Chng, Wee Joo

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.

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 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 Introduction: Elranatamab (Elra) is a bispecific antibody (BsAb) targeting BCMA that is approved for patients with triple class exposed relapsed refractory myeloma (RRMM) on the basis of the MagnetisMM-3 phase 2 trial. For BCMA naïve patients, an overall response rate (ORR) of 61.0% and median progression free survival (PFS) of 17.2m was observed with a median overall survival (OS) of 24.6m. However, efficacy and safety information in the real world is lacking. Methods: This was an international retrospective study of patients with RRMM treated with Elra monotherapy outside of clinical trials. Data was collected through the International Myeloma Foundation Immunotherapy Database from 7 countries (UK, USA, Canada, Greece, Spain, Czech Republic and Singapore). High-risk cytogenetic abnormalities (HRCA) were defined as 1q+, t(4;14), t(14;16), t(14;20), and/or del(17p). Response was assessed using IMWG consensus criteria. Patient characteristics were summarized by frequency (percentage) or median (range). PFS, OS were evaluated using the Kaplan-Meier method and reported with 95% confidence intervals. Results: 79 patients were included. Median age was 67 years (range: 41-95y) with 20% ≥75 years. Racial distribution was: 75% White, 16% Black/African American, 8% Asian/Pacific. 55% were ECOG performance status (PS) 1-2. Patients received a median of 5 prior lines (range 1-11), and 35% were BCMA exposed (9% CAR-T, 5% ADC, 7% BsAb, 8% BsAb plus CAR-T, 4% ADC plus BsAb). Of those with available data, 45% had HRCA,13% had extramedullary disease (EMD) and 32% had penta-drug refractory RRMM. Overall, 48% would not have been eligible for the MagnetisMM-3 trial. Median follow-up was 6.3m (range 0.5-35.0). ORR was 53% (PR 11%, VGPR 33%, CR 8%, sCR 1%) and 67% for BCMA naïve patients. Responses were significantly lower for BCMA exposed patients (ORR 31%) but did not differ by age (51% &lt;75yrs vs 60% ≥75yrs). On univariate analysis, prior BCMA exposure, platelets &lt;50, presence of HRCA and penta-refractoriness were significantly associated with a lower response rate. PFS for the whole cohort at 6 and 12m was 64% (95%CI, 54-77%) and 52% (40-67%); for BCMA naïve patients, it was 77% (65-90%) and 67% (54-84%), respectively. Within the whole cohort, PFS was shorter for: BCMA exposed (median 4.0m vs not reached (NR)), platelets &lt;50 (2.0 vs 21.7m), HRCA (7.2m vs NR), penta-refractory (4.3m vs NR). PFS did not differ significantly by EMD, PS, age, or creatinine clearance. OS for the whole cohort at 6 and12m was 74% (64-85%) and 58% (45-74%); for BCMA-naïve patients, it was 80% (43-85%) and 70% (57-87%), respectively. Within the whole cohort, OS was shorter for: BCMA exposed (median 10.3m vs NR), platelets &lt;50 (4.3m vs NR), HRCA (10.7m vs NR) and penta-refractory (10.3m vs NR). Univariate regression analysis demonstrated that prior BCMA exposure, platelets &lt;50 and penta-refractoriness were significantly associated with a worse PFS and OS, and HRCA predicted poorer survival CRS was observed in 41% of patients (grade(G)1: 35%, G2: 5%, ≥G3: 0%) with most occurring with the first step up dose (SUD): SUD1: 29%, SUD2: 15%, full dose: 4%. Tocilizumab was used in 20% and steroids in 3%. ICANS was observed in 4 cases (5%): G1: 2, G2: 1, G4: 1. Treatment was with steroids (n=3) and tocilizumab (n=2). G3-4 thrombocytopenia was observed in 19% and 14% required platelet transfusions. G3-4 neutropenia occurred in 25% with overall 31% requiring GCSF. Infections were reported in 33 (42%) patients with median time to infection of 41 days. A total of 94 infection episodes were observed over 581 personal months. There were 2 infection-related deaths reported (1 had IVIG, 1 did not). 64% had hypogammaglobulinemia (IgG &lt; 400mg/dl) and IVIG was given in 65% of patients. Conclusions: In this first international real world analysis, Elranatamab achieved a response rate of 67% and a 12m PFS of 67% in BCMA naïve patients, similar to the MagnetisMM-3 trial despite almost half not meeting trial eligibility. However, prior BCMA exposure, platelets &lt;50, high risk cytogenetics and penta refractory status were predictors of poorer outcomes. Acknowledgements: The International Myeloma Foundation, International Myeloma Working Group (IMWG)

Abstract Background: BCMA- and GPRC5D-targeting immunotherapies including CART cell therapy and Bispecific antibodies are currently approved for the treatment of multiple myeloma. However, clinical outcomes after dual antigenic exposure remain undefined. Herein we report the first report of BCMA-GPRC5D dual targeted multiple myeloma (DEMM). Methods: We conducted a retrospective multi-center study of RRMM patients treated with both BCMA- and GPRC5D-targeted treatments (TT) (CAR T, bispecific antibodies, ADCs) between November 1, 2022, and July 1, 2025. Outcomes included PFS1 (post-dual exposure), and overall survival (OS). Kaplan-Meier estimates and event-free probabilities were calculated. Results: One hundred and fifty patients who underwent TCE treatments were included and 49 patients met the criteria for inclusion. Median age was 65 years, 22.4% had creatinine clearance &lt;=30 and ECOG 2 or greater was present in 22.2%; 57% had high-risk cytogenetics (IMWG 2016), and 60.5% were penta-refractory. Patients received a median of 6 prior lines of therapy (LOT) before 1st TCE and 9 prior LOT before DEMM. 65.3% received 1 TCE, 30.6% received 2 TCE and 4.1% received 3 TCE before DEMM. Similarly, 67.3% received 1 BCMA, 24.5% received 2 BCMA TT and 4.1% received 3 BCMA TT before DEMM. Prior TT included- BCMA CART (57.1%), BCMA Bispecific (57.1%), BCMA ADC (18.4%), other TCE (10.2%). The last dual exposure was GPRC5D Bispecific in 91.8%, BCMA Bispecific in 6.1% and BCMA CART in 2%. The median followup post relapse was 3.4 months (range 0.0-16 mos). The median PFS during the last dual exposure TT was 3.98 months (95% CI: 2.96–6.70). 32.7% did not receive any subsequent LOT and died due to progressive disease. 67.3% of patients had progressive MM and received next LOT. Median PFS1 was 1.77 months (95% CI: 1.28–6.21) with 3-, 6-, and 12-month event-free probabilities of 44%%, 19% and 0% respectively. Median OS was 5.7 months (95% CI: 2.53-12.16) for DEMM from the time of refractoriness to dual antigenic targets. Conclusions: Patients dual-exposed to BCMA- and GPRC5D-directed therapies have a poor prognosis, 32.7% had not received further treatment and in those who received treatment the PFS1 was less than 2 months and an OS of 5.7 months from progression. This reflects an area of high unmet need for the patients that are dual-exposed to BCMA- and GPRC5D-directed therapies. Further data on the cohort will be updated at the meeting. Acknowledgements include, the International Myeloma Foundation, IMWG.

Despite significant improvements in survival of patients with multiple myeloma (MM), outcomes remain heterogeneous, and a significant proportion of patients experience suboptimal outcomes. Importantly, traditional prognostic factors based on data from patients treated with older therapies no longer capture prognosis accurately in the contemporary era of novel triplet or quadruplet therapies. Therefore, risk stratification requires refinement in the context of available and investigational treatment options in routine practice and clinical trials, respectively. The current identification of high-risk MM (HRMM) in routine practice is based on the Revised International Staging System, which stratifies patients using a combination of widely available serum biomarkers and chromosomal abnormalities assessed via fluorescence in situ hybridization. In recent years, a substantial body of evidence concerning additional clinical, biological, and molecular/genomic prognostic factors has accumulated, along with new MM risk stratification tools and consensus reports. The International Myeloma Society, along with the International Myeloma Working Group, convened an Expert Panel with the primary aim of revisiting the definition of HRMM and formulating a practical and data-driven consensus definition, based on new evidence from molecular/genomic assays, updated clinical data, and contemporary risk stratification concepts. The Panel proposes the following Consensus Genomic Staging (CGS) of HRMM which relies upon the presence of at least one of these abnormalities: (1) del(17p), with a cutoff of >20% clonal fraction, and/or TP53 mutation; (2) an IgH translocation including t(4;14), t(14;16), or t(14;20) along with 1q+ and/or del(1p32); (3) monoallelic del(1p32) along with 1q+ or biallelic del(1p32); or (4) β2 microglobulin ≥5.5 mg/L with normal creatinine (<1.2 mg/dL).

Introduction: Talquetamab (Talq) is a GPRC5D targeting bispecific antibody recently approved for the treatment of relapsed refractory multiple myeloma (MM) based on the MonumenTAL-1 study. Real World Evidence (RWE) is needed to understand the safety and efficacy of Talq in patients treated outside of a clinical trial as they may have different outcomes and toxicities. Here we report outcomes of 118 patients treated with Talq. Methods: Patients treated with standard-of-care Talq were included. Data was collected through a retrospective chart review from 01/2023 until 7/2024 from 7 International Myeloma Foundation (IMF) associated MM academic centers. Results: 118 patients were included in the analysis. The median age was 64, 37% had HR disease, 22% had EMD at presentation. The median LOT was 6, median number of immunotherapies before TAL was 2 (range 1,4) and 71% received prior BCMA therapy. 72% were triple refractory and 44% were penta refractory. 25% (n=60) would not have been eligible for TAL clinical trial due to exclusion criteria and15% had an ECOG of 2 or greater. 18% (n=97) received TAL as an outpatient and the median number of hospital days was 9 (0,37) for inpatients. CRS during Step up Dose (SUD) 1 was present in 30% Gr 1 (57%), Gr2 (11%), Gr 3 (6%), CRS during SUD 2 was present in 31%, Gr 1 (65%), Gr 2 (11%), CRS during SUD 3 when administered was present in 14% , Gr 1 (82%), Gr 2 (6%) and with first full dose was 12% , Gr 1 (71%), unknown (29%). ICANS occurred in 6% (7/97), Gr 1 (14%), Gr 2 (29%), Gr 3 (14%) and unknown in 43% there was no evidence of HLH. Skin toxicity was present in 62% of patients (n=105/118) with 4% needing dose interruptions and presented as rash (20%), dryness (42%) and itching (20%). Nail toxicity was present in 20% (n=65/118), with 9% needing dose interruptions. Dysgeusia was present in 51% (n=97/118), with 10% needing dose interruptions. Oral toxicity manifest as stomatitis (10%), glossitis (1%), ulcerations (2%), dry mouth (27%), was present in 34% (n=61/118), with 12.5% needing dose interruptions. Infections were present in 34% (n=82/118) and CMV reactivation in 23% while only 1 patient needed treatment for CMV. The Overall Response Rate (ORR) was 64.9% with a VGPR rate or higher of 43.3% in this population. Updated efficacy data including PFS will be reported at the time of presentation Conclusions: This is the first largest RWE of the safety and efficacy of Talq in a heavily pretreated population with a high prior BCMA exposure. The ORR is consistent with a prior study by Jakubowiak et al which showed an ORR OF 65.7% after prior T cell engagers. The safety profile - CRS, ICANS, skin and oral toxicities was similar to the MonumenTAL study, CMV reactivation was higher and this may be related to treatment with prior immunotherapies and should be monitored in the future. This report shows that Talq has a similar safety and efficacy profile in the real world when sequenced after prior BCMA therapies.

AbstractBackgroundCD38 has been established as an important therapeutic target for multiple myeloma (MM), for which two CD38 antibodies are currently approved—daratumumab and isatuximab. CD38 is an ectoenzyme that degrades NAD and its precursors and is involved in the production of adenosine and other metabolites.AimAmong the various mechanisms by which CD38 antibodies can induce MM cell death is immunomodulation, including multiple pathways for CD38‐mediated T‐cell activation. Patients who respond to anti‐CD38 targeting treatment experience more marked changes in T‐cell expansion, activity, and clonality than nonresponders.ImplicationsResistance mechanisms that undermine the immunomodulatory effects of CD38‐targeting therapies can be tumor intrinsic, such as the downregulation of CD38 surface expression and expression of complement inhibitor proteins, and immune microenvironment‐related, such as changes to the natural killer (NK) cell numbers and function in the bone marrow niche. There are numerous strategies to overcome this resistance, which include identifying and targeting other therapeutic targets involved in, for example, adenosine production, the activation of NK cells or monocytes through immunomodulatory drugs and their combination with elotuzumab, or with bispecific T‐cell engagers.

Summary: The multiple myeloma treatment landscape has changed dramatically. This change, paralleled by an increase in scientific knowledge, has resulted in significant improvement in survival. However, heterogeneity remains in clinical outcomes, with a proportion of patients not benefiting from current approaches and continuing to have a poor prognosis. A significant proportion of the variability in outcome can be predicted on the basis of clinical and biochemical parameters and tumor-acquired genetic variants, allowing for risk stratification and a more personalized approach to therapy. This article discusses the principles that can enable the rational and effective development of therapeutic approaches for high-risk multiple myeloma.