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•Elotuzumab combined with PVd is a novel, 4 drug combination in relapsed MM.•The regimen is tolerated well and effective in patients with a median of 3 prior lines of treatment, including anti-CD38 antibody therapy.

•The combination of ibrutinib and venetoclax induced deep and durable responses in treatment-naïve patients with Waldenström macroglobulinemia.•Planned study therapy was stopped early due to a higher-than-expected occurrence of ventricular arrhythmia in 4 of the 45 participants.

Patients with cancer can develop neurologic deficits that frequently, but not exclusively, arise from intracranial involvement by malignancy. In this case series, we highlight 3 patients with new focal neurologic deficits in the setting of hematologic cancers without baseline intracranial disease. The first, with Waldenstrom macroglobulinemia, develops bradyphrenia, inattention, and disorientation. Patients 2 and 3 have diagnoses of chronic lymphocytic leukemia (CLL), with one experiencing a first lifetime seizure and the other right hemiparesis, rash, headache, and intermittent speech arrest. A description of the pathophysiology of the final diagnosis, suggestive imaging characteristics, and historical outcomes follows to improve future diagnostic precision.

Although caregivers of patients with multiple myeloma (MM) play a critical role in supporting their loved ones throughout the illness course, studies examining caregiver quality of life (QOL), psychological distress, and prognostic awareness are lacking. We conducted a cross-sectional, multisite study of patients undergoing treatment with MM and their caregivers. Eligible caregivers were enrolled to 1 of 3 cohorts based on lines of therapy. Caregivers completed validated questionnaires to assess their QOL, psychological distress, and perceptions of prognosis. We enrolled 127 caregivers of patients with MM (newly diagnosed [n = 43], 2-3 lines of therapy [n = 40], and ≥4 lines of therapy [n = 44]). Caregiver QOL and psychological distress did not differ by line of therapy. The rate of clinically significant anxiety, depression, and posttraumatic stress disorder symptoms were 44.1% (56/127), 15.8% (20/127), and 24.4% (31/127), respectively. When examined in dyads, caregivers reported higher rates of clinically significant anxiety (44.4% [55/124] vs 22.5% [28/124]) compared with patients with MM. Most caregivers (84.2%, 101/120) reported that the oncologist had informed them that the patient's cancer was incurable; however, only 50.9% (58/114) and 53.6% (59/110) of caregivers acknowledged the patient's cancer was terminal and incurable, respectively. Caregivers of patients undergoing treatment for MM experience substantial psychological distress across the disease continuum, particularly anxiety. The majority of caregivers of patients with MM report that knowing the patient's prognosis is extremely important and report that the oncologist told them that the patient was incurable. Nevertheless, a significant portion of caregivers believe that the patient's MM is curable.

Although caregivers of patients with multiple myeloma (MM) play a critical role in supporting their loved ones throughout the illness course, studies examining caregiver quality of life (QOL), psychological distress, and prognostic awareness are lacking. We conducted a cross-sectional, multisite study of patients undergoing treatment with MM and their caregivers. Eligible caregivers were enrolled to 1 of 3 cohorts based on lines of therapy. Caregivers completed validated questionnaires to assess their QOL, psychological distress, and perceptions of prognosis. We enrolled 127 caregivers of patients with MM (newly diagnosed [n = 43], 2-3 lines of therapy [n = 40], and ≥4 lines of therapy [n = 44]). Caregiver QOL and psychological distress did not differ by line of therapy. The rate of clinically significant anxiety, depression, and posttraumatic stress disorder symptoms were 44.1% (56/127), 15.8% (20/127), and 24.4% (31/127), respectively. When examined in dyads, caregivers reported higher rates of clinically significant anxiety (44.4% [55/124] vs 22.5% [28/124]) compared with patients with MM. Most caregivers (84.2%, 101/120) reported that the oncologist had informed them that the patient’s cancer was incurable; however, only 50.9% (58/114) and 53.6% (59/110) of caregivers acknowledged the patient’s cancer was terminal and incurable, respectively. Caregivers of patients undergoing treatment for MM experience substantial psychological distress across the disease continuum, particularly anxiety. The majority of caregivers of patients with MM report that knowing the patient’s prognosis is extremely important and report that the oncologist told them that the patient was incurable. Nevertheless, a significant portion of caregivers believe that the patient’s MM is curable.

The SRC family kinase (SFK) HCK is transcriptionally upregulated and activated by mutated MYD88 (MYD88Mut), a key adaptor for Toll-receptor signaling. HCK activates BTK, AKT, and ERK in MYD88Mut lymphomas. SYK, a B-cell receptor (BCR) component, is activated in MYD88Mut lymphoma cells. Although the SFK LYN serves as a trigger for SYK activation in MYD88Mut ABC DLBCL cells, LYN activity is muted in MYD88Mut Waldenstrom macroglobulinemia (WM) cells. We therefore investigated a role for HCK in mediating SYK activation. Overexpression of wild-type (WT) (HCKWT) or gatekeeper mutated (HCKThr333Met) HCK in MYD88Mut lymphoma cells triggered SYK activation. Conversely, HCK knockdown reduced p-SYK in MYD88Mut lymphoma cells. Coimmunoprecipitation experiments showed that HCK was complexed with p-SYK in MYD88Mut BCWM.1 and TMD8 cells, but not in MYD88 WT Ramos cells. Rescue experiments in MYD88Mut lymphoma cells expressing HCKThr333Met led to persistent HCK and SYK activation and resistance to the HCK inhibitor A419259. Treatment of primary MYD88Mut WM cells with A419259 reduced p-HCK and p-SYK expression. Taken together, our findings show that SYK is activated by HCK in MYD88Mut B-cell lymphomas cells, broaden the prosurvival signaling generated by aberrant HCK expression in response to MYD88Mut, and help define HCK as an important therapeutic target in MYD88Mut B-cell lymphomas.

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 CXCR4mutations (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 CXCR4at 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 CXCR4mutations (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. CXCR4mutations impacted VGPR attainment, time to major response, and 4-year PFS rate.

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.

MYD88 and CXCR4 mutations are common in Waldenström macroglobulinemia (WM). Mutated CXCR4 (CXCR4Mut) impacts BTK-inhibitor response. We conducted a phase 1 trial of the CXCR4-antagonist ulocuplumab with ibrutinib in this first-ever study to target CXCR4Mut in WM. Ibrutinib was initiated at 420 mg/d with cycle 1 and continued until intolerance or progression; ulocuplumab was given cycles 1 to 6, with a 3 + 3 dose-escalation design. Each cycle was 4 weeks. Thirteen symptomatic patients, of whom 9 were treatment-naive patients were enrolled. Twelve were evaluable for response. At best response, their median serum immunoglobulin M declined from 5574 to 1114 mg/dL; bone marrow disease decreased from 65% to 10%, and hemoglobin increased from 10.1 to 14.2 g/dL (P < .001). The major and VGPR response rates were 100% and 33%, respectively, with VGPRs observed at lower ulocuplumab dose cohorts. Median times to minor and major responses were 0.9 and 1.2 months, respectively. With a median follow-up of 22.4 months, the estimated 2-year progression-free survival was 90%. The most frequent recurring grade ≥2 adverse events included reversible thrombocytopenia, rash, and skin infections. Ulocuplumab dose-escalation did not impact adverse events. The study demonstrates the feasibility of combining a CXCR4-antagonist with ibrutinib and provides support for the development of CXCR4-antagonists for CXCR4Mut WM. This trial was registered at www.clinicaltrials.gov as #NCT03225716.

Patients with plasma cell dyscrasias (PCDs) experience an increased burden of influenza, and current practice of single-dose annual influenza vaccination yields suboptimal protective immunity in these patients. Strategies to improve immunity to influenza in these patients are clearly needed. We performed a randomized, double-blind, placebo-controlled clinical trial comparing tandem Fluzone High-Dose influenza vaccination with standard-of-care influenza vaccination. Standard-of-care vaccination was single-dose age-based vaccination (standard dose, <65 years; high dose, ≥65 years), and patients in this arm received a saline placebo injection at 30 days. A total of 122 PCD patients were enrolled; 47 received single-dose standard-of-care vaccination, and 75 received 2 doses of Fluzone High-Dose vaccine. Rates of hemagglutinin inhibition (HAI) titer seroprotection against all 3 strains (H1N1, H3N2, and influenza B) were significantly higher for patients after tandem high-dose vaccination vs control (87.3% vs 63.2%; P = .003) and led to higher seroprotection at the end of flu season (60.0% vs 31.6%; P = .04). These data demonstrate that tandem high-dose influenza vaccination separated by 30 days leads to higher serologic HAI titer responses and more durable influenza-specific immunity in PCD patients. Similar vaccine strategies may also be essential to achieve protective immunity against other emerging pathogens such as novel coronavirus in these patients. This trial was registered at www.clinicaltrials.gov as #NCT02566265.

Background: BCMA-directed CAR T-cell (CAR T) therapy has demonstrated remarkable efficacy in patients with relapsed/refractory multiple myeloma (rrMM). Pivotal trials such as the KarMMa and CARTITUDE studies using ide-cel and cilta-cel respectively, have shown ORR of 73% and 98%, leading to FDA approval of these products. Notably, ide-cel conferred a median overall survival (OS) of 19.4 months with a median duration of response (DOR) of 10.7 months. Similarly, cilta-cel conferred a median progression-free survival (PFS) of 34.9 months and a 27-month OS rate of 70%. Although these and real-world outcomes are promising, relapse after BCMA CAR T therapy occurs in 27-64% of responders and remains a challenge. Various salvage treatments are being explored including repeat BCMA CAR T therapy with a different product.

Background:Peripheral neuropathy (PN) occurs in 20-25% of patients with an IgM paraprotein and up to 50% of these patients have an anti-myelin associated glycoprotein (MAG) antibody which is frequently associated with sensory ataxia and distal limb weakness negatively affecting function and quality of life. While rituximab is active, its activity is limited as a monotherapy and often associated with an IgM flare that can potentiate PN. BTK-inhibitors can block rituximab-associated IgM flare and are proven to markedly reduce serum IgM in Waldenström's Macroglobulinemia (WM). We therefore initiated this trial to evaluate a novel treatment for anti-MAG PN.

Background:BTK inhibitors and BCL2 antagonists as monotherapy are highly active and well tolerated in Waldenström macroglobulinemia (WM). We initiated a prospective study evaluating ibrutinib and venetoclax in treatment-naive WM. Study therapy was stopped on March 31, 2022, after four ventricular arrhythmia events, including two grade 5 events. Herein, we present follow-up data after stopping therapy to assess ongoing safety and response durability of this combination in WM.

Background:Clinical data support the combination of a CD38 monoclonal antibody, an immunomodulatory drug, a proteasome inhibitor, and a glucocorticoid for the treatment of newly diagnosed multiple myeloma (NDMM). Isatuximab (Isa) is approved in combination with carfilzomib and dexamethasone (dex) for relapsed, refractory MM based on the results of the IKEMA study, as well as with pomalidomide and dex based upon ICARIA and is now being explored in novel combinations in the newly diagnosed setting. Our study evaluated the addition of isa to weekly carfilzomib (K), lenalidomide (len), and dex in all-risk, transplant-eligible patients with NDMM and stratifies maintenance based on cytogenetic risk.

Serum IgM measurements represent the current standard for assessing changes in disease burden in Waldenström's Macroglobulinemia (WM). Many agents used to treat WM can significantly affect serum IgM levels without impacting the underlying burden of clonal lymphoplasmacytic cells thereby producing discordant findings. Such agents can raise (CD20-directed monoclonal antibodies, IMiDs), or lower (BTK-, proteasome-, MTOR- inhibitors) serum IgM levels, and impact categorical response assessment. Somatic mutations in MYD88 are found in 95-97% of WM patients, and support tumor growth through activation of multiple pro-survival pathways that include HCK/BTK, SYK and ERK. Nearly all MYD88 mutations in WM are of the L265P variant. Previous studies by us and others have shown that serial quantitative measurements of both bone marrow (BM) and peripheral blood (PB) MYD88 L265P (c.978 T>C) by allele-specific PCR can be used to assess changes in underlying BM disease burden (Blood 121:2051-2058; Leukemia 28:1698-1704). However, the utility of using quantitative allele-specific MYD88 L265P (qMYD88 L265P) analysis has not been studied in prospective clinical trials. As such, we performed a comprehensive study of qMYD88 L265P response assessment utilizing BM and PB CD19-selected tissue across 5 prospective clinical studies in WM: Ixazomib, Dexamethasone and Rituximab (IDR; NCT02400437)Ibrutinib monotherapy (IBR; NCT02604511); Venetoclax monotherapy (VEN; NCT02677324); Ibrutinib plus Ulocuplomab (IBR/ULO; NCT03225716); and Ibrutinib plus Venetoclax (IBR/VEN; NCT04273139). Changes in MYD88 L265P ΔCt were assessed as reported above with ΔCt = Mutant Ct - Wild-type Ct, and higher ΔCt values indicating a lower mutant allele burden, with each ΔCt unit reduction representing a 50% decrease in mutant MYD88 L265P burden. Changes in MYD88 L265P ΔCt were compared to changes in underlying BM disease burden and categorical response assessment using the current (IWWM-11) response criteria (Semin Hematol. 60:97-106). Across all five trials, BM (r=0.52; p<0.001) and PB (r=0.43; p<0.001) MYD88 L265P ΔCt changes from baseline were highly correlated at best response with corresponding changes in underlying BM disease burden determined by repeat BM biopsies. As shown in Fig. 1, comparing changes from baseline in BM MYD88 L265P ΔCt assessments across studies showed marked differences, with greatest reductions observed in patients treated with IBR/VEN, IDR, and VEN alone, than for those treated with IBR alone or IBR/ULO. Similar findings were also observed for corresponding PB MYD88 L265P ΔCt assessments from baseline, with changes in PB MYD88 L265P ΔCt strongly correlating with those of BM MYD88 L265P ΔCt findings across all 5 clinical trials (r=0.67; p<0.001), thereby signifying the ability to use PB MYD88 L265P ΔCt assessments to evaluate treatment responses. We next compared findings from BM and PB MYD88 L265P ΔCt to changes from baseline in serum IgM levels across all 5 trials. At best response, major categorical responses denoted by >50% reduction in serum IgM using IWWM-11 criteria showed commensurate decreases in BM and PB MYD88 L265P ΔCt from baseline in patients receiving IBR/VEN, IDR and VEN alone ( Fig. 2). In contrast, minimal changes in BM and PB MYD88 L265P ΔCt from baseline were observed at best response for most major responders on IBR or IBR/ULO, including individuals who achieved very good partial responses denoted by >90% decrease in IgM by IWWM-11 criteria. In this first prospective evaluation of BM and PB qMYD88 L265P response assessment, we show that both BM and PB L265P qMYD88 analysis can provide more accurate assessment of treatment related changes in disease burden over the current standard of IgM response assessment alone, and can be used to more robustly evaluate clinical trial performance byidentifying treatments or regimens that produce more meaningful tumor reductions in WM patients.

Background:Waldenström's Macroglobulinemia (WM) patients carry MYD88 (MYD88 MUT) and CXCR4 (CXCR4 MUT) mutations in 95-97% and 30-40% of cases, respectively. The mechanisms of MYD88-driven lymphomagenesis remain to be clarified. Our previous transcriptome analysis highlighted WNK2 as a highly dysregulated gene in MYD88 MUTWM (Guerrera ML et al, Haematologica 2018). WNK2 is a serine/threonine protein kinase that negatively regulates ERK1/2 activation in a kinase-dependent manner; is a known tumor suppressor in certain solid cancers, where it is primarily silenced by promoter methylation. ERK1/2 is a pro-survival signal in WM; its activation is accompanied by the release of inflammatory cytokines and can mediate ibrutinib resistance. We previously demonstrated WNK2 transcriptional and protein upregulation in CXCR4 WTand silencing in CXCR4 MUTWM and identified several mechanisms of WNK2 transcriptional dysregulation including i) the preferential expression of short isoforms lacking the kinase domain; ii) the recurrence of an identical, aberrant, exon skipping event in all gene isoforms; and iii) aberrant methylation and chromatin accessibility in CXCR4 WTvs CXCR4 MUTWM. We therefore hypothesized that spliced WNK2 may contribute to MYD88 MUTWM oncogenesis.

Consensus Panel 1 (CP1) of the 11thInternational Workshop on Waldenstrom's Macroglobulinemia (IWWM-11) was tasked with updating guidelines for the management of symptomatic, treatment-naïve patients with WM. The panel reiterated that watchful waiting remains the gold standard for asymptomatic patients without critically elevated IgM or compromised hematopoietic function. For first-line treatment, chemoimmunotherapy (CIT) regimens such as dexamethasone, cyclophosphamide, rituximab (DRC), or bendamustine, rituximab (Benda-R) continue to play a central role in managing WM, as they are effective, of fixed duration, generally well-tolerated, and affordable. Covalent BTK inhibitors (cBTKi) offer a continuous, generally well-tolerated alternative for the primary treatment of WM patients, particularly those unsuitable for CIT. In a Phase III randomized trial updated at IWWM-11, the second-generation cBTKi, zanubrutinib, was less toxic than ibrutinib and induced deeper remissions, thus categorizing zanubrutinib as a suitable treatment option in WM. While the overall findings of a prospective, randomized trial updated at IWWM-11 did not show superiority of fixed duration rituximab maintenance over observation following attainment of a major response to Benda-R induction, a subset analysis showed benefit in patients >65 years and those with a high IPPSWM score. Whenever possible, the mutational status of MYD88and CXCR4should be determined before treatment initiation, as alterations in these 2 genes predict sensitivity towards cBTKi activity. Treatment approaches for WM-associated cryoglobulins, cold agglutinins, AL amyloidosis, Bing-Neel syndrome (BNS), peripheral neuropathy, and hyperviscosity syndrome follow the common principle of reducing tumor and abnormal protein burden rapidly and deeply to improve symptoms. In BNS, ibrutinib can be highly active and produce durable responses. In contrast, cBTKi are not recommended for treating AL amyloidosis. The panel emphasized that continuous improvement of treatment options for symptomatic, treatment-naïve WM patients critically depends on the participation of patients in clinical trials, whenever possible.

We report the long-term outcome of a multicenter, prospective study examining fludarabine and rituximab in Waldenström macroglobulinemia (WM). WM patients with less than 2 prior therapies were eligible. Intended therapy consisted of 6 cycles (25 mg/m2 per day for 5 days) of fludarabine and 8 infusions (375 mg/m2 per week) of rituximab. A total of 43 patients were enrolled. Responses were: complete response (n = 2), very good partial response (n = 14), partial response (n = 21), and minor response (n = 4), for overall and major response rates of 95.3% and 86.0%, respectively. Median time to progression for all patients was 51.2 months and was longer for untreated patients (P = .017) and those achieving at least a very good partial response (P = .049). Grade 3 or higher toxicities included neutropenia (n = 27), thrombocytopenia (n = 7), and pneumonia (n = 6), including 2 patients who died of non–Pneumocystis carinii pneumonia. With a median follow-up of 40.3 months, we observed 3 cases of transformation to aggressive lymphoma and 3 cases of myelodysplastic syndrome/acute myeloid leukemia. The results of this study demonstrate that fludarabine and rituximab are highly active in WM, although short- and long-term toxicities need to be carefully weighed against other available treatment options. This study is registered at clinicaltrials.gov as NCT00020800.

Waldenström macroglobulinemia (WM) is a B-cell malignancy characterized by an IgM monoclonal gammopathy and bone marrow (BM) infiltration with lymphoplasmacytic cells (LPCs). Excess mast cells (MCs) are commonly present in WM, and provide growth and survival signals to LPCs through several TNF family ligands (CD40L, a proliferation-inducing ligand [APRIL], and B-lymphocyte stimulator factor [BLYS]). As part of these studies, we demonstrated that WM LPCs secrete soluble CD27 (sCD27), which is elevated in patients with WM (P < .001 vs healthy donors), and serves as a faithful marker of disease. Importantly, sCD27 stimulated expression of CD40L on 10 of 10 BM MC samples and APRIL on 4 of 10 BM MC samples obtained from patients with WM as well as on LAD2 MCs. Moreover, the SGN-70 humanized monoclonal antibody, which binds to CD70 (the receptor-ligand partner of CD27), abrogated sCD27 mediated up-regulation of CD40L and APRIL on WM MCs. Last, treatment of severe combined immunodeficiency–human (SCID-hu) mice with established WM using the SGN-70 antibody blocked disease progression in 12 of 12 mice, whereas disease progressed in all 5 untreated mice. The results of these studies demonstrate a functional role for sCD27 in WM pathogenesis, along with its utility as a surrogate marker of disease and a target in the treatment of WM.

Thalidomide enhances rituximab-mediated, antibody-dependent, cell-mediated cytotoxicity. We therefore conducted a phase 2 study using thalidomide and rituximab in symptomatic Waldenstrom macroglobulinemia (WM) patients naive to either agent. Intended therapy consisted of daily thalidomide (200 mg for 2 weeks, then 400 mg for 50 weeks) and rituximab (375 mg/m2 per week) dosed on weeks 2 to 5 and 13 to 16. Twenty-five patients were enrolled, 20 of whom were untreated. Responses were complete response (n = 1), partial response (n = 15), and major response (n = 2), for overall and major response rate of 72% and 64%, respectively, on an intent-to-treat basis. Median serum IgM decreased from 3670 to 1590 mg/dL (P < .001), whereas median hematocrit rose from 33.0% to 37.6% (P = .004) at best response. Median time to progression for responders was 38 months. Peripheral neuropathy to thalidomide was the most common adverse event. Among 11 patients experiencing grade 2 or greater neuropathy, 10 resolved to grade 1 or less at a median of 6.7 months. Thalidomide in combination with rituximab is active and produces long-term responses in WM. Lower doses of thalidomide (ie, ≤ 200 mg/day) should be considered given the high frequency of treatment-related neuropathy in this patient population. This trial is registered at www.clinicaltrials.gov as #NCT00142116.

Waldenström's macroglobulinemia is a B-cell disorder characterized by bone marrow infiltration with lymphoplasmacytic cells and demonstration an immunoglobulin M monoclonal gammopathy. Despite advances in therapy, Waldenström's macroglobulinemia remains incurable. As therapeutic agents are needed for the treatment of Waldenström's macroglobulinemia. In ongoing efforts, we and others have sought to exploit made in the understanding of the biology of Waldenström's macroglobulinemia so as to better target therapeutics for this malignancy. Importantly, part of these efforts, we have prioritized the development of stem cell–sparing drugs because autologous stem cell transplantation remains salvage option in Waldenström's macroglobulinemia. These efforts have led to the development of several novel agents for treating Waldenström's macroglobulinemia, including bortezomib; monoclonal antibodies and/or blocking protein targeting CD40, CD52, or CD70, a proliferation- ligand and B-lymphocyte stimulator; the immunomodulator thalidomide as an enhancer of rituximab activity, as well as agents interfering cell factor, phosphatidylinositol 3-kinase/Akt, phosphodiesterase, cholesterol, and protein kinase C ß signaling. This report provides biologic studies and clinical efforts for the development of these novel agents in the treatment of Waldenström's macroglobulinemia.

Polymorphisms in Fc?RIIa and Fc?RIIIa receptors are associated with responses to the CD20-directed immunoglobulin G1 (IgG1) monoclonal antibody rituximab among patients with indolent lymphoma. At odds with the aforementioned clinical observations has been the finding that IgG1 binding is impacted by polymorphisms in Fc?RIIIa but not Fc?RIIa. One possibility for this discrepancy might involve linkage of polymorphisms between Fc?RIIa and Fc?RIIIa.

Alemtuzumab is a monoclonal antibody used in the treatment of CD52-expressing B-cell malignancies, including Waldenström's macroglobulinemia (WM). Recent studies demonstrate high levels of alemtuzumab activity in relapsed/refractory disease. One potential target of alemtuzumab is bone marrow mast cells (BMMCs), which provide growth and survival signaling for WM lymphoplasmacytic cells.

Waldenström macroglobulinemia (WM) is a B-cell disorder characterized by the infiltration of lymphoplasmacytic cells into bone marrow and the presence of an IgM monoclonal gammopathy. As part of the Third International Workshop on WM, held October 7 to 10, 2004 in Paris, France, a consensus panel charged with providing treatment recommendations for WM updated its recommendations on both frontline and salvage therapies. The panel considered encouraging results from recent studies that addressed the use of extended-dose rituximab as well as other treatment options: therapy with either nucleoside analogs and alkylator agents, rituximab in combination with nucleoside analogs, nucleoside analogs plus alkylator agents, or combination chemotherapies, such as CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) or cyclophosphamide and dexamethasone. The panel determined that these were reasonable treatment options for WM patients and such therapeutic approaches were likely to yield results that are at least as good as if not better than the currently recommended use of single-agent alkylator, nucleoside analog, or standard-dose rituximab therapy. Such approaches were deemed to be reasonable treatment for WM patients in both the upfront and salvage settings, though randomized studies addressing the efficacy and toxicity of such novel approaches over previously established standard of care options are needed.

Recently, a consensus panel of experts recommended that patients with Waldenström's macroglobulinemia (WM) who are candidates for future autologous transplantation should have limited alkylator or nucleoside analogue exposure due to potential stem cell harm. Cyclophosphamide/doxorubicin/vincristine/prednisone/rituximab (CHOP-R) is a stem cell–sparing regimen that has been extensively evaluated in patients without WM or non-Hodgkin's lymphoma. As such, we analyzed the outcome of 13 patients with WM who received CHOP-R at our institution. Patients had a median age of 54 years and a median of 1 previous therapy. Ten of 13 patients (77%) had relapsed (n = 3) or refractory (n = 7) disease. Eight and 6 patients had previously received fludarabine and rituximab, respectively. Intended therapy consisted of 6 cycles of standard-dose CHOP and 6 infusions of rituximab (375 mg/m2). Three patients received additional rituximab as maintenance therapy. Median immunoglobulin M and serum viscosity for all patients decreased from 5230 mg/dL to 1690 mg/dL (P= 0.001) and from 2.9 cP to 1.6 cP (P= 0.01), respectively, and the median hematocrit level rose from 30.5% to 39.3% (P= 0.001). Clinical responses were as follows: 3 complete responses unconfirmed, 8 partial responses, 1 minor response. At a median follow-up of 9 months (range, 6 to 37 months), 10 of the 11 patients who had a major response remained in remission. Therapy was well tolerated for most patients. Two patients had febrile neutropenia with documented bacteremia and recovered without complications. Circulating effector cell levels were also evaluated in 6 patients before and after CHOP-R, because rituximab activity is mediated in part by antibody-dependent cell-mediated cytotoxicity activity. No significant change in CD3+, CD4+, CD8+, and CD16+/CD56+ effector cell levels occurred following CHOP-R as assessed by multicolor flow cytometry.

CD5, CD10, and CD23 are cell surface antigens used to distinguish B-cell disorders. The expression of these antigens and their clinical significance in Waldenström's macroglobulinemia (WM), an uncommon B-cell disorder, remains to be clarified. We therefore determined expression of CD5, CD10, and CD23 by flow cytometric analysis on bone marrow lymphoplasmacytic cells (CD19+?/? light chain restricted) for 171 serially biopsied patients with findings of the consensus panel definition of WM. Importantly, we also correlated laboratory and clinical data, as well as existence of a familial history of a B-cell disorder in view of reports suggesting familial predisposition in WM. These studies demonstrated tumor cell expression of CD5, CD10, and CD23 in 15 of 171 patients (9%), 11 of 161 patients (7%), and 37 of 105 patients (35%), respectively. Coexpression of CD23 with CD5 or CD10 was common. Tumor Lymphoplasmacytic from 10 of 15 (66%) and 3 of 11 (27%) patients with WM that expressed CD5 and CD10, respectively, also showed expression of CD23 (P= 0.01 and P= 0.08, respectively). Among patients with CD23 expression, increased serum immunoglobulin (Ig) M levels were observed compared with patients without CD23 expression (P= 0.05). No differences in age at diagnosis; presence of adenopathy and/or splenomegaly; bone marrow involvement; serum IgA, IgB, and ß2 macroglobulin levels; hematocrit; platelet count; or familial history of WM or a related Bcell disorder were observed among patients with and without CD5, CD10, and CD23 expression. These studies demonstrate that CD5, CD10, and CD23 are commonly found in WM and that their expression should not exclude the diagnosis of WM. Moreover, expression of CD23 may define a clinically distinct subset of patients with WM.

Waldenstrom's macroglobulinemia (WM) is a malignant disorder of lymphoplasmacytic cells that produce a monoclonal immunoglobulin M (IgM). Since the original description by Jan Waldenström of three patients with symptoms of hyperviscosity due to circulating monoclonal IgM, the definition of WM has been controversial. Standardized criteria for diagnosis have now been proposed, including the presence of any IgM monoclonal protein and marrow and/or nodal lymphoplasmacytic cells. Although previous response criteria have generally incorporated parameters for monoclonal protein reduction and/or improvement of marrow/nodal involvement, specific and uniform response criteria are needed to facilitate comparisons of response, remission duration, progression-free survival, and overall survival in clinical trials similar to those previously established for other diseases such as chronic lymphocytic leukemia, lymphoma, and myeloma. This is of particular importance as new agents are developed and evaluated. This presentation represents consensus recommendations for uniform response criteria for use in assessing responses to treatment for patients with WM, which were prepared in conjunction with the Second International Workshop held in Athens, Greece during September 2002. Semin Oncol 30:127-131. © 2003 Elsevier Inc. All rights reserved.

This presentation represents consensus recommendations for the treatment of patients with Waldenstrom's macroglobulinemia (WM), which were prepared in conjunction with the second International Workshop held in Athens, Greece during September 2002. The faculty adopted the following statements for the management of patients with Waldenstrom's macroglobulinemia: (1) Alkylating agents, nucleoside analogues, and rituximab are reasonable choices for first line therapy of WM. (2) Both cladribine and fludarabine are reasonable choices for the therapy of WM. (3) Combinations of alkylating agents, nucleoside analogues, or rituximab should at this time be encouraged in the context of a clinical trial. (4) In WM, rituximab can cause a sudden rise in serum IgM and viscosity levels in certain patients, which may lead to complications, therefore close monitoring of these parameters and symptoms of hyperviscosity is recommended for WM patients undergoing rituximab therapy. (5) For relapsed disease, it is reasonable to use an alternate first line agent or re-use of the same agent; however, since autologous stem cell transplantation may have a role in treating patients with relapsed disease it is recommended that for patients in whom autologous transplantation is seriously being considered, exposure to alkylator or nucleoside analogue drugs should be limited. (6) Combination chemotherapy for patients who can tolerate myelotoxic therapy, thalidomide alone or with dexamethasone, can reasonably be considered to have relapsed. (7) Autologous stem cell transplantation may be considered for patients with refractory or relapsing disease. (8) Allogeneic transplantation should only be undertaken in the context of a clinical trial. (9) Plasmapheresis should be considered as interim therapy until definitive therapy can be initiated. (10) Rituximab should be considered for patients with IgM-related neuropathies. (11) Corticosteroids may be useful in the treatment of symptomatic mixed cryoglobulinemia. (12) Splenectomy is rarely indicated but has been used to manage painful splenomegaly and hypersplenism. Semin Oncol 30:121-126. © 2003 Elsevier Inc. All rights reserved.

This presentation represents consensus recommendations on prognostic markers and criteria to initiate therapy in patients with Waldenstrom's macroglobulinemia (WM), which were prepared in conjunction with the Second International Workshop held in Athens, Greece during September 2002. The panel recommended that initiation of therapy should not be based on the IgM level per se since this may not correlate with the clinical manifestations of WM. The consensus panel agreed that initiation of therapy was appropriate for patients with constitutional symptoms such as recurrent fever, night sweats, fatigue due to anemia, or weight loss. The presence of progressive, symptomatic lymphadenopathy or splenomegaly provide additional reasons to begin therapy. The presence of anemia with a hemoglobin value of = 10 g/dL or a platelet count < 100 × 109/L due to marrow infiltration also justifies treatment. Certain complications such as hyperviscosity syndrome, symptomatic sensorimotor peripheral neuropathy, systemic amyloidosis, renal insufficiency, or symptomatic cryoglobulinemia may also be indications for therapy. Recommendations for follow-up of watch-and-wait patients are that those with monoclonal gammopathy of undetermined significance (MGUS) should have serum protein electrophoresis repeated each year. Patients with asymptomatic (smoldering) macroglobulinemia should be evaluated every 6 months. Regarding prognostic markers, hemoglobin and ß2-microglobulin levels at diagnosis are important prognostic markers in WM: they influence the timing of treatment and survival. Age is a consistently important prognostic factor for survival. However, the panel felt that current data are inadequate to support the use of any prognostic marker to select the timing and type of therapy, and called for studies on the application of prognostic markers in WM. Semin Oncol 30:116-120. © 2003 Elsevier Inc. All rights reserved.

This presentation represents consensus recommendations for the clinicopathological definition of Waldenstrom's macroglobulinemia (WM), which were prepared in conjunction with the Second International Workshop held in Athens, Greece during September 2002. WM is an uncommon lymphoproliferative disorder characterized primarily by bone marrow infiltration and IgM monoclonal gammopathy. It should be considered a distinct clinicopathological entity rather than a clinical syndrome secondary to IgM secretion. The underlying pathological diagnosis in WM is lymphoplasmacytic lymphoma as defined by the World Health Organization (WHO) and Revised European-American Lymphoma (REAL) classification criteria. The concentration of monoclonal IgM can vary widely in WM and it is not possible to define a concentration that reliably distinguishes WM from monoclonal gammopathy of undetermined significance (MGUS) and other lymphoproliferative disorders. A diagnosis of WM can therefore be made irrespective of IgM concentration if there is evidence on a bone marrow trephine biopsy of bone marrow infiltration by lymphoplasmacytic lymphoma with predominantly an intertrabecular pattern, supported by appropriate immunophenotypic studies. Simple criteria to distinguish patients with symptomatic WM who require therapy from those with asymptomatic WM and MGUS were also proposed. Patients with clinical features attributable to IgM monoclonal gammopathy but no overt evidence of lymphoma are considered to constitute a distinct clinical group and the term “IgM-related disorders” is proposed. Semin Oncol 30:110-115. © 2003 Elsevier Inc. All rights reserved.

Background:Waldenström's macroglobulinemia (WM) is a rare, indolent B-cell lymphoproliferative disorder characterized by expansion of clonal IgM-secreting cells (Advani P, et al. Hematol Oncol Stem Cell Ther. 2019;12:179-188). While ibrutinib is the only Bruton tyrosine kinase inhibitor (BTKi) currently approved by the US FDA and EMA for WM, other BTKi's are currently under investigation. More than 90% of patients with WM have somatic mutations in MYD88, and 30%-40% of these patients have activating mutations in CXCR4WHIM(Xu L, et al. Br J Haematol. 2016;172:735-744; Treon SP, et al. Blood. 2014;123:2791-2796). CXCR4WHIMin WM is associated with high serum IgM level, symptomatic hyperviscosity, earlier time to treatment, and inferior response to approved and investigational BTKi (Schmidt J, et al. Br J Haematol. 2015;169:795-803;Tam C, et al. Blood. 2020; 136:2038-2050). Inhibition of CXCR4 can sensitize CXCR4WHIM-expressing cells to ibrutinib (Cao Y, et al. Leukemia. 2015;29:169-176). Mavorixafor is an oral small-molecule antagonist of CXCR4. In vitrodata have shown that mavorixafor inhibits CXCL12 binding and extracellular signal regulated kinase hyperactivation for CXCR4mutations.

Background:Multiple myeloma (MM) is an incurable hematologic malignancy requiring long-term, continuous therapy. Despite its chronic and unrelenting course, studies examining quality of life (QOL), psychological distress, and prognostic awareness by line of therapy are lacking.

MYD88 mutations are common in B-cell malignancies including Waldenstrom Macroglobulinemia (WM) and ABC subtype of Diffuse Large B-cell Lymphoma (ABC DLBCL). Mutated MYD88 activates BTK, and triggers downstream pro-survival signaling that includes NF-kB and ERK (Yang et al, Blood 2013; Blood 2016). ERK related signaling triggers inflammatory cytokine production including IL-6 and IL-10 (Chen et al, Blood 2016). Ibrutinib covalently binds to BTK Cys481and inactivates BTK and downstream NF-kB and ERK signaling. Ibrutinib is approved for the treatment of WM and is associated with high overall response rates (>90%) and long term progression free survival in WM though intolerance to therapy, as well as resistance related to acquired BTK Cys481mutations frequently leads to treatment discontinuation. We therefore investigated a novel, non-covalent BTK-inhibitor, pirtobrutinib that binds to BTK at non-Cys481 amino acids (G473-K483). Pirtobrutinib showed highly selective anti-proliferative activity against MYD88 mutated WM (BCWM.1, MWCL-1) and ABC DLBCL (TMD-8 and HBL-1) versus MYD88 wild-type (OCI-Ly7, OCI-Ly19, Ramos, and RPMI-8226) cells, with marked apoptotic effect exhibited against primary MYD88 mutated WM cells at pharmacologically achievable levels (100-500 nM). Importantly, pirtobrutinib blocked BTK activity and overcame ibrutinib resistance in BCWM.1 WM and TMD-8 ABC DLBCL cells transduced to express both wild-type and mutated BTK (BTK Cys481Ser) with similar efficacy. The downstream signaling consequences of pirtobrutinib in vector only, wild-type and mutant BTK Cys481expressing BCWM.1, MWCL-1, TMD-8 and HBL-1 cells was also examined. Treatment of vector only and wild-type BTK Cys481expressing WM and ABC DLBCL cells with ibrutinib or pirtobrutinib abrogated both p-BTK and p-ERK signaling. In contrast, only pirtobrutinib blocked p-BTK and p-ERK signaling in mutant BTK Cys481expressing WM and ABC DLBCL cells. In previous studies, we showed that inflammatory cytokine production that included IL-6 and IL-10 driven by ERK triggered ibrutinib resistance in wild-type BTK Cys481MYD88 mutated lymphoma cells co-cultured with their mutated BTK expressing counterparts (Chen et al, BLOOD 2018). ERK-driven cytokine resistance to ibrutinib was postulated to explain how disease progression occurs in patients with modest variant expression of mutated BTK Cys481(Woyach et al, JCO 2017; Xu et al, Blood 2017). Co-culture of BTK Cys481mutated expressing TMD-8 cells with wild-type BTK expressing TMD-8 cells triggered resistance of the latter to ibrutinib. Treatment with pirtobrutinib blocked IL-6 and IL-10 production and overcame the protective effects conferred by BTK Cys481mutated TMD-8 cells in these experiments. Lastly, oral administration of pirtobrutinib blocked p-BTK and p-ERK in BTK Cys481mutated TMD-8 tumors xenografted in mice. Our findings therefore show that pirtobrutinib inhibits growth of MYD88 mutated lymphoma cells in a highly selective manner and can trigger apoptosis of primary WM patient BM lymphoplasmacytic cells at levels comparable to ibrutinib. Moreover, pirtobrutinib effectively blocked mutated BTK Cys481driven BTK and ERK1/2 activation and produced similar cellular efficacy in both BTK wild-type and BTK Cys481mutated cells. Pirtobrutinib also blocked the protective effect conferred to BTK wild-type cells through paracrine cytokines released by BTK Cys481Serexpressing cells. Lastly, pirtobrutinib blocked BTK and ERK1/2 activation in TMD8-BTK Cys481Serxenografted mice. The findings support the development of pirtobrutinib in MYD88 driven lymphomas, including those resistant to ibrutinib on the bases of BTK Cys481mutations.

The treatment of multiple myeloma (MM) continues to evolve with new drugs, resulting in dramatically improved outcomes. Despite these advances, MM remains an incurable disease, with Extraosseous/Extramedullary disease (EMD) playing a major role in the development of relapsed refractory disease. EMD is defined by the development of plasma cell neoplasms that arise in tissues other than bones. EMD can present at diagnosis or develop during the disease course of MM. Sometimes EMD can be solitary without bone marrow (BM) involvement. Determining the molecular underpinnings of EMD are critical to advance the care of such patients. A few reports suggest a possible role of Ras mutations in the intramedullary to extramedullary transition in a limited number of patients. Therefore, the molecular biology of developing EMD has not yet been clearly defined.

Background:Clinical data support the combination of a CD38 monoclonal antibody, an immunomodulatory drug, a proteasome inhibitor, and a glucocorticoid for the treatment of newly diagnosed multiple myeloma (NDMM). Recently, the GRIFFIN study evaluated the addition of the CD38 antibody, daratumumab to lenalidomide, bortezomib, and dexamethasone in transplant-eligible NDMM and demonstrated improved efficacy with an acceptable safety profile. Isatuximab is a newer CD38 monoclonal antibody that binds to a specific epitope of the CD38 receptor. In addition to antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and complement-dependent cytotoxicity, isatuximab eliminates MM cells via direct apoptosis without the need for crosslinking. Isatuximab enhances immune function by boosting the activation and cytotoxic activity of natural killer cells and by depleting CD38+ immune suppressor cells such as regulatory T cells and inducing clonal expansion of T cells. Isatuximab is approved in combination with carfilzomib and dexamethasone for relapsed, refractory MM based on the results of the IKEMA study. The MANHATTAN study evaluated the 4-drug combination of daratumumab, lenalidomide, carfilzomib, and dexamethasone. The primary end point, minimal residual disease negativity was achieved in 29 of 41 patients (71%; 95% CI, 54%-83%). Building upon these data, our study evaluates the addition of isatuximab to weekly carfilzomib, lenalidomide, and dexamethasone.

Background: Subcutaneous daratumumab (dara-SC) has several advantages over intravenous daratumumab (dara-IV). It has significantly shorter administration time, lower rates of systemic reactions, and smaller administration volume, while maintaining comparable efficacy and safety. Its fixed dosing allows for easier preparation. At our institution, standard approach is to monitor for 4h following the initial dara-SC dose for those at high risk for systemic reactions, defined as no prior dara use, treatment break ≥90d, or any prior history of reactions. We also administer montelukast and fexofenadine for the first 2 doses of dara-SC in addition to the usual standard pre-medications. Herein, we share our experience with dara-SC use in both dara-naïve and dara-exposed patients in order to gain practical insight, such as optimal monitoring duration, considerations for transitioning between dara-IV and dara-SC, and the place of therapy for dara-IV based on adverse events (AEs).

Introduction:

Multiple myeloma (MM) and Waldenström macroglobulinemia (WM) are associated with significant immunoparesis. Based on the ongoing COVID-19 pandemic, there is an urgent need to understand whether patients are able to mount a sufficient response to COVID-19 vaccines.

Background:Multiple myeloma (MM) is an incurable hematologic malignancy requiring long-term, continuous therapy. Although caregivers of MM patients play a critical role in supporting their loved ones throughout the illness course, studies examining caregiver quality of life (QOL), psychological distress, and prognostic awareness are lacking.