). Venetoclax is a potent BCL2 antagonist and triggers in vitro apoptosis of WM cells. The activity of venetoclax in WM remains to be clarified., Patients and Methods: We performed a multicenter, prospective phase II study of venetoclax in patients with previously treated WM (NCT02677324). Venetoclax was dose-escalated from 200 mg to a maximum dose of 800 mg daily for up to 2 years., Results: Thirty-two patients were evaluable, including 16 previously exposed to Bruton tyrosine kinase inhibitors (BTKis). All patients were MYD88 L265P -mutated, and 17 carried CXCR4 mutations. The median time to minor and major responses was 1.9 and 5.1 months, respectively. Previous exposure to BTKis was associated with a longer time to response (4.5 v 1.4 months; P < .001). The overall, major, and very good partial response rates were 84%, 81%, and 19%, respectively. The major response rate was lower in those with refractory versus relapsed disease (50% v 95%; P = .007). The median follow-up time was 33 months, and the median progression-free survival was 30 months. CXCR4 mutations did not affect treatment response or progression-free survival. The only recurring grade ≥ 3 treatment-related adverse event was neutropenia (n = 14; 45%), including one episode of febrile neutropenia. Laboratory tumor lysis without clinical sequelae occurred in one patient. No deaths have occurred., Conclusion: Venetoclax is safe and highly active in patients with previously treated WM, including those who previously received BTKis. CXCR4 mutation status did not affect treatment response., Competing Interests: Jorge J. CastilloConsulting or Advisory Role: Janssen, Roche/Genentech, Beigene, AbbVie/PharmacyclicsResearch Funding: Pharmacyclics (Inst), AbbVie (Inst), Janssen (Inst), BeiGene (Inst), TG Therapeutics (Inst) John N. AllanHonoraria: AstraZeneca, AbbVie, Pharmacyclics/Janssen, BeiGeneConsulting or Advisory Role: AbbVie/Genentech, Pharmacyclics, Ascentage Pharma, BeiGene, Janssen Oncology, Epizyme, AstraZeneca, TG Therapeutics, ADC TherapeuticsResearch Funding: Genentech, Janssen, Celgene, TG Therapeutics Tanya SiddiqiConsulting or Advisory Role: Juno Therapeutics, AstraZeneca, BeiGene, Celgene, Pharmacyclics, Bristol Myers Squibb/CelgeneSpeakers' Bureau: Pharmacyclics/Janssen, AstraZeneca, BeiGene, Bristol Myers Squibb/CelgeneResearch Funding: Juno Therapeutics (Inst), Kite, a Gilead company (Inst), Acerta Pharma (Inst), TG Therapeutics (Inst), BeiGene (Inst), Pharmacyclics (Inst), Celgene (Inst), Oncternal Therapeutics (Inst), Bristol-Myers Squibb/Sanofi (Inst) Ranjana H. AdvaniConsulting or Advisory Role: Genentech/Roche, Seattle Genetics, Takeda, Portola Pharmaceuticals, Celgene, Sanofi, Kura Oncology, Merck, Karyopharm Therapeutics, ADC Therapeutics, Daiichi Sankyo, Bristol Myers Squibb/Celgene, Epizyme, IncyteResearch Funding: Millennium (Inst), Seattle Genetics (Inst), Genentech/Roche (Inst), Pharmacyclics (Inst), Janssen (Inst), Merck (Inst), Kura Oncology (Inst), Forty Seven (Inst), Cyteir (Inst) Catherine A. FlynnConsulting or Advisory Role: Pharmacyclics, Karyopharm Therapeutics Shayna SarosiekResearch Funding: Acrotech Biopharma (Inst) Andrew R. BranaganConsulting or Advisory Role: Pharmacyclics/Janssen, Genzyme, Adaptive Biotechnologies, BeiGene, Karyopharm Therapeutics, CSL Behring Xia LiuEmployment: Merck (I) Guang YangEmployment: AbbVie (I), Blueprint MedicinesStock and Other Ownership Interests: Blueprint MedicinesHonoraria: Janssen Matthew S. DavidsHonoraria: Research to PracticeConsulting or Advisory Role: Genentech, Janssen, Pharmacyclics, TG Therapeutics, AbbVie, AstraZeneca, Celgene, MEI Pharma, Adaptive Biotechnologies, Verastem, Ascentage Pharma, BeiGene, Lilly, Novartis, Takeda, Bristol Myers SquibbResearch Funding: Genentech (Inst), TG Therapeutics (Inst), Pharmacyclics (Inst), Surface Oncology (Inst), MEI Pharma (Inst), Verastem (Inst), Ascentage Pharma (Inst), AstraZeneca (Inst), Novartis (Inst)Travel, Accommodations, Expenses: TG Therapeutics, Janssen, AbbVie, BeiGene, Genentech Richard R. FurmanHonoraria: Janssen, AstraZeneca, Pharmacyclics, Janssen Biotech, Genentech/Roche, Loxo, TG Therapeutics, Verastem, Acerta Pharma, AstraZeneca, Beigene, Incyte, OncoTracker, AbbVie, MorphoSys, SanofiResearch Funding: Acerta Pharma, TG TherapeuticsExpert Testimony: AbbVie, Janssen OncologyTravel, Accommodations, Expenses: TG Therapeutics, Janssen OncologyOther Relationship: Incyte, Janssen Biotech Steven P. TreonHonoraria: Abbvie/Pharmacyclics, Janssen Oncology, BeiGeneConsulting or Advisory Role: Janssen, Pharmacyclics, Beigene, X4 Pharmaceuticals, Bristol Myers SquibbResearch Funding: Pharmacyclics, Bristol Myers Squibb (Inst), X4 Pharmaceuticals (Inst), Lilly (Inst), Beigene (Inst), AbbVie (Inst)Patents, Royalties, Other Intellectual Property: My institution holds patents related to use of MYD88 and CXCR4 testing for which a predetermined financial distribution to the laboratory and individuals is provided. I have not received any income to this date related to these patents (Inst)Travel, Accommodations, Expenses: Janssen OncologyOther Relationship: Janssen, Pharmacyclics, BeigeneNo other potential conflicts of interest were reported.

CXCR4 mutations impact disease presentation and treatment outcomes in Waldenström macroglobulinaemia (WM). Non-uniform testing for CXCR4 mutations may account for discordant findings in WM clinical trials. We compared two approaches used in these trials for detection of the most common CXCR4 (S338X) variant: targeted next-generation sequencing (NGS) using unselected bone marrow (BM) samples, and combined allele-specific polymerase chain reaction (AS-PCR) and Sanger sequencing with unselected and CD19-selected BM samples. Our findings showed that targeted NGS frequently yielded false-negative results. Both CD19 selection and AS-PCR markedly improved detection of CXCR4 S338X mutations. Sensitivity was adversely impacted by low BM involvement and CXCR4 mutation clonality., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Ibrutinib is associated with durable responses in patients with Waldenström macroglobulinaemia (WM). We hypothesized that response depth is predictive of progression-free survival (PFS) in WM patients treated with ibrutinib. Using landmark analyses, we evaluated response depth in two cohorts of WM patients treated with ibrutinib monotherapy. The learning cohort was composed of 93 participants from two clinical trials, and the validation cohort of 190 consecutive patients treated off clinical trial. Rates of partial response (PR) or better at six months in learning and validation cohorts were 64% and 71% respectively (P = 0·29). In the learning cohort, three-year PFS rates for patients who attained PR or better at six months versus not were 81% and 57% respectively (P = 0·009). In the validation cohort, three-year PFS rates for patients who attained PR or better at six months versus not were 83% and 54% respectively (P = 0·008). In multivariate analyses, attaining PR or better at six months was associated with superior PFS in the learning [hazard ratio (HR) 0·38; P = 0·01] and validation cohorts (HR 0·18; P = 0·004). Attaining PR at six months on ibrutinib emerges as an intermediate outcome of interest and should be validated as surrogate for PFS in clinical trials evaluating Bruton tyrosine kinase inhibitors in WM., (© 2020 British Society for Haematology and John Wiley & Sons Ltd.)

Proteasome inhibition is a standard of care for the primary treatment of patients with Waldenström macroglobulinemia (WM). We present the long-term follow-up of a prospective, phase II clinical trial that evaluated the combination of ixazomib, dexamethasone, and rituximab (IDR) in 26 treatment-naive patients with WM. IDR was administered as 6 monthly induction cycles followed by 6 every-2-month maintenance cycles. The MYD88 L265P mutation was detected in all patients, and CXCR4 mutations were detected in 15 patients (58%). The median time to response (TTR) and time to major response (TTMR) were 2 and 6 months, respectively. Patients with and without CXCR4 mutations had median TTR of 3 months and 1 month, respectively (P = .003), and median TTMR of 10 months and 3 months, respectively (P = .31). The overall, major, and very good partial response (VGPR) rates were 96%, 77%, and 19%, respectively. The rate of VGPR in patients with and without CXCR4 mutations were 7% and 36%, respectively (P = .06). The median progression-free survival (PFS) was 40 months, the median duration of response (DOR) was 38 months, and the median time to next treatment (TTNT) was 40 months. PFS, DOR, and TTNT were not affected by CXCR4 mutational status. The safety profile was excellent with no grade 4 adverse events or deaths to date. IDR provides a safe and effective frontline treatment option for symptomatic patients with WM. This study was registered at www.clinicaltrials.gov as #NCT02400437., (© 2020 by The American Society of Hematology.)

Cases of non-IgM lymphoplasmacytic lymphoma (LPL) are rare. We performed a case-control study comparing features and outcomes of 31 non-IgM LPL cases and 93 Waldenström macroglobulinemia (WM) controls matched by age, sex, and year of diagnosis. Odds of MYD88 mutations were lower (odds ratio (OR) 0.22, p  = .05), and median time to treatment was shorter in cases than in controls (4 vs. 32 months; p  < .001). Odds of extramedullary disease were higher (OR 4.20, p  = .01), while odds of neuropathy (OR 0.22, p  = .25), and hyperviscosity (OR 0.26, p  = .26) were lower in cases than in controls. Odds of using chemoimmunotherapy were higher (OR 2.62, p  = .11) while odds of using proteasome inhibitors (OR 0.35, p  = .15) and BTK inhibitors (OR 0.17, p  = .21) were lower in cases than in controls. There were no differences in response and overall survival (OS) between cases and controls. Despite clinicopathological differences, response, and survival outcomes are similar between non-IgM LPL cases and WM controls.

Rituximab-containing regimens are commonly used for frontline therapy in patients with symptomatic Waldenström macroglobulinemia (WM). We had observed that a portion of WM patients experienced deepening of response months to years after therapy completion. We carried a retrospective study aimed at describing this phenomenon. We gathered baseline data, and responses at end of induction, end of maintenance and best response. Deepening of response was defined as ≥25% decrease in serum IgM achieved at a later time from therapy completion. Of 178 patients included, 116 (65%) received maintenance therapy and 62 (35%) were observed. In patients who received maintenance, 44 (38%) had ≥25% decrease in serum IgM level after the end of maintenance with a median time from end of maintenance to lowest IgM level of 1.6 years (range 0.1-7.9 years). In patients who were observed, 19 (31%) had ≥25% decrease in serum IgM level after the end of induction with a median time from end of induction to lowest IgM level of 1.6 years (range 0.2-5.1 years). Baseline hemoglobin <11.5 g/dL, bone marrow involvement ≥50%, CXCR4 mutations and serum IgM ≥4000 mg/dL were associated with lower odds of deepening of response after therapy completion. Deepening of response was associated with better progression-free survival (PFS; HR 0.46, 95% CI 0.26-0.80; P = .006) and better survival after frontline treatment initiation (SAFTI; HR 0.21, 95% CI 0.06-0.73; P = .01). In conclusion, deepening of response occurs in one third of WM patients after completing rituximab-containing regimens and was associated with better PFS and SAFTI., (© 2019 Wiley Periodicals, Inc.)

Ibrutinib is associated with response rate of 90% and median progression-free survival (PFS) in excess of 5 years in Waldenström macroglobulinaemia (WM) patients. CXCR4 mutations are detected in 30-40% of patients with WM and associate with lower rates of response and shorter PFS to ibrutinib therapy. Both frameshift (CXCR4 FS ) and nonsense (CXCR4 NS ) CXCR4 mutations have been described. The impact of these mutations on outcomes to ibrutinib have not been evaluated in WM patients. We studied consecutive patients with a diagnosis of WM, on ibrutinib therapy, for the presence of CXCR4 FS and CXCR4 NS mutations and evaluated the differences in response and PFS between groups. Of 180 patients, 68 patients (38%) had CXCR4 mutations; 49 (27%) had CXCR4 NS and 19 (11%) had CXCR4 FS mutations. In multivariate models, patients with CXCR4 NS had lower odds of major response (Odds ratio 0·25, 95% confidence interval [CI] 0·12-0·53; P < 0·001) and worse PFS (Hazard ratio 4·02, 95% CI 1·95-8·26; P < 0·001) than patients without CXCR4 mutations. CXCR4 FS was not associated with worse major response or PFS rates than patients without CXCR4 mutations. Our results suggest different response and PFS rates to ibrutinib for WM patients with CXCR4 NS and CXCR4 FS , and advocate in favour of CXCR4 mutational testing as well as CXCR4-directed therapy., (© 2019 British Society for Haematology and John Wiley & Sons Ltd.)

Little is known about TP53 mutations in Waldenström Macroglobulinaemia (WM). We evaluated 265 WM patients for TP53 mutations by next-generation sequencing, and validated the findings by Sanger sequencing. TP53 mutations were identified and validated in 6 (2·6%) patients that impacted the DNA-binding domain. All six were MYD88- and CXCR4-mutated. Ibrutinib showed activity in patients carrying all three mutations. With a median follow-up of 18 months, 2 (33%) with biallelic TP53 inactivation died of progressive disease. TP53 mutations are rare in WM, and associate with MYD88 and CXCR4 mutations. WM patients with TP53 mutations show response to ibrutinib., (© 2018 British Society for Haematology and John Wiley & Sons Ltd.)

MYD88 mutations are present in 95% of Waldenstrom Macroglobulinaemia (WM) patients, and support diagnostic discrimination from other IgM-secreting B-cell malignancies. Diagnostic discrimination can be difficult among suspected wild-type MYD88 (MYD88 WT ) WM cases. We systematically reviewed the clinical, pathological and laboratory studies for 64 suspected MYD88 WT WM patients. World Health Organization and WM consensus guidelines were used to establish clinicopathological diagnosis. Up to 30% of suspected MYD88 WT WM cases had an alternative clinicopathological diagnosis, including IgM multiple myeloma. The estimated 10-year survival was 73% (95% confidence interval [CI] 52-86%) for MYD88 WT versus 90% (95% CI 82-95%) for mutated (MYD88 MUT ) WM patients (Log-rank P < 0·001). Multivariate analysis only showed MYD88 mutation status (P < 0·001) as a significant determinant for overall survival. Diffuse large B-cell lymphoma (DLBCL) was diagnosed in 7 (15·2%) and 2 (0·76%) of MYD88 WT and MYD88 MUT patients, respectively (Odds ratio 23·3; 95% CI 4·2-233·8; P < 0·001). Overall survival was shorter among MYD88 WT patients with an associated DLBCL event (Log-rank P = 0·08). The findings show that among suspected MYD88 WT WM cases, an alternative clinicopathological diagnosis is common and can impact clinical care. WM patients with MYD88 WT disease have a high incidence of associated DLBCL events and significantly shorter survival versus those with MYD88 MUT disease., (© 2017 John Wiley & Sons Ltd.)