Lin, Yi

Background: There is an increased risk of second primary malignancies including second hematological malignancies (SHM) in multiple myeloma (MM) patients undergoing autologous stem cell transplant (auto-SCT) followed by lenalidomide maintenance. We analyzed the characteristics and outcomes of patients who developed SHM after an auto- SCT for MM. Methods: A retrospective study of all MM patients who underwent auto- SCT at Mayo Clinic, Rochester between January 1, 1990, and 31 August 2023 and later developed SHM. Demographic, clinical and pathologic data were collected retrospectively. Overall survival (OS) was calculated from the date of auto-SCT to the date of last follow up. Statistical analyses were performed using GraphPad prism 9.0. Chi-square test was used to calculate the difference between categorical variables. Kaplan Meier method and log rank test were used to estimate OS. Results: Among 3513 patients who underwent at least 1 auto-SCT, 104 (2.9%) developed a SHM at a median follow up of 59 (range, 0.2-265) months. Patients who developed SHM, more frequently received pretransplant alkylating agents (37.5 vs 24.2 %, odds ratio [OR], 1.87; P=0.003) and topoisomerase II inhibitors (anthracyclines/etoposide) (17.3% vs 10.4%, OR [1.79]; P=0.03) compared to a control group of MM patients without SHM. Further, exposure to lenalidomide (77.8% vs 57.6%, OR[2.59]; P <0.0001) and radiation therapy (32.6% vs 23.1%, [1.54]; P=0.04) were more often seen in the SHM cohort compared to control group. Among the 381 patients who underwent > 1 auto- SCT, 3.1% developed SHM. Therapy related myeloid neoplasms (t-MN) accounted for 90.3% of cases [n=94; t-myelodysplastic syndrome (t-MDS=64), t-acute myeloid leukemia (t-AML=12), t-MDS transformed to AML(n=16), chronic myeloid leukemia (n=1), MDS/myeloproliferative neoplasm overlap syndrome (n=1)]. Eight patients (7.6%) developed therapy related B- cell acute lymphoblastic leukemia (t-ALL); Philadelphia (Ph) negative ALL (n=7) and Ph- like ALL (n=1). One patient each developed mixed phenotype acute leukemia and acute leukemia, not otherwise specified. Sixty patients (57.6%) were males and the median age at diagnosis of SHM was 70 (range, 43-84) years. The median time from auto-SCT to diagnosis of SHM was 58.5 (range, 7-236) months. In a multivariate analysis, receiving an alkylating agent (hazard ratio [95% confidence interval]: 2.51 [1.54 to 4.01]; P = 0.0002) and/or topoisomerase II inhibitor as induction for MM (3.12 [1.59 to 5.88]; P = 0.0006), exposure to lenalidomide (7.08 [3.92 to 13.50]; P = <0.0001) and radiation therapy (1.60 [1.02 to 2.44]; P = 0.03) were independent predictors of developing SHM. At diagnosis, 57% (n=37) of t-MDS and 71% (n=20) with t-AML had high risk disease per R-IPSS and 2022 European Leukemia Net respectively. Clonal abnormality in chromosome 5 and/or 7 was present in 45% (n=42) of patients. Complex and monosomal karyotype was seen in 32% (n=30) with t-MN. The most frequently mutated genes based on next generation sequencing data included TP53 (n=33), DNMT3A (n=9), RUNX1 (n=5), TET2 (n=4) and CEBPA (n=4). In the t-MDS/AML cohort, 3 patients (3.1%) underwent second auto-SCT and 9 (9.5%) received allogenic SCT (allo-SCT) for SHM. After a median follow-up of 27.2 months, the median OS from t-MDS/AML diagnosis was 8.04 months (95%CI, 6.1-11.0 months) and there was no difference in median OS for allo-SCT recipients versus nonrecipients (9.1 vs 6.8 months, P =0.19). In the t-ALL (n=8) cohort, all of them received lenalidomide based induction and five received lenalidomide maintenance. Most of the t-ALL patients had adverse risk cytogenetics [IKZF1 deletion (n=2), complex karyotype (n=2), TP53 mutation (n=1) and P2RY8-CRLF2 fusion (n=1)]. Three patients with t-ALL underwent allo-SCT and the median OS for allo-SCT recipients versus non recipients were 8.3 vs 7.9 months respectively, P=0.50. Among patients with SHM, 92.3% (n = 96) have died with SHM (72%) being the most common cause of death. MM patients who developed SHM had an inferior OS when compared to those without SHM (median OS, 75 vs 90 months, P =0.006). Conclusion: SHM following auto-SCT tends to have aggressive disease biology with poor outcomes. Short term follow up underestimates the risk of SHM and the higher incidence noted in our study may be due to longer follow up. As the OS in MM patients continues to improve, SHM remains an important challenge in improving long term outcomes.

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.

Background Emerging evidence has demonstrated rare subacute to late neurological toxicities (NTs) after BCMA CAR T-cell therapy (CAR-T) in multiple myeloma (MM). These adverse events can be categorized as: 1) Parkinsonism (PD), 2) cranial nerve (CN) palsies, and 3) peripheral neuropathies/Guillan Barré syndrome (GBS). These toxicities can cause significant morbidity, but given their relative rarity in clinical trials, there is limited data regarding evaluation and treatment. To our knowledge, this is the largest and only global registry of delayed NTs after BCMA CAR-T. Methods We retrospectively established a registry of NTs via the Immune Therapy Working Committee of the International Myeloma Working Group (IMWG). We gathered data pertaining to demographics, MM characteristics, MM response, NT signs/symptoms, diagnostic workup, and treatment. Result A total of 52 patients with delayed neurotoxicity were included from 14 institutions and 6 countries; 92% received ciltacel, 4% idecel, and 4% investigational CAR-T. Median age at CAR-T infusion was 65 years; 69% were male and 88% were Caucasian. Median bone marrow plasma cell (PC) burden was 15% prior to CAR-T (range 0-95%). Patients received a median of 4 prior lines of therapy (LOT), with 67% progressing on last LOT. Seventeen percent had pre-existing neurological diagnoses (including stroke, epilepsy, migraines). We identified sixteen cases of PD (94% with movement disorder, 69% with cognitive impairment, 75% with personality changes), occurring at a median of 26 days (range: 15-87) after CAR-T. Ninety four percent had CRS (grade (G)1 50%, G2 38%, G3 6%, G4 0%), while 19% had ICANS (G1 13%, G2 6%, G3-G4 0%). Median peak absolute lymphocyte count (ALC) was 9.5 x 109/L, peak C-reactive protein (CRP) 60.9 mg/L, and peak ferritin 1893.5 ug/L within the first 30 days. Concurrently, 3 upper respiratory infections (URIs) and 2 low-level HHV7 in the cerebrospinal fluid (CSF) were detected. A median of 73% of T-cells in the CSF were CAR-T, based on a flow cytometry assay. Ten patients received steroids (median 19 days after symptoms, 70% partial response, 20% no response, 10% unknown), 2 received intrathecal (IT) methotrexate-based therapy (median 32 days after symptoms, 1 with no response, 1 unknown), 5 received intravenous (IV) cyclophosphamide (median 31 days after symptoms, 40% full response, 20% partial response, 40% no response), 4 received high-dose IVIG ≥1g/kg for one or more dose (50% partial response, 50% no response), and 6 received dopamine agonists. There were 37 CN palsies (76% CN7, 15% CN6, 7% CN5, 2% CN3), occurring at a median of 37.5 days (range: 7-482) after CAR-T. Eighty one percent had CRS (G1 68%, G2 14%, G3-G4 0%); 11% had G1 ICANS (G2-G4 0%). Median peak ALC was 4.1 x 109/L, CRP 25.4 mg/L, and ferritin 543 ug/L within the first 30 days. We identified 2 concurrent URIs, 4 CMV viremia (50% with viral load >1500 IU/mL), 1 HHV6 viremia, and 1 HSV in the CSF. Thirty-two (86%) received steroids for a median duration of 12 days, 50% with full response, 3% with no response, and 47% with partial response (of which 43% had later full recovery without further intervention). One received IT methotrexate and another received IV cyclophosphamide without response. Thirteen (41%) received IVIG, of which 38% was high-dose IVIG. Four patients with CN palsies developed peripheral neuropathy/GBS. Eight patients (15%) in this cohort were not heavily pre-treated (≤1 prior LOT); 7 developed CN palsies (6 after ciltacel, 1 after investigational CAR-T) and 1 PD (after idecel). These patients had median <5% PC; none had extramedullary disease. Median ALC was 4.14 x 109/L, CRP 33 mg/L, and ferritin 448.5 ug/L within the first 30 days. Conclusions Delayed NT requires prompt recognition, evaluation for alternative causes, and treatment. In our cohort, the majority of patients were male and Caucasian, suggesting that sex and race may impact the likelihood of developing NT. Individuals with PDs had greater inflammatory response (CRS, ALC, CRP, ferritin) compared to those with CN palsies. CN palsies responded to steroids and/or IVIG, whereas PD had at best partial response to steroids, prompting additional therapy. These toxicities notably did occur in less heavily pre-treated patients, perhaps driven by immune fitness and greater circulating T-cells rather than MM burden. At the time of the annual meeting, data will be updated with additional NTs from less heavily pre-treated patients.

Introduction: Ven is a BCL2 inhibitor that has shown clinical efficacy in RRMM patients (pts) particularly those that harbor t(11;14). Ven has been evaluated in clinical trials as a single agent, in combination with dexamethasone (dex), immunomodulatory drugs (IMiD), proteasome inhibitors (PI), and anti-CD38 monoclonal antibodies (MAb) yet its place in the therapeutic landscape remains in question. In this retrospective analysis, we aim to evaluate the real-world efficacy of Ven-based regimens in RRMM pts treated outside of a clinical trial across the 3-site MCCC. Methods: We retrospectively analyzed the medical records of pts with RRMM treated with Ven-based regimens between January 2015 and October 2023 at the MCCC. Refractoriness was defined by progression on or within 60 days of stopping treatment. Categorical variables were compared with Chi-square tests and continuous variables were compared with t-tests. Outcomes were estimated using the Kaplan-Meier method and curves were compared between the groups using log-rank tests. Results: 83 pts were included in the analysis. The median age was 71 (39-93), 63% were male, 93% were white, 27% had ISS III, 18% had high risk cytogenetics (HRCyto), 76% had t(11;14), the median prior lines of therapy (LOT) was 4 (1-15), 68% received ≥ 4 prior LOT, 87% received prior autologous transplant, 58% were triple-class refractory (TCR), 64%/23% were penta-drug exposed/refractory (PDE/R), 8% received prior BCMA-directed therapies (BDT), 58% received Ven+dex, 25% received Ven+PI +/-dex, 6 % received Ven+anti-CD38 MAb+/-dex and 11% received Ven+other. The median follow-up time from start of a Ven-based regimen was 29 months (mo). The median Ven dose was 800mg (20-1600) with 25% of pts receiving Ven ramp-up dosing. The overall response rate (ORR) to a Ven-based regimen was 58% and was 64% for pts with t(11;14) and 40% for pts without t(11;14); p=0.06. Ven-treated pts with HRCyto had inferior PFS (3mo) and OS (8mo) compared to patients who did not have HRCyto who had a PFS of 9mo (p=0.020) and OS of 80mo (p<0.001). The ORR for TCR and PDR pts were 52% and 42%, respectively. No significant ORR differences were noted across the different Ven-based regimens (p=0.32). The median PFS for pts with t(11;14) was 10mo compared to 2mo for pts w/o t(11;14); p=<0.001. The median OS for pts with t(11;14) was 80mo compared to 10mo for pts without t(11;14); p=0.001. Ven-treated pts who received 1-3 prior LOT has superior ORR, median PFS, and median OS; 89%, 25mo, and 99mo, respectively, compared to pts who received ≥4 prior LOT who achieved an ORR of 43% (p<0.001), median PFS of 5mo (p<0.001) and median OS of 25mo (p<0.001). Ven-treated pts that were TCR had inferior PFS (5mo) and OS (26mo) compared to pts who were not TCR who achieved a PFS of 12mo (p<0.001) and a median OS of 80mo (p=0.02).Ven-treated pts that were PDR had inferior PFS (4mo) and OS (22mo) compared to pts who were not PDR who achieved a PFS of 9mo (p<0.001) and a median OS of 80mo (p=0.02).Ven-treated pts who received prior BDT (n=7) achieved an ORR of 29% and had a median PFS and OS of 2mo and 6mo, respectively on a Ven-based therapy. 59 pts received additional therapy in the post Ven-progression setting. The ORR to post-Ven progression therapies was 53% (n=31/59), the median PFS was 9mo and median OS was 35mo. The most common post-Ven progression regimens used were PI-based (n=16; ORR=56%), anti-CD38 MAb-based (n=14; ORR=50%), BDT (n=12; ORR=83%), selinexor-based (n=3; ORR=0%) with BDT resulting in highest ORR (p=0.048) and PFS (p=0.005). Conclusions: Ven-based regimens are effective in heavily pre-treated pts with RRMM however they are more effective when used within 1-3 prior LOT, in pts with t(11;14), and in pts without HRCyto, TCR or PDR MM. BDT appear to be the most efficacious therapies in the post-Ven progression setting.

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: Cilta-cel is approved in the US and EU for the treatment (tx) of patients (pts) with len-refractory MM after ≥1 line based on the randomized, phase 3 CARTITUDE-4 trial (NCT04181827). At the first interim analysis (15.9-month [mo] median follow-up), cilta-cel significantly improved progression-free survival (PFS) vs SoC (hazard ratio [HR], 0.26 [protocol-specified weighted analysis]; P<0.0001). At the second interim analysis, overall survival (OS) was significantly improved with cilta-cel vs SoC (HR, 0.55; P=0.0009). MRD negativity is a prognostic marker of prolonged survival outcomes for pts with MM. We report MRD negativity, including overall and sustained MRD negativity, overall MRD-negative complete response or better (≥CR), and MRD-negative ≥CR at mo 12, from the prespecified second interim analysis of CARTITUDE-4. Methods: Eligibility criteria were previously described. Pts were assigned 1:1 to cilta-cel or SoC (pomalidomide, bortezomib, and dexamethasone [PVd]/daratumumab, pomalidomide, and dexamethasone [DPd]). Pts in the cilta-cel arm underwent apheresis, received bridging therapy (PVd/DPd), and then a single cilta-cel infusion (target dose, 0.75×106 CAR+ viable T cells/kg) 5-7 days (d) after the start of lymphodepletion. PFS was the primary endpoint; ≥CR rate, overall response rate, overall MRD-negativity rate, and OS were key secondary endpoints. MRD was assessed centrally via next-generation sequencing (clonoSEQ v2.0; Adaptive Biotechnologies). MRD was evaluated at d 56 post infusion in the cilta-cel arm; and in both arms at suspected ≥CR and at 6, 12, 18, and 24 mo post infusion (cilta-cel arm) or cycle 1 d 1 (SoC arm), as well as yearly until progression/start of subsequent therapy in pts in ≥CR. Sustained MRD negativity (10−5) was defined as confirmed MRD negativity ≥12 mo apart and without MRD positivity in between. Pts were evaluable for sustained MRD negativity if they achieved MRD negativity and had ≥1 evaluable MRD sample ≥12 mo after the first negative result or progressed/died/started subsequent tx <12 mo after the first negative result. Results: 419 pts were randomized (intent-to-treat [ITT] set; cilta-cel, n=208; SoC, n=211); 176 pts in the cilta-cel arm received cilta-cel as study tx. As of May 1, 2024, median follow-up for the study was 33.6 mo. At the 10−5 threshold, 145 pts in the cilta-cel arm and 103 in the SoC arm were evaluable for MRD. MRD-negativity rates (10−5) in the ITT set and the MRD-evaluable subset were higher with cilta-cel vs SoC (ITT, 62% vs 18%; MRD evaluable, 89% vs 38%; both P<0.0001). Across subgroups, cilta-cel vs SoC consistently increased overall MRD-negativity rates (10−5). In the ITT set, 48% of the cilta-cel arm achieved MRD negativity (10−5) by d 56, with the MRD-negative rate rising to 60% by 6 mo post cilta-cel infusion. Overall MRD-negativity rates at the 10−6 threshold in the ITT set were higher with cilta-cel vs SoC (57% vs 9%; P<0.0001). In the cilta-cel arm, 119 (57%) pts vs 26 (12%) in the SoC arm achieved overall MRD-negative (10−5) ≥CR (P<0.0001). At the 12-mo MRD assessment, 92 (44%) pts in the cilta-cel arm vs 17 (8%) in the SoC arm (P<0.0001) had MRD-negative (10−5) ≥CR. In pts with MRD-negative (10−5) ≥CR at mo 12, median PFS was not reached (NR; 95% CI, not estimable [NE]-NE) with cilta-cel and 37.8 mo (95% CI, 25.0-NE) with SoC; median OS was NR (95% CI, NE-NE) and NR (95% CI, 37.8 mo-NE), respectively. Sustained MRD-negativity rates (10−5) in the ITT set were 40% in the cilta-cel arm vs 6% in the SoC arm (P<0.0001); among 110 and 26 evaluable pts for sustained MRD, sustained MRD-negativity rates were 75% vs 50% (P=0.0159). Among the 176 pts who received cilta-cel as study tx, overall MRD negativity at 10−5 was achieved by 129 (73%) pts (89% of 145 evaluable pts). Conclusions: At 33.6-mo median follow-up in CARTITUDE-4, cilta-cel vs SoC significantly increased overall MRD-negativity rates >3-fold in the ITT set, with pts achieving MRD negativity rapidly post cilta-cel. The prognostic value of MRD-negative ≥CR at mo 12 was shown, as median PFS was >3 years in pts with MRD-negative ≥CR at mo 12, regardless of tx. These data further underscore the benefit of cilta-cel, which led to significant >3-fold increases vs SoC in rates of MRD-negative ≥CR at any time and at mo 12, and sustained MRD negativity. Our MRD data demonstrate higher rates of deep and sustained MRD negativity achieved with cilta-cel vs SoC in tx of len-refractory MM as early as first relapse.

Background: Multiple Myeloma (MM) is predominantly a disease of older adults. However, older patients vary widely in physiological status and treatment tolerance. The simplified frailty index (Facon 2020) incorporates age, ECOG performance status, and comorbidities (Charleston Comorbidity Index [CCI]) to classify patients as frail or non-frail. While frailty is associated with increased toxicity with conventional systemic therapies, its impact on outcomes of older patients treated with bispecific antibodies (BsAbs) has not been established. Thus, we conducted a retrospective study to evaluate the efficacy and toxicity of BsAbs in older patients based on frailty. Methods: This is a single institution study. We included patients with MM ≥65 years who initiated treatment with a BsAb at Mayo Clinic in Rochester, MN from August, 2018 to January, 2024. Patients who received a BsAb on trial or as standard of care were included. For patients who received 2 different BsAbs at different timepoints, we included the first treatment only. We grouped patients into frail and non-frail based on the simplified frailty index (score ≥2 = frail). We evaluated the overall response (ORR) and ≥very good partial response (VGPR) rates, progression-free (PFS) and overall (OS) survival, early mortality (within 90 days) including early non-relapse mortality (NRM), and toxicities including cytokine release syndrome (CRS), immune effector cell associated neurotoxicity syndrome (ICANS) and healthcare utilization. P values were insignificant (>0.05) unless otherwise stated. PFS and OS were calculated from the day of BsAb start. Results: A total of 99 patients age 65-89 years were included. The products used were teclistamab (N=43), talquetamab (N=2), and investigational agents (N=54); 67% were ≥70 and 29% were ≥75 years; 39% were female, 95% were non-Hispanic White and 4% were Black/African American. Seventy patients (71%) were considered frail and 29 (29%) were non-frail. At the time of BsAb start, a higher proportion of frail patients had platelets <75 x 10^9/L (30% vs 8%, P=0.04). Otherwise, there was no significant difference between frail and non-frail patients in age (median: 72 vs 70), hemoglobin <8 g/dL (19% vs 12%), absolute neutrophil count <1 x 10^9/L (6% vs 8%), presence of high-risk FISH (70% vs 60%), ISS stage 3 (32% vs 41%), high LDH (58% vs 61%), presence of extramedullary disease (39% vs 25%), serum creatinine ≥2 mg/dL (15% vs 8%), bone marrow plasma cell% (20% in both), triple- (83% vs 90%) and penta-class refractoriness (63% vs 48%), number of prior lines of therapy (median: 6 in both), prior exposure to BCMA-directed therapy (24% vs 21%, P=0.80) and prior autologous stem cell transplant (73% vs 86%). Step-up dosing was used in 81% vs 48% of patients (P=0.001), and treatment was initiated in the outpatient setting in 46% vs 28% (P=0.12) in frail and non-frail patients, respectively. The median follow-up was 1.9 (95%CI: 1.0-2.3) years. There was no significant difference between frail and non-frail patients in ORR (52% vs 62%), ≥VGPR (46% vs 48%), 1-year PFS (36% vs 48%, P=0.26), or 1-year OS (57% vs 61%, P=0.30), respectively. Age and CCI alone were not associated with PFS or OS, but ECOG >1 was associated with decreased PFS (hazard ratio: 3.1, P=0.001) and OS (hazard ratio: 3.1, P<0.001). There was no significant difference between frail vs non-frail patients in grade 3/4 thrombocytopenia (39% vs 17%, P=0.06), grade 3/4 neutropenia (27% vs 35%), total days of hospitalization (median: 8 vs 5, P=0.35), number of unplanned admissions in 6 months (median: 1 in both), or total hospital days for unplanned admissions (1 vs 2 days). There was no significant difference between frail and non-frail patients in early mortality (23% vs 10%, P=0.17), including early NRM (4% in both), CRS (59% vs 66%), grade 3-4 CRS (3% vs 7%), or CRS recurrence (21% vs 10%). ICANS occurred in 5 (9%) frail patients and 1 non-frail patient (grade 2); among frail patients, grades were: 1 in 3 patients, 3 in 1 patient, and 4 in 1 patient. Similarly, there was no significant difference in CRS/ICANS between the 2 groups when patients with and without step-up dosing were analyzed separately. Conclusion: Frailty, defined using the simplified frailty index, was not significantly associated with inferior efficacy or increased toxicity with BsAb therapy among older patients with MM. Poor performance status predicted inferior PFS and OS, while age and comorbidity scores did not.

Background: A deeper understanding of the cytogenetic features has enabled robust risk stratification for patients with newly diagnosed multiple myeloma (NDMM). However, heterogeneity persists in the currently available prognostic tools and there is further room for personalization. We assess the utility of PC-PRO, a test to measure the proportion of monotypic plasma cells in the synthetic phase (S-phase) of cell cycle, as a prognostic marker for NDMM. Methods: Patients with active MM diagnosed between January 2013 and January 2023 with a flow cytometry-based S-phase assessment at diagnosis were included. Flow cytometric immunophenotyping was performed using the following antibodies: CD19, CD38, CD45, CD138, cytoplasmic kappa and lambda immunoglobulin, and DAPI (4',6-diamidino-2-phenylindole). The percentage of plasma cells in S-phase was determined by measuring the proportion of cells with DNA content of the monotypic plasma cells between the G0/G1 and G2/M peaks. Plasma cell clonality was detected through demonstrating CD38 and CD138 positivity along with immunoglobulin light chain restriction, abnormality of CD19/ CD45 expression and/or ploidy difference by DAPI staining. High-risk cytogenetic abnormalities (HRCA) by FISH were defined as follows: presence of deletion 17p (del17p), t(4;14), t(14;16), t(14;20), 1q gain/amplification, 1p deletion (when available). Additionally, the second iteration of the revised ISS (R2-ISS), incorporating both laboratory and cytogenetic features as well an adaptation of the recently proposed International Myeloma Working Group (IMWG) Classification for high-risk disease, was utilized for risk stratification. All time-to-event analyses were performed using the Kaplan Meier method and compared using the log-rank test. Univariable and multivariable Cox proportional hazards analyses were performed to assess the independent prognostic impact of S-phase. Results: A total of 823 patients were included in the study. The median follow-up was 6 years [95% Confidence interval (CI): 5.5-6.3 years] and estimated median overall survival (OS) was 8.3 years. The median S-phase value for the cohort was 0.8 % (interquartile range: 0.5-1.4%), with 135 (16%) patients harboring an S-phase of ≥2% at diagnosis. Applying the R2-ISS prognostic model to our cohort, 11% (79/706) patients were stratified to the R2-ISS high-risk cohort; 93 patients (out of 788, 12%) had 2 or more HRCA at diagnosis. Patients with a S-phase ≥2% at diagnosis had a median OS of 3.9 years (95% CI: 2.9-5.7) vs. 9.2 years [95% CI: 7.9-not reached (NR)] for patients with a S-phase <2% [Hazard ratio (HR): 2.2 (95% CI: 1.7-2.8), p<0.0001]. The median OS was inferior for cohorts with an increasing S-phase value: S-phase of 0.1-1%: HR: 1 (standard), S-phase 1.1-3%: HR 1.7 (95% CI: 1.3-2.1), S-phase >3%: HR 3.0 (95% CI: 2.2-4.1)]. On a multivariable analysis including S-phase ≥2%, age at diagnosis of MM (>65 years) and R2-ISS high-risk status, S-phase ≥2% was an independent predictor of inferior OS [hazard ratio (HR) 1.9 (95% CI: 1.4-2.6), p<0.0001]. Age >65 years [HR 1.9 (95% CI: 1.5-2.5), p<0.0001] and R2-ISS high-risk status [HR 1.8 (1.3-2.6), p=0.001] were also independent predictors of OS. Within the sub cohort of patients with 2 or more of the listed high-risk cytogenetic features (n=93, 12%), a S-phase ≥2% (n=24) was associated with a worse median OS of 1.6 years (95% CI: 0.7-NR) vs. 6.2 years (95 % CI:3.3-NR) for S-phase <2% (p=0.002). Conclusion: Flow cytometry-based determination of the proportion of monotypic plasma cells in S-phase is an easy-to-study and powerful prognostic tool for NDMM. A S-phase of ≥2% at diagnosis is a predictor of OS independent of age and R2-ISS high-risk stage. An S-phase of ≥2% was able to identify a distinct group with markedly inferior outcomes even within the sub cohort of patients with 2 or more high-risk cytogenetic features.