Kastritis, Efstathios

Solitary plasmacytomas (SPs) are rare localized tumors of clonal plasma cells, either in the bone (solitary bone plasmacytoma) or in soft tissue/extraosseous (extramedullary) with either no or with minimal bone marrow (BM) infiltration (<10% clonal plasma cells by immunohistochemistry) and no evidence of systemic involvement or myeloma defining events. Approximately 50% of SPs will progress to symptomatic myeloma within 5 years after initial definitive local radiotherapy. Increased availability of improved diagnostic and monitoring tools has increased the sensitivity of detection of additional lesions and marrow involvement and has implications for the follow-up strategy after treatment. Thus, the definitions and requirements for the diagnosis and follow-up of SPs are evolving. The diagnosis of SP requires the careful exclusion of multiple myeloma (MM) that would require systemic therapy, by using all the available methods to detect systemic disease (advanced imaging, sensitive BM assessment methods, blood and urine tests). Local radiotherapy remains the mainstay of therapy, and despite the availability of innovative drugs for MM, the clinical benefit of systemic therapy currently remains poorly defined. The International Myeloma Working Group provides here updated recommendations for the diagnosis, evaluation, treatment, and response assessment of patients with SPs, incorporating recent data and advances in diagnostic tools.

PURPOSE In immunoglobulin light chain (AL) amyloidosis, amyloid fibrils cause organ dysfunction. Anselamimab, a monoclonal antibody, selectively binds to amyloid fibrils, accelerating their clearance. METHODS Newly diagnosed patients with European modification of Mayo 2004 stage IIIa or IIIb AL amyloidosis were randomly assigned to receive anselamimab or placebo with cyclophosphamide, bortezomib, and dexamethasone (with or without daratumumab). The primary end point was a hierarchical composite of time to all-cause mortality (ACM) and frequency of cardiovascular hospitalizations (CVHs), analyzed using the Finkelstein-Schoenfeld test and win ratio estimation. RESULTS Among 406 randomly assigned patients, the primary end point win ratio for anselamimab versus placebo was 1.11 (95% CI, 0.83, 1.50; P = .332) and the hazard ratio (HR) for ACM was 0.80 (95% CI, 0.57, 1.13; P = .290). CVH rates in the anselamimab and placebo groups were 0.59 (95% CI, 0.42, 0.83) and 0.89 (95% CI, 0.55, 1.43), respectively ( P = .145). Among patients with kappa isotype (n = 72), the win ratio was 2.06 (95% CI, 0.98, 4.31; P = .100) and anselamimab reduced ACM by 62% versus placebo (HR, 0.38; 95% CI, 0.17 to 0.86; nominal P = .012), and CVH by 71% (IRR, 0.29; 95% CI, 0.10 to 0.87; nominal P = .028) with improvements in Kansas City Cardiomyopathy Questionnaire-Overall Score. There was no clinical benefit observed in the lambda population. Anselamimab was generally well-tolerated; safety data were comparable between treatment arms overall. CONCLUSION Treatment with anselamimab, an antifibril antibody used alongside antiplasma cell dyscrasia therapy, while not meeting the primary end point in the overall population, significantly improved ACM and CVH in patients with kappa AL, potentially offering a new therapeutic option for this isotype.

ABSTRACT Talquetamab is a GPRC5D × CD3 bispecific antibody approved for relapsed/refractory multiple myeloma (RRMM). This is the first real‐world study to comprehensively report muco‐cutaneous toxicities, infections, and efficacy of talquetamab in 151 patients across five countries with the longest follow‐up reported enabling better efficacy and toxicity estimates. The median age was 64 years; high‐risk cytogenetics were present in 42%; ECOG ≥ 2 in 22%; 12% had creatinine clearance < 30; and 55% would not have met MonumenTAL‐1 eligibility. Patients received a median of 6 prior lines of therapy, 53% were penta‐refractory, and 75% received prior BCMA therapy. Talquetamab was associated with skin toxicity in 39.7%, nail toxicity in 75.5%, dysgeusia in 60.4%, and oral toxicities in 62.9%, with grade ≥ 3 events uncommon (≤ 4%) and dose interruptions infrequent (9.6% for skin toxicity, 6.9% for dysgeusia, and 4.0% for oral toxicities). These findings underscore the need for improved supportive care for muco‐cutaneous toxicities. In multivariate analysis, only platelet count < 50 (HR 1.8, 95% CI 1.15–2.83) was associated with inferior PFS, while penta‐refractory status, absolute lymphocyte count < 0.4, and prior BCMA‐targeted therapy were not statistically significant. With a median follow‐up of 12.7 months, the overall response rate was 67.6%, median progression‐free survival was 7 months, and 12‐month overall survival was 65%. This study shows that talquetamab efficacy is maintained in a heavily pretreated real‐world population with high prior BCMA exposure and notable comorbidity burden.

ABSTRACT Systemic AL amyloidosis is a clonal plasma cell dyscrasia, where toxic free light chains (FLCs) lead to vital organ damage, with risk of early mortality despite effective therapies. Notably, there is a paucity of data on the incidence and predictors of early mortality in the daratumumab (Dara) era. We conducted a multi‐center retrospective cohort study to develop and validate a risk‐prediction model for early mortality (all‐cause death within 6 months) in patients treated with Dara‐based frontline regimens. We used univariate analysis to identify covariates for a logistic regression model predictive of 6‐month mortality and generated a clinical risk score. Among 339 patients across eight centers, 36 (10.6%) experienced early mortality. Multivariate analysis identified four independent predictors: NT‐proBN P > 5300 pg/mL (odds ratio [OR] 3.83, p = 0.006), A ge > 75 years (OR 2.96, p = 0.073), absence of t(11;14) on C ytogenetics (OR 3.0, p = 0.022), and E COG performance status (OR 1.72 per unit increase, p = 0.044). The resulting PACE score stratified patients into three risk groups with a 6‐month mortality of 1.2% (low‐risk), 11.7% (intermediate‐risk), and 50.0% (high‐risk). The PACE score demonstrated superior discrimination (C‐index 0.78) for early mortality compared to Mayo 2004 (0.69) and Mayo 2012 (0.55) staging systems. External validation confirmed robust discrimination (C‐index 0.73) with corresponding 6‐month mortality rates of 4.2%, 15.25%, and 37.04% across respective risk groups. The PACE score provides a clinically applicable tool for early mortality risk stratification in AL amyloidosis patients receiving Dara‐based therapy, and will enable improved patient counseling, clinical trial design, and identification of ultra‐high‐risk patients requiring intensive monitoring and novel therapies.

Abstract Recent therapeutic advances, including bispecific antibodies (bsAbs), have improved outcomes for patients with relapsed/refractory multiple myeloma (RRMM). However, early mortality (EM) remains a significant challenge, even in the era of novel immunotherapies. We conducted a multicenter, retrospective analysis of real-world patients with RRMM treated with commercial bsAbs to evaluate the incidence and causes of EM. Between May 2022 and June 2025, a total of 441 patients were treated across 7 countries. EM, defined as death within 12 months of therapy initiation, occurred in 148 patients (34%), with a median time from bsAb initiation to death of 2.87 months (interquartile range, 1.38-6.85). The leading cause of EM was progressive disease (72%), followed by infection (13%); regardless of the cause of death, 82% had active disease at the time of death. Our findings highlight that despite encouraging efficacy, EM remains high among real-world bsAb recipients, emphasizing the need for improved disease control strategies and supportive care interventions.

Abstract Waldenström macroglobulinemia (WM) is characterized by recurrent MYD88 and CXCR4 mutations, whose prognostic value in patients treated with chemoimmunotherapy remains unclear. Moreover, the typically prolonged progression-free survival (PFS) correlates inconsistently with overall survival (OS), underscoring the importance of examining other surrogates. Progression of disease within 24 months (POD24), an established early end point, delineates functionally high-risk patients in other indolent lymphomas. This international study evaluated 253 patients receiving frontline fixed-duration bendamustine-rituximab (BR), a common chemoimmunotherapy for WM. At a median follow-up of 5.9 years, 5-year PFS and OS were 65% and 87%, respectively; 5-year PFS was similar between MYD88L265P (90%) and MYD88wild-type (WT) subcohorts (64% each; P = .4). Among 89 patients with known CXCR4 status, the subcohort with CXCR4mutation (28%) had shorter PFS (median 3.3 vs 8.8 years; hazard ratio [HR], 2.8; P = .0036) and OS (HR, 2.6; P = .036) compared with CXCR4WT. POD24 occurred in 11.5% of patients who demonstrated inferior subsequent OS (5-year OS, 71% vs 86%; HR, 3.1; P = .005) and higher mortality (standardized mortality ratio [SMR], 3.7), unlike the non-POD24 group, whose mortality was comparable to the matched general population (SMR, 1.1). In conclusion, BR is effective irrespective of the MYD88 status, but CXCR4 mutations and POD24 portend worse outcomes. Patients without POD24 represent a cohort with distinctly favorable outcome.

PURPOSE Outcomes in systemic light chain (AL) amyloidosis have improved with modern therapy limiting utility of existing risk stratification models. We validate a new staging system, incorporating longitudinal strain (LS) to the biomarker-based (NT-proBNP and Troponin-T) staging system in the contemporary treatment era (2015-2024). METHODS AL International Staging System (AL-ISS) was derived from a cohort of patients with AL amyloidosis from the UK National Amyloidosis Centre (2015-2019). The model was validated in patient cohorts from Europe (Greece, Italy, the Netherlands, and Switzerland), the United States (2015-2024), and the United Kingdom (2020-2024). RESULTS In total, 2,493 patients were included (derivation, n = 573; validation n = 1,920). In a multivariable model for the derivation cohort, LS ≥ –9% and cardiac biomarkers at previously validated thresholds (NT-proBNP 332 ng/L and 8,500 ng/L and high-sensitivity troponin T ≥ 50 ng/L) were independent poor prognostic factors stratifying patients into stages I, II, IIIA, IIIB, and IIIC. In the validation cohort, the patient stages were stage I: 317 (17%), II: 782 (41%), IIIA: 551 (29%), IIIB: 174 (9%), and IIIC: 96 (5%), respectively (first-line daratumumab treated: 826; 43%). With a median follow-up of 34 months, median overall survival (OS) was not reached (NR); estimated 1-year, 2-year, and 3-year OS was 82%, 74%, and 70% respectively. The median survival for stages I to II, IIIA, IIIB, and IIIC were NR, 67, 26, and 7 months (1-year OS IIIC 53% v 68% for IIIB in the daratumumab-treated patients), respectively ( P < .001). External validation exhibited good predictive performance: 12-month calibration slope was 1.09, Harrell C 0.69, Royston D 1.19, and R 2 D 0.25. Stage IIIC independently discriminated the poorest outcome across all cohorts. CONCLUSION This defines and validates a new staging system from systemic AL amyloidosis with robust identification of an ultra-poor risk stage (IIIC) in contemporarily treated patients.

ABSTRACT Acute renal failure due to cast nephropathy (CAN) is a severe complication of multiple myeloma (MM). Here, we aimed to identify parameters associated with renal outcomes and survival in newly diagnosed MM patients with CAN‐related acute renal failure and to validate the IMWG criteria for renal response. CAN diagnosis was based on biopsy or clinical assessment. Of 787 registered patients, 354 met the inclusion criteria, requiring at least two therapy cycles with documented chemotherapy response, renal response, and eGFR. Baseline free light chain (FLC) levels (median 6825.65 mg/L) decreased below 500 mg/L in 67.8% of patients. According to IMWG classification, renal complete response, partial response, and minimal response were achieved in 33.9%, 19.5%, and 28.0% of patients, respectively. The best eGFR values > 60 mL/min/1.73 m 2 were observed in 33.9% of patients, while 33.3%, 22.3%, and 10.5% had best eGFR values of 30–59, 15–29, and < 15 mL/min/1.73 m 2 , respectively. Renal response correlated with baseline FLC levels, IgG kappa, eGFR, and ECOG status in multivariate analysis, as well as with myeloma response and FLC reduction in univariate analysis. Median overall survival was 77.6 months. Survival correlated with age, myeloma response, ECOG status, FLC kappa type, baseline eGFR, standard‐risk cytogenetics, and calcium levels, among other factors. A comparison of IMWG renal response criteria with classification based solely on best eGFR showed similar utility. Of 136 patients requiring dialysis, 80 (58.8%) were able to discontinue dialysis during therapy. Bortezomib containing myeloma therapy, along with significant FLC reduction, was associated with favorable outcome.

Introduction: Teclistamab (Tec) is the first approved BCMA x CD3 bispecific antibody for the treatment of triple-class-exposed patients with relapsed/refractory multiple myeloma (RRMM) based on the pivotal MajesTEC-1 study. Tec was associated with high overall response rate (ORR) of 63% in heavily pretreated patients. After a longer follow-up of 30.4 months, CR rate was 46.1%, median duration of response (DOR) was 24 months (95% CI, 17.0 - not estimable), and median progression-free survival (PFS) was 11.4 months (95% CI, 8.8 - 16.4). Herein, we present updated analysis of real-world outcomes and safety with tec in RRMM with extended follow-up of more than 12 months. Methods: This is an international multicenter retrospective study of patients with RRMM treated with tec on-label at 9 academic centers from 5 countries (United States, United Kingdom, Greece, Spain, and Canada) through the International Myeloma Working Group (IMWG) Immunotherapy Committee. Patients with RRMM treated with commercial tec at the respective institutions between May 24, 2022 to January 4, 2024 were included. Median follow-up was 14 months with data collected until July 15, 2024. High-risk cytogenetic abnormalities (HRCA) was defined as 1q+, t(4;14), t(14;16), t(14;20), and/or del(17p). Response was assessed using the IMWG consensus criteria. Patient characteristics were summarized by frequency (percentage) or median (interquartile range [IQR] or range). PFS, overall survival (OS), DOR were evaluated using the Kaplan-Meier method. Results: There were 223 patients included in this analysis with the following characteristics: median age of 67 (range 33-91) with 24% ≥75 years; 45% female; 74% White, 10% Black, 9% Asian, and 7% other/unknown; 86 of 176 (49%) with high risk cytogenetics, including del(17p), t(4;14), t(14;16), t(14;20), and gain/amp 1q; 29.4% (37/126) with known extramedullary disease; 14% with creatinine clearance ≤30 ml/min. Patients received a median of 6 (IQR, 4-8) prior lines of therapy with 52% (107/206) being penta-drug refractory. Among 212 patients with available data, 161 (75.9%) patients would have been ineligible for MajesTEC-1. There were 94 (42%) patients who received prior BCMA-directed therapy (29.8% antibody-drug conjugate [ADC] alone; 45.7% CART alone; 6.3% bispecific antibody alone; 17.0% ADC and CART). Median time from diagnosis to tec initiation was 6.1 (range 0.6-29.2) years. For the 206 response-evaluable patients, ORR was 66%, including 25.2% ≥CR, 33.5% VGPR, and 7.3% PR. ORR for the 90 response-evaluable patients with prior BCMA-directed therapy was 54.5% (21.1% ≥CR, 26.7% VGPR, 6.7% PR). After a median follow-up of 14 (95%CI, 13-14) months, median PFS and OS were 8.8 (95% CI, 5.5-14) and 20 (95% CI, 18-not reached [NR]) months, respectively. 12-month PFS estimate was 46% (95% CI, 40%-54%), and 12-month OS rate was 65% (95% CI, 59%-72%). Median DOR was 17 (95% CI, 17-NR) months with 12-month estimate of 68% (95% CI, 60%-77%). Tec step-up dosing occurred in the outpatient setting for 57 (25.6%) patients. CRS occurred in 119 out of 222 (53.6%) patients with almost all being grade 1-2, except for 1 grade 4 event. ICANS occurred in 18 out of 216 (8.3%) patients (grade 1-2: 5.1%; grade 3-4: 2.8%). Any grade infection occurred in 130 (58.3%) patients; 25.1% of patients had grade ≥3 infection, including 10 patients with grade 5 infection. While receiving teclistamab, 79 (35.4%) patients had ≥2 infections. IVIG was given in 114 out of 164 (69.5%) patients. Conclusion: In this multicenter international real-world analysis of outcomes and safety associated with tec, ORR was high at 66% with 25.2% of patients achieving ≥CR. CR rates may be underestimated due to infrequent bone marrow confirmation in the real-world datasets. Encouragingly, ORR was 54.5% in BCMA exposed RRMM patients, including 21.1% with ≥CR. After a median follow-up of 14 months, heavily pretreated patients including patients with prior BCMA therapy had durable responses with median PFS of 8.8 months and median DOR of 17 months. There were no new safety signals noted in this real-world study. This is the largest real-world study to date of teclistamab with long-term follow-up of more than 12 months. Additional data including more patients, longer follow-up and results from difficult to treat subgroups will be presented at the meeting.