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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: Teclistamab (Tec), a first-in-class BCMA bispecific T-cell antibody, received regulatory approval for the treatment of RRMM based on the MajesTEC-1 study [Moreau et al, NEJM, 2022] which demonstrated an overall response rate (ORR) of 63% and median progression free survival (PFS) of 11.3 months. However, less than 15% (N=24) of patients (pts) enrolled in MajestTEC-1 were ≥75 years, an age cohort that is often underrepresented in clinical trials and comprises approximately one third of MM pts at diagnosis [SEER 22 2017-2021]. In this multicenter retrospective study, we report the real-world safety and efficacy of a large cohort of elderly (≥75 years) RRMM pts treated with Tec. Methods: Pts with RRMM who received standard-of-care Tec across 13 U.S. academic institutions were included in the study. The follow-up data cutoff was 30 April 2024. Pts were divided by age into two groups: age <75 years (<75 group) and age ≥75 years (≥75 group). High-risk cytogenetic abnormalities (HRCA) were defined as the presence of del(17p), t(4;14), t(14;16) and/or gain or amplification of 1q21. Disease response and progression was evaluated using IMWG criteria. Time-to-event analyses were evaluated using the Kaplan-Meier method. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) assessment was based on the American Society for Transplantation and Cellular Therapy consensus grading. Results: Among 385 pts, 83 (22%) were in the ≥75 group (median age 78, range 75-92) and 302 (78%) in the <75 group (median age 65, range 31-74). Compared to pts in the <75 group, those in the ≥75 group were more often white (78% vs. 63%, p=0.009). Both the ≥75 and <75 age groups had a median of 6 prior lines of therapy, a similar proportion with ECOG ≥2 at start of Tec (29% vs. 24%, respectively; p=0.37), and a high proportion of pts with triple-class-refractory disease (77% vs. 85%, p=0.06) and pts who would have been ineligible MajesTEC-1 (73% vs. 80%, p=0.20). In contrast, pts in the ≥75 group had a lower incidence of adverse MM risk factors compared to the <75 group, including HRCA (44.6% vs. 57.9%, p=0.03), ultra high-risk (≥2 HRCA) MM (12% vs. 24%, p=0.02), extramedullary disease (22% vs. 40%, p=0.02), hemoglobin <8 g/dL (10% vs. 21%, p=0.02) or albumin <3 g/dL (6% vs. 19%, p=0.04) at the time of starting Tec. Moreover, a lower proportion of pts in the ≥75 group had prior autologous stem cell transplantation (43% vs. 72%, p<0.0001) or prior BCMA-directed therapy (33% vs. 55%, p=0.0003). The median time from diagnosis to start of Tec was longer for pts in the ≥75 group (7.21 years vs. 5.81 years, p=0.02). There was no significant difference in rates of any-grade CRS (52% vs. 59%, p=0.27), CRS grade 2-4 (10% vs. 11%, p=0.74) or any-grade ICANS (19% vs. 13%, p=0.12) between the ≥75 and <75 age groups, respectively. Four pts in the entire cohort developed CRS grade 3-4, one of whom was in the ≥75 group. Ten pts developed grade 3 ICANS (none grade 4), three of whom were in the ≥75 group. There was no significant difference between the ≥75 group and <75 group in ORR (62% vs. 53%, p=0.17) and ≥very good partial response (VGPR) rate (53% vs. 44%, p=0.14). After a median follow-up period of 9.9 months (95% CI 9.6-10.6 months), the median PFS in the ≥75 group was 10.7 months (95% CI 6.6-NR) vs. 5.2 months (95% CI 6.6-NR) in the <75 group (p=0.005). At the time of data cut-off, the median overall survival (OS) for pts in the ≥75 group had not been reached (95% CI NR - NR) compared to 16.1 months (95% CI 14.0 - NR) in the <75 group (p=0.048). In multivariable analysis for the entire cohort, age ≥75 was not significantly associated with either PFS (HR 0.87, 95% CI 0.54-1.39; p=0.55) or OS (HR 0.60, 95% CI 0.30-1.19; p=0.15). Conclusions: This analysis of a large cohort of RRMM pts treated with Tec in the real-world setting demonstrates comparable efficacy and safety outcomes in elderly (aged ≥75 years) pts to those reported in the overall study population of MajesTEC-1. The adverse baseline disease characteristics and inferior efficacy in pts <75 years age compared to ≥75 years likely reflect patient selection and prescribing patterns in the early era of access to commercial BCMA bispecific therapy with Tec. In multivariable analysis there was no significant impact of age ≥75 on survival outcomes. OP, DD & LF: co-first authors. KKP, HCL & AGC: co-senior authors

Introduction. Ciltacabtagene autoleucel (cilta-cel) and idecabtagene vicleucel (ide-cel), two anti-B-cell maturation antigen (BCMA) CAR T therapies, have demonstrated remarkable responses and improved survival among patients with relapsed/refractory multiple myeloma (RRMM) in the clinical trials and standard of care (SOC) setting. Here, we compare safety, efficacy, and survival for patients treated with SOC ide-cel and cilta-cel. Methods. Data were from a retrospective chart review of RRMM patients leukapheresed by 12/31/2022 with the intent to receive SOC ide- or cilta-cel at 19 institutions in the US Multiple Myeloma Immunotherapy Consortium. An inverse probability of treatment weighting (IPTW) approach was used to compare outcomes by therapy type (cilta- vs. ide-cel), balancing on age, sex, race and ethnicity, performance status, extramedullary disease, high-risk cytogenetics, prior BCMA therapy, bone marrow plasma cells, penta-refractory status, lymphodepleting chemotherapy, baseline ferritin, low cell dose, and bridging therapy response. Logistic regression and Cox proportional hazard models were used to examine the association of treatment type with safety, efficacy, and survival accordingly, while adjusting for IPTW weights. We employed propensity score matching utilizing the same covariates to identify the association of treatment type with progression-free survival (PFS) within relevant patient sub-groups. Results. A total of 641 patients were leukapheresed by 12/31/2022 with ide-cel (n=386) and cilta-cel (n=255). 586 patients were infused (n=350 for ide-cel; n=236 for cilta-cel) with a median follow-up of 13.0 and 12.6 months, respectively. After IPTW, patient characteristics were well-balanced. Patients treated with cilta-cel were more likely to have grade ≥ 3 cytokine release syndrome (CRS) (OR=5.52, 95% CI=1.76-17.30, p=0.004), infections (OR=2.07, 95% CI=1.44-2.97, p<0.001), and delayed neurotoxicity (NT) (OR=20.97, 95% CI=4.75-92.42, p<0.001) compared to patients treated with ide-cel. In the cilta-cel cohort, 24 patients (10%) experienced delayed NT compared to 2 patients (1%) in the ide-cel cohort. Although not statistically significant, patients treated with cilta-cel were more likely to have any second primary malignancies (SPMs) (OR=1.87, 95% CI=0.94-3.71, p=0.08) and any SPMs excluding non-melanoma skin cancers (OR=1.78, 95% CI=0.78-4.10, p=0.2) but no association was observed for odds of hematologic SPMs (OR=0.98, 95% CI=0.26-3.61). No association was observed for therapy type with any or severe immune effector cell-associated neurotoxicity syndrome, any CRS, severe cytopenias, and non-relapse mortality. Compared to ide-cel, cilta-cel was associated with better treatment responses of ≥ complete response (OR=2.38, 95% CI=1.61-3.51, p<0.001) and ≥ partial response (OR=1.74, 95% CI=0.99-3.05, p=0.06). Patients treated with cilta-cel had a longer PFS and overall survival (OS) than ide-cel (HR=0.47, 95% CI=0.35-0.62, p<0.001 and HR=0.63, 95% CI=0.42-0.93, p=0.02, respectively), and these findings were similar in the intention to treat cohort (PFS: HR=0.44, 95% CI=0.34-0.55, p<0.001; OS: HR=0.55, 95% CI=0.41-0.73, p<0.001, respectively). We observed consistent findings when repeating the analyses restricting the ide-cel cohort to patients infused during the same time-period as FDA approval for cilta-cel (≥ March 2022), restricting to patients with data on all covariates, and restricting to sites that contributed data for both products. In a propensity matched population, (n=380; n=190 for cilta-cel and n=190 for ide-cel), patients treated with cilta-cel had superior PFS compared to those treated with ide-cel in most subgroups with respect to age and disease characteristics including extramedullary disease, high-risk cytogenetics, and elevated baseline ferritin (p<0.05). Conclusion. Our results suggest superior efficacy of cilta-cel with a higher incidence of certain toxicities compared to ide-cel in the SOC setting. This study provides valuable information for patient counseling and guiding the selection of CAR T-cell therapy for specific patient populations. Further validation through similar large-scale real-world experiences or prospective studies is needed to confirm our results and enhance applicability in the clinical setting. *DH, LP, & DD are co-first authors * YL, KP, & SS are co-last authors

Background: Tec is a BCMA-directed bispecific antibody (BsAb) approved for RRMM after ≥4 prior lines of therapy (LOT) based on the MajesTEC-1 trial. However, patients who had previously received a BCMA-DT were excluded from MajesTEC-1. Herein, we evaluated outcomes of RRMM patients with prior exposure to BCMA-DT treated with standard-of-care Tec. Methods: This was a multicenter retrospective cohort study. We compared variables between different groups using Chi-squared and Kruskal-Wallis tests, and assessed progression free survival (PFS) and overall survival (OS) using Kaplan Meier and Cox proportional hazards model. We used the maximally selected rank statistics method to determine the optimal cut-off point for continuous variables to find the most significant difference in PFS among different groups. Results: A total of 385 patients were included in this study. 193 patients had received a prior BCMA-DT, of whom 77%, 22%, and 1% had received 1, 2, and 3 prior anti-BCMA agents, respectively. In patients who had received a prior BCMA-DT, 35% were aged ≥70 years, 24% had ECOG performance status (PS) ≥2, 61% had high-risk FISH, 32% had extramedullary disease (EMD) at Tec initiation, and 42% were penta-refractory. Compared to the cohort without prior BCMA-DT (n=192), patients who were treated with prior BCMA-DT were more likely to have high risk FISH (61% vs 49%, p=0.02), and higher median number of prior LOT (7 vs 5, p <0.001). The specific types of prior BCMA-DTs with the respective overall response rate (ORR) to the most recent prior BCMA-DT were: antibody drug conjugate only (ADC, n=47, ORR 43%), chimeric antigen receptor T-cell therapy only (CAR T, n=99, ORR 86%), BsAb only (n=6, ORR 100%), ADC + CAR T (n=36, ORR 56%), and other ADC/CAR T/BsAb combinations (n=5, ORR 60%). Median follow up was 9.9 (95% CI:9.5-10.6) months. Patients with prior receipt of BCMA-DT had a lower ORR (51.4% vs 61.5%; p=0.012) and ≥very good partial response rate (39.4% vs 52.6%, p=0.009), but similar ≥complete response rate (22.3% vs 24%; p=0.78) to Tec compared to those without prior BCMA-DT. Moreover, patients with prior BCMA-DT had worse median PFS compared to patients without prior BCMA-DT (prior BCMA-DT: 4.6 months, 95% CI: 2.7-7.5; without prior BCMA-DT: 8.2 months, 95% CI: 5.7-12.2; p=0.017). On multivariable analysis incorporating prior BCMA-DT, age, cytogenetics, EMD, and ECOG PS, receipt of prior BCMA-DT was not independently associated with PFS (HR 1.25, 95% CI 0.95-1.64, p=0.1). The estimated 1-year OS rate was 58.9% (95% CI: 51.64-67.2) for the prior BCMA-DT group vs 65.1% (95% CI: 58.1-73.1) for the group without prior BCMA-DT, p=0.16. For the prior BCMA-DT cohort, response rates to Tec were numerically higher in patients who received CAR T (ORR 51.2%) followed by ADC (ORR 45.5%), and bispecific (ORR 30%) as their most recent prior BCMA-DT (p=0.39). No significant difference in PFS was noted when stratifying patients by number of prior BCMA-DTs, types of all prior BCMA-DTs received, type of most recent prior BCMA-DT, or depth of response to most recent BCMA-DT. Patients who responded to Tec had a numerically longer median time from most recent BCMA-DT exposure to Tec initiation compared to non-responders: 10.5 vs 7.5 months, p=0.48. We found that the optimal cut-off for time from last BCMA-DT exposure to Tec initiation was 8.7 months. Patients with > 8.7 months between last exposure to prior BCMA-DT and Tec initiation had a superior median PFS with Tec (8.1 months, 95% CI: 4.6-11.7) compared to patients with < 8.7 months from last exposure to prior BCMA-DT (2.5 months, 95% CI: 1.1-5.7), p=0.001. The toxicity profile for patients with prior BCMA-DT was similar to those who had not received a prior BCMA-DT. Grade ≥2 CRS occurred in 8.7% vs 13% (p=0.18), and grade ≥2 ICANS in 7.7% vs 6.7%, (p=0.85) of patients with and without prior BCMA-DT, respectively. Patients in the prior BCMA-DT cohort were more likely to have grade 3 thrombocytopenia in the first 30 days after Tec initiation (10.7% vs 6.6%; p=0.08). Conclusion: This is the largest study to date of any BCMA-directed BsAb among BCMA-exposed patients. Receipt of prior BCMA-DT was associated with a trend toward worse PFS, although not statistically significant, and lower likelihood of attaining an overall response. Waiting >9 months between sequencing BCMA therapies may be associated with improved PFS. D.D., M.A.V.M., J.A.D: co first authors; F.A., C.F., L.S.: co senior authors

Introduction: Tissue biopsies are needed to establish a diagnosis of systemic AL amyloidosis. Biopsy can be obtained from an involved organ with suspected amyloid deposition (target biopsy) or from sites in which amyloid commonly deposits (surrogate biopsy). The choice of biopsy site depends on institutional and physician preference. Two commonly used sites for surrogate biopsies are abdominal fat pad and bone marrow. The present systematic review and meta-analysis aims to evaluate the diagnostic test accuracy of fat pad and bone marrow biopsies as surrogate biopsy sites in the diagnosis of AL amyloidosis. Methods: As part of the ASH AL Amyloidosis Diagnostic Guideline, we performed systematic reviews for seven prioritized PICO questions related to the screening, diagnosis and organ involvement evaluation of AL amyloidosis. We conducted electronic searches on PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception until 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 had a fat pad sample or bone marrow biopsy and a target organ biopsy for suspicion of AL amyloidosis allowing for the calculation of diagnostic test accuracy measures. 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.. 20 studies with 2955 patients reporting on bone marrow biopsy, 25 with 4702 patients on fat pad sampling were included. The pooled sensitivity for bone marrow biopsy was 55.1% (95% CI 45.8-64.0, I2 = 94%) (Certainty of evidence: Low ⨁⨁◯◯), For fat pad sampling sensitivity was 76.6% (95% CI 72.1-80.8, I2 = 84.2%) (Certainty of evidence: Moderate ⨁⨁⨁◯). Among the included studies, 1 evaluated the sensitivity of fat pad sampling and bone marrow biopsy combined and found it to be 89%. No included studies evaluated specificity for bone marrow biopsy or fat pad sample. Conclusion: Combination of fat pad and bone marrow biopsy together significantly improve sensitivity for amyloid detection compared to either fat pad sampling or bone marrow biopsy alone.

Abstract Ciltacabtagene autoleucel (cilta-cel) was approved in 2022 for patients with relapsed/refractory multiple myeloma (RRMM). We report outcomes with cilta-cel in the standard-of-care setting. Patients with RRMM who underwent leukapheresis for cilta-cel manufacturing between 1 March 2022 and 31 December 2022 at 16 US academic medical centers were included. Overall, 255 patients underwent leukapheresis and 236 (92.5%) received cilta-cel, of which 54% would not have met CARTITUDE-1 eligibility criteria. In treated patients (N = 236), cytokine release syndrome was seen in 75% (grade ≥3, 5%), immune effector cell–associated neurotoxicity syndrome in 14% (grade ≥3, 4%), and delayed neurotoxicity in 10%. Overall and complete response rates were as follows: all patients who received cilta-cel (N = 236), 89% and 70%; patients receiving conforming cilta-cel (n = 191), 94% and 74%; and conforming cilta-cel with fludarabine/cyclophosphamide lymphodepletion (n = 152), 95% and 76%, respectively. Nonrelapse mortality was 10%, most commonly from infection. After a median follow-up of 13 months from cilta-cel, the median progression-free survival (PFS) was not reached, with 12-month estimate being 68% (95% confidence interval, 62-74). High ferritin levels, high-risk cytogenetics, and extramedullary disease were independently associated with inferior PFS, with a signal for prior B-cell maturation antigen–targeted therapy (P = .08). Second primary malignancies excluding nonmelanoma skin cancers were seen in 5.5% and myeloid malignancies/acute leukemia in 1.7%. We observed a favorable efficacy profile of standard-of-care cilta-cel in RRMM, despite more than half the patients not meeting the CARTITUDE-1 eligibility criteria.

7508 Background: Idecabtagene vicleucel (Ide-cel) has demonstrated excellent efficacy in patients with relapsed/refractory multiple myeloma (RRMM). However, outcomes in patients with extramedullary disease (EMD) remain to be better characterized. Methods: We included patients from 11 US academic centers, who were evaluated for EMD and were infused with ide-cel between May 2021 and April 2023. Patients with soft tissue or visceral lesions non-contiguous from bony lesions were classified as having true EMD, with paraskeletal disease classified as non-EMD. Disease responses were evaluated using the IMWG criteria. Time-to-event analyses were performed from the date of ide-cel infusion. Results: Among 351 patients with RRMM treated with ide-cel, 84 (24%) had EMD prior to infusion. Median follow-up for the entire cohort was 18.2 months (95% CI: 17-19.3). Baseline characteristics at ide-cel infusion for EMD and non-EMD cohorts are depicted in the table. For the EMD and non-EMD cohorts, the Day 30 objective response rates (ORR) were 58% vs. 69% (p=0.1), Day 30 ≥complete response rates were 16% vs 24% (p=0.11), the Day 90 ORR were 52% vs 82% (p<0.001), and best ORR were 58% vs 82%, respectively. The median progression-free survival (PFS) was 5.3 months (95% CI: 4.1-6.9) for the EMD cohort vs. 11.1 months (95% CI: 9.2-12.6; p<0.0001) for the non-EMD cohort. The median duration of response for EMD among day 30 responders was 6.4 months (95% CI: 5.1-8.4). In a multivariable analysis, EMD was an independent predictor of inferior PFS [hazard ratio 1.8 (95% CI: 1.2-2.5), p<0.001] after adjusting for ECOG status, revised ISS stage, penta-drug refractoriness, elevated ferritin, prior BCMA-directed therapy and use of bridging therapy. Pattern of progression in the EMD cohort (n=68/84) included EMD site only (21%), hematologic only (22%), or both (57%), with comparable PFS for type of progression (p=0.19). The median overall survival (OS) was 14.8 months [95% CI: 9-Not reached (NR)] for EMD and 26.9 months [95% CI: 26.3 vs NR, p=0.006)] for the non-EMD group. Rates of Grade ≥2 cytokine release syndrome or neurotoxicity syndrome were comparable between the two cohorts. Conclusions: Patients with EMD demonstrate significantly inferior Day 90 ORR and presence of EMD is an independent risk factor for inferior PFS. [Table: see text]

Multi-agent regimens incorporating immunomodulatory (IMiD®) agents such as thalidomide, lenalidomide, and pomalidomide have become the preferred standard of care for the treatment of patients with multiple myeloma (MM), resulting in improved survival outcomes. Currently, there are three IMiD agents approved for the treatment of MM: thalidomide, lenalidomide, and pomalidomide. Lenalidomide is commonly used to treat patients with newly diagnosed MM and as maintenance therapy following stem cell transplant or after disease relapse. Pomalidomide, the focus of this review, is approved in patients with relapsed/refractory MM (RRMM). Despite survival benefits, IMiD agents each have different safety profiles requiring consideration both prior to starting therapy and during treatment. Adverse event (AE) management is essential, not only to ensure treatment adherence and thus ensure optimal efficacy but also to maintain patient quality of life. Here, we discuss AEs associated with pomalidomide and present five clinically relevant hypothetical case studies in patients with RRMM to provide scenario-driven guidance regarding treatment selection and AE prevention and management in the clinical setting. Lastly, as new treatment approaches continue to be explored in MM, we also discuss novel cereblon E3 ligase modulator (CELMoD™) agents including iberdomide (CC-220) and mezigdomide (CC-92480).

Abstract In a retrospective analysis at 11 US medical centers, bridging therapy (BT) impact after receiving idecabtagene vicleucel was assessed in 214 patients. 79% received BT, including 12% Selinexor-containing, 45% alkylator-based, 15% proteasome inhibitor combinations, and 18% immunomodulatory drugs +/- monoclonal antibody combinations (IMiD +/- mAb combos). BT recipients had worse performance status, higher stage disease, ferritin and CRP pre-infusion. The overall response rate to BT was 12%, with no difference among BT subgroups. Safety profiles were similar, but Selinexor had a higher grade ≥2 ICANS incidence. Median progression-free survival (PFS) was 6.7 months in BT vs. 11.5 months in no-BT (p=0.007). Median PFS was longest with IMiD +/- mAb combos (12 months), comparable to no-BT, and significantly longer than other BT subgroups (p=0.01). Alkylator-based BT had inferior PFS compared to IMiD +/- mAb combos (p=0.03). Median overall survival (OS) for the BT was 13.8 months vs. not reached in no-BT (p=0.002). Alkylator-based BT had shorter OS compared to others (11.97 months vs. NR; p=0.001). Stepwise Cox regression showed alkylator-based BT and response

*Drs. Yifan Zhai and Sikander Ailawadhi are co-corresponding authors Background R/R MM is an incurable condition, with virtually inevitable relapse. AL amyloidosis is a rare disease that may cause serious illness and even death. Lisaftoclax is a novel, potent, selective BCL-2 inhibitor under clinical development for treatment of patients with hematologic malignancies or solid tumors, and has shown clinical antitumor benefits. In a previous study on chronic lymphocytic leukemia, lisaftoclax was shown to require only a short (daily vs weekly) dose ramp-up to mitigate tumor lysis syndrome and was associated with a low incidence of adverse events (AEs) (Ailawadhi et al. J Clin Oncol 2021;39:abstract 7502; Davids et al. Blood 2022;140[suppl 1]:2326-2328). Methods This multicenter study evaluated lisaftoclax combined with pomalidomide and dexamethasone (Arms A and C) or daratumumab, lenalidomide, and dexamethasone (Arm B) in patients with R/R MM (Arm A and B) or R/R amyloidosis (Arm C). Eligible patients had an ECOG performance status ≤ 2; ≥ 1 prior line of therapy; and adequate organ function. Patients with R/R amyloidosis also needed confirmed symptomatic organ involvement, in addition to purpura and/or carpal tunnel syndrome. Lisaftoclax was administered orally daily (QD) at 5 dose levels (400, 600, 800, 1,000, and 1,200 mg) without ramp-up in repeated 28-day cycles. Pomalidomide, daratumumab, and lenalidomide were administered per label use. Dexamethasone 40 mg (20 mg for patients aged &gt; 75 years) was administered on Days 1, 8, 15, and 22 of 28-day cycles. Study objectives were safety and efficacy assessments of the combination treatments. Results As of July 3, 2023, a total of 30 patients were enrolled: 22 in Arm A at dose levels of 400 (n = 3), 600 (n = 4), 800 (n = 3), 1,000 (n = 6), and 1,200 mg (n = 6); 3 in Arm B at 600 mg; and 5 in Arm C at 400 (n = 1) and 600 mg (n = 4). A total of 66.7% of patients were male, and the median (range) age was 70.5 (24-88) years, with 66.7% of patients above the age of 65. The median (range) lines of prior therapies was 4 (1-19), and median (range) time from diagnosis to first dose was 5.2 (1-29) years. The median (range) number of treatment cycles was 4 (1-19). A total of 18 patients were triple-class-exposed, 7 had received pomalidomide, and 3 harbored t(11;14) at baseline. A total of 19 patients reported experiencing any-grade lisaftoclax treatment-related adverse events (TRAEs), including neutropenia or nausea (16.7% each); and thrombocytopenia, leukopenia, abdominal distension, constipation, or diarrhea (6.7% each). Seven patients experienced grade ≥ 3 TRAEs, including neutropenia (10%) and febrile neutropenia, iron deficiency anemia, thrombocytopenia, prolonged electrocardiogram QT interval, and acute kidney injury (3.3% each). Two patients experienced lisaftoclax-related serious AEs, of which 1 was febrile neutropenia and 1 acute kidney injury. In Arm B, 1 patient experienced a dose-limiting toxicity (prolonged QT interval). A total of 12 patients discontinued treatment because of disease progression (n = 8), an AE (n = 1), noncompliance (n = 1), and investigator/patient decision (n = 2). In Arm A, 21 patients with R/R MM were evaluable, of whom 9 experienced a partial response (PR) and 5 a very good PR (VGPR). The overall response rate (ORR [PR or better]) was 66.7%, with a median (range) time to response of 1.2 (1-3) months. After a median (range) time to response of 1.4 (1-2) months, 2 patients with R/R MM in Arm B achieved a PR (n = 1) or VGPR (n = 1). In Arm C, 3 patients with R/R amyloidosis achieved a hematologic VGPR; the ORR was 60%; the median (range) time to response was 0.9 (1-1) month; and 1 patient experienced organ function improvement. Conclusion Lisaftoclax, combined with novel therapeutic regimens, was well tolerated and has demonstrated preliminary antitumor activity in patients with AL amyloidosis or R/R MM. Internal study identifier: APG-2575-MU101; clinical trial registration: NCT04942067.