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

Abstract Systemic light chain (AL) amyloidosis is a rare, acquired protein misfolding disorder characterized by extracellular deposition of misfolded immunoglobulin light chain fibrils, resulting in organ damage. Treatment is based on anti‐plasma cell regimens derived from multiple myeloma therapy. To date, no approved regimens exist for relapsed/refractory cases. This retrospective multicenter study, performed at 11 centers across Germany, evaluated the efficacy and tolerability of the treatment with teclistamab in 52 patients with relapsed/refractory AL amyloidosis. Hematologic response (≥very good partial response [VGPR]) was achieved in 81% of patients at Day 15, which increased to 95% at 3 months. Flow‐minimal residual disease (MRD) was negative in 96% (23/24) of cases. Cardiac and renal responses (≥partial response [PR]) at 6 months were 65% and 78%, respectively. Cytokine release syndrome occurred in 37% of cases, with two classified as Grade 3 and none as Grade 4. Neutropenia Grade 3 or 4 occurred in 5/52 (10%) of patients. The 1‐year overall survival was 83%, and the median overall survival was not reached after a median follow‐up time of 8.8 months. Factors including difference between involved and non‐involved free light chains (dFLC) ≥ 180 mg/L, N‐terminal pro‐brain natriuretic peptide (NTproBNP) ≥ 8500 pg/mL, glomerular filtration rate (GFR) < 20 mL/min/1.73 m2, and dialysis did not significantly impact overall survival. In total, nine patients deceased, six of whom deceased due to bacterial infections. Patients receiving immunoglobulin replacement therapy had a 2.01 lower risk of infections Grade 3 or 4 and a 6.14 lower risk of death. Our findings demonstrate the efficacy of teclistamab in a heavily diseased and pretreated cohort with AL amyloidosis and highlight the necessity of a concomitant immunoglobulin replacement therapy.

Abstract Introduction: In RRMM, increasing rates of pt attrition and decreasing durability of responses with each line of therapy (LOT) necessitate early treatment (tx) with the most effective therapies. Immunotherapies that are widely accessible across different MM tx settings have the potential to change the trajectory of RRMM. Teclistamab (Tec), the first approved BCMA×CD3 bispecific antibody (BsAb) for heavily pretreated RRMM, provided deep, durable responses in MajesTEC-1, with improved efficacy and safety in earlier LOTs. Daratumumab (Dara), a standard-of-care (SoC) foundational CD38 targeted therapy with direct on-tumor activity, has been shown to deplete immunosuppressive T-cells and expand cytotoxic T-cells, creating an immune-permissive microenvironment for synergistic Tec-mediated killing of MM cells. MajesTEC-3 (NCT05083169) evaluates Tec-Dara vs SoC DPd/DVd in RRMM. We report initial results for this first phase 3 study of BsAb therapy in MM. Methods: Eligible pts had 1-3 prior LOTs including a PI and lenalidomide (Len; pts with 1 prior LOT must have been Len-refractory) with progressive disease (PD) on or after the last LOT. Pts with prior BCMA-directed therapy or refractory to anti-CD38 were excluded; prior anti-CD38 exposure was permitted. Pts were randomized 1:1 to Tec-Dara or DPd/DVd. The Tec-Dara group received 28-day cycles (C) of Tec (1.5 mg/kg QW in C1-2 [C1 preceded by the approved step-up dose schedule]; 3 mg/kg Q2W in C3-6; and 3 mg/kg Q4W in C7+) with Dara; steroids were not required after C1 Day 8. Tec and Dara dosing were aligned with the approved Dara schedule. DPd/DVd were administered per approved schedules. Progression-free survival (PFS) by IRC was the primary endpoint; secondary endpoints included complete response or better (≥CR), overall response, minimal residual disease (MRD) negativity (10–5; next-generation sequencing), overall survival (OS), time to worsening of symptoms (MySIm-Q), and safety. Results: 587 pts were randomized (Tec-Dara, n=291; DPd/DVd, n=296). Median (range) age was 64 (25-88) yrs, median number of prior LOTs was 2 (1-3). With 34.5-mo median follow-up, Tec-Dara significantly improved PFS vs DPd/DVd (HR, 0.17; 95% CI, 0.12-0.23; P<0.0001); mPFS was NR and 18.1 mo, and 36-mo PFS rate was 83.4% and 29.7%, respectively. PFS benefit was consistent across all prespecified and clinically relevant pt subgroups, including age ≥75 yrs, Len-refractory, high-risk cytogenetics, ≥60% bone marrow plasma cells, soft-tissue plasmacytomas, and anti-CD38 exposed. Significantly higher rates of ≥CR (81.8% vs 32.1%; OR, 9.56; 95% CI, 6.47-14.14), overall response (89.0% vs 75.3%; OR, 2.65; 95% CI, 1.68-4.18), and MRD-negativity (58.4% vs 17.1%; OR, 6.78; 95% CI, 4.53-10.15) were observed with Tec-Dara (P<0.0001). There were 45 deaths with Tec-Dara and 96 with DPd/DVd, primarily due to PD (4.6%; 20.3%). OS significantly favored Tec-Dara (HR, 0.46; 95% CI, 0.32-0.65; P<0.0001), including across all prespecified subgroups. The 36-mo OS rates were 83.3% and 65.0%, respectively and >90% of Tec-Dara pts alive at 6 mo were also alive at 30 mo. Median time to worsening of MM symptoms was NR with Tec-Dara vs 39.9 mo with DPd/DVd (HR, 0.50; 95% CI, 0.34-0.72; P=0.0002). At data cutoff, 49.4% of pts remained on study tx (Tec-Dara, 71.0%; DPd/DVd, 28.3%). Median tx duration was twice as long with Tec-Dara vs DPd/DVd (32.4 vs 16.1 mo). Frequency of grade 3/4 (Tec-Dara, 95.1%; DPd/DVd, 96.6%) and grade 5 (7.8%; 6.2%) treatment-emergent adverse events (TEAEs), were comparable (safety set: Tec-Dara, n=283; DPd/DVd, n=290). Serious TEAEs occurred in 70.7% Tec-Dara and 62.4% DPd/DVd pts; tx discontinuations due to TEAEs were low (4.6% vs 5.5%). Any grade infections occurred in 96.5% and 84.1% of Tec-Dara and DPd/DVd pts, respectively; grade 3/4 infections occurred in 54.1% and 43.4%. New onset grade ≥3 infections decreased over time, coinciding with transition to Q4W dosing and supported by antimicrobial and Ig prophylaxis guidance. CRS rate was 60.1% (grade 1/2: 44.2%/15.9%) and ICANS was 1.1% with Tec-Dara. Conclusion: We demonstrate the clinically remarkable and statistically significant PFS and OS benefits of Tec-Dara vs SoC triplets in RRMM, with 83.4% of Tec-Dara pts alive and progression-free at 3 yrs. Infections with Tec-Dara were well managed with established protocols. This highly effective, off-the-shelf, immunotherapy combination represents a new SoC for RRMM as early as first relapse.

Disease burden at the time of BCMA-directed chimeric antigen receptor (CAR) T-cell infusion is a key determinant of outcome in relapsed or refractory multiple myeloma (RRMM). Bridging therapy is frequently administered between leukapheresis and infusion to prevent disease progression, yet its clinical impact remains unclear. We conducted a multicenter real-world cohort study of 399 patients with RRMM treated with BCMA-directed CAR T-cell therapy, including 348 (87%) who received bridging therapy. Bridging therapy recipients had more advanced and biologically adverse disease, including higher rates of high-risk cytogenetics and penta-class refractoriness. Bridging efficacy varied substantially by regimen (P.

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 .

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

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

Use of anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T-cell (CAR-T) therapy to treat relapsed/refractory multiple myeloma is increasing. Studies suggest that effective bridging therapy (BT) prior to anti-BCMA CAR-T therapy can enhance efficacy and safety outcomes. Through qualitative interviews and a consensus workshop, 10 European experts shared their clinical experience regarding optimal BT selection, efficacy, safety and outcomes post-CAR-T, focussing on heavily pretreated patients and emerging BT options, such as bispecific T-cell engagers. Experts agreed that BT should aim to reduce tumour burden and maintain or improve patient performance status, while avoiding treatment-related toxicity that could delay or prevent CAR-T infusion. The balance between treatment duration and achieving an adequate response is important, and patient characteristics are key for BT selection, especially in difficult-to-treat populations. Here, we discuss the unique therapy talquetamab, a GPRC5DxCD3 bispecific antibody, which demonstrates robust efficacy and rapid response rates in clinical trials, and is being considered as a BT option before anti-BCMA CAR-T therapy based on expert experience and real-world data. This consensus, based on clinical experience, aims to provide guidance on BT for healthcare professionals (HCPs) involved in anti-BCMA CAR-T therapy and aid standardisation of care in this rapidly advancing field.

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

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.

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

Purpose: Although emerging therapies for multiple myeloma (MM) have improved treatment options, long-term disease control in relapsed/refractory (r/r) MM remains a challenge. While the effect of natural killer cell alloreactivity in haploidentical allogeneic hematopoietic cell transplantation (HCT) with post-transplantation cyclophosphamide (PTCy) as graft-versus-host disease (GvHD) prophylaxis is considered a standard treatment option for several hematologic neoplasms, its use in MM is controversial. In this retrospective analysis, we evaluated a small cohort of consecutive patients with MM who underwent haploidentical allogeneic HCT with PTCy. Patients and Methods: With a median follow-up of 68 months (range, 2-109 months), seven consecutive patients with r/r MM underwent haploidentical HCT. All were heavily pre-treated, having received proteasome inhibitors, anti-CD38 antibody, immunomodulatory drugs, and at least one autologous HCT. Three patients received a chemotherapy-based reduced-intensity conditioning regimen combined with radioimmunotherapy. GvHD prophylaxis in all patients consisted of PTCy in combination with tacrolimus and mycophenolate mofetil. Results: All patients showed stable engraftment with complete donor chimerism. Haploidentical HCT resulted in initial response in all patients, with four patients achieving a complete remission (CR) and three a very good remission (VGPR) at first disease assessment post-HCT. All individuals surviving beyond day +100 experienced disease relapse or progression. Among the six surviving patients median time to relapse was 26.5 months (range, 5-81 months). At last follow-up, four of five surviving patients maintained a CR, while one patient remained in a very good partial remission, all following subsequent individualized therapies. Acute GvHD grades III-IV were observed in two patients, while four developed mild-to-moderate chronic GvHD, with no GvHD-related deaths at the last follow-up. Conclusion: In this small, selected cohort, haploidentical allogeneic HCT with individualized pre-treatment and conditioning regimens was associated with disease control in heavily pretreated patients with r/r MM.

Supp. Table S7. Multivariable logistic regression analyses: Hospitalization ≥ 14 days

Supp. Table S1. Patient and disease characteristics – CAR-HEMATOTOX (HTX) < 3 vs. ≥ 3

Abstract Background Ciltacabtagene autoleucel (cilta-cel) is a BCMA-directed chimeric antigen receptor (CAR) T-cell therapy approved for relapsed or refractory multiple myeloma (RRMM). Following the CARTITUDE-1 results in heavily pretreated patients, the randomized phase 3 CARTITUDE-4 trial demonstrated superior progression-free survival (PFS) and overall survival for cilta-cel compared with standard of care in lenalidomide-refractory patients after one to three prior lines, leading to label expansion in 2024. However, real-world data characterizing outcomes in this earlier-line indication are lacking. Methods We analyzed all patients with RRMM receiving standard-of-care cilta-cel between 2022 and 2025 from the German Registry for Stem Cell Transplantation and Cellular Therapy. Patients were stratified by prior lines of therapy into an Early group (1–3 prior lines) and a Late group (> 3 prior lines). The primary endpoint was PFS. Secondary endpoints included overall response rate, response conversion, and safety outcomes including cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome (ICANS), non-ICANS neurotoxicity, and non-relapse mortality. Prognostic associations were assessed using restricted cubic spline Cox regression and univariable Cox models. Results Of 606 patients, 177 (30%) were treated in the Early and 429 (70%) in the Late setting. The overall response rate was 91% and 88%, with complete response in 63% and 54%, respectively. The 12-month PFS was 79% for Early and 70% for Late cilta-cel. Depth of response was the strongest predictor of PFS in both cohorts, with patients maintaining complete response showing 100% PFS at 12 months irrespective of treatment line. Extramedullary disease was adversely prognostic in both groups, whereas high-risk cytogenetics were not associated with inferior PFS in the Early group. Non-ICANS neurotoxicity occurred less frequently in the Early group (3% versus 8%), while non-relapse mortality was comparable (6% versus 7%). Conclusions This analysis demonstrates that cilta-cel in earlier lines of therapy achieves deep responses and high PFS consistent with the CARTITUDE-4 trial. These results provide real-world evidence for the deployment of cilta-cel as early as first relapse and may be a benchmark outside prospective trials.