Matsue, Kosei

Abstract Background: Intravenous (IV) isatuximab plus pomalidomide and dexamethasone (Isa-Pd) is approved for treatment in patients with relapsed/refractory multiple myeloma (RRMM) based on the ICARIA-MM study. Subcutaneous (SC) administration of Isa offers potential advantages such as shorter administration duration and greater patient comfort compared with IV routes. Isa SC via an on-body injector (OBI), an investigational wearable bolus injector, demonstrated safety and efficacy in a Phase 1b study in patients with RRMM. The IRAKLIA trial (NCT05405166) was the first Phase 3 trial evaluating the non-inferiority of Isa-Pd SC via an OBI vs Isa-Pd IV in patients with RRMM. Here, we report the findings of the IRAKLIA trial in the East Asian subgroup with RRMM. Methods: This global, multicenter, open-label study enrolledpatients aged ≥18 years with RRMM who had received ≥1 prior line of therapy (LOT) including lenalidomide and a proteasome inhibitor (PI). Patients were randomized 1:1 to Isa SC (1400 mg) or Isa IV (10 mg/kg) weekly in Cycle (C)1, then every 2 weeks in addition to P (4 mg orally daily, Day [D]1-21) and d (40 mg orally [20 mg if age ≥75 years] weekly). Treatment was administered in 4-week cycles and continued until disease progression, unacceptable toxicity, or patient withdrawal. Co-primary endpoints included overall response rate (ORR) and observed Isa concentration before dosing (Ctrough) at steady state (predose at C6D1). Key secondary endpoints included rate of very good partial response or better (≥VGPR), Ctroughlevel Cycle 2 Day 1 (C2D1), infusion reaction incidence, and patient satisfaction rate based on the patient experience and satisfaction questionnaire (PESQ) at C5D15. Results: The East Asian subgroup consisted of 105 patients from China (Mainland, n=82 and Taiwan, n=1) and Japan(n=22) (SC, n=50; IV, n=55). Baseline characteristics of the East Asian subgroup were generally balanced between the two arms and generally comparable to the overall global population (median age 62 years; median 2 prior LOT; 29.5% high-risk cytogenetics; 82.9% refractory to lenalidomide; 7.6% prior exposure to daratumumab). After a median of 13.0 months follow-up, ORR in the SC and IV arm was 74.0% and 70.9%, respectively (relative risk [95% CI] = 1.044 [0.815 – 1.335]). The mean (SD) of Ctroughat C6D1 was 502 (232) µg/mL for SC arm and 282 (123) µg/mL for IV arm. The geometric mean ratio (90% CI) comparing SC to IV for Ctrough at steady state was 1.756 (1.346 – 2.290). The ≥VGPR rates were 58.0% for SC and 50.9% for IV (relative risk [95% CI] = 1.139 [0.798 – 1.631]). The mean(SD) of C2D1 Ctroughlevel was 420 (161) µg/mL for the SC arm and 262 (111) µg/mL for IV arm. The geometric mean ratio (90% CI) comparing SC to IV for Ctrough at C2D1 was 1.673 (1.321 to 2.120). The infusion reaction incidence was 0% and 21.8% for SC and IV, respectively. Grade ≥3treatment-emergent adverse events were observed in 82.0% and 87.3% of patients in the SC and IV arms, respectively. Treatment discontinuation rates were 6% for the SC arm and 12.7% for the IV arm. Injection site reactions (ISRs) occurred in 4% (2/50) of patients in the SC arm and in 0.21% (2/964) of SC injections (all Grade 1), with 99.3% of SC injections completed successfully. Isa SC patients expressed higher satisfaction with their injection method, with 64.0% of patients reporting “satisfied” or “very satisfied” vs 52.7% of Isa IV patients (odds ratio [95% CI] = 1.594 [0.728 – 3.489]). Conclusions: The efficacy, safety and pharmacokinetic results between Isa SC vs IV + Pd in the East Asian population from the IRAKLIA study were consistent with the results of the overall global population, in which non-inferiority of ORR, Ctrough at C6D1, ≥VGPR and Ctrough at C2D1 was demonstrated and statistically significantly fewer infusion reactions and higher patient satisfaction were also noted for SC vs IV. These results support the potential use of Isa SC delivered via OBI in East Asian patients and demonstrate the potential of this delivery method to improve patient experience and practice efficiency.

8525 Background: RRMM patients (pts) triple-class exposed (to immunomodulatory drugs [IMiDs], proteasome inhibitors [PIs] and anti-CD38 monoclonal antibodies [mAbs]) have limited treatment (tx) options. The ongoing phase II KarMMa study (NCT03361748) is examining idecabtagene vicleucel (ide-cel; bb2121), a BCMA targeted CAR T cell therapy, in RRMM pts with ≥3 prior regimens (IMiD, PI and CD38 mAb inclusive) who are refractory to their last tx per IMWG criteria. This study aimed to 1) assess tx patterns and outcomes in real world (RW) RRMM pts similar to the KarMMa population and; 2) compare outcomes with SoC in a synthetic cohort vs ide-cel in KarMMa. Methods: In this global, noninterventional, retrospective study (KarMMa-RW), pt-level data from clinical sites, registries and databases were collated into a single data model. RW pts meeting KarMMa eligibility criteria (eligible cohort; EC) were compared with KarMMa (N = 128) using trimmed stabilized inverse probability of tx weighted propensity scores (IPTW PS) for pts in both studies with Poisson regression for ORR and ≥VGPR, and Cox models with study as a term for PFS. All models were adjusted for unbalanced covariates. Results: Of 1949 RW pts, 1171 were refractory to last regimen (median age, 68 y; median no. of prior regimens, 5; triple-class refractory, 41%). Further selection for subsequent tx, organ function and no comorbidities yielded 190 EC pts who had > 90 distinct tx regimens. With a median follow-up of 11.3 mo (KarMMa) and 10.2 mo (EC) at data cutoff (Oct 30, 2019), ORR, ≥VGPR and PFS were significantly improved in KarMMa vs EC (Table). Conclusions: Results from the KarMMa-RW study confirm that there is no clear SoC for heavily pretreated RW RRMM pts and responses are suboptimal with currently available therapies. Ide-cel showed deep, durable responses and significantly improved PFS in RRMM pts, representing a potential new tx option in RRMM. Clinical trial information: tbd . [Table: see text]

Abstract Introduction: For decades conventional skeletal survey (CSS) has been the standard imaging technique for the detection of bone impairment caused by Multiple Myeloma (MM). The development of cross-sectional imaging techniques like Whole Body Computed Tomography (WBCT) with or without Positron Emission Tomography (PET/PET-CT) and magnetic resonance imaging (MRI) led to the use of these techniques in several centers worldwide and to the implementation of their findings into the revised diagnostic criteria of MM. The aim of the current multicenter study was to compare sensitivity and prognostic significance of WBCT and CSS in patients with monoclonal plasma disorders. Methods: For the current retrospective analysis 308 patients with different stages of monoclonal plasma cell disorders from 8 centers were included. Compact discs with pseudonymized imaging data of WBCT and CSS were sent to the organizing center and uploaded to the picture archiving and communication system. In addition, questionnaires were completed by each center to collect clinical data of the patients. Image analysis was performed in consensus reading by three experienced radiologists (LAM, SD, VK) blinded to the clinical data of the patients. Osteolytic lesions in 19 pre-specified anatomic regions were characterized as "definitely present", "probably present", "probably absent" and "definitely absent". For the analysis only "definitely present" and "probably present" entries were counted as myeloma lesions. To define symptomatic or active versus smoldering myeloma based on the presence of bone lesions, findings of CSS were used to simulate the situation before the introduction of WBCT. For comparison of WBCT and CSS only those anatomic regions having valid measurements from both methods performed within 30 days without treatment in the meantime were considered. WBCT and CSS were tested for differences in detection sensitivity with the exact McNemar test. Results: Of 308 submitted datasets; 160 patients were without prior treatment and 56 of them had smoldering myeloma. Of 160 patients 80 (50%) had no osteolytic lesions on either CSS or WBCT and 33 (20.6%) showed osteolyses on both techniques. In 9 patients (5.6%) osteolyses were found on CSS but not in WBCT while 38 patients (23.8%) were positive on CT alone. Of note is that for some CT-scans, the upper extremities were not evaluable due to positioning during the examination. Odds ratio for osteolyses on WBCT compared to CSS was 4.22 (P < 0.0001). The regions where WBCT was most significantly superior in detecting osteolyses were the iliac bone, thoracic and lumbar spine as well as the ribs. CSS compared to WBCT revealed osteolyses in more patients only in the proximal extremities: for left humerus 10 (6.5%) versus 3 (1.9%), right humerus 12 (7.7%) versus 4 (2.6%), left femur 11 (7.1%) versus 7 (4.5%) and right femur 10 (6.5%) versus 8 (5.2%) respectively. Of 157 evaluable patients 63 (40.1%) showed osteoporosis (defined by radiological criteria) on both techniques while 29 (18.5%) had osteoporosis on WBCT only and 10 (6.4%) on CSS only (OR 2.90, P = 0.003). In the 56 patients with smoldering myeloma, with bone disease being defined according to the findings of CSS 12 (21.4%), were positive for osteolyses on WBCT (P = 0.0005). Conclusion: WBCT shows significantly more sites of bone destruction compared to conventional X-ray imaging particularly in skeletal regions composed primarily of trabecular bone while CSS shows more osteolyses in the appendicular skeleton - in part due to a limited field of view. More than 20% of patients with smoldering myeloma based on CSS have active disease that needs treatment based on WBCT. Therefore, WBCT is the current standard for the detection of osteolytic lesions in myeloma. The prognostic significance of WBCT and CSS findings for survival and correlation with clinical parameters will be reported at the meeting. Disclosures Hillengass: Celgene: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; Novartis: Research Funding; Amgen: Consultancy, Honoraria; Sanofi: Research Funding. Plesner:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Dimopoulos:Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Genesis: Consultancy, Honoraria. Goldschmidt:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Chugai: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Lentzsch:Celgene: Consultancy, Honoraria; BMS: Consultancy. Terpos:Takeda: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Genesis: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Novartis: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Honoraria.