Bortezomib-induced peripheral neuropathy (BIPN) remains a common treatment side effect in patients with multiple myeloma (MM). Data from rodent models indicate a role of proinflammatory cytokines in BIPN pathophysiology, making them potential therapeutic targets. We therefore tested cytokine levels throughout the course of BIPN in a cohort of MM patients. We performed an interim analysis of a monocentric, non-randomized, observational study including 113 patients with MM. Three groups of patients—within their first cycle of BTZ treatment (FC), with ongoing BTZ treatment at the time of recruiting (OT), and with BTZ treatment in the past (PT)—were compared to controls. Sixteen FC patients were followed up for a median of 6 months. Serum TNF-α, IL-6, and CCL2, the cytokines most often implied in the animal models, were analyzed via the ELLA device. CCL2 levels were not different among our patient groups or in comparison with healthy controls. Compared to healthy controls, the FC group had the highest IL-6 levels, followed by the PT and then the OT group. The FC group also had higher TNF-α levels compared to all other groups. Six months after inclusion, patients showed a decrease in TNF-α levels compared to their baseline. There was no correlation between TNF-α levels and neuropathy severity or impairment in daily life. Factors related to MM may influence systemic cytokine levels in BIPN patients, limiting conclusions on their role in BIPN pathophysiology and their utility as drug targets.

Supp. Table S14. Multivariable logistic regression analyses: Treatment response (≥ PR vs. MR/SD/PD)

Supp. Table S10. Cytopenias before and during treatment – m-EASIX ≤ median vs. > median

Advancements in frontline therapies have substantially improved outcomes in newly diagnosed multiple myeloma (NDMM); however, many patients will not achieve deep responses and will relapse. Teclistamab, a BCMA×CD3 bispecific antibody, in combination with daratumumab, has demonstrated strong efficacy in relapsed/refractory multiple myeloma versus standard of care as early as first relapse. This ongoing phase 2 GMMG-HD10/DSMM-XX (MajesTEC-5) study evaluates teclistamab-based regimens in transplant-eligible NDMM. In this prespecified pooled analysis of three cohorts, 49 patients received teclistamab/daratumumab/lenalidomide (Tec-DR; arms A and A1) or Tec-DR with bortezomib (Tec-DVR; arm B). Primary endpoints were incidence and severity of adverse events (AEs) and serious AEs; secondary endpoints included overall response rate (ORR), minimal residual disease (MRD) negativity and MRD-negative complete response (CR). The current analysis spans the induction and autologous stem cell transplantation phases until the premaintenance timepoint. Grade 3 or 4 treatment-emergent AEs (TEAEs) occurred in 91.8% (45/49); most were hematologic (lymphopenia (59.2%; 29/49), neutropenia (59.2%; 29/49) and leukopenia (18.4%; 9/49)). No grade 5 TEAEs were reported. Serious AEs occurred in 55.1% (27/49); pyrexia (12.2% (6/49)) was most common. Any-grade and grade 3 or 4 infections occurred in 81.6% (40/49) and 36.7% (18/49), respectively, the most common grade 3 or 4 infections being COVID-19 and pneumonia (6.1% (3/49) each). Cytokine release syndrome occurred in 67.3% (33/49); all were grade 1 or 2, all resolved and none led to discontinuation of any study treatment. No treatment-related immune effector cell-associated neurotoxicity syndrome (ICANS) events occurred. Across arms, the MRD-negative CR rate was 91.8% (45/49) by the premaintenance timepoint; the MRD negativity rate was 100% in evaluable samples at postinduction cycle 3 (1 × 10-5 (46/46)), cycle 6 (1 × 10-5 (46/46) and 1 × 10-6 (46/46)) and premaintenance (1 × 10-5 (40/40)); the ORR was 100% (49/49). Total median stem cell yield was 8.1 × 106 per kg. Data support the feasibility of Tec-D(V)R induction in transplant-eligible NDMM, with a consistent safety profile compared with individual regimen components and notable early MRD negativity rates. ClinicalTrials.gov identifier: NCT05695508 .

Systemic AL amyloidosis is a rare disorder characterized by the deposition of misfolded monoclonal immunoglobulin light chains as insoluble amyloid fibrils in various tissues and organs, leading to serious and life-threatening organ dysfunction. Treatment is mostly directed against plasma cells (PCs) and focuses on stopping the production of the amyloid-forming light chains, with a goal of achieving fast and deep hematologic responses and thus preventing further organ damage. Daratumumab, a human IgGk monoclonal antibody targeting CD38, in combination with bortezomib, cyclophosphamide, and dexamethasone, is the first and only regimen indicated both in the United States and Europe for the treatment of newly diagnosed AL amyloidosis and has demonstrated high rates of hematologic and organ responses. However, some patients become refractory to initial therapy and most patients will ultimately relapse. Unfortunately, there is no currently approved treatment regimen for patients with relapsed or refractory disease. Teclistamab (Tec) is a first-in-class B-cell maturation antigen (BCMA) x CD3 bispecific antibody that has demonstrated deep and durable responses in multiple myeloma (MM), leading to its approval for triple-class exposed relapsed/refractory MM. BCMA is widely expressed on both MM and amyloid PCs; in vivo data confirm that soluble BCMA levels positively correlate with involved free light chain levels in patients with AL amyloidosis [Godara A, et al. Blood. 2019;134(Suppl 1):4409]. Moreover, the results from 2 recent retrospective case series suggest that Tec may induce rapid and deep hematologic responses in patients with heavily pretreated AL amyloidosis with no unexpected adverse events [Forgeard N, et al. Blood. 2024;143(8):734-737; Stalker M, et al. Blood. 2023;142(Suppl 1):2035], justifying prospective clinical trials with Tec in AL amyloidosis. The ongoing phase 2 TeclistAMY (EMN40) trial is evaluating the efficacy and safety of Tec monotherapy in patients with previously treated AL amyloidosis. This ongoing international, multicenter, open-label, single-arm phase 2 study will enroll approximately 30 patients aged ≥18 years with histologic diagnosis of systemic AL amyloidosis (affecting ≥1 organ), an Eastern Cooperative Oncology Group performance status of 0-2, Mayo stage I-IIIA cardiac disease at screening, measurable hematologic disease, a creatinine clearance of ≥20 mL/min, and absence of symptomatic MM. Patients must have received ≥1 line of treatment (including daratumumab and bortezomib), and have a wash-out period of ≥14 days from date of last administration of any previous antitumor therapy or investigational treatment for AL amyloidosis. Following initial step-up dosing in Cycle 1, Tec will be administered at a dose of 1.5 mg/kg on Days 8 and 15 of Cycle 1; from Cycle 2 onwards, Tec will be administered every 4 weeks at a dose of 3 mg/kg. All patients will undergo six 28-day cycles of treatment. Patients may continue to receive treatment for a maximum of 12 cycles if clinically indicated and upon discussion between the investigator and the sponsor. A safety analysis will be performed by an Independent Data Monitoring Committee after 6 patients have completed ≥1 cycle of treatment; if no safety signals are observed, the trial will continue as planned. The primary endpoint is hematologic complete response rate after 3 cycles. Secondary endpoints include hematologic overall response rate, very good partial response or better, duration and time to hematologic response, rate and depth of organ response, hematologic progression-free survival, major organ deterioration–progression-free survival, major organ deterioration–event-free survival, time to subsequent therapy, overall survival, safety/tolerability, minimal residual disease after 3 cycles of therapy, and quality of life. Continuous and categorical variables will be summarized using descriptive statistics; time-to-event variables will be evaluated using the Kaplan–Meier method. The study is being conducted at 10 sites across 6 countries, and the first patient was enrolled in July, 2025. The ClinicalTrials.gov identifier is NCT06649695.

Super-resolution microscopy in combination with genetic labeling methods allows imaging of single proteins in cells. However, visualizing endogenous proteins on primary cells remains challenging due to the use of sterically demanding antibodies for labeling. Here, we demonstrate how immunolabeling conditions and antibody cross-linking influence the quantification and identification of membrane receptor stoichiometry on cells using single-molecule localization microscopy. We developed an optimized immunolabeling and analysis protocol and demonstrate the performance of the approach by resolving the molecular organization of endogenous CD45, CD69, and CD38 on Jurkat T cells. To demonstrate the usefulness of the method for immunotherapy applications, we investigated the interaction of primary multiple myeloma cells with the therapeutic monoclonal antibodies daratumumab and isatuximab and a polyclonal anti-CD38 antibody. Our approach might lay the foundation for improved personalized diagnostics and treatment with therapeutic antibodies.

Supp. Table S6. Univariable logistic regression analysis: Hospitalization ≥ 14 days

Supp. Table S16. Univariable Cox regression analysis: Overall survival

Supplementary Figure 1 illustrates the longitudinal course of myeloma-related parameters throughout the patient’s treatment, as well as the therapeutic response assessed by ^68Ga-Pentixafor PET/CT. Supplementary Figure 2 shows the BCMA-CAR integration sites in the patient’s genome and their distribution Supplementary Figure 3 shows the quality control parameters and the cell type distribution of the whole dataset in the index patient Supplementary Figure 4 shows transcriptomic changes regarding cytotoxicity and IFN-II induced genes as well as activation of (CAR) T cells detected via flow cytometry Supplementary Figure 5 shows inference of CD4+ CAR T cells with other cell types as determined via Cell Phone DB Supplementary Figure 6 illustrates the functional imaging results obtained via the course of treatment Supplementary Figure 7 shows the scRNA-sequencing results from the control group and the parkinson patient in pre-treatment sampels as well as 10 days post treatment. Supplementary Figure 8: Shows the gating strategy of the flow cytometry data.

Purpose Continuous therapy in multiple myeloma (MM) can impose cumulative toxicities and psychosocial burden. This mixed‑methods study quantified patient preferences for treatment‑free intervals (TFIs), monitoring trade‑offs, and actionable service improvements across inpatient and outpatient care. Methods A 12-month, single-center mixed-methods survey (n = 100) at a German tertiary center collected sociodemographics, treatment exposure, and structured items on TFI importance, preferred TFI length, monitoring intensity, relapse-risk trade-offs, inpatient stressors, and patient-generated improvement proposals. Quantitative analyses comprised descriptive statistics and hypothesis‑driven group comparisons; qualitative data were analyzed using inductive thematic analysis with double‑coding and consensus. Results TFIs between inpatient treatments were rated 10/10 “very important” by 49.5% and 0/10 “not important” by 9.1%. Predominant inpatient stressors were separation from family (27%), treatment‑related symptoms/side effects (23%), fatigue (17%), food quality (15%), waiting times (14%), and shared rooms (12%). In the outpatient setting, 77% found regular check‑ups reassuring, while 13% found them burdensome. When trading TFI length against relapse risk, 67% prioritized risk minimization and 7% would accept higher risk for longer TFIs. Preferred minimal TFIs were < 4 weeks (23%), 4–8 weeks (19%), and > 8 weeks (39%). Narratives emphasized physical/emotional recovery, autonomy, restoration of routines, and pragmatic levers (single rooms, better food, shorter waits, flexible scheduling, staffing). Conclusion People living with MM value TFIs - especially post‑inpatient - for recovery, while favoring vigilant, risk‑adapted monitoring. Preference‑sensitive TFI planning with explicit safety triggers and hybrid in‑person/telehealth follow‑up may enhance quality of life without compromising safety.

Supp. Table S18. Multivariable Cox regression analyses: Overall survival

Teclistamab is the first approved B-cell maturation antigen×CD3 bispecific antibody with weight-based dosing for triple-class-exposed relapsed/refractory multiple myeloma (RRMM). We evaluated the safety and efficacy of teclistamab combined with the anti-CD38 monoclonal antibody daratumumab in the phase 1b TRIMM-2 study. Eligible patients had RRMM (≥3 prior lines of therapy [LOT] or were double-refractory to a proteasome inhibitor and immunomodulatory drug); prior anti-CD38 exposure was permitted. Patients received subcutaneous daratumumab per approved schedule plus weight-based or fixed-dose subcutaneous teclistamab. The primary endpoint was safety; secondary endpoints included overall response rate (ORR) and duration of response (DOR). Progression-free survival (PFS) was an exploratory endpoint. Sixty-one patients received the weight-based recommended phase 2 doses (RP2D; teclistamab 1.5 mg/kg QW or 3.0 mg/kg Q2W); median number of prior LOTs was 5 (range, 1-14). Median follow-up was 12.0-months. The most common treatment-emergent adverse events (TEAEs) were infections, cytokine release syndrome, neutropenia, and anemia; grade 3/4 TEAEs occurred in 93.4% and 7 died from TEAEs. No dose-limiting toxicities occurred. ORR was 68.9% (complete response or better, 44.3%); median DOR was not reached. Median PFS was 26.3 months. A cohort exploring fixed-dose teclistamab (100-300 mg) ended prematurely after a safety signal for fatal infections was identified; out of an abundance of caution, all patients were switched to weight-based dosing. In conclusion, the fully immune-based combination of weight-based RP2D teclistamab plus daratumumab demonstrated deep and durable responses, with a well-characterized safety profile. Results highlight the importance of infection management, including early immunoglobulin replacement. Registered at ClinicalTrials.gov: NCT04108195.

BACKGROUND AND AIMS:Bortezomib-induced peripheral neuropathy (BIPN) remains a common treatment side effect in patients with multiple myeloma (MM). Data from rodent models indicate a role of proinflammatory cytokines in BIPN pathophysiology, making them potential therapeutic targets. We therefore tested cytokine levels throughout the course of BIPN in a cohort of MM patients. METHODS:We performed an interim analysis of a monocentric, non-randomized, observational study including 113 patients with MM. Three groups of patients-within their first cycle of BTZ treatment (FC), with ongoing BTZ treatment at the time of recruiting (OT), and with BTZ treatment in the past (PT)-were compared to controls. Sixteen FC patients were followed up for a median of 6 months. Serum TNF-α, IL-6, and CCL2, the cytokines most often implied in the animal models, were analyzed via the ELLA device. RESULTS:CCL2 levels were not different among our patient groups or in comparison with healthy controls. Compared to healthy controls, the FC group had the highest IL-6 levels, followed by the PT and then the OT group. The FC group also had higher TNF-α levels compared to all other groups. Six months after inclusion, patients showed a decrease in TNF-α levels compared to their baseline. There was no correlation between TNF-α levels and neuropathy severity or impairment in daily life. INTERPRETATION:Factors related to MM may influence systemic cytokine levels in BIPN patients, limiting conclusions on their role in BIPN pathophysiology and their utility as drug targets.

The significant clinical benefit of bispecific T-cell engagers (TCE) for the treatment of relapsed/refractory multiple myeloma (RRMM) may be offset by serious toxicities and treatment failure. Risk scores such as the CAR-HEMATOTOX (HTX), Endothelial Activation and Stress Index (EASIX), and modified EASIX (m-EASIX) can identify patients at risk for complications before chimeric antigen receptor (CAR) T-cell therapy, but their utility prior to TCE therapy remains elusive. We analyzed associations with outcomes and toxicities in independent discovery (n = 123) and validation (n = 155) cohorts treated with TCEs. Patients with HTX ≥3 or m-EASIX > median (>0.86) had a significantly increased risk of prolonged hospitalization, antibiotic treatment, and fever during step-up dosing. We also observed associations with cytopenias requiring therapeutic intervention, higher severe infection and intervention densities, as well as inferior response rates and reduced progression-free and overall survival. Our findings highlight the potential of these clinical scores to improve risk stratification before TCE therapy. SIGNIFICANCE:Scores such as HTX, EASIX, and m-EASIX have emerged as helpful tools to enable risk stratification before CAR T-cell therapy. In this study, we demonstrate their utility in patients with RRMM receiving TCEs. HTX ≥3 and m-EASIX > median (>0.86) proved to be risk markers for infections, therapeutic interventions, and poor outcomes. See related commentary by Banerjee and Dhodapkar, p. 345.

BACKGROUND:Proteasome inhibitors (PIs) are indispensable for the treatment of multiple myeloma (MM), the second most common hematologic malignancy. Although primary resistance to PIs is rare, most patients eventually relapse and develop acquired resistance, with underlying mechanisms that remain incompletely understood and appear to be drug-specific. In the case of bortezomib, resistance is often associated with PSMB5 mutations. In contrast, resistance to carfilzomib (CFZ) is mediated by overexpression of the drug efflux transporter ABCB1. However, the regulatory mechanisms driving ABCB1 upregulation in CFZ-resistant MM remain unclear. METHODS:An integrative multi-omics analysis was conducted using paired samples from a CFZ-sensitive and -resistant MM patient, alongside resistant cell line models. Whole-genome sequencing (WGS), whole-genome bisulfite sequencing (WGBS), and RNA sequencing (RNA-seq) were used to assess the genotype (structural variants, single nucleotide variants, and copy number variations), methylation status, and the expression of the ABCB1 locus. ABCB1 promoter methylation levels and expression levels in an independent MM subcohort were analyzed to determine clinical relevance. Functional validation was performed using dual-luciferase reporter assays, DNMT1 knockdown, and treatment with DNA methyltransferase inhibitors (DNMTis) to evaluate methylation-dependent regulation of ABCB1 expression. RESULTS:Significant hypomethylation of the ABCB1 downstream promoter region was identified (GH07J087598) in a CFZ-resistant patient sample, which correlated with elevated ABCB1 expression. Consistent with the paired CFZ-resistant case, the independent MM subcohort showed a significant inverse association between ABCB1 promoter methylation and ABCB1 expression. These findings align with results obtained from CFZ-resistant MM cell line models, which demonstrated reduced promoter methylation and elevated ABCB1 expression compared to their wild-type counterparts. Furthermore, treatment with DNA methyltransferase inhibitors as well as DNMT1 knockdown enhanced ABCB1 expression while demethylating the promoter, thereby validating the functional significance of promoter hypomethylation in ABCB1 overexpression. CONCLUSIONS:Our findings highlight ABCB1 promoter hypomethylation as a potential epigenetic driver of CFZ resistance in MM. These results underscore the clinical relevance of epigenetic regulation in drug resistance and the potential of targeting DNA methylation as a therapeutic strategy to overcome resistance in MM.

Abstract Gastrointestinal (GI) involvement is a clinically relevant but undercharacterized manifestation of systemic light chain amyloidosis (AL). We aimed to define the clinical spectrum, histologic patterns, and outcomes of symptomatic GI involvement in AL. We retrospectively analyzed 4396 patients with AL from 2010 to 2024, of whom 521 (11.9%) had provider-attributed symptomatic GI involvement; 66% had biopsy-proven GI AL. Symptoms most commonly included early satiety (61%), bowel irregularities (58%), nausea (35%), abdominal pain (28%), and dysphagia (23%). Autonomic neuropathy was frequent (43% clinician attributed; 23% via autonomic reflex testing) and contributed to dysmotility-related symptoms, often without GI biopsy positivity. Among 747 GI biopsies, mucosal infiltration predominated (71%) and was associated with bleeding (22% vs 9%), cachexia, and inferior survival, whereas vascular involvement was associated with lower bleeding risk. Combined involvement of mucosa, submucosa, and vessels conferred the worst prognosis (median overall survival [mOS], 2.4 vs 5.1 vs 7.8 years for 3 vs 2 vs 1 layer); mOS was 6.8 years and was primarily driven by cardiac stage and hematologic response (very good partial response [VGPR] or better: hazard ratio, 0.20; 95% CI 0.13-0.32), with more favorable outcomes in patients with isolated GI involvement. Cachexia and persistent diarrhea were the main drivers of morbidity, need for nutritional support, and GI-related mortality (odds ratio, 2.7 for the combined end point). GI bleeding rarely recurred after achieving VGPR or better. Overall, mucosal involvement, cachexia, and dysmotility define clinically meaningful GI AL and support systematic assessment of autonomic dysfunction as well as evaluation of the need for nutritional support as a GI-specific end point for AL trials.

Supp. Table S11. Univariable Cox regression analysis: Time to severe infection

Supp. Table S3. Complications and toxicities

Supp. Table S9. Cytopenias before and during treatment – CAR-HEMATOTOX (HTX) < 3 vs. ≥ 3

Chimeric antigen receptor (CAR) T cells exhibit high response rates in B-cell malignancies, but most patients eventually relapse. A key mechanism of treatment failure is the loss or downregulation of tumor antigen expression, yet strategies to modulate cell surface levels of CAR T-cell targets remain largely unexplored. Here, we identify B-cell maturation antigen (BCMA), a central CAR T-cell target in multiple myeloma (MM), as a highly shortlived protein that undergoes K48-linked polyubiquitylation at the plasma membrane, leading to its p97-dependent degradation via the ubiquitin-proteasome system (UPS). This previously unprecedented mechanism of plasma membrane protein regulation enables significant enhancement of BCMA expression via proteasome inhibitors (PIs). The clinically approved PI carfilzomib (CFZ) significantly enhances the efficacy of BCMAdirected CAR T cells against both PI-sensitive and-refractory MM cells in vitro and in vivo. Notably, CFZ treatment of 10 patients with BMCA CAR T-cell therapy relapse, under the CFZ after BCMA CAR T-cell (CarCAR) protocol, resulted in increased BCMA expression in all patients. However, clinical responses were observed only in those with residual and/or expanding CAR T cells, suggesting restored CAR T-cell function. These findings provide a rationale for the use of CFZ treatment in relapsed or refractory MM after BCMA CAR T-cell therapy, advocate for future trials combining CFZ with BCMA CAR T cells, and provide a framework for exploring UPS-dependent degradation of other immunotherapy antigens.