Ibrutinib and venetoclax as primary therapy in symptomatic, treatment-naïve Waldenström macroglobulinemia

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.

Report of consensus panel 1 from the 11th International Workshop on Waldenstrom's Macroglobulinemia on management of symptomatic, treatment-naïve patients

Consensus Panel 1 (CP1) of the 11th International 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 MYD88 and CXCR4 should 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.

Report of consensus panel 7 from the 11th international workshop on Waldenström macroglobulinemia on priorities for novel clinical trials

Recent advances in the understanding of Waldenström macroglobulinemia (WM) biology have impacted the development of effective novel agents and improved our knowledge of how the genomic background of WM may influence selection of therapy. Consensus Panel 7 (CP7) of the 11th International Workshop on WM was convened to examine the current generation of completed and ongoing clinical trials involving novel agents, consider updated data on WM genomics, and make recommendations on the design and prioritization of future clinical trials. CP7 considers limited duration and novel-novel agent combinations to be the priority for the next generation of clinical trials. Evaluation of MYD88, CXCR4 and TP53 at baseline in the context of clinical trials is crucial. The common chemoimmunotherapy backbones, bendamustine-rituximab (BR) and dexamethasone, rituximab and cyclophosphamide (DRC), may be considered standard-of-care for the frontline comparative studies. Key unanswered questions include the definition of frailty in WM; the importance of attaining a very good partial response or better (≥VGPR), within stipulated time frame, in determining survival outcomes; and the optimal treatment of WM populations with special needs.

Report of consensus panel 5 from the 11th international workshop on Waldenstrom's macroglobulinemia on COVID-19 prophylaxis and management

Consensus Panel 5 (CP5) of the 11th International Workshop on Waldenstrom's Macroglobulinemia (IWWM-11; held in October 2022) was tasked with reviewing the current data on the coronavirus disease-2019 (COVID-19) prophylaxis and management in patients with Waldenstrom's Macroglobulinemia (WM). The key recommendations from IWWM-11 CP5 included the following: Booster vaccines for SARS-CoV-2 should be recommended to all patients with WM. Variant-specific booster vaccines, such as the bivalent vaccine for the ancestral Wuhan strain and the Omicron BA.4.5 strain, are important as novel mutants emerge and become dominant in the community. A temporary interruption in Bruton's Tyrosine Kinase-inhibitor (BTKi) or chemoimmunotherapy before vaccination might be considered. Patients under treatment with rituximab or BTK-inhibitors have lower antibody responses against SARS-CoV-2; thus, they should continue to follow preventive measures, including mask wearing and avoiding crowded places. Patients with WM are candidates for preexposure prophylaxis, if available and relevant to the dominant SARS-CoV-2 strains in a specific area. Oral antivirals should be offered to all symptomatic WM patients with mild to moderate COVID-19 regardless of vaccination, disease status or treatment, as soon as possible after the positive test and within 5 days of COVID-19-related symptom onset. Coadministration of ibrutinib or venetoclax with ritonavir should be avoided. In these patients, remdesivir offers an effective alternative. Patients with asymptomatic or oligosymptomatic COVID-19 should not interrupt treatment with a BTK inhibitor. Infection prophylaxis is essential in patients with WM and include general preventive measures, prophylaxis with antivirals and vaccination against common pathogens including SARS-CoV-2, influenza, and S. pneumoniae.

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.

A phase II study of daratumumab with weekly carfilzomib, pomalidomide, and dexamethasone in relapsed and refractory multiple myeloma

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Background: Daratumumab (dara), carfilzomib (K), pomalidomide (P), and dexamethasone (d) are established in relapsed multiple myeloma (MM) with activity in 3-drug combinations including: dara Kd; dara Pd; and KPd. The paradigm in relapsed/refractory disease is moving towards more intensive and well-tolerated combinations to achieve deeper and more durable responses while ensuring tolerability. Quadruplet regimens are now becoming standard in newly diagnosed MM, and we explored a 4-drug regimen in relapsed disease. Preliminary results of a phase 2 study of dara KPd with a twice/week schedule of K showed an ORR of 86% in pts with a median of 1 prior line (Jasielec et al., ASH 2020). Here we report an ongoing study of dara with weekly KPd (dara wKPd) to improve the accessibility of this regimen. Methods: This phase 2 study (NCT04176718) will enroll up to 43 pts with relapsed/refractory MM who have received at least 1 prior therapy, including both lenalidomide and a proteasome inhibitor. Prior therapy with dara, K, or P was permitted except for K and P given together as last line of therapy. Dara wKPd was given on a 28-day schedule. Dara was given according to the dara Pd schedule. An initial cohort received dara 16 mg/kg iv (with first dose split over two days); the trial was amended to dara 1800 mg sc. K 56 mg/m2 iv was given weekly on days 1, 8, 15; for C1D1, dose was 20 mg/m2. P 4 mg was given po on days 1-21. Dex 40 mg was given weekly with the dose split over two days. Treatment was until progression or unacceptable toxicity. The primary endpoints are overall response and the safety profile of dara wKPd. Secondary endpoints include PFS. Results: At time of data cutoff, 24 pts were enrolled; median age was 65 (range 42-73), and median number of prior regimens was 2 (range 1-3). All pts were refractory to their last line of therapy and had prior lenalidomide and bortezomib. Additional prior therapies included: pomalidomide (54%), carfilzomib (13%), ixazomib (46%), cyclophosphamide (4%), auto SCT (29%). High risk FISH was present (out of 24 pts): del 17p (13%); t(14;16) (8%); gain of 1q (46%). Median follow up was 8.4 months. 2 pts came off study due to neutropenia leading to delay in treatment. Grade 3-4 hematologic AEs included neutropenia (46%) and thrombocytopenia (25%). There was 1 episode of febrile neutropenia. Common non hematologic AEs (all; grade 3-4) included fatigue (42%; 0%); dyspnea (38%; 4%); increase in ALT/AST (29%; 8%); insomnia (21%; 0%); neuropathy (17%; 0%). 22 pts were evaluable for response, with an overall response rate of 95% (PR 23%, VPGR 68%, CR 5%). Median PFS at 12 months was 86.2% (95% CI, 70%-100%). Conclusions: Dara wKPd shows some of the highest response rates (95%) reported to date in relapsed/refractory MM. This likely reflects the incorporation of 4 active drugs in 1 regimen and builds on the efficacy of dara-based triplet regimens, with manageable toxicity and convenience of weekly K. Clinical trial information: NCT04176718.

Zanubrutinib for the treatment of adults with Waldenstrom macroglobulinemia

INTRODUCTION

The development of Bruton tyrosine kinase (BTK) inhibitors has significantly changed the treatment landscape for patients with Waldenström macroglobulinemia (WM). Ibrutinib was the first BTK inhibitor to receive FDA approval for this disease, but in recent years additional more selective BTK inhibitors have become available. Zanubrutinib, the most recently FDA-approved therapy for WM, has demonstrated comparable efficacy regarding hematologic response, but with an improved side effect profile compared to other BTK inhibitors.

AREAS COVERED

In this review, we highlight the pivotal studies that have formed the foundation for the use of zanubrutinib in WM, including safety and efficacy data from prospective clinical trials of the currently available BTK inhibitors.

EXPERT OPINION

BTK inhibitors are very effective in WM and have an overall response rate higher than 90%. The side effect profile of these medications is manageable, but does include a risk of atrial fibrillation, infection, and bleeding. The newer BTK inhibitors, such as acalabrutinib and zanubrutinib, are known to have less off-target effects and are potential treatment options. BTK inhibitors should be considered as a treatment option in treatment-naïve and previously treated disease depending on the individual patient preferences, comorbidities, and molecular profile.

Quality of life, psychological distress, and prognostic perceptions in patients with multiple myeloma

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 perceptions of prognosis by line of therapy are lacking.

METHODS

The authors conducted a cross-sectional, multisite study of patients undergoing treatment for MM (excluding maintenance) between June 2020 and January 2021. The authors conducted purposeful sampling and recruited patients to 3 cohorts based on lines of therapy: 1) newly diagnosed receiving first-line therapy; 2) 2 to 3 lines; and 3) 4 or more lines. Patients completed validated questionnaires to assess their QOL, fatigue, psychological distress, and perceptions of prognosis.

RESULTS

A total of 180 patients with MM were enrolled (newly diagnosed [n = 60], 2 to 3 lines [n = 60], and ≥4 lines of therapy [n = 60]). QOL, symptom burden, and fatigue scores did not differ by lines of therapy. There were no statistically significant differences in psychological distress by line of therapy. The rates of clinically significant depression, anxiety, and post-traumatic stress disorder symptoms were 23.9% (43 of 180), 23.9% (43 of 180), and 24.4% (44 of 180), respectively. Most patients (84.7%, 149 of 176) reported that their oncologist told them their cancer was incurable, but only 30.6% (53 of 173) acknowledged that they were terminally ill, and 42.0% (73 of 174) reported that they thought their cancer was incurable.

CONCLUSIONS

Patients with MM undergoing treatment experience impaired QOL and elevated psychological distress across the disease continuum, regardless of line of therapy. A substantial proportion of patients with MM have significant misperceptions about their prognosis and the curability of their illness despite reporting being informed of the prognosis by their oncologist.

LAY SUMMARY

This study discusses 180 patients with MM (newly diagnosed [n = 60], 2-3 lines [n = 60], and ≥4 lines of therapy [n = 60]). Quality of life, symptom burden, and fatigue scores do not differ by lines of therapy. There are also no statistically significant differences in psychological distress by line of therapy. The rates of clinically significant depression, anxiety, and post-traumatic stress disorder symptoms are 23.9%, 23.9%, and 24.4%, respectively. Most patients (84.7%) report that their oncologist told them their cancer was incurable, but only 30.6% acknowledge that they are terminally ill, and 42.0% report that they thought their cancer was incurable.

Venetoclax in Previously Treated Waldenström Macroglobulinemia

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.

Phase 1 study of ibrutinib and the CXCR4 antagonist ulocuplumab in CXCR4-mutated Waldenström macroglobulinemia

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.

Lifestyle considerations in multiple myeloma

As the prognosis for multiple myeloma (MM) has significantly improved and patients remain on therapy longer, there is a need for supportive care interventions to optimize patient quality of life (QOL) and functional status over the course of cancer treatment. MM is characterized by a significant symptom burden and a relatively lower QOL compared to other cancers. This review evaluates the role of healthy lifestyle behaviors in improving both the physical functioning and psychological well-being of the MM population. We (1) describe the current literature on physical activity, weight management, diet, sleep, and substance use in the context of MM, (2) present important considerations for incorporating lifestyle factors into clinical practice, and (3) identify directions for future research. Developing MM-specific guidelines for modifiable lifestyle changes that take into account both the length of treatment and the unique disease features (i.e. osteolytic lesions and anemia) may provide a promising path for improved patient QOL and functioning.

Long-term follow-up of ibrutinib monotherapy in treatment-naive patients with Waldenstrom macroglobulinemia

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.

Natural history of Waldenström macroglobulinemia following acquired resistance to ibrutinib monotherapy

Ibrutinib is highly active and produces long-term responses in patients with Waldenström macroglobulinemia (WM), but acquired resistance can occur with prolonged treatment. We therefore evaluated the natural history and treatment outcomes in 51 WM patients with acquired resistance to ibrutinib monotherapy. The median time between ibrutinib initiation and discontinuation was 2 years (range, 0.4-6.5). Following discontinuation of ibrutinib, a rapid increase in serum IgM level was observed in 60% (29/48) of evaluable patients, of whom 10 acutely developed symptomatic hyperviscosity. Forty-eight patients (94%) received salvage therapy after ibrutinib. The median time to salvage therapy after ibrutinib cessation was 18 days (95% CI 13-27). The overall and major response rates to salvage therapy were 56% and 44%, respectively, and the median duration of response was 48 months (95% CI 34-not reached). Quadruple-class (rituximab, alkylator, proteasome inhibitor, ibrutinib) exposed disease (OR 0.20, 95% CI 0.05-0.73) and salvage therapy 07 days after discontinuing ibrutinib (OR 4.12, 95% CI 1.07-18.9) were identified as independent predictors of a response to salvage therapy. The 5-year overall survival (OS) following discontinuation of ibrutinib was 44% (95% CI 26-75%). Response to salvage therapy was associated with better OS after ibrutinib (HR 0.08, 95% CI 0.02-0.38). TP53 mutations were associated with shorter OS, while acquired BTKC481S mutations had no impact. Our findings reveal that continuation of ibrutinib until subsequent treatment is associated with improved disease control and clinical outcomes.

Perceptions of prognosis in caregivers of multiple myeloma (MM) patients

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Background: Caregivers of patients with cancer play a critical role in supporting patients when making informed decisions about their medical care. Although MM patients and their caregivers face an incurable illness, data describing caregiver perceptions of the patient’s prognosis and factors associated with accurate prognostic perceptions are lacking. Methods: We conducted a cross-sectional, multisite study of caregivers of MM patients between 6/2020-1/2021. Eligible caregivers were identified by the patient as the primary caregiver and enrolled in 1 of 3 cohorts based on lines of therapy: 1) caregivers of newly diagnosed patients receiving first-line therapy; 2) 2-3 lines; 3) ≥4 lines. Caregivers completed the Perception of Treatment and Prognosis Questionnaire to assess their perceptions of the illness and prognosis. We also used the CareGiver Oncology Quality of Life (QOL) questionnaire, the Hospital Anxiety and Depression Scale, the Post-Traumatic Stress Disorder Checklist–Civilian Version, and the Brief COPE to assess caregiver QOL, psychological distress, and coping strategies. We used a multivariate logistic regression analysis to examine whether caregiver factors (i.e. demographics), line of therapy, QOL, psychological distress, or coping were associated with caregiver perceptions of the patient’s prognosis. Results: We enrolled 113 caregivers of MM patients (newly diagnosed (n=39), 2-3 lines (n=37), and ≥ 4 lines (n=37)). Overall, 89.2% (99/111) of caregivers reported that it is ‘extremely’ or ‘very’ important to know about the patient’s prognosis and the majority (58.0%, 65/112) stated that they had received adequate information regarding the patient’s prognosis. Caregivers reported that prognostic information was ‘extremely’ or ‘very’ helpful in making decisions about treatment (93.3%, 97/104), preparing for the future (88.2%, 90/102), and coping with the disease (85.6%, 89/104). Most caregivers (84.7%, 94/111) reported that the oncologist told them the patient’s cancer was incurable. In contrast, only 53.6% (59/110) of caregivers reported that they thought the patient’s cancer was incurable and 48.6% (52/107) acknowledged that the patient is terminally ill. In a multivariate analysis, we found that the use of positive reframing coping (OR=0.71, 95%CI=0.52-0.97, P=0.033) was associated with lower odds of reporting an accurate perception of prognosis. Caregiver demographics, line of therapy, QOL, and psychological distress were not associated with their perceptions of the patient’s prognosis. Conclusions: Although the majority of caregivers of MM patients report that knowing the patient’s prognosis is extremely important, a substantial minority still have significant misperceptions of the patient’s prognosis. Interventions are needed to promote effective coping and enhance caregiver perceptions of the patient’s prognosis to facilitate informed decision-making in this population.

Bone marrow involvement and subclonal diversity impairs detection of mutated CXCR4 by diagnostic next-generation sequencing in Waldenström macroglobulinaemia

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.

Tandem high-dose influenza vaccination is associated with more durable serologic immunity in patients with plasma cell dyscrasias

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.

Clinical application of genomics in Waldenström macroglobulinemia

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

Long-Term Follow-Up of Ibrutinib Monotherapy in Symptomatic, Previously Treated Patients With Waldenström Macroglobulinemia

We report the long-term findings and final analysis of a pivotal multicenter trial of ibrutinib monotherapy in previously treated patients with Waldenström macroglobulinemia (WM).

Consensus Statement on the Management of Waldenström Macroglobulinemia Patients During the COVID-19 Pandemic

In the light of the COVID-19 pandemic, the International Workshop on Waldenström Macroglobulinemia (IWWM) Treatment Recommendations Panel felt the need to provide a consensus statement for the management of Waldenström Macroglobulinemia (WM) patients during this challenging time. We followed the current recommendations by the American Society of Hematology, which have been modified accordingly to fit the specific realities associated with the management of WM. In this Consensus Statement, the Panel addresses questions related to treatment initiation, preferred therapies, minimizing visit to clinics and infusions centers, supportive care and guidance for WM patients in clinical trials. Finally, we also provide information on timing and appropriateness of testing and management of COVID-19 infected patients, as well as ways to get physicians and patients involved in registry studies that could help others.

Genomic Landscape of Waldenström Macroglobulinemia and Its Impact on Treatment Strategies

Next-generation sequencing has revealed recurring somatic mutations in Waldenström macroglobulinemia (WM), including MYD88 (95%-97%), CXCR4 (30%-40%), ARID1A (17%), and CD79B (8%-15%). Deletions involving chromosome 6q are common in patients with mutated MYD88 and include genes that modulate NFKB, BCL2, Bruton tyrosine kinase (BTK), and apoptosis. Patients with wild-type MYD88 WM show an increased risk of transformation and death and exhibit many mutations found in diffuse large B-cell lymphoma. The discovery of MYD88 and CXCR4 mutations in WM has facilitated rational drug development, including the development of BTK and CXCR4 inhibitors. Responses to many agents commonly used to treat WM, including the BTK inhibitor ibrutinib, are affected by MYD88 and/or CXCR4 mutation status. The mutation status of both MYD88 and CXCR4 can be used for a precision-guided treatment approach to WM.

Clinical and Serologic Responses After a Two-dose Series of High-dose Influenza Vaccine in Plasma Cell Disorders: A Prospective, Single-arm Trial

BACKGROUND

Patients with multiple myeloma (MM) and other plasma cell disorders are highly susceptible to influenza infections, which are major causes of morbidity in this population, despite the routine administration of a seasonal influenza vaccination. Existing data are limited by small and retrospective studies, which suggest poor seroprotection rates of < 20% after standard influenza vaccination in patients with MM.

PATIENTS AND METHODS

Patients with plasma cell dyscrasia (n = 51) were treated with a 2-dose series of high-dose inactivated trivalent influenza vaccine during the 2014 to 2015 influenza season. Laboratory-confirmed influenza infections were identified through seasonal surveillance, sera were collected for influenza hemagglutination antibody inhibition (HAI) titer assays, and logistic regression models were used to identify the clinical correlates to the HAI serologic responses.

RESULTS

Influenza vaccine was well tolerated, without any vaccine-related grade ≥ 2 adverse events. Only 3 patients (6%) experienced laboratory-confirmed influenza. The rates of HAI seroprotection against all 3 vaccine strains (A/California/7/2009 [H1N1] pdm09-like virus; A/Texas/50/2012 [H3N2]-like virus; and a B/Massachusetts/2/2012-like virus) increased from 4% at baseline to 49% and 65% after 1 and 2 doses, respectively. The risk factors associated with a lower likelihood of HAI serologic response included plasma cell disorder requiring therapy, less than a partial response found on disease response assessment, and active conventional chemotherapy. Alternatively, active therapy with an immunomodulatory drug alone or with a proteasome inhibitor was associated with a greater likelihood of an HAI serologic response.

CONCLUSION

These data have demonstrated that, in contrast to the historically poor results with standard influenza vaccination, this novel high-dose booster vaccination strategy leads to high rates of seroprotection. Randomized controlled studies are needed to compare this novel strategy to the standard vaccination strategy.

Clonal Immunoglobulin against Lysolipids in the Origin of Myeloma

Antigen-driven selection has been implicated in the pathogenesis of monoclonal gammopathies. Patients with Gaucher's disease have an increased risk of monoclonal gammopathies. Here we show that the clonal immunoglobulin in patients with Gaucher's disease and in mouse models of Gaucher's disease-associated gammopathy is reactive against lyso-glucosylceramide (LGL1), which is markedly elevated in these patients and mice. Clonal immunoglobulin in 33% of sporadic human monoclonal gammopathies is also specific for the lysolipids LGL1 and lysophosphatidylcholine (LPC). Substrate reduction ameliorates Gaucher's disease-associated gammopathy in mice. Thus, long-term immune activation by lysolipids may underlie both Gaucher's disease-associated gammopathies and some sporadic monoclonal gammopathies.

Long-term outcomes to fludarabine and rituximab in Waldenström macroglobulinemia

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/m(2) per day for 5 days) of fludarabine and 8 infusions (375 mg/m(2) 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.

Thalidomide and rituximab in Waldenstrom macroglobulinemia

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/m(2) 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, Collapse

Key Words Collapse

MESH Headings

• Adult
• Aged
• Aged, 80 and over
• Antibodies, Monoclonal/administration & dosage
• Antibodies, Monoclonal/adverse effects
• Antibodies, Monoclonal, Murine-Derived
• Antineoplastic Combined Chemotherapy Protocols/adverse effects
• Antineoplastic Combined Chemotherapy Protocols/therapeutic use
• Disease-Free Survival
• Dose-Response Relationship, Drug
• Drug Administration Schedule
• Female
• Follow-Up Studies
• Humans
• Immunoglobulin M/blood
• Male
• Middle Aged
• Neoadjuvant Therapy
• Receptors, IgG/genetics
• Rituximab
• Thalidomide/administration & dosage
• Thalidomide/adverse effects
• Treatment Outcome
• Waldenstrom Macroglobulinemia/blood
• Waldenstrom Macroglobulinemia/drug therapy
• Waldenstrom Macroglobulinemia/genetics

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Grants

• K23 CA087977 NCI NIH HHS
• K23CA087977-03 NCI NIH HHS

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Novel agents in the treatment of Waldenström's macroglobulinemia

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

Establishment of BCWM.1 cell line for Waldenström's macroglobulinemia with productive in vivo engraftment in SCID-hu mice

A significant impairment in understanding the biology and advancing therapeutics for Waldenstrom's macroglobulinemia (WM) has been the lack of a representative cell line and animal model. We, therefore, report on the establishment of the BCWM.1 cell line, which was derived from the long-term culture of CD19(+) selected bone marrow lymphoplasmacytic cells isolated from an untreated patient with WM. BCWM.1 cells morphologically resemble lymphoplasmacytic cells (LPC) and propagate in RPMI-1640 medium supplemented with 10% fetal bovine serum. Phenotypic characterization by flow cytometric analysis demonstrated typical WM LPC characteristics: CD5(-), CD10(-), CD19(+), CD20(+), CD23(+), CD27(-), CD38(+), CD138(+), CD40(+), CD52(+), CD70(+), CD117(+), cIgM(+), cIgG(-), cIgA(-), ckappa(-), clambda(+), as well as the survival proteins APRIL and BLYS, and their receptors TACI, BCMA and BAFF-R. Enzyme-linked immunosorbent assay studies demonstrated secretion of IgMlambda and soluble CD27. Karyotypic and multicolor fluorescence in situ hybridization studies did not demonstrate cytogenetic abnormalities. Molecular analysis of BCWM.1 cells confirmed clonality by determination of IgH rearrangements. Inoculation of BCWM.1 cells in human bone marrow chips implanted in severe combined immunodeficient-hu mice led to rapid engraftment of tumor cells and serum detection of human IgM, lambda, and soluble CD27. These studies support the use of BCWM.1 cells as an appropriate model for the study of WM, which in conjunction with the severe combined immunodeficient-hu mouse model may be used as a convenient model for studies focused on both WM pathogenesis and development of targeted therapies for WM.

Multicenter Clinical Trial of Bortezomib in Relapsed/Refractory Waldenstrom's Macroglobulinemia: Results of WMCTG Trial 03-248

PURPOSE

Waldenstrom's macroglobulinemia (WM) is a B-cell disorder. Despite advances in the therapy, WM remains incurable. As such, novel therapeutic agents are needed for the treatment of WM.

EXPERIMENTAL DESIGN

In this multicenter study, 27 patients with WM received up to eight cycles of bortezomib at 1.3 mg/m(2) on days 1, 4, 8, and 11. All but one patient had relapsed/or refractory disease.

RESULTS

Following therapy, median serum IgM levels declined from 4,660 to 2,092 mg/dL (P < 0.0001). The overall response rate was 85%, with 10 and 13 patients achieving minor and major responses, respectively. Responses were prompt and occurred at median of 1.4 months. The median time to progression for all responding patients was 7.9 (range, 3-21.4+) months. The most common grade III/IV toxicities occurring in > or =5% of patients were sensory neuropathies (22.2%), leukopenia (18.5%), neutropenia (14.8%), dizziness (11.1%), and thrombocytopenia (7.4%). Sensory neuropathies resolved or improved in nearly all patients following cessation of therapy.

CONCLUSIONS

The results of these studies show that bortezomib is an active agent in relapsed and refractory WM.

Genetic linkage of Fc gamma RIIa and Fc gamma RIIIa and implications for their use in predicting clinical responses to CD20-directed monoclonal antibody therapy

BACKGROUND

Polymorphisms in FcgammaRIIa and FcgammaRIIIa 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 FcgammaRIIIa but not FcgammaRIIa. One possibility for this discrepancy might involve linkage of polymorphisms between FcgammaRIIa and FcgammaRIIIa.

MATERIALS AND METHODS

As such, we performed allelespecific polymerase chain reaction and directed sequencing of the genomic DNA coding region of FcgammaRIIA and FcgammaRIIIA for 52 healthy individuals.

RESULTS

Two common polymorphisms were observed for FcgammaRIIA (at positions 27 and 131) and FcgammaRIIIA (at positions 48 and 158). Importantly, we observed linkage among polymorphisms within and between FcgammaRIIa and FcgammaRIIIa, including the expression of histidine at FcgammaRIIa-131 and valine at FcgammaRIIIa, both of which are associated with enhanced responses to rituximab. The results of these studies demonstrate that there is wide linkage within and between polymorphisms in FcgammaRIIa and FcgammaRIIIa and might provide an explanation for why polymorphisms at FcgammaRIIa are associated with rituximab responses despite a lack of impact on IgG1 binding.

CONCLUSION

Knowledge of such linkages could facilitate the development of diagnostic tests aimed at identifying patients who might be more suitable for treatment with rituximab and possibly other therapeutic antibodies.

Hepatitis C viral infection is not associated with Waldenström's macroglobulinemia

While a familial predisposition may exist in up to 20% of patients with Waldenström's Macroglobulinemia (WM), the precipitating cause of this B-cell malignancy remains unknown in most patients. In previous studies, an association between hepatitis C virus (HCV) infection and WM has been suggested as etiological. This relationship has been the subject of debate, however, with some studies demonstrating increased incidence of HCV infection among WM patients and other studies showing no such association exists. This discordance might be attributable to the analytical method used, HCV antibody detection, which might be ineffective in patients with immunosuppression. We therefore analyzed the prevalence of HCV in a large population of WM patients utilizing both an HCV antibody detection immunoassay as well as qualitative polymerase chain reaction assay to directly detect HCV presence in serum samples. None of 100 randomly tested WM patients in this study tested positive for HCV by either analytical method. Our results therefore demonstrate a lack of association between HCV and WM.

CD52 is expressed on human mast cells and is a potential therapeutic target in Waldenstrom's Macroglobulinemia and mast cell disorders

BACKGROUND

Alemtuzumab is a monoclonal antibody used in the treatment of CD52-expressing B-cell malignancies, including Waldenstrom'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.

PATIENTS AND METHODS

We therefore examined BMMCs (FceRI+, CD117+) from WM and other mast cell (MC) disorders for expression of CD52.

RESULTS

We identified cell surface antigen expression by multicolor flow cytometric analysis and found CD52 expressed on human mast-derived cell line-1 (HMC-1) and LAD2 MC lines, on BMMC from 13 of 15 patients with WM, and on BMMCs from 4 of 4 patients with systemic mastocytosis (SM). None of 4 healthy donors expressed CD52. Reverse-transcriptase polymerase chain reaction analysis confirmed CD52 expression in the HMC-1 and LAD2 MC lines, in BMMCs from 14 of 15 patients with WM, and 3 of 3 patients with SM. CD52 transcripts were also detected in BMMCs from 6 of 6 healthy donors, despite the absence of CD52 cell surface expression. Importantly, we observed high levels of alemtuzumab-mediated, antibody-dependent, cell-mediated cytotoxicity against LAD2 MCs and BMMCs from patients with WM and SM.

CONCLUSION

These studies demonstrate that CD52 is widely expressed on human MCs and WM bone marrow lymphoplasmacytic cells and provide the preclinical rationale for the use of alemtuzumab in the treatment of WM and possibly other MC-related disorders.

Mast cells in Waldenstrom's macroglobulinemia support lymphoplasmacytic cell growth through CD154/CD40 signaling

Bone marrow (BM) mast cells (MC) are commonly found in association with lymphoplasmacytic cells (LPC) in patients with Waldenström's macroglobulinemia (WM). We therefore sought to clarify the role of MC in WM. Co-culture of sublethally irradiated HMC-1 MC, KU812 basophilic cells, or autologous BM MC along with BM LPC from WM patients resulted in MC dose-dependent tumor colony formation and/or proliferation as assessed by 3H-thymidine uptake studies. Furthermore, by immunohistochemistry, multicolor flow cytometry and/or RT-PCR analysis, CD40 ligand (CD154), a potent inducer of B-cell expansion, was expressed on BM MC from 32 of 34 (94%), 11 of 13 (85%), and 7 of 9 (78%) patients, respectively. In contrast, MC from five healthy donors did not express CD154. By multicolor flow cytometry, CD154 was expressed on BM LPC from 35 of 38 (92%) patients and functionality was confirmed by CD154 and CD40 agonistic antibody stimulation, which induced proliferation, support survival and/or pERK phosphorylation of LPC. Moreover, MC induced expansion of LPC from 3 of 5 patients was blocked in a dose dependent manner by use of a CD154 blocking protein. These studies demonstrate that in WM, MC may support tumor cell expansion through constitutive CD154-CD40 signaling and therefore provide the framework for therapeutic targeting of MC and MC-WM cell interactions in WM.

Update on treatment recommendations from the Third International Workshop on Waldenstrom's Macroglobulinemia

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.

Characterization of familial Waldenström's macroglobulinemia

BACKGROUND

Familial clustering of B-cell disorders among Waldenström's macroglobulinemia (WM) patients has been reported, though the frequency and any differences in disease manifestation for familial patients remain to be defined.

PATIENTS AND METHODS

We therefore analyzed clinicopathological data from 257 consecutive and unrelated WM patients. Forty-eight (18.7%) patients had at least one first-degree relative with either WM (n = 13, 5.1%), or another B-cell disorder including non-Hodgkin's lymphoma (n = 9, 3.5%), myeloma (n = 8, 3.1%), chronic lymphocytic leukemia (n = 7, 2.7%), monoclonal gammopathy of unknown significance (n = 5, 1.9%), acute lymphocytic leukemia (n = 3, 1.2%) and Hodgkin's disease (n = 3, 1.2%). Patients with a familial history of WM or a plasma cell disorder (PCD) were diagnosed at a younger age and with greater bone marrow involvement.

RESULTS

Deletions in 6q represented the only recurrent structural chromosomal abnormality and were found in 13% of patients, all non-familial cases. Interphase FISH analysis demonstrated deletions in 6q21-22.1 in nearly half of patients, irrespective of familial background.

CONCLUSIONS

The above results suggest a high degree of clustering for B-cell disorders among first-degree relatives of patients with WM, along with distinct clinical features at presentation based on familial disease cluster patterns. Genomic studies to delineate genetic predisposition to WM are underway.

CD5, CD10, and CD23 expression in Waldenstrom's macroglobulinemia

CD5, CD10, and CD23 are cell surface antigens used to distinguish B-cell disorders. The expression of these antigens and their clinical significance in Waldenstrom'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+ k/l 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 b2 macroglobulin levels; hematocrit; platelet count; or familial history of WM or a related B-cell 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.

Polymorphisms in FcγRIIIA (CD16) Receptor Expression Are Associated With Clinical Response to Rituximab in Waldenström’s Macroglobulinemia

Purpose

Rituximab is an important therapeutic for Waldenström’s macroglobulinemia (WM). Polymorphisms in FcγRIIIA (CD16) receptor expression modulate human immunoglobulin G1 binding and antibody-dependent cell-mediated cytotoxicity, and may therefore influence responses to rituximab.

Patients and Methods

Sequence analysis of the entire coding region of FcγRIIIA was undertaken in 58 patients with WM whose outcomes after rituximab were known.

Results

Variations in five codons of FcγRIIIA were identified. Two were commonly observed (FcγRIIIA-48 and FcγRIIIA-158) and predicted for amino acid polymorphisms at FcγRIIIA-48: leucine/leucine (L/L), leucine/arginine (L/R), and leucine/histidine (L/H). Polymorphisms at FcγRIIIA-158 were phenylalanine/phenylalanine (F/F), phenylalanine/valine (F/V), and valine/valine (V/V). A clear linkage between these polymorphisms was detected and all patients with FcγRIIIA-158F/F were always FcγRIIIA-48L/L, and patients with either FcγRIIIA-L/R or -L/H always expressed at least one valine at FcγRIIIA-158 (P ≤ .001). The response trend was higher for patients with FcγRIIIA-48L/H (38.5%) versus -48L/R (25.0%) and LL (22.0%), and was significantly higher for patients with FcγRIIIA-158V/V (40.0%) and -V/F (35%) versus -158F/F (9.0%; P = .030). Responses for patients with FcγRIIIA-48L/L were higher when at least one valine was present at FcγRIIIA-158 (P = .057), thereby supporting a primary role for FcγRIIIA-158 polymorphisms in predicting rituximab responses. With a median follow-up of 13 months, no significant differences in the median time to progression and progression-free survival were observed when patients were grouped according to their FcγRIIIA-48 and -158 polymorphisms.

Conclusion

The results of these studies therefore support a predictive role for FcγRIIIA-158 polymorphisms and responses to rituximab in WM.

Extended rituximab therapy in Waldenström's macroglobulinemia

BACKGROUND

Waldenström's macroglobulinemia (WM) is a CD20 expressing B-cell malignancy represented by the pathological diagnosis of IgM secreting lymphoplasmacytic lymphoma. Major response rates of 30% have been reported in most studies with standard dose rituximab, i.e. 4 weekly infusions at 375 mg/m(2)/week.

METHODS

In an effort to increase rituximab activity in WM, an extended dose schedule employing two sets of four (375 mg/m(2)/week) infusions at weeks 1-4 and 12-16 was evaluated. Expression of the complement resistance antigens CD46, CD55 and CD59 was also evaluated on tumor cells pre- and post-therapy to determine impact on response.

RESULTS

Twenty-nine patients were enrolled and 26 patients completed the intended therapy. On an intent to treat analysis, 14 (48.3%) patients achieved a partial response, and 5 (17.2%) patients achieved a minor response. Responses were observed in 18/24 (75%) patients with a serum IgM level of <6000 mg/dl, and only 1 of 5 (20%) patients with a level of >6000 mg/dl (P=0.03). The median time to best response was 17 months, and only 2 of 19 responding patients progressed with a median follow-up of 29 months. No differences in baseline expression of the complement resistance antigens CD46, CD55 and CD59 were observed among responding and non-responding patients, although post-therapy CD55 expression was higher in non-responding patients (P=0.002).

CONCLUSIONS

These data show that extended rituximab therapy is active and may lead to more major responses over standard dose rituximab in WM. WM patients with serum IgM levels of <6000 mg/dl are more likely to benefit from extended rituximab therapy.

Clinical Responses to Sildenafil in Waldenstrom's Macroglobulinemia

Waldenstrom's macroglobulinemia (WM) is an incurable B-cell malignancy. Interestingly, an unusual response activity was observed in 5 patients with WM that appeared related to their use of sildenafil, a phosphodiesterase inhibitor used to treat erectile dysfunction. One patient demonstrated a complete remission, and 4 other patients demonstrated less dramatic, but also unexpected, responses associated with sildenafil. In view of these findings, WM tumor cells were culture-sorted with sildenafil at pharmacologically achievable levels and apoptosis was demonstrated in tumor cells from all 5 patients. These studies suggest that sildenafil may be an active agent in the treatment of WM.

Paradoxical increases in serum IgM and viscosity levels following rituximab in Waldenstrom's macroglobulinemia

BACKGROUND

The anti-CD20 monoclonal antibody rituximab is an important therapeutic in Waldenstrom's macroglobulinemia (WM), producing response rates of 50-70%. Responses, which are based on serum IgM levels, have typically been evaluated at 12 weeks. Paradoxically, we have observed that serum IgM levels can abruptly rise following rituximab therapy in patients with WM, and can often lead to morbidity on the basis of hyperviscosity.

PATIENTS AND METHODS

Eleven WM patients with CD20+ tumor cells who received rituximab at our Institution and had serum IgM levels measured within a 12-week period following start of therapy were evaluated. Therapy consisted of four weekly infusions of rituximab at 375 mg/m(2). Pre- and post-therapy serum IgM levels were determined by nephelometry and corresponding serum viscosity levels were determined by viscometry.

RESULTS

Ten of the 11 patients demonstrated an abrupt rise in serum IgM levels, with a >25% increase occurring in eight (73%) patients. Mean serum IgM levels for all 10 spiking patients rose from 4370 (range, 655-7940) to a peak of 5865 (range, 872-11 800) mg/dl (P=0.004), which occurred at a mean of 4 (range, 1-8) weeks following initiation of therapy. Mean serum viscosity levels also increased from 3.5 to 5.6 centipoise (CP) (P=0.09) in eight patients for whom pre- and post-therapy studies were obtained. A subdural hemorrhage occurred in one patient when serum IgM levels rose from 7530 to 11 800 mg/dl, and serum viscosity increased from 3.9 to 10.1 CP. Two other spiking patients with pre-therapy IgM levels of >5000 mg/dl experienced worsening headaches and/or epistaxis attributed to increasing serum viscosity.

CONCLUSIONS

Abrupt increases in serum IgM levels commonly occur following rituximab therapy in WM. Careful clinical and laboratory monitoring is warranted, particularly if patients have pre-therapy serum IgM levels of >5000 mg/dl. The mechanism of this effect is under active investigation, and may be related to CD20 signaling triggered by rituximab.

Uniform response criteria in Waldenstrom's macroglobulinemia: consensus panel recommendations from the Second International Workshop on Waldenstrom's Macroglobulinemia

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.

Prognostic markers and criteria to initiate therapy in Waldenstrom's macroglobulinemia: consensus panel recommendations from the Second International Workshop on Waldenstrom's Macroglobulinemia

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 <or= 10 g/dL or a platelet count < 100 x 10(9)/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 beta(2)-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.

Treatment recommendations in Waldenstrom's macroglobulinemia: consensus panel recommendations from the Second International Workshop on Waldenstrom's Macroglobulinemia

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.

Clinicopathological definition of Waldenstrom's macroglobulinemia: consensus panel recommendations from the Second International Workshop on Waldenstrom's Macroglobulinemia

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.