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Summary: While the current approach to precursor hematologic conditions is to “watch and wait,” this may change with the development of therapies that are safe and extend survival or delay the onset of symptomatic disease. The goal of future therapies in precursor hematologic conditions is to improve survival and prevent or delay the development of symptomatic disease while maximizing safety. Clinical trial considerations in this field include identifying an appropriate at-risk population, safety assessments, dose selection, primary and secondary trial endpoints including surrogate endpoints, control arms, and quality-of-life metrics, all of which may enable more precise benefit–risk assessment.

Introduction: Patients with TCE RRMM have a high disease burden and often report worsening HRQoL with additional lines of therapy. The single-arm, phase 2 KarMMa study demonstrated that ide-cel, a B-cell maturation antigen (BCMA)-directed chimeric antigen receptor T cell therapy, improved HRQoL from baseline in patients with TCE RRMM who had received ≥ 3 prior regimens (Delforge M, et al. Blood Adv 2022;6:1309-1318). Furthermore, in the phase 3 KarMMa-3 clinical trial (NCT03651128), ide-cel significantly improved progression-free survival and response compared with standard regimens in patients with TCE RRMM who had received 2-4 prior regimens (Rodriguez-Otero P, et al. N Engl J Med 2023;388:1002-1014). Here we assessed the comparative effects of ide-cel versus standard regimens on HRQoL in patients with TCE RRMM who had received 3-4 prior regimens including an immunomodulatory agent, a proteasome inhibitor, and daratumumab (an anti-CD38 monoclonal antibody) using data from the KarMMa-3 study. Methods: Patient-reported outcomes (PROs) were assessed by the European Organization for Research and Treatment of Cancer (EORTC) Quality-of-Life Questionnaire-Core 30 (QLQ-C30), EORTC Quality of Life Questionnaire Multiple Myeloma Module (QLQ-MY20), and EQ-5D-5L. The pre-specified primary domains of interest included EORTC QLQ-C30 global health status/QoL, physical functioning, cognitive functioning, fatigue, and pain; EORTC QLQ-MY20 disease symptoms and side effects of treatment; and the EQ-5D-5L visual analog scale (EQ-5D VAS). PROs were collected at screening (baseline), the day of ide-cel infusion (ide-cel) or first treatment dose (standard regimens), monthly from 2 to 28 months, and thereafter every 3 months. Comparisons were performed on least squares (LS) mean changes from baseline through 28 months between arms using constrained longitudinal data analysis (cLDA). Effect size was estimated by Hedges' g. The comparative effects of ide-cel versus standard regimens on time to confirmed improvement and time to confirmed deterioration (defined by prespecified change thresholds) were assessed via stratified Cox proportional hazards regression analyses. All P values are nominal and not adjusted for multiple testing. Statistical significance was set at P < 0.05. Results: Baseline characteristics were well balanced among the patients in the ide-cel arm (n = 167) and the standard regimen arm (n = 93), with a median age of 63 years and a median time of 4.7 years from RRMM diagnosis to study screening. Completion rates of HRQoL assessments were high over time for most visits (> 75%). At baseline, mean HRQoL domain scores were similar between arms. Overall LS mean changes from baseline to 28 months showed significant differences in favor of ide-cel versus standard regimens (nominal P < 0.05) for 11 domains (effect sizes of 0.26-0.82), and 7 (4 primary: global health status/QoL, cognitive functioning, pain, EQ-5D VAS; 3 secondary: dyspnea, insomnia, constipation) of them exceeded the prespecified MID thresholds (Table). Time to confirmed improvement was significantly shorter (nominal P < 0.05) in the ide-cel arm than in the standard regimen arm for 10 domains, including all primary domains except pain. Time to confirmed deterioration was longer in the ide-cel arm than the standard regimen arm for most domains, with significant differences in emotional functioning, cognitive functioning, and dyspnea (EORTC QLQ-C30). Finally, side effects of treatment favored the ide-cel versus standard regimen arm (EORTC QLQ-MY20) (Table). Conclusions: These patient-reported findings demonstrate that compared with standard regimens, treatment with ide-cel improved MM-relevant disease symptoms, functioning, and overall health status/HRQoL of patients with TCE RRMM in the KarMMa-3 trial. These data further substantiate the superior treatment outcomes of ide-cel over standard regimens in this patient population. Overall, treatment with ide-cel may help alleviate detriments to HRQoL in these patients with complex disease.

Background: An interim analysis (data cutoff date April 18, 2022) of the international, open-label, phase 3 KarMMa-3 trial (NCT03651128) showed the chimeric antigen receptor T cell therapy idecabtagene vicleucel (ide-cel) significantly improved progression-free survival and treatment response rates, as well as HRQoL, as compared with standard regimens, in patients with triple-class exposed (TCE) RRMM who had received 2-4 prior regimens (Rodriguez-Otero P, et al. N Engl J Med 2023;388:1002-1014; Delforge M, et al., HemaSphere, 2023;7(S3):P905). The aim of the present study was to analyze the effect of ide-cel versus standard regimens (daratumumab [DARA], pomalidomide, and dexamethasone [DEX]; DARA, bortezomib, and DEX; ixazomib, lenalidomide, and DEX; carfilzomib and DEX; or elotuzumab, pomalidomide, and DEX) on HRQoL in KarMMa-3 trial participants with an extended follow-up of patient-reported outcomes (PRO) data collection (data cutoff date April 28, 2023). Methods: In KarMMa-3, HRQoL was assessed using the European Organisation for Research and Treatment of Cancer (EORTC) Quality-of-Life Questionnaire-Core 30 (QLQ-C30), EORTC Quality of Life Questionnaire Multiple Myeloma Module (QLQ-MY20), and EQ-5D-5L. HRQoL assessments were completed at screening (baseline); the day of ide-cel infusion or the first dose of standard treatment; and monthly from 2 to 28 months; and every 3 months thereafter. The prespecified primary outcomes of interest were EORTC QLQ-C30 global health status/QoL, physical functioning, cognitive functioning, fatigue, and pain; EORTC QLQ-MY20 disease symptoms and side effects of treatment; and the EQ-5D visual analog scale (EQ-VAS). Least squares (LS) mean changes from baseline through month 25 for ide-cel and standard regimens were compared by constrained longitudinal data analysis (cLDA). Effect sizes were estimated by Hedges' g. The effect of ide-cel versus standard regimens on time to confirmed improvement and deterioration in HRQoL (defined by prespecified change thresholds and sustained duration) were compared by stratified Cox proportional hazards regression. There was no adjustment for multiple testing, and all P values reported are nominal. Results: Overall, 254 patients were randomized to the ide-cel arm and 132 to the standard regimens arm. Baseline characteristics were well balanced across treatment arms; both arms had a median age of 63 years, a median of 3 prior anti-myeloma regimens, and median time from MM diagnosis to screening was 4 years. The baseline HRQoL scores were generally comparable between treatment arms. Overall LS mean changes from baseline to month 25 showed significant differences (nominal P value < 0.05) in favor of ide-cel for 18 out of 21 HRQoL domains, with effect sizes (Hedges' g) of 0.27 to 0.82 (Table). For 13 of these domains (including 6 primary domains of interest), the difference in overall LS mean change from baseline exceeded the prespecified minimum important difference (MID) threshold. Time to confirmed improvement was significantly shorter in the ide-cel arm than the standard regimens arm for 19 domains, including all primary domains of interest (Table). Time to confirmed deterioration showed trends of being longer in the ide-cel arm than the standard regimens arm for most domains and was significantly longer for emotional functioning, cognitive functioning, social functioning, dyspnea, and constipation as measured by the EORTC QLQ-C30. The time to confirmed deterioration in side effects of treatment (based on the EORTC QLQ-MY20) was significantly longer for patients in the ide-cel arm and time to confirmed improvement was significantly faster, as compared with the standard regimens arm (Table). Conclusions: In the KarMMa-3 trial, patients with TCE RRMM who had received 2-4 prior regimens, ide-cel significantly and meaningfully improved MM-relevant symptoms, functioning, and overall health status/HRQoL compared with standard regimens. Confirmed HRQoL improvements in the ide-cel arm occurred sooner than standard regimens. PRO improvements were sustained over more than 2 years, which is notable after a single infusion treatment with ide-cel. These patient-reported findings further support the benefit of ide-cel in this patient population.

Background HPN217 is a B Cell Maturation Antigen (BCMA)-targeting tri-specific T cell engager (TCE). HPN217 contains three binding domains including anti-BCMA for MM cell binding, anti-albumin for half-life extension, and anti-CD3 for T cell engagement and activation. HPN217 is a small (~50 kDa) globular protein, designed to increase the therapeutic window by minimizing off-target toxicities and cytokine release syndrome (CRS). HPN217 is under investigation in patients (pts) with heavily pretreated relapsed/refractory MM (RRMM). Methods This study is designed to assess the safety, pharmacology and early clinical activity of HPN217 using fixed and step-dose (prime dose followed by target doses) regimens in dose escalation cohorts along with expansion of selected regimens for further evaluation. Pts with RRMM who have received at least 3 prior therapies including a proteasome inhibitor, an immunomodulatory drug, and CD38-targeted therapy are eligible. Prior exposure to a BCMA-targeting agent is permitted. Primary objectives include evaluation of safety, tolerability, pharmacokinetics (PK), and determination of the Recommended Phase 2 Dose(s) (RP2D). Secondary objectives include preliminary efficacy. HPN217 is administered IV once weekly or once every 2 weeks. Adverse events (AEs) are graded by CTCAE 5.0, and ASTCT for cytokine release syndrome (CRS) and ICANS. Clinical activity is assessed per IMWG Response Criteria. Results Dose escalation has been completed. 97 pts were enrolled across 15 dose escalation cohorts and expansion of 3 regimens with the highest target dose levels from dose escalation (12mg weekly; 24mg every 2 weeks; 24mg weekly for 1 cycle followed by 24mg every 2 weeks). As of 26 June 2023, across all cohorts, 94 pts were treated and had received a median (range) of 6 (2-19) prior lines of treatment (62% penta-exposed, 17% BCMA-targeted therapy, 68% prior transplantation). Median age was 70 (38-85) years. 36 pts (38%) remain on treatment. The most common (≥25%) treatment-emergent adverse events (TEAEs) across all cohorts and in the 12mg and 24mg cohorts are summarized in Table 1. Dose limiting toxicities (DLTs) of reversible transaminitis (Gr 3, n=1; Gr 4, n=1) in 2 pts at 2.86 mg fixed dose during dose escalation informed the choice of 2.15 mg as priming dose in the highest step dose cohorts; a maximum tolerated dose (MTD) has not been reached in step dose cohorts. All CRS events were grade 1-2 except one event of grade 3 CRS at 24 mg. Grade 1 ICANS was reported in 2 pts. Responses were observed at doses ≥ 2.15 mg. Among the 12mg and 24mg cohorts, 55% (22/40) of efficacy-evaluable pts currently have had a confirmed response (PR or better) including 2 pts with prior BCMA directed CAR-T cell therapy; disease assessments for recently enrolled patients are pending. Among pts with a response, 73% (16/22) have had a confirmed response of VGPR or better. Across all dose levels, the median time on treatment for pts with a confirmed response was 40 weeks (range 8.3-114 weeks), including 9 patients on treatment for over 12 months, with data maturing to include longer follow-up on patients recently enrolled. HPN217 exhibited linear and dose proportional PK across all dose groups with a median half-life of 68 hours (range 26-197 hours). Transient cytokine increases were higher with the initial/priming dose compared to subsequent/target doses. Conclusions Dose escalation of HPN217, a novel half-life extended BCMA-targeting T-cell engager, has been completed; the MTD was not reached in step dose cohorts. The 12mg and 24mg target doses are well tolerated with manageable adverse event profiles similar to those at lower dose levels and are associated with robust and durable clinical responses. Additional follow up of recently enrolled pts in 12 mg and 24 mg cohorts will inform the choice of the RP2D(s), and complete data on all pts enrolled will be presented. NCT04184050

Introduction: ISB 1342 is a humanized CD38xCD3 bispecific T-cell engager using Ichnos proprietary Bispecific Engagement by Antibodies based on the T cell receptor (BEAT ®) platform, designed to simultaneously bind CD38 on multiple myeloma (MM) cells and CD3ε on T cells, to induce tumor killing. This mechanism of action is different from existing monospecific CD38 targeting therapies and was designed to overcome resistance to daratumumab in MM. ISB 1342 exhibits potent killing of the primary MM cells and MM cell lines with low sensitivity to daratumumab ( Pouleau B. et al. Blood 2023; 142 (3): 260-273). We report here, the updated findings from the weekly dose-escalations of intravenous (IV) and subcutaneous (SC) injections of an ongoing, single-agent phase 1 study (NCT03309111) of ISB 1342 in patients with RRMM. Methods: Adult patients with RRMM that relapsed after or were refractory to prior therapies, including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 antibody; received ISB 1342 on a weekly (QW) schedule by IV or SC injection with a priming dose on the first day in 2 parallel dose-escalation schemas. Patients had measurable disease per the International Myeloma Working Group (IMWG) criteria (2016). Dose escalation in the QW schedule began at 0.2/0.3 mg/kg priming/treatment dose and followed a “3 + 3” design. The primary study objectives are to determine the maximum tolerated dose (MTD) and select a recommended phase 2 dose (RP2D) of ISB 1342. Secondary objectives includ evaluation of anti-myeloma activity, pharmacokinetics (PK), pharmacodynamics, and immunogenicity of ISB 1342. Results: As of July 18, 2023, based on ongoing clinical database, 39 subjects had received weekly IV infusions of ISB 1342 in 8 dose-escalation groups from 0.2/0.3 mg/kg to 4.0/16.0 mg/kg as priming/treatment dose; and 7 additional subjects had received weekly SC injections at 2.0/8.0 mg/kg. Two different formulations have been tested in SC group. Median number of cycles administered was 2. The majority were male (57%) and white (74%); 13% were Black or African American. The median age was 69 years (range, 54-76) and the median time since diagnosis was 6.6 years (range, 2.8-22.2). The median number of prior anti-myeloma lines of therapy was 6 (range 1-12). Twenty-one (67%) subjects were considered to be triple-class refractory and 18 (48%) penta-drug refractory. Forty-one (89%) subjects experienced treatment-related adverse events (TRAEs) of any grade. Most TRAEs were grade 1-2, including infusion related reactions (37%), cytokine release syndrome (CRS, 34%, all grade 1or 2), anemia (24%), neutropenia (24%), and thrombocytopenia (17%). Five subjects in SC group (71% of SC) had injection site reaction, all grade 1 or 2. Grade 3 or higher TRAEs occurring in more than 5% of subjects were infusion related reaction (no grade 4), anemia (no grade 4), neutropenia, leukopenia. No Grade 5 TRAE was observed. After QW IV infusion, ISB 1342 serum concentration peaked at the end of infusion and then showed bi-exponential decline. ISB 1342 serum exposures increased in a dose linear fashion across the tested IV infusion dose range. The limited PK data after SC injection suggest slow presentation of ISB 1342 into the systemic circulation leading to lower C max and delayed T max relative to IV. Transient increases in serum cytokines were observed within 24 hours after ISB 1342 dosing, including IFNg, TNFa, IL-2, IL-6 and IL-10. Transient increases in T-cell activation were observed by flow cytometry at 24-48 hours after ISB 1342 dosing at 1.0 / 4.0 μg/kg and above, based on increased expression of CD69 on peripheral blood CD4+ and CD8+ T-cell populations (Figure 1). Comparison of the available data from subjects treated at 2 / 8 μg/kg (Cohort 109) indicated reduced T-cell activation following SC compared to IV administration of ISB 1342. The efficacy signals observed in Cohorts 108 and 109 are consistent with the estimates of the lower boundary of the predicted efficacious dose range using a quantitative systems pharmacology (QSP) model based on preclinical data. Updated clinical data, including response rates and safety data, will be present at the meeting. Conclusions: Treatment with ISB 1342 was well tolerated at higher dose levels evaluated. Observed CRS events were moderate. No increased risk of infection has been observed . Updated safety, efficacy, biomarker and PK data will be presented.

Introduction A single ide-cel infusion showed significantly longer median progression-free survival (PFS) vs std regimens (13.3 vs 4.4 months [mo], HR 0.49, 95% CI 0.38-0.65, P < 0.001) with deep, durable responses in heavily pretreated TCE RRMM at an interim analysis (IA) of KarMMa-3 (NCT03651128); safety data were consistent with prior studies (Rodríguez-Otero et al. NEJM 2023). Ide-cel benefits were consistent across pts in high-risk subgroups and across 2-4 prior lines of therapy (Tx). Results of the preplanned final PFS analysis of KarMMa-3 with 12.3 mo additional follow-up are reported. Methods In the phase 3 KarMMa-3 trial, pts with RRMM who received 2-4 prior regimens, including an immunomodulatory agent, proteasome inhibitor, and daratumumab, and were refractory to last regimen were randomized 2:1 to ide-cel or a std regimen (DPd, DVd, IRd, Kd, or EPd). In the ide-cel arm, pts could receive ≤ 1 cycle of optional bridging Tx for disease control. Pts in the std regimens arm could receive ide-cel after confirmed disease progression (PD). The primary endpoint was IRC-assessed PFS in the ITT population; final PFS was planned to be analyzed with ~289 events. Key secondary endpoints were IRC-assessed overall response rate (ORR) and overall survival (OS); other secondary endpoints included complete response rate (CRR), duration of response (DOR), minimal residual disease (MRD) status, time to next anti-myeloma Tx (TTNT; time from randomization to next anti-myeloma Tx [MTx]), event-free survival (EFS; time from randomization to first PD, next MTx or any-cause death, whichever is first), PFS2 (time from randomization to second objective PD or any-cause death, whichever is first), safety, and health-related quality of life (QOL). Results Of 386 randomized pts (ide-cel, n = 254; std regimens, n = 132), 225 received ide-cel and 126 received a std regimen. Baseline characteristics were generally balanced. Median follow-up from randomization to data cutoff (April 28, 2023) was 30.9 mo (range 12.7-47.8). Ide-cel significantly improved median PFS (95% CI) vs std regimens (13.8 [11.8-16.1] vs 4.4 [3.4-5.8] mo), representing a 51% reduced risk of PD or death (HR 0.49, 95% CI 0.38-0.63; Figure); 18 mo PFS rates were 41% vs 19%, respectively. Ide-cel significantly improved ORR vs std regimens (71% vs 42%) with deeper (CRR 44% vs 5%; ≥CR and MRD negative status [sensitivity level 10 -5], 22% vs 1%), more durable responses (median DOR 16.6 vs 9.7 mo; Table). PFS and ORR benefits of ide-cel vs std regimens were consistent with the IA. Interim OS will be included in the presentation. In pts who received ide-cel (n = 225) or a std regimen (n = 126), median PFS (95% CI) was 15.7 (12.5-18.9) vs 4.4 (3.4-5.8) mo, respectively. In the ITT population, median TTNT, EFS, and PFS2 were numerically longer with ide-cel vs std regimens. Median (range) TTNT was 20.9 (16.6-24.2) vs 7.0 (5.3-8.5) mo. Median (95% CI) EFS was 13.3 (11.3-15.7) vs 3.9 (3.0-5.3) mo. Median PFS2 (95% CI) was 23.5 (18.4-27.9) vs 16.7 (12.2-20.3) mo; ide-cel was next MTx in 70 (53%) pts in the std regimens arm. In the treated population, grade (gr) 3/4 infections occurred in 66/249 (27%) pts in the ide-cel arm vs 25/126 (20%) in the std regimens arm. In the ide-cel safety population, any gr cytokine release syndrome occurred in 197/225 (88%) pts, gr ≥ 3 in 11 (5%); median time to first onset was 1 d (1-14), median duration was 4 d (1-51). Any gr investigator-identified neurotoxicity occurred in 34/225 (15%) pts, gr ≥ 3 in 7 (3%); median time to onset was 3 d (range 1-317); median duration was 2.5 d (range 1-252). Ide-cel continued to demonstrate durable, clinically meaningful improvements in pt-reported outcomes, including symptoms, functioning, and QOL vs std regimens. Conclusions In this final PFS analysis of KarMMa-3, significantly longer PFS was maintained with ide-cel; PD or death risk reduced by 51%; responses were deeper and more durable vs std regimens. CRR with ide-cel increased since the IA, indicating a deepening response, but were unchanged with std regimens. A single ide-cel infusion vs continuous treatment with std regimens resulted in longer median TTNT and PFS2, indicating improved long-term disease control. The ide-cel safety profile was consistent with previous reports, with no parkinsonism or Guillain-Barré syndrome reported. These data continue to support use of ide-cel in pts with TCE RRMM. Study support 2seventy bio and Celgene, a Bristol-Myers Squibb Company.