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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 Multiple myeloma (MM) is a hematological cancer characterized by the proliferation of plasma cells (PC). Progressive disease (PD) criteria are primarily characterized by an increase in (1) serum M-protein (SPEP), (2) urinary M-protein (UPEP), (3) serum free light chains (sFLC), or (4) PC percentage in the bone marrow. An essential aspect of the PD criteria is the requirement for confirmatory results from blood or urine analyses. However, in many cases, patients may be taken off treatment in favor of a new therapy after only one assessment. This can introduce clinical trial endpoint inaccuracies when confirmatory values are missing, resulting in increased censoring and underestimation of the progression rate (if the second assessment is not done). Moreover, in subjects with high tumor burden and rapidly progressing disease, it is often urgent to confirm PD before starting a subsequent line of treatment. This study assessed the necessity of repeating biomarkers to confirm PD if two biomarkers meet the progression criteria. Methods In this retrospective study, between 2002 and 2020, we assessed all consecutive patients with relapsed MM enrolled in any therapeutic clinical trial at Mayo Clinic. We included patients with measurable disease if SPEP and sFLC were available at the time of assessment. Patients required at least two consecutive assessments (by the same method) to be included in our study. PD was based on the IMWG criteria. Relapse characterized by the development of new bone lesions or extramedullary relapse without meeting biochemical progression criteria was an exclusion criterion. Patients starting a new line of treatment after non-confirmed PD were also excluded. Furthermore, patients who did not meet simultaneous progression criteria and had unconfirmed PD (did not meet IMWG criteria at the second assessment) were excluded from the analysis (n=15). The probability of meeting the progression threshold with 1 and 2 consecutive assessments was calculated. We then examined the proportions of patients meeting PD by 2 biomarkers simultaneously at the first assessment. Results We evaluated episodes of treatment among 434 patients enrolled in clinical trials, including 601 episodes: 593 episodes of biochemical confirmed PD and 8 episodes when patients did not progress but who met simultaneous progression criteria at the same time with two different biomarkers. Per measurable disease criteria, MM isotypes were 71.0% IgG, 16.8% IgA, 0.9% IgM, 1.2% IgD, 0.3% biclonal, and 9.8% light chain. According to the standard IMWG response criteria (sequential criteria), 78% and 9% of episodes reached the progression threshold with serum and urine M-components, respectively, with two consecutive assessments. For the FLC, 21% of episodes met the progression criteria. No patients had a second bone marrow examination for confirmation of PD. At the first available assessment, 82%, 19%, and 2% of episodes met progression threshold, respectively, with serum M-protein, urine M-protein, and both (serum + urine M-protein). Additionally, 58%, and 19%, episodes met the progression threshold at the first assessment with FLC and bone marrow examination, respectively. Moreover, 67% of patients with IgA myeloma meet the progression threshold with the total quantitative IgA. With the simultaneous criteria at time of first assessment, 403 episodes meet progression threshold: 45% with SPEP+sFLC (n=269/593), 4% with SPEP+UPEP (n=21/593), 9% with sFLC+UPEP (n=55/593), 11% with BME only (n=66/593), and 0.3% with qIgA +dFLC/UPEP (n=2/593). Thus, among these 413 episodes, which meet progression criteria by 2 simultaneous values at the time of the first assessment, 98% (n=413/(413+8)) of these patients (positive predictive value of the new criteria) subsequently had confirmed progression by sequential value. Conclusions In summary, we showed that the simultaneous criteria allow to identify patients with true progressive disease without overestimating the progression rate of myeloma. Therefore, confirmatory results of progression for relapsed MM patients having two biomarkers meeting criteria of progression at the same time is useless for determining disease progression.

Background. Study of myeloid neoplasms (MN) has been rapidly transformed by genome characterization. Gene mutations have been reported to influence disease phenotype and risk of disease progression, and the evaluation of mutational status can provide valuable insights to improve the decision-making process. In this international study, we evaluated the clinical impact of mutational screening in patients with CMML, which is characterized by significant clinical and genomic heterogeneity, including a substantial proportion of patients with poor outcomes and unmet needs. Currently, only limited molecular information has been incorporated into CMML classification and prognostication. Methods. We retrospectively collected 3182 CMML patients. We used MOSAIC, an AI-based framework for multimodal analysis in rare cancers (PMID: 38875514) to develop innovative, molecular-based tools for classification and prognostication. An independent validation of the results on 516 prospectively collected patients was performed. Results. Bayesian Networs and Hierarchical Dirichlet Processes were used to identify genomic associations and define a CMML molecular classification. We identified 11 clusters with distinct clinical and genomic features, including splicing machinery, signal transduction and tyrosine kinase pathways aberrations, and high-risk molecular signatures (i.e., AML-like and TP53 mutations). Up to 15% of patients showed clear genomic overlap with other MN. Importantly, extensive multi-color flow cytometry on T lymphocytes, NK and myeloid cells (BD FACSymphony A5 Cell Analyzer) revealed specific immunologic and inflammation signatures associated with molecular subgroups. We then integrated molecular and clinical information to build an international CMML Prognostic Scoring System (iCPSS). We assessed the performance of different statistical and AI-based methods; L1-penalized Cox Model resulted as the best performing method. Selected features included hematological parameters (WBC, Hb, PLT and marrow blasts), cytogenetic abnormalities, and mutations in 10 genes (ASXL1, DNMT3A, EZH2, NRAS, RUNX1, SETBP1, STAG2, TET2, TP53, U2AF1). By Bayesian thresholds optimization, we identified 5 risk classes (i.e., very-low, low, intermediate, high and very-high) with median overall survival (OS) ranging from 99 to 9 months (P<.001), and median leukemia-free survival (LFS) ranging from 210 to 18 months (P<.001). iCPSS provided better patient discrimination across all clinical endpoints compared to currently available prognostic tools, with a Concordance Index (CI) for OS of 0.75 versus 0.62-0.64, respectively. Notably, compared to available scoring systems, up to 40% of patients were reassigned to higher or lower risk classes by the iCPSS. External validation on an independent prospective cohort confirmed that the performance of iCPSS is superior to existing prognostic models (CI for OS 0.71 vs 0.54-0.61, respectively) To demonstrate the clinical utility of iCPSS, we focused on 753 patients who underwent allogeneic stem cell transplantation (HSCT). In multivariable analysis, iCPSS stratified the probability of OS post-HSCT (P<.001) and identified groups of patients with different probabilities of disease relapse, ranging from 9% to 62% (P<.001). We employed a clinical- and genomic-based decision support system (PMID: 38723212) to determine the optimal timing of HSCT. Preliminary analyses indicated that higher-risk patients according to iCPSS (i.e., intermediate, high, and very high) benefit from an immediate HSCT strategy. Lower-risk patients (i.e., very low and low) had life expectancy maximized with delayed HSCT. Modeling decision analysis using iCPSS compared to conventional scores, resulted in a change in transplantation policy for a significant proportion of patients (up to 25%). Conclusion. Molecular information significantly improves the classification of CMML patients, providing a basis for refining diagnostic boundaries with other MN and for a more rational inclusion of patients in clinical trials. The iCPSS demonstrated superior performance over currently available scoring systems and improved HSCT decision making process.

Introduction: Response assessment is used to evaluate effectiveness of hypomethylating agent (HMA)-based therapy in myelodysplastic syndromes/neoplasms (MDS) in clinical practice and trials. Recently, the clinical response criteria (IWG 2023) and the clinical-molecular risk assessment (IPSS-M) in MDS were published. However, it remains unknown whether the IWG 2023 response criteria have an independent impact on overall survival (OS) when adjusting for baseline IPSS-M risk. Additionally, the association of IWG 2023 response criteria with OS in patients (pts) undergoing allogeneic stem cell transplantation (allo-HCT) versus those who do not is unknown. Lastly, it is unclear if optimal time-to-transplant impacts OS in MDS pts who achieve a IWG 2023 defined remission with HMA therapy. We examined these questions in a large population of MDS pts within the multi-institutional international consortium for MDS (icMDS) VALIDATE database. Methods: High-risk MDS pts with IPSS ≥1.5 or IPSS-R >3.5 treated with HMA-based therapy were included in the study. Baseline IPSS-M risk was stratified into very low/low/moderate low (VL+L+ML), moderate-high/high (MH+H), and very high (VH). Response to treatment was evaluated using the IWG 2023 criteria and grouped into: composite complete response (cCR) and no cCR. cCR included: complete response (CR), CR equivalent (CRequ), CR bilineage (CRbi), CR unilineage (CRuni), and CR with partial hematologic recovery (CRh). We analyzed the differential impact of achieving cCR on HMA-based therapy prior to transplant on OS in pts who either did or did not undergo allo-HCT, while adjusting for their baseline IPSS-M risk in Cox regression analysis. Optimal time-to-transplant was determined based on age and IPSS-M category as described by Tentori et al. (JCO 2024). Pts proceeding to allo-HCT were stratified on whether they underwent transplant within the optimal time-to-transplant timeframe after MDS diagnosis or not. VALIDATE protocol was exempted, acknowledged, or approved by all centers' IRBs. VALIDATE is supported by an independent grant from AbbVie. Results: We analyzed 762 MDS pts. The median age at MDS diagnosis was 68 years (range: 19-95 years) and 64% of pts were male. Distribution of the baseline IPSS-M risk was: VL+L+ML in 110 (14%) pts, MH+H in 347 (46%) pts, VH in 305 (40%) pts. Pts received azacitidine monotherapy, decitabine monotherapy, and HMA-based combination therapy (e.g. HMA + venetoclax) in 52%, 21%, and 28% of cases, respectively. A total of 282/762 (37%) pts achieved cCR as their best response to HMA-based therapy. The median OS for all pts was 18.7 months (95% CI: 16.6-21.3 months). Pts who did not undergo allo-HCT (n=436, 57%) had an improved median OS if they achieved cCR when compared to pts in the no cCR group in all IPSS-M risk groups (VL+L+ML: 23.5 months vs. 10.7 months; MH+H: 20.8 months vs. 11.6 months; VH: 13.8 months vs. 7.5 months). Cox analysis demonstrated an independent effect of cCR on OS in these pts when adjusted for baseline IPSS-M risk (cCR vs. no cCR: HR 0.60, 95% CI 0.48-0.76, p<0.001). In contrast, in pts who subsequently received an allo-HCT (n=326, 43%), achieving cCR with HMA prior to allo-HCT did not provide an additional OS benefit, when adjusted for baseline IPSS-M risk (cCR vs. no cCR: HR 1.00, 95% CI 0.73-1.38, p=0.986). The median time-to-transplant was 6.7 months and 34% of transplanted MDS pts received their allo-HCT during the optimal timeframe. Among pts who achieved cCR with HMA-based therapy prior to allo-HCT, optimal time-to-transplant was associated with significantly improved OS (optimal vs. non-optimal timing: HR 0.55; p=0.033). Conclusion: Baseline IPSS-M risk and allo-HCT had an independent impact on OS, while IWG 2023 defined cCR had an independent effect on OS only in non-transplanted MDS pts. While this retrospective analysis occurred at large academic centers with specific expertise in the management of MDS, our data may have an impact on clinical practice: (i) failure to achieve cCR on HMA therapy prior to transplant should not impact the decision to proceed to allo-HCT, (ii) upfront allo-HCT without prior HMA therapy might also be an option if the clinical situation and availability of donors allow, and (iii) allo-HCT should ideally be performed during the timeframe that is considered optimal as defined by pt age and baseline IPSS-M.

Background: Light chain (AL) amyloidosis is a rare and understudied plasma cell disorder. It is caused by abnormal misfolding of monoclonal immunoglobulin light chains, leading to extracellular deposition of amyloid, ultimately resulting in organ dysfunction and death. Since AL amyloidosis is uncommon, therapies are adapted from the more common plasma cell disorders like multiple myeloma. Daratumumab, a monoclonal antibody targeting CD38, was first tested in several prospective and retrospective studies in AL patients with relapsed refractory disease. The ANDROMEDA study (Kastritis E et al, NEJM 2021) established daratumumab in combination with CyBorD (Cyclophosphamide-Bortezomib-Dexamethasone) followed by daratumumab maintenance as the new standard of care compared to CyBorD alone for newly diagnosed patients. Consequently, daratumumab maintenance has become universally offered to all newly diagnosed AL amyloidosis patients. Notably, there was no second randomization before the initiation of maintenance therapy in ANDROMEDA. Hence, a critical question that remains is whether the superior efficacy observed in the investigational arm of the ANDROMEDA trial is solely a result of the addition of daratumumab during the induction phase or if the maintenance phase contributed to the favorable outcomes in the investigational arm. We hypothesize that a shorter duration of maintenance would prove non-inferior to the standard duration of daratumumab maintenance in patients with AL amyloidosis that have responded to Daratumumab-CyBorD induction. To answer this question we are conducting a pragmatic phase 2 randomized trial assessing the optimal duration of daratumumab maintenance in patients with AL amyloidosis who have responded to Daratumumab-CyBorD induction. Study Design, Patients and Methods: We use broadened eligibility criteria consistent with pragmatic trial design. The estimated total enrollment is up to 96 patients. The main eligibility criteria are patients with biopsy-proven AL Amyloidosis who have completed 6 cycles of Dara-CyBorD-based induction treatment and achieved an adequate response to induction (defined as hematological complete response (CR), hematological very good partial response (VGPR), or hematological partial response (PR) with at least one organ response). Patients in whom bortezomib and/or cyclophosphamide were omitted from induction due to toxicity concerns or adverse effects are allowed. The major exclusion criteria are patients who were concomitantly diagnosed with multiple myeloma based on International Myeloma Working Group (IMWG) criteria. This phase II, open-label, multicenter trial (NCT05898646) randomizes patients who have attained an adequate response to 6 cycles of Dara-CyBorD-based induction in a 1:1 ratio, using a dynamic allocation procedure that balances the marginal distributions of the stratification factors (age, cardiac stage, and t(11;14) status). Randomization is to either single-agent daratumumab maintenance of 6 cycles duration (experimental arm) or 18 cycles of daratumumab maintenance (control arm) (cycle = 28 days). Treatment is allowed to be given at a local facility After completing maintenance treatment, patients will follow up every 3 months for up to 36 months from registration. The primary endpoint of the trial is to evaluate the non-inferiority of a shorter (6 cycles) daratumumab maintenance measured by event-free survival (EFS) compared to the standard maintenance of 18 cycles in newly diagnosed AL amyloidosis who receive 6 cycles of daratumumab-CyBorD based induction. EFS in this study is defined as time from registration to any of the following events: hematological progression, organ progression, subsequent anti-plasma cell therapy in the absence of hematological progression but with persistent organ dysfunction or death, whichever occurs first. Secondary endpoints are depth of hematological and organ response, bone marrow measurable residual disease negativity rate, duration of response, quality of life, and survival. By investigating whether a shorter duration of maintenance is non-inferior to the standard duration, we aim to inform clinical practice and potentially reduce the toxicities associated with prolonged maintenance therapy, including hypogammaglobulinemia, recurrent infections, the need for intravenous gammaglobulin replacement, and financial toxicity.

Introduction. Platelet-activating anti-Platelet factor 4 (PF4) antibodies mediate a number of thrombotic thrombocytopenic syndromes, including heparin-induced thrombocytopenia (HIT), and more recently recognized conditions, vaccine-induced immune thrombotic thrombocytopenia (VITT), adenovirus-associated thrombotic thrombocytopenia, and monoclonal gammopathy of thrombotic significance (MGTS). In MGTS (Blood. 2023 Apr 6;141(14):1772-1776), a monoclonal IgG antibody to PF4 mediates a chronic prothrombotic state characterized by recurrent thrombosis. More recent evidence suggests that MGTS may present with negative results in HIT enzyme-linked immunosorbent assay (ELISA) and serotonin release assay (SRA), and positivity only in PF4-dependent functional assays such as the PF4-dependent P-selectin expression assay (PEA; submitted). The presence of MGUS in patients has long been associated with high risks of thrombotic disease (Blood. 2010 Jun 17;115(24):4991-8), but the mechanism by which they predispose to thrombosis has been relatively unexplored. In this study, we evaluated a cohort of MGUS patients who experience thrombosis for the presence of platelet-activating anti-PF4 antibodies. M ethods. An administrative database search was performed of Mayo Clinic records to identify patients who had a diagnosis of MGUS, and thrombosis. Research samples from 134 MGUS patients with IgG monoclonal protein and thrombosis were obtained from Mayo Clinic's dysproteinemia biobank and subjected to PF4 antigen-based and functional screening. Research studies were approved by the Institutional Review Board of Mayo Clinic. Results. Of the 134 patients, 17 (12.7%) activated platelets in the PEA (≥19%). To exclude non-specific activation (e.g. due to HLA antibodies), secondary PEA testing was performed to assess whether platelet activation was mediated by a HIT-like antibody (i.e., PF4- and IgG-dependent, and inhibitable with high concentrations of heparin). Four patients, hereafter referred to as patients 1-4, were identified as having a HIT-like antibody, as demonstrated by PF4-dependent platelet activation that could be inhibited with high concentrations of heparin (100 U/mL), and blockade of the platelet IgG receptor, FcγRIIa. Patients 1 and 2 had persistent, platelet-activating anti-PF4 antibodies based on PEA testing of multiple samples obtained several years apart. Patient 1 had a recurrent, multi-year history of deep venous thrombosis (DVT), while patient 2 had one DVT episode. Patient 3 demonstrated a HIT antibody-like profile in the PEA in two of three samples available for testing and had a history of thrombotic cerebrovascular accident (CVA). Patient 4 demonstrated a HIT-like platelet-activating antibody in only one of four samples tested, and consistent with this finding, had an MGUS identified on clinical testing at only one time point (“small” IgG lambda, not quantified), 3 months prior to the platelet-activating sample. This patient experienced multiple thrombotic events including DVTs, left atrial thrombus and embolic CVA, pulmonary embolism and acute limb ischemia. All patients tested negative in two FDA-approved antigen-based HIT assays tested (Immucor PF4 IgG and Zymutest HIA IgG), similar to a recent MGTS case (submitted). SRA was negative in both Patients 1 & 2, weakly positive in Patient 3 (33%, with high CV), and positive (72%) in Patient 4. Conclusions. Definitive diagnosis of patients with MGTS provides insight into a mechanism of “unexplained” thrombosis and may offer additional treatment pathways for these patients with recurrent thrombosis (New Eng J of Med, 2024 Aug 8). Serologic testing in two patients correlated strongly with observations of thrombosis, and the study confirmed recent findings that anti-PF4 antibodies may present with unusual serology that is neither HIT- nor VITT-like (with negative results in both ELISA and SRA). The incidence of confirmed/suspected MGTS was 3% (4/134) in this population of MGUS patients with thrombosis. Prospective studies are needed to confirm these observations.

Background: Acute promyelocytic leukemia (APL) is one of the most treatable leukemias in the current era, with cure rates upwards of 90%. Early mortality due to coagulopathies often seen at diagnosis is a major driver of adverse outcomes. Prompt initiation of all-trans retinoic acid (ATRA) is crucial for suspected APL, as it is known to reverse these coagulopathies. Chemotherapy-free protocols consisting of arsenic trioxide (ATO) and ATRA have become the standard of care for low-risk APL with high cure rates and reduced hematologic toxicities. For high-risk disease, there are multiple treatment options that have not been compared. Since APL is rare, there is a lack of real-world data for this disease. This retrospective review aimed to assess the outcomes of APL patients (pts) across multiple institutions and to examine the most common induction regimens, characteristics linked to early (30-day) mortality, and supportive care strategies. Methods: This retrospective study involved 9 institutions in the US and was conducted through the Consortium on Myeloid Malignancies and Neoplastic Diseases (COMMAND). Data included pts admitted from 8/5/2006 through 2/3/2024 with a confirmed diagnosis of APL. Each institution received a data-collection form and contributed data on APL pts from presentation to last follow-up. Key data categories included patient demographics, presenting laboratory and molecular data, treatment regimen, supportive care, and patient outcomes. Results: Data for 412 pts were identified with a median age of 51 (range 17-90) and 49% were female. Cardiovascular comorbidities were present in 44% of pts and 16% had a known pulmonary comorbidity. At presentation 109 (27%) had high risk-disease, defined as a white blood cell count (WBC) greater than 10 x 109/L. A FLT3 mutation was seen in 50% of tested pts, WT1 (22%), KRAS (3.6%), and NRAS (6.5%). The median WBC at presentation was 2 x 109/L (range: 0-166 x 109/L) and the median platelet count was 27 x 109/L (range: 2.0-315 109/L). Twenty-six percent presented with grade 2+ thrombosis, bleeding, or both. A higher percentage of pts with high-risk vs. low-risk disease presented with grade 2+ thrombosis, bleeding, or both (43% vs. 20%), DIC (60% vs. 36%), and mutated FLT3 (81% vs. 37%). The majority of pts received a chemotherapy-free induction regimen consisting of ATRA plus ATO. It was determined that 36 (8.7%) pts received induction with intermittent ATO plus ATRA (Burnett AK, Lancet Oncol 2015), 276 (67%) received daily ATO plus ATRA (Ravandi F, J Clin Oncol 2009 and Lo Coco, NEJM 2013), and 70 (17%) received a regimen inclusive of an anthracycline plus ATRA. Eleven pts did not start an induction regimen other than single-agent ATRA due to early death, while 19 had their regimen classified as “other” because they did not follow a conventional induction path. In total, 295/358 (82%) received ATRA within 24 hours of admission. At least 1 dose of gemtuzumab ozogamicin was given to 58 (14%) pts, of which 35 (60%) were considered high risk. The incidence of differentiation syndrome (DS) was 37% (n=154). Among the 243 pts who received steroid prophylaxis, 30% developed DS, compared to 52% of those who did not receive prophylaxis. Among the 360 pts with at least 1 available PCR result after starting induction, 94% achieved PCR-negativity. The 30-day mortality rate was 6.6%. On univariate analysis, presenting variables associated with a higher 30-day mortality include older age, diabetes, cardiovascular comorbidities, thrombosis or bleeding, DIC, eGFR < 60, elevated total bilirubin and D-dimer levels, and high-risk disease. The median overall survival (OS) of the cohort was not reached, and the 5- and 10-year OS was 88% (95% CI: 84-91%) and 79% (95% CI: 72-87%) respectively. The cumulative incidence of relapse at 3 years was 2.7% (95% CI: 1.4 - 5.1%), with no additional relapses observed. The incidence of CNS relapse at 3 years was 0.9% (95% CI: 0.3% - 2.8%), with 2 of the 4 pts classified as high-risk. Conclusion: This is the largest real-world evidence data collection in the US evaluating the outcome of pts with APL in the current era, inclusive of ATO as front-line induction. Outcomes for this disease remain extremely positive, with low 30-day mortality rates noted in this study along with durable OS rates and low incidence of relapse. Additional information on outcomes, safety, and supportive care will be presented at the meeting.

Introduction: Measurable residual disease (MRD) is a well-validated prognostic marker and interim outcomes measure in patients with multiple myeloma (MM). Despite its broad acceptance as a robust prognostic marker, the MRD status is only available down the treatment line, and there is limited information on the markers at diagnosis that can predict achievement of MRD negativity post-transplant. This study explored the relationship between baseline risk factors and post-autologous stem cell transplantation (post-ASCT) MRD status, as well as the combined impact of these baseline factors and post-ASCT MRD status on progression-free survival (PFS) and overall survival (OS). Patients and Methods: We conducted a retrospective, single-center study of patients achieving at least VGPR after ASCT between 01/01/2016 and 12/30/2023, majority (n=814, 98%) received ASCT in the frontline setting. MRD testing was performed between days 60-100 post-transplant using next-generation flow cytometry with a sensitivity of at least 1x10^5 nucleated cells (minimum 2x10^6 cells assessed). Treatment response and disease progression were determined by IMWG criteria. High-risk disease (HRD) was defined as presence of International Staging System ISS stage 3, high lactate dehydrogenase, 1q gain, 17p deletion, or t(4;14) chromosomal abnormalities. We calculated PFS/OS from transplant day 0 to first documented event (progression or death). Categorical variables were compared using chi-square and Fisher's exact tests. Non-parametric tests compared continuous variables, and logistic regression analyses tested associations between clinical/lab variables and MRD status post-ASCT. Time-to-event analyses were performed using Kaplan-Meier and compared using log-rank test. Multivariable analyses were conducted using the Cox regression model. Result: The study cohort included 831 newly diagnosed MM patients. The median follow-up for the cohort was 50 months (95% CI: 48-51). 48% (n=402) achieved MRD negativity (MRD-neg) post-ASCT. Univariate analysis demonstrated that R2-ISS stage, depth of response pre-ASCT, and presence of t(11;14) to be associated with worse MRD-negativity rates. Multivariate analysis revealed that t(11;14) significantly decreased the odds of MRD-negativity (p<0.0001, OR=0.4, 95% CI: 0.3-0.6) and a deeper pre-ASCT response was associated with increase odd of MRD-negativity OR-4.7 (95%CI 3.2-7.4) p<0.0001. Patients with MRD-positive disease post-transplant had an inferior estimated median PFS of 57.6 months (95% CI: 49-69) with a 5-year PFS of 49% (95% CI: 43-56), compared to an estimated median PFS of 83.3 months (95% CI: NA) and a 5-year PFS of 66% in MRD-negative patients (p<0.0001, HR=1.9, 95% CI: 1.5-2.5). Similarly, MRD positivity was associated with an inferior OS [estimated median of 92.6 months (95% CI NA) ,5-year OS 76% (95%CI 72-82) for MRD-pos vs. Median OS NR, 5-year OS 85%(95%CI NA) in MRD-neg; p=0.003, HR=1.69, 95% CI: 1.2-2.38)]. In MRD-neg patients, a baseline bone marrow plasma cells BMPC% >60% was significantly associated with worse PFS (HR=1.9, 95% CI: 1.26-2.99; p<0.01). High-risk disease was not associated with an inferior PFS or OS in patients with MRD-negativity. For MRD-neg patients, estimated median PFS was not reached for those without HRD, 5-year PFS was 66% (95%CI 51-85), compared to 83 months(95%CI 65-NA) for those with HRD, 5-year PFS was 65%(95%CI57-74), p=0.6441. The median OS was not reached in either group (p=0.07). Five-year OS was 94% (95%CI 86-100) in MRD-neg without HRD vs. 81%(95%CI 75-87) with HRD (p=0.07). In MRD-pos patients, median PFS was 81 months (95%CI 58-NA) for those without HRD, 5-year PFS of 59% (95%CI 46-77), compared to PFS of 41 months(95%CI 36-52) for those with HRD ,5-year PFS of 39% (95%CI 31.3-47) , p=0.003. Median OS was not reached in MRD-pos patients without HRD, but it was 59.8 months ( for those with HRD (p=0.0012). Five-year OS was 94% (95%CI 89-99) in MRD-pos without HRD vs. 67%(95%CI 60-74) with HRD (p<0.0001). For every 1 log increase in the residual cell % on MRD testing in MRD-pos patients, the hazard ratio for PFS increased by 42% (p=0.0002, HR=1.42, 95% CI: 1.2-1.7). Conclusion: Patients with t(11;14) have a reduced likelihood of achieving MRD negativity post-ASCT, whereas high-risk cytogenetics did not impact MRD-negativity rates. Achievement of MRD negativity post-ASCT mitigates the impact of high-risk characteristics.