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Introduction: For cardiac transthyretin (ATTR) amyloidosis, bone scintigraphy has emerged as a noninvasive diagnostic tool. The use of different tracers, namely Pyrophosphate (PYP), 3,3-diphosphono-1,2-propanodicarboxylic acid (DPD), HydroxymethyleneDiphosphonate (HMDP), allow for the detection of amyloid deposits in the heart. The aim of this systematic review is to evaluate the diagnostic test accuracy of bone scintigraphy in ATTR and light chain (AL) amyloidosis. Methods: As part of the ASH AL Amyloidosis Diagnostic Guideline, we performed systematic reviews for 7 prioritized PICO questions related to the screening, diagnosis and organ involvement evaluation of AL amyloidosis. Electronic searches were conducted on PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception till January 2024. Two reviewers independently and in duplicate performed title and abstract screening and full text article screening on LASER AI, with conflicts resolved by a third reviewer. Studies were eligible if they included patients that performed both a bone scintigraphy scan and an endomyocardial biopsy for suspicion of ATTR amyloidosis. Test positivity for the visual score was defined to be ≥2, for the heart over contralateral (H/CL) ratio it was > 1.5 at one hour and >1.3 at 3 hours. Diagnostic test accuracy measures of interest were sensitivity, specificity, positive and negative predictive value. Statistical analysis was performed on STATA 18.0. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the certainty of evidence. Results: After deduplication, we retrieved 29,237 studies from electronic databases. 12 studies with 1127 patients reported on visual score in patients suspected to have ATTR amyloidosis. The pooled sensitivity for visual score was 96% (95% CI 92.0-98.0) while specificity was 90% (95% CI 84.0-95.0) (Certainty of evidence (COE): Moderate ⨁⨁⨁◯). 3 studies reported on ATTR visual score in combination with evaluating for monoclonal gammopathy, the pooled sensitivity was decreased to 93% (95% CI 65-99) and while specificity increased to 99% (95% CI 80-100) (COE: Moderate ⨁⨁⨁◯). H/CL was evaluated in 5 studies with 189 patients; pooled sensitivity was 97% (95% CI 89.0-99.0) and specificity was 88% (95% CI 64-97) (COE: Low ⨁⨁◯◯). We also performed subgroup analyses for the diagnostic test accuracy of visual score for the different tracers (PYP, DPD, HMDP) in patients suspected to have ATTR amyloidosis. DPD was found to have the highest sensitivity which was found to be 97% (95% CI 91.0-99.0) and a specificity of 95 (95% CI 86.0-98.0) (4 studies, n = 297 COE: Moderate ⨁⨁⨁◯). The sensitivity and specificity for PYP was 95% (95% CI 87.0-98.0) and 90% (95% CI 79.0-96.0) (7 studies, n = 377 COE: Moderate ⨁⨁⨁◯). 1 study reported on HMDP with a sensitivity and specificity of 79% (95% CI 49.0-95.0) and 100% (95% CI 59.0-100.0) (COE: Low ⨁⨁◯◯). Conclusion: Bone scintigraphy has a high sensitivity and specificity for the diagnosis of ATTR amyloidosis, particularly in patients without a monoclonal gammopathy.

Introduction: Although endomyocardial biopsy is the gold standard, echocardiography, and Cardiac Magnetic Resonance (CMR) play a pivotal role in the diagnosis of cardiac amyloidosis. In this systematic review, we aim to estimate the diagnostic test accuracy (DTA) of CMR and echocardiography for cardiac amyloidosis. Methods: As part of the American Society of Hematology guidelines on the diagnosis of Amyloidosis, we searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception till January 2024 for relevant studies. Two reviewers independently performed title and abstract screening and full-text article screening on LASER Al and extracted relevant data using a piloted Excel sheet. We performed statistical pooling using Stata 18.0 software. We evaluated risk of bias using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of the evidence. We report diagnostic test accuracy as sensitivity (95% confidence interval) and specificity (95% confidence interval). Results: After screening 29,237, we included 9 studies assessing DTA of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) using an endomyocardial biopsy (EMB) as a reference test in patients with amyloidosis (light chain and ATTR). The majority of studies didn't report on the type of amyloidosis where only 2 out of 9 were in patients with light chain amyloidosis. The pooled estimates for sensitivity and specificity of LGE are 0.95 (0.88. 0.98), and 0.81 (0.60, 0.92), respectively. We did a sensitivity analysis and included only LGE suggestive for amyloidosis which didn't change sensitivity but led to an increase in specificity for amyloidosis to 0.87 (0.76, 0.94), respectively. The pooled estimates were based on moderate certainty in the evidence. For 2-dimensional echocardiography, we addressed DTA for different echocardiographic findings and we did not limit the reference to EMB. A panel of experts judged whether the reference was acceptable or not. Acceptable reference was EMB alone or a combination of extracardiac biopsy plus cardiac imaging (CMR or echocardiography) with or without positive cardiac biomarkers (troponin or BNP or NT-proBNP). Six studies (n=2063) addressed interventricular septum thickness (IVS), sensitivity was 0.77 (0.69, 0.84) and specificity was 0.71 (0.60, 0.81). 4 out of 6 studies used 12 mm as a cutoff while the other 2 studies used 13 mm as a cutoff. Only 2 studies (n=1667) assessed the DTA of posterior wall thickness (PWT), with sensitivity ranging from 0.76 to 1.00, and specificity ranging from 0.84 to 0.89. Six studies (n=438) addressed diastolic dysfunction (grade 2,3), with a sensitivity of 0.71 (0.40, 0.90), and specificity of 0.75 (0.64, 0.84). 7 studies (n=472) reported DTA of only diastolic dysfunction grade 3. When compared to diastolic dysfunction (grade 2,3, sensitivity decreases to 0.42 (0 28. 0.58) and specificity increases to 0.89 (0.83. 0.94). For E/A ratio, only 2 studies (n=127) were included. Sensitivity ranged from 0.45 to 0.65, and specificity ranged from 0.85 to 0.98. Four studies (n=1596) yielded a sensitivity of 0.86 (0.65, 0.95) and specificity of 0.76 (0.55, 0.89) of left ventricular global longitudinal strain (GLS). All except one used -17% as a cutoff for GLS. For apical sparing on GLS, pooled estimates from 8 studies (n=2253) led to a sensitivity of 0.72 (0.64, 0.78) and specificity of 0.78 (0.64, 0.88). There was a variation of cutoff across studies. The certainty of evidence for echocardiographic findings was low to moderate. Conclusion: CMR is a more accurate test with better performance compared to echocardiography.

Introduction: Systemic amyloid light chain (AL) amyloidosis is a rare disease with severe sequelae, including cardiac and renal dysfunction and failure. Various biomarker-based staging systems have been established to inform prognosis and treatment. However, a single International Classification of Diseases, Tenth Revision (ICD-10) diagnosis code collectively applies to all stages of the disease, and while several studies have reported disease costs using healthcare claims data, stage-specific costs are not well understood. The current study aimed to estimate the healthcare utilization and costs of prevalent patients with AL amyloidosis by Mayo 2012 stage (I, II, III, IV). Methods: A multi-center medical chart review of patients with AL amyloidosis was conducted across six hematology clinics in the United States. Enrolled patients were ≥18 years old with a diagnosis of AL amyloidosis, documentation of Mayo 2012 stage at diagnosis, ≥1 office visit during the 6 months prior to the site's IRB approval date, and ≥1 year of available medical records. We collected 1 year of healthcare utilization data for each patient, in addition to clinical characteristics at diagnosis, which was prior to the 1-year observation period for most patients. Observation periods ranged from 11/2020 to 6/2023. Demographics, AL amyloidosis clinical history (e.g., organ involvement, lines of therapy, treatment response), laboratory values, and AL amyloidosis-related healthcare utilization (e.g., office visits, laboratory tests, procedures, medications, emergency department visits, inpatient stays) were collected. Patients were stratified by Mayo 2012 stage at diagnosis. Patients' 1-year healthcare costs were calculated by combining abstracted utilization data with the Centers for Medicare and Medicaid Services 2023 Physician Fee Schedule for procedures, Medi-Span® Price Rx® Pro for pharmacy and drug administration costs, and published literature for costs unavailable in these sources. Costs were adjusted to 2023 USD using the Consumer Price Index inflation calculator from the US Bureau of Labor Statistics. Results: The study included 61 patients: 15 stage I, 16 stage II, 17 stage III, and 13 stage IV. Overall, patients had a mean age at diagnosis of 62.4 years (standard deviation ([SD] 10.1), 39.3% were female (n=24), and 67.2% (n=41) of patients were non-Hispanic White, 14.8 % (n=9) Non-Hispanic Black, 6.6% (n=4) Asian, 1.6% (n=1) Hispanic, and 9.8% (n=6) other race/ethnicity. Most patients had Medicare (45.9%, n=28) or private health insurance (34.4%, n=21). The average duration of disease (i.e., time from diagnosis to date of last office visit prior to their site's IRB approval date) was 4.5 years (SD 3.5). All patients had involvement of ≥1 organ system and 45.9% (n=28) had involvement of ≥2 organ systems at diagnosis. More than half of patients had renal (55.7%, n=34) or cardiac (52.5%, n=32) involvement. Nearly all patients completed first-line therapy at any point prior to their last office visit (93.4%, n=57); a minority of patients (9.8%, n=6) initiated first-line therapy, and 3 patients (4.9%) had a hematopoietic stem cell transplantation, one each in stages I, II, and III, during the study period. The median estimated AL amyloidosis-related healthcare costs (USD) during the 1-year study period were $95,253 (interquartile range [IQR] $2,869-497,504) for stage I, $190,796 ($5,249-499,470) for stage II, $414,677 ($28,365-533,081) for stage III, and $523,504 ($191,830-526,596) for stage IV. Discussion: This is the first study of AL amyloidosis that reports costs of care stratified by Mayo 2012 stage. In a prevalent population with AL amyloidosis, we found that overall, patients with AL amyloidosis have significant ongoing costs of care after completion of initial therapy at each Mayo 2012 stage, with stage IV patients having the highest AL amyloidosis-related costs. The percent of patients with cardiac or renal organ involvement is possibly higher than represented in this study; given the rapid progression and high early mortality rate seen with stage III and IV disease, some of these patients may not have fulfilled the 1-year observation period requirement and thus were excluded from the study. These data describe the significant and continued burden faced by patients with AL amyloidosis and the health care system for the years beyond initial diagnosis and completion of front-line treatment.

Splenic marginal zone lymphoma (SMZL) is a B-cell malignancy with a typically indolent course. However, some patients have more aggressive disease and initial treatment can range from observation to chemoimmunotherapy. The reason for this spectrum of disease behavior is incompletely understood but the tumor microenvironment (TME) likely plays a role as recent studies have shown that an optimized antitumor immune response in SMZL patients would allow the immune system to better target malignant B cells and irradicate the disease. Regulatory CD4+T cells (Tregs) are crucial in maintaining TME homeostasis by suppressing effector T cells and malignant B cells and in this study, we therefore explored the key factors influencing the function and development of intratumoral Tregs in SMZL patients. We identified two distinct Treg subsets in the TME of SMZL patients: CD26+Tregs and CD161+Tregs, each with unique phenotypic profiles, functions, and prognostic significance. CD161+Tregs suppress CD8+T cells and malignant B cells more effectively than CD26+Tregs, which only inhibit CD8+T cells. Clinically, patients with inferior outcomes have significantly higher numbers of CD26+Tregs and fewer CD161+Tregs. To delineate differences between these subsets, we performed Cellular Indexing of Transcriptomes and Epitopes Sequencing (CITE-seq) on biopsies from 7 SMZL patients. We found that cytokine-inducible SH2-containing protein (CISH) is the most highly expressed gene in CD26+Tregs compared to CD161+Tregs, aside from FOXP3. CISH has been reported to be a negative regulator of immune effector cell activation in tumor models. Although CISH deficiency leads to a loss of Foxp3 expression and reduced Treg suppressive function, the mechanism by which CISH modulates Treg function, especially immune suppression in hematologic malignancies, remains largely unknown. To further investigate the mechanism of CISH in Treg function in MZL patients, we conducted CITE-seq analysis on a larger cohort of MZL patients (n=12), divided into groups based on outcomes (EFS24 failed, n=4; EFS24 achieved, n=8). The CITE-seq analysis results showed significantly higher CISH expression in Tregs from patients with inferior outcomes (P=1.07E-06). We then explored factors influencing CISH expression and found that TCR engagement and treatment with cytokines (IL-15, IL-2, and IL-7) elevated CISH expression in Tregs. While we previously observed that lymphoma B cells could enhance Foxp3 expression in CD4+CD25-T cells, this study we found that B cells could also enhance CISH and CD26 expression in CD4+CD25-T cells in vitro, indicating that a high frequency of B cells in the environment may lead to increased CISH expression in Treg cells leading to an unfavorable outcome in patients. We further investigated the role of CISH in the function of Treg cells. Following CISH knockdown in Treg cells, we observed decreased CD26 expression and reduced suppressive function on CD8+ T cell proliferation. Using CRISPR-Cas9, we knocked out CISH in the Karpas 299 cell line, a human T cell lymphoma line that constitutively expresses CD25, Foxp3, and CISH. CISH-KO Karpas 299 cells showed significantly less apoptosis and Foxp3 expression compared to CISH-WT cells. Bulk RNA-seq analysis of CISH-KO and CISH-WT Karpas 299 cells revealed that CISH-KO cells showed enhanced DNA replication and cell cycle pathway activity. Taken together, our results suggest that high expression of CISH in Tregs may predict an unfavorable outcome in SMZL patients. Malignant B-cells in the TME of SMZL patients may promote expression of CD26 and CISH in Tregs, thereby modulating Treg function. Targeting CISH could decrease the immunosuppressive activity of Tregs in the TME, potentially optimizing antitumor immunity in SMZL patients.

Introduction: Light-chain (AL) amyloidosis is caused by the secretion of immunoglobulin light chains by monoclonal plasma cells. The increase in the levels of these monoclonal proteins may proceed the development of any clinical symptoms, and their identification in the serum and urine remains an integral part of establishing a diagnosis of AL amyloidosis. This systematic review aims to evaluate the diagnostic test accuracy of serum immunofixation (SIFE), urine immunofixation (UIFE), and free light chain (FLC) ratio for the diagnosis of AL amyloidosis. Methods: As part of the ASH AL Amyloidosis Diagnostic Guideline, we performed systematic reviews for 7 prioritized PICO questions related to the screening, diagnosis and organ involvement evaluation of AL amyloidosis. Electronic searches were conducted on PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception till January 2024. Two reviewers independently and in duplicate performed title and abstract screening and full text article screening on LASER AI, with conflicts resolved by a third reviewer. Eligible studies were those that included patients who performed one of the three tests (SIFE, UIFE, and κ/λ FLC) and had their AL amyloidosis diagnosis confirmed via a biopsy. Diagnostic test accuracy measures of interest were sensitivity, specificity, positive and negative predictive value. Statistical analysis was performed on OpenMeta[Analyst]. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the certainty of evidence. Results: After deduplication, we retrieved 29,237 studies from electronic databases. 31 studies with 3973 patients reported on the use of serum immunofixation (SIFE) with a pooled sensitivity of 72.4% (95% CI 68.1%-76.4%). 27 studies with 2855 patients reported on the use of urine immunofixation UIFE for the diagnosis of AL amyloidosis with a pooled sensitivity of 78.6% (95% CI 74.6%-82%). 29 studies with 5305 patients reported on the use of κ/λ FLC ratio amyloidosis with a pooled sensitivity of 79.9% (95% CI 73.7%-84.9%). 24 studies reported on the use of both SIFE and UIFE with a sample size of 3751 patients and a pooled sensitivity of 90% (95% CI 85.3%-93.3%). 3 studies reported on the use SIFE and κ/λ FLC ratio with 321 patients and a pooled sensitivity of 97.7% (95% CI 95.6%-99.9%). Finally, we identified 10 studies that performed SIFE,UIFE, and κ/λ FLC ratio concurrently with 1926 patients and a pooled sensitivity of 99% (95% CI 97%-99.7%) of all three tests and considering a result abnormal if any of the components had a positive result. We also identified 5 studies with 957 patients reporting on the concurrent use of SIFE, UIFE, and κ/λ FLC ratio for the diagnosis AL amyloidosis and differentiation of AL from ATTR amyloidosis in a population of patients with suspected cardiac amyloid involvement, the pooled sensitivity was found to be 99%(95% CI 99%-100%) and with a pooled specificity of 77%(95% CI 75%-80%). Certainty of evidence moderate for all outcomes. Conclusion: The combined use of SIFE, UIFE, and κ/λ FLC ratio has a high sensitivity for the diagnosis of AL amyloidosis, and the tests remain a valuable initial screening of AL amyloidosis and differentiation from ATTR amyloidosis.

Introduction: In patients with systemic light-chain amyloidosis, cardiac involvement is common. Cardiac involvement (presence and severity) is the most important predictor of mortality in patients with AL amyloidosis. Endomyocardial biopsy remains the gold standard, but it is a costly and invasive test. Consequently, cardiac biomarkers are used for screening for cardiac involvement and have significant prognostic value.In this systematic review, we aim to estimate the diagnostic test accuracy (DTA) of Nt-proBNP, BNP, and high sensitivity troponin for cardiac amyloidosis. Methods: As part of the American Society of Hematology guidelines on the diagnosis of Amyloidosis, we searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception till January 2024 for relevant studies. Two reviewers independently performed title and abstract screening and full-text article screening on LASER Al and extracted relevant data using piloted Excel sheets. The panel judged whether the reference test is acceptable or not. Acceptable reference test is EMB alone or a combination of extracardiac biopsy plus cardiac imaging (CMR or echocardiography) with or without positive cardiac biomarkers (troponin or BNP or NT-proBNP). For statistical analysis, we only included studies reporting on both the sensitivity and specificity of the cardiac biomarker. We used Stata 18.0 software for meta-analysis. We evaluated risk of bias using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of the evidence. We report diagnostic test accuracy as sensitivity (95% confidence interval) and specificity (95% confidence interval). Results: After screening 29,237 studies, a total of 10 studies addressed DTA of Nt-proBNP for cardiac amyloidosis. These studies used a wide variety of cutoffs for diagnosis of cardiac involvement, ranging from 150 to 5000 ng/L and a cutoff of 332 ng/L was the most studied and reported. The pooled estimates for sensitivity and specificity of Nt-proBNP using 332 as cutoffs are 0.99 ( 0.97, 1) and 0.53 (0.3, 0.75), respectively. The pooled estimates were based on 4 studies (n=645) with moderate certainty in the evidence. For BNP, DTA was assessed in 3 studies (n= 257). Each study used a different cutoff for BNP (73, 100, and 412 ng/L). The sensitivity and specificity of BNP in each study were comparable and not significantly affected by the cutoff variation. Pooled sensitivity and specificity across studies, were 0.87 (0.80, 0.92), and 0.79 (0.71, 0.85), respectively. The certainty in evidence for the DTA of BNP was low. Eight studies reported on DTA of high sensitivity troponin, with cutoffs ranging from 14 to 86 ng/L. Meta-analysis of studies reporting on cutoff 14 ng/L yielded sensitivity of 0.94 (0.87, 0.97) and specificity of 0.11 (0.08, 0.16) with moderate certainty evidence. Increasing the cutoff to 35 ng/l led to a decrease in sensitivity to 0.82 (0.66, 0.92) and an increase in specificity to 0.86 (0.74, 0.93) with low certainty evidence. Conclusion: Cardiac biomarkers are highly sensitive, valuable initial tests for increasing suspicion of cardiac involvement in patients with AL amyloidosis. However, they lack specificity and, on their own, are insufficient for a definitive diagnosis of cardiac involvement. These biomarkers may be used in conjunction with other diagnostic tests to accurately identify and assess the extent of cardiac involvement.

Background: Despite substantial improvements in early mortality (EM) for patients with systemic light chain amyloidosis (AL), rates remained high in the bortezomib-era, at approximately 25% (Muchtar et al. Blood. 2017). However, the therapeutic landscape in AL amyloidosis has changed with the ANDROMEDA trial, which led to the approval of daratumumab in combination with bortezomib, cyclophosphamide, and dexamethasone (Dara-VCd) in the frontline setting. The incidence and predictors of EM in the context of daratumumab-based frontline therapy have not been studied. Methods: We performed an international multicenter retrospective cohort study of all consecutive patients with newly diagnosed AL treated with frontline Dara-VCd or Dara-Vd, and followed until 12/31/2023. EM was defined as death from any cause within 6 months of treatment initiation. Our primary objective was to identify the rate and significant predictors of EM. Univariate logistic regression was used to identify significant predictors of EM, which were then included in a multivariate logistic regression model. The receiver operator characteristic (ROC) analysis was used to determine the best threshold values that discriminated EM rates for the following continuous variables: age, dFLC (involved-uninvolved), eGFR, NT-proBNP, albumin, and high-sensitivity Troponin-T (hs-TnT). Other variables tested in univariate analysis were the following: ECOG performance status, NYHA functional class, sex, race, light chain isotype, percent bone marrow plasma cells, status of the following cytogenetic abnormalities-t(11;14), +1q, hyperdiploidy, del(13q), high-risk translocations, and del(17p), and the number of organs involved (2 vs 1). To build the clinical prediction score, each variable was weighted according to the β coefficient (natural logarithm of odds ratio) obtained from the multivariable regression. The β coefficients were rounded to the nearest 0.5 and multiplied by 2 to obtain an even number. Results The study cohort included 335 AL patients treated with daratumumab-based frontline therapy (92.2% Dara-VCd, 7.8% Dara-Vd), with all surviving patients having at least 6 months of follow-up. The median age at diagnosis was 66.5 years (range, 59.4 - 71.3), and 6.7% (n = 22) were Non-Hispanic blacks. Median dFLC at diagnosis was 22.91 mg/dL (range, 0.2-1093.4), and median NT-proBNP was 2415 pg/mL (range, 13-70,000). Mayo 2004 stages IIIA/IIIB represented 44% of the total cohort, with 17% having ECOG ≥ 2 and 25.4% having NYHA Class III/IV symptoms. The cumulative incidence of EM was 10.7%, with the incidence in patients with Mayo 2004 stage I, II, IIIA, and IIIB being 0%, 8%, 12.5%, and 25% respectively. On univariate analysis with unadjusted odds ratio (OR), the following variables significantly predicted EM: Age ≥ 75 (OR=2.8, p=0.013) ECOG ≥ 2, (OR 4.9, p<0.001), NYHA Class ≥ III (OR=4.95, p<0.001), dFLC ≥9 mg/dL (OR, 10.18, p=0.023), eGFR <33 mL/min/1.73 m2 (OR=2.7, p=0.026), NT-proBNP >5276 pg/mL (OR=7.69, p <0.001), hs-TnT >70 ng/L (OR=5.88, p<0.001), and absence of t(11; 14) (OR=2.33, p=0.041). These variables were entered into multivariate regression, except for ECOG and NYHA, which were combined to create a single variable (values ranging from 0-8), and hs-TnT was dropped due to substantial missing data as centers used different troponin assays. NT-proBNP was rounded to 5300 pg/ml for ease of clinical application. Based on the multivariate analysis, the following scores were assigned to each variable: Age ≥75 (2.0), ECOG+NYHA (1.0 x combined score), NT-proBNP >5,300 pg/ml (2.0), and absence of t(11;14) (3.0). This led to a score ranging from 1-15, and two risk-groups: low-risk (score <9; 87.5%) and high-risk (score ≥9; 12.5%). The respective cumulative incidence of EM was 6.1% versus 50% (p<0.001). The c-index of the model was 0.725 (95% CI, 0.676-0.774). Conclusion: Using variables that are readily available in the clinic, we have developed a two-tiered risk-prediction model for EM in AL amyloidosis in the context of daratumumab-based frontline therapy. The model needs to be externally validated in an independent dataset.

Background and significance: Light chain (AL) amyloidosis is a plasma cell malignancy characterized by the production of amyloidgenic clonal light chains that deposit in various tissues. The addition of daratumumab to bortezomib, cyclophosphamide and dexamethasone (Dara-VCD) has improved the depth of hematologic and organ responses and is an approved induction therapy in newly diagnosed AL amyloid patients (DOI: 10.1056/NEJMoa2028631). However, this approach has not yet demonstrated an overall survival (OS) benefit and follow up remains short. With strict adherence to eligibility criteria, in particular severity of cardiac involvement, autologous stem cell transplantation (ASCT) as consolidative therapy is safe with transplant related mortality on par with multiple myeloma. This approach generates deep and sustained responses, but it is unclear if it offers an additional survival benefit following Dara-VCD induction. The only randomized trial evaluating the role of ASCT in AL amyloid is outdated (DOI: 10.1056/NEJMoa070484) and no randomized data exist to inform the optimal use of ASCT in the era of Dara-VCD induction. Furthermore, multi-organ involvement in AL amyloid drives morbidity and mortality thus the impact of any consolidative therapy on cardiac and renal involvement in addition to overall survival but must be defined. Finally, the approval of Dara-VCD therapy was based on complete hematologic response rates but there is increasing data demonstrating that achieving minimal residual disease (MRD) negativity by either bone marrow next generation flow cytometry (DOI: 10.1002/ajh.26562) or peripheral blood mass spectrometry (DOI: 10.1038/s41408-020-0291-8) generates improved organ response, hematologic progression free survival, and possibly OS. Methods: This randomized phase 3 SWOG led intergroup trial (S2213; NCT06022939) is being conducted within the United States and will accrue a total of 143 participants per arm. The primary endpoint will compare MOD-PFS (major organ deterioration progression free survival: defined as time from randomization to death, cardiac/renal progression, or hematologic progression) between participants receiving an ASCT with those receiving 3 cycles of Dara-VCD consolidation following 3 cycles of uniform Dara-VCD induction. Following the assigned consolidation, all patients will receive 18 months of daratumumab maintenance therapy. A median MOD-PFS of 31 months is anticipated in the non-ASCT arm. This study has 90% power and a two-sided significance level of 0.05 to detect a hazard ratio of 0.62 corresponding to a MOD-PFS of 50 months in the ASCT arm. Important additional endpoints include OS, hematologic PFS, cardiac and renal responses, MRD negativity both by peripheral blood mass spectrometry and bone marrow next generation flow cytometry, delayed utilization of ASCT, and quality of life. Key inclusion criteria include non-severe cardiac AL amyloid (NT-proBNP <5000; TnT < 0.06; NYHA I or II, EF ≥ 40%), CrCl ≥30 mL/min, serum dFLC > 2 mg/dL, and supine systolic BP ≥ 90 mmHg. Importantly, patients are permitted to have up to one full cycle or 28 days of any plasma cell directed therapy prior to enrollment. This trial was activated on 12/1/2023 with the first patient enrolled 07/01/2024. Funding: NIH/NCI/NCTN grants U10CA180888, U10CA180819; and in part by Janssen Pharmaceuticals Inc. of Johnson & Johnson (now J&J Innovative Medicine).

Introduction MYD88 L265P mutations (MUT) are found in 90% of patients with Waldenstrom macroglobulinemia (WM) and lead to the activation of pro-survival signaling. Limited literature has demonstrated that patients with MYD88 wild-type (WT) WM have poorer responses to conventional therapies and a higher likelihood of histological transformation. Increasingly the role of non-coding genomics in lymphomagenesis has demonstrated importance and currently, the epigenetic landscape of MYD88 WT WM remains underexplored. This study utilized a multi-omics approach to assess DNA methylation in MYD88 WT WM compared to MYD88 MUT patients and controls. Methods Bone marrow samples were prospectively collected from 20 subjects [3 MYD88 WT/CXCR4 WT WM, 12 MYD88 MUT WM and 5 normal controls] and positive selection for CD19+ and/or CD138+ B cells was performed. The analysis focused on the comparison between MYD88 WT WM to normal controls and MYD88-WT to MUT WM. Genome-wide DNA methylation analysis was performed, and CpG methylation ratios were segmented into 200-bp regions. Differentially methylated regions (DMRs) were determined using a Q-value <0.05 and absolute methylation difference ≥10%. Next, RNA-seq data was interrogated and differentially expressed genes (log2fold change>0.5 or <-0.5, false discovery rate<0.05) with corresponding promoter hypo- or hypermethylation were assessed. Ingenuity Pathway Analysis was used to determine potentially epigenetically regulated pathways using a corrected p<0.05. Results Comparing MYD88 WT WM samples to controls, a statistically greater number of hypermethylated DMRs were observed across genomic regions (hyper- vs hypomethylated): promoter (29129 vs 6300), 3'untranslated region (UTR) (2068 vs 1551), 5'UTR (10169 vs 735), intron (30344 vs 24511), exon (2224 vs 6855), CpG island (30372 vs 1240) and CpG shore (14477 vs 5872) (all p<0.001). Next, mRNA analysis demonstrated that 214 genes were differentially up-/downregulated with concordant promoter hypo-/hypermethylation. On the assessment of promoter-methylation-based pathways, multiple pathways involved in cell signaling, proliferation, gene regulation, cytokine and immune signaling and metabolism were found to be deregulated. Most pathways were found to be negatively enriched in MYD88 WT patients compared to controls including several members of interleukin (IL) signaling (IL-2, IL-3, IL,7) and regulators of cell proliferation and signaling including mTOR, PI3K/AKT, and p53. Positive enrichment of the PTEN, FGFR3 and ERK/MAPK pathways were observed. Underlying multiple pathways was promoter hypermethylation with corresponding mRNA downregulation of AKT3 and PIK3CA. Furthermore, promoter hypomethylation with transcript upregulation of PTEN was observed. Next, in comparison of MYD88 WT to MUT samples, a statistically greater number of hypermethylated DMRs were observed across genomic regions (hyper- vs hypomethylated): promoter (24829 vs 2544), 3'UTR (3534 vs 378), 5'UTR (6111 vs 605), intron (52292 vs 5360), exon (21066 vs 2187), CpG island (18334 vs 1551) and CpG shore (16351 vs 1957) (all p<0.001). Assessing mRNA expression, 354 genes were up-/downregulated with concordant promoter hypo-/hypermethylation. Pathway analysis revealed positive enrichment of the mitotic G1 phase to G1/S transition pathway with upregulation of the CDK4, LYN, and PSMA6 transcripts in MYD88 WT compared to MUT samples. Further, negative enrichment of cell signaling regulators including the RHO GTPase family, IL pathways (IL-4, IL-8, IL-13, IL-17) and integrin signaling were found in MYD88 WT compared to MUT samples. Underlying multiple pathways were downregulation with promoter hypermethylation of BCL2, an important regulator of apoptosis. Conclusion Genome-wide methylation analysis of MYD88 WT WM revealed a unique DNA methylation profile, with potential epigenetic alteration of key oncogenic transcripts and pathways. The negative enrichment of cell signaling and cytokine/inflammatory pathways in MYD88 WT samples compared to controls and MYD88 MUT WM suggests an epigenetic mechanism for immune evasion and potentially underlies the reduced response to conventional WM-directed therapies. Overall, this study reveals that MYD88 WT WM is epigenetically distinct from MYD88 MUT WM and regulators such as methylation may underlie the unique clinical and phenotypic properties observed.

Abstract Waldenstrom macroglobulinemia (WM) is a lymphoplasmacytic lymphoma associated with an increase in serum immunoglobulin M (IgM) monoclonal protein. The underlying causes of the disease are still not fully understood, but cells in the bone marrow (BM) microenvironment (TME) are anticipated to play a significant role in disease progression. We previously reported that myeloid-derived suppressor cells (MDSCs), a phenotypically heterogeneous group of cells known for their ability to suppress immune responses, are expanded in the bone marrow of patients with WM and that the expansion of MDSCs is particularly notable for increased numbers of polymorphonuclear MDSCs (PMN-MDSCs). In the present study, we evaluated the ability of WM cells to attract MDSCs to the tumor microenvironment (TME). We also evaluated whether PMN-MDSCs suppress the cytotoxic function of T-cells and thereby promote the survival of WM cells. Our study confirms the expansion of MDSCs, notably PMN-MDSCs in BM of WM patients as compared to normals. We also found that PMN-MDSCs expressing CD66b was a predominant population in WM patients. To determine the phenotype and transcriptome of both PMN-MDSCs and monocytic MDSCs (M-MDSCS) in WM, we compared BM aspirates from WM patients to normal bone marrow (NBM) and performed cellular indexing of transcriptomes and epitopes by sequencing (CITEseq) analysis (WM=3, NBM=2) followed by qPCR validation. We found that MDSCs in WM express significantly higher levels of HIF1-α overall (p<0.02) compared to NBM. Furthermore, PMN-MDSCs are more abundant in WM bone marrow than M-MDSCs and express significantly higher levels of CXCR4 (p<0.001), myeloperoxidase (MPO; p<0.0003), and azuricidin (AZU1; p<0.0004), suggesting an activated phenotype. To determine whether WM cells attract MDSCs to the BM, we performed a transwell assay and showed that WM cells (BCWM.1 cell line) attracted MDSCs, particularly PMN-MDSCs, to a greater extent than M-MDSCs (n=3; p<0.001). We next evaluated whether MDSCs prevent cytotoxic T-cells from lysing WM cells. In-vitro co-culture studies with BCWM.1 cells and T-cytotoxic cells (B:CD8-T) showed that T-cytotoxic cells were able to lyse the WM cell line by 46.4% , (median range 46.4 - 47.8%, p=0.001). However, when BCWM.1 cells and T-cytotoxic cells were co-cultured in the presence of MDSCs (i.e B:CD8-T:M), the specific lysis of BCWM.1 cells was reduced by 12.6% respectively (range 2.2- 12.6%, p<0.001). Furthermore, we observed that B:CD8-T:M co-culture significantly reduced CD8-T cell activation as compared to activated T cells alone (17.9%) (median range 17.8- 18%, p<0.001). In contrast, no affect was observed with B: CD8-T coculture by 91% (range 90.6- 91.4% p<.001) confirming that MDSCs suppress CD8-T cell activation. Our study therefore provides evidence that MDSCs in WM have an activated phenotype and that PMN-MDSCs in WM are attracted by malignant cells in the bone marrow. Furthermore, we find that the increased presence of PMN-MDSCs in the WM bone marrow environment suppresses T-cell lysis of malignant cells and may thereby contribute to disease progression. These findings provide a strong rationale for targeting MDSCs as a potential therapeutic strategy in WM.