Badros, Ashraf

Abstract Idecabtagene vicleucel (ide-cel) was the first chimeric antigen receptor T-cell therapy to gain US Food and Drug Administration approval for patients with relapsed/refractory multiple myeloma (RRMM). The clinical outcomes of standard of care (SOC) ide-cel in racially and ethnically diverse populations have been understudied. This study pooled data from 207 patients with RRMM (28% patients of racial and ethnic minority groups) treated with SOC ide-cel across 11 institutions to examine racial and ethnic differences in the incidence of toxicities and adverse events, response to ide-cel, and survival. This study included 22 (11%) Hispanic, 36 (17%) non-Hispanic Black, and 149 (72%) non-Hispanic White patients with RRMM. Compared with Hispanic and non-Hispanic White patients, non-Hispanic Black patients had higher median levels of C-reactive protein (1.0, 0.8, and 3.5 mg/dL, respectively; P = .02) and baseline ferritin (362.0 vs 307.0 vs 680.5, respectively; P = .08) and were more likely to develop cytokine release syndrome (77%, 85%, and 97%, respectively; P = .04). Although best overall response rate was lower among Hispanic patients (59%) than among non-Hispanic Black (86%) and White patients (86%; P = .01), there were no racial and ethnic differences in progression-free or overall survival. We provide, to our knowledge, the first and largest investigation of clinical outcomes of SOC ide-cel by race and ethnicity. Despite differences in safety and response to ide-cel, our findings encourage the use of ide-cel in all patients with RRMM. These findings should be confirmed in larger samples of diverse patients with RRMM, with longer follow-up time.

Abstract Introduction : Despite recent advances, MM remains incurable and new therapeutic options are needed, particularly for pts with RRMM. IBER is a novel, potent oral cereblon E3 ligase modulator (CELMoD ®) compound with enhanced tumoricidal and immune-stimulatory effects compared with immunomodulatory (IMiD ®) agents. Preclinically, IBER demonstrated marked synergy with DEX and with other standard myeloma treatments. CC-220-MM-001 (NCT02773030) is an ongoing phase 1/2 study evaluating IBER with different treatment combinations in independent cohorts of pts with RRMM; in phase 1, the recommended phase 2 dose of IBER, when given in combination with DEX, was determined at 1.6 mg (Lonial S, et al. Blood 2019;134[suppl 1]:3119). Here we report results from the dose expansion of IBER + DEX in pts with heavily pretreated, triple-class exposed (including ≥ 1 IMiD agent, ≥ 1 proteasome inhibitor [PI], and ≥ 1 anti-CD38 monoclonal antibody [mAb]) RRMM. Methods : Eligible pts had RRMM; had received ≥ 3 prior lines of therapy, including lenalidomide (LEN), pomalidomide (POM), a PI, a glucocorticoid, and an anti-CD38 mAb; had experienced disease progression within 60 days of last myeloma therapy; and were refractory to an IMiD agent, a PI, a glucocorticoid, and an anti-CD38 mAb. Pts with central nervous system involvement were not eligible. Pts who had received prior anti-BCMA therapy were excluded, but included in a supportive cohort for safety and preliminary efficacy assessment. IBER (1.6 mg) was given orally on days (D) 1-21, in combination with DEX (40 mg; 20 mg if > 75 years of age) on D1, 8, 15, and 22 of each 28-day cycle. Thrombo-embolism prophylaxis was mandatory for all pts. Primary objective was to determine efficacy expressed as overall response rate (ORR). Secondary endpoints included additional efficacy and safety assessments. Exploratory endpoints included evaluation of health-related quality of life (HRQoL). Results : As of June 2, 2021, 107 pts had received IBER + DEX. Median age was 64 (44-83) years; median time since initial diagnosis was 6.9 (1.6-24.5) years. Extramedullary plasmacytomas were present in 25.2% of pts; 29.9% of pts had high-risk cytogenetics. Median number of prior regimens was 6 (3-23). All pts were triple-class exposed; prior therapies included autologous stem cell transplantation (78.5%), PIs (100%), IMiD agents (LEN [100%] and POM [100%]), and anti-CD38 mAbs (100%); 99.1% of pts were refractory to last myeloma regimen and 97.2% of pts were triple-class refractory. Median follow-up was 7.69 (0.5-17.5) months, with a median number of 4 (1-17) cycles received and 13 (12.1%) pts continuing treatment. Main reason for discontinuation was progressive disease (69.2%). ORR was 26.2%, with 1 (0.9%) stringent complete response, 8 (7.5%) very good partial responses, and 19 (17.8%) partial responses (Table); the clinical benefit rate (≥ minimal response) was 36.4% and disease control rate (≥ stable disease) was 79.4%. Median duration of response was 7.0 (4.5-11.3) months (Table), median progression-free survival was 3.0 (2.8-3.7) months, and median overall survival was 11.2 (9.0-not reached) months. Similar response rates were observed among a cohort of pts also exposed to BCMA therapies (N = 24, Table). Grade (Gr) 3-4 treatment-emergent adverse events (TEAEs) were reported in 88 (82.2%) pts. Most frequent (≥ 20% pts) hematologic Gr 3-4 TEAEs were neutropenia (44.9%; and 4.7% febrile neutropenia), anemia (28.0%), thrombocytopenia (21.5%), and leukopenia (20.6%). Gr 3-4 infections were reported in 27.1% of pts; Gr 3-4 pneumonia and COVID-19 occurred in 10.3% and 4.7% of pts, respectively. Occurrence of other Gr 3-4 non-hematologic TEAEs was generally low, including gastrointestinal disorders (5.6%), fatigue (2.8%), rash (1.9%). Fifty-six (52.3%) pts and 20 (18.7%) had IBER dose interruptions and reductions due to TEAEs, respectively. Five (4.7%) pts discontinued due to TEAEs. No pt discontinued IBER due to neutropenia. Overall, HRQoL was maintained in these pts. Conclusions : IBER + DEX demonstrated promising efficacy in pts with heavily pretreated, triple-class exposed and refractory RRMM, as well as in pts who had previously received anti-BCMA therapy; this combination was generally well tolerated and TEAEs were manageable with dose reductions and interruptions. These results support the further development of IBER in MM, including phase 3 trials in combination regimens. Figure 1 Figure 1. Disclosures Lonial: Abbvie: Consultancy, Honoraria; AMGEN: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria; BMS/Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Popat: GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Abbvie, Takeda, Janssen, and Celgene: Consultancy; Takeda: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; AbbVie, BMS, Janssen, Oncopeptides, and Amgen: Honoraria; Janssen and BMS: Other: travel expenses. Hulin: Sanofi: Honoraria; Celgene/BMS: Honoraria; Janssen: Honoraria; Takeda: Honoraria; abbvie: Honoraria. Jagannath: Legend Biotech: Consultancy; Bristol Myers Squibb: Consultancy; Karyopharm Therapeutics: Consultancy; Janssen Pharmaceuticals: Consultancy; Sanofi: Consultancy; Takeda: Consultancy. Oriol: Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Richardson: Karyopharm: Consultancy, Research Funding; Regeneron: Consultancy; AbbVie: Consultancy; Celgene/BMS: Consultancy, Research Funding; Oncopeptides: Consultancy, Research Funding; GlaxoSmithKline: Consultancy; Protocol Intelligence: Consultancy; Janssen: Consultancy; Secura Bio: Consultancy; Takeda: Consultancy, Research Funding; Sanofi: Consultancy; AstraZeneca: Consultancy; Jazz Pharmaceuticals: Consultancy, Research Funding. Weisel: Adaptive Biotechnologies: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: 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, Research Funding; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy; Novartis: Honoraria; Pfizer: Honoraria. Minnema: Cilag: Consultancy; Janssen: Consultancy; Alnylam: Consultancy; Celgene: Other: Travel expenses; Kite/Gilead: Consultancy; BMS: Consultancy. Badros: J&J: Research Funding; Janssen: Research Funding; BMS: Research Funding; GlaxoSmithKline: Research Funding. Knop: BMS/Celgene: Consultancy, Honoraria, Research Funding; Amgen: Research Funding; Janssen: Consultancy; Oncopeptides: Consultancy; Pfizer: Consultancy; Sanofi: Consultancy. Stadtmauer: Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding. Chen: Bristol Myers Squibb: Current Employment. Nguyen: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Amin: Bristol Myers Squibb: Current Employment. Kueenburg: Celgene a BMS company: Current Employment. Peluso: Celgene, a Bristol-Myers Squibb Company: Current Employment. van de Donk: BMS/Celgene: Consultancy, Honoraria; Janssen: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Cellectis: Research Funding; Takeda: Consultancy; Roche: Consultancy; Novartis /bayer/servier: Consultancy.

Abstract Introduction: Belantamab mafodotin (belamaf) is a B-cell maturation antigen (BCMA)-targeting antibody-drug conjugate approved in the United States (US) and Europe as a monotherapy for triple-class refractory adult patients with relapsed or refractory multiple myeloma (RRMM). This hypothesis-generating post-hoc analysis of DREAMM-2 trial (NCT03525678) data examined relationships between corneal exam findings (superficial punctate keratopathy and/or microcyst like epithelial changes), best-corrected visual acuity (BCVA), and direct patient-reported ocular symptoms per the Ocular Surface Disease Index (OSDI) questionnaire. This approach could provide insight into the relationship between corneal exam findings, BCVA, and ocular symptoms and their impact on quality of life to help determine if BCVA decline and symptoms could guide dosing. Currently, in the US, eye exams with eye-care professionals (ECPs) are required for each belamaf treatment, which can add to patients' therapy-related burden. Identifying a surrogate marker for results from corneal exam findings would help providers determine if dosing adjustments are necessary. Methods: Eye exams (including a corneal exam and BCVA assessment using the Snellen chart) were performed on all patients receiving single-agent belamaf (2.5 mg/kg) by ECPs at baseline (BL) and before each dose, administered q3w. Corneal exam findings (keratopathy) and BCVA were assessed per protocol-defined criteria, and grade (GR) assessment was based on the worst finding in the worse eye. BCVA and keratopathy grading were relative to BL. Patient-reported ocular symptoms and vision-related functioning, as per the OSDI, were used to evaluate the impact of treatment-related ocular toxicity. The OSDI is a patient-reported outcome questionnaire that assesses eye symptoms and effects on vision-related function in the past week and was performed in all patients before each belamaf dose. Items 1-5 address the frequency of eye-related symptoms (eg, painful or sore eyes, blurred vision) while items 6-9 address the frequency of functional limitations (eg, driving at night or reading). OSDI was considered positive, clinically meaningful, and potentially associated with treatment when at least one question 1-5 (ie, sensitivity to light, gritty or painful eyes, blurred or poor vision) was reported as experienced "all of the time" and at least one question 6-9 (ie, driving at night, reading, working with PC, or watching TV) was reported as experienced "most of the time." Results: Overall, GR 3-4 (severe) keratopathy was observed only 5% of the time in patients who did not report frequent ocular symptoms as measured by the OSDI questionnaire (no items 1-9 ≥ "most of the time"). A further breakdown of the questions revealed that, in patients who reported no items 1-5 "all of the time" AND no items 6-9 ≥ "most of the time" (OSDI negative), GR 3-4 keratopathy was observed only 6% of the time (Table). When considering individual OSDI items, in patients who reported "no deterioration from BL" for any of the OSDI eye-related symptoms or functional limitations, GR 3-4 keratopathy was observed ~3%-7% of the time while GR 0-2 (mild) keratopathy was observed ~23%-34% of the time. Similar results were observed in patients with BCVA ≤20/30 at BL who reported "no deterioration from BL" for any eye-related adverse events (AEs) or functional limitations (GR 3-4 keratopathy: ~2%-6% of the time; GR 0-2 keratopathy: ~19%-28% of the time); patients with worse visual acuity at BL (BCVA >20/30) who reported "no deterioration" for items 1-9 had lower incidence of GR 3-4 and GR 0-2 keratopathy (~0%-1% and ~3%-8%, respectively). Conclusions: The results from this hypothesis-generating post-hoc analysis suggest that hematologists/oncologists may be able to use clinical indicators/tools (eg, ocular symptoms, the OSDI tool) as potential surrogate markers for eye exam results to help determine whether dosing changes are needed. This approach will be explored in trials with other belamaf dose regimens that are currently under evaluation. If the results are validated, it may be possible for hematologists/oncologists to manage belamaf dose modifications, due to ocular AEs, without a confirmatory eye exam by the ECP, reducing the patient burden. Funding Source: GSK (205678). Drug linker technology licensed from Seagen; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. Figure 1 Figure 1. Disclosures Popat: Takeda: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; AbbVie, BMS, Janssen, Oncopeptides, and Amgen: Honoraria; Abbvie, Takeda, Janssen, and Celgene: Consultancy; Janssen and BMS: Other: travel expenses. Badros: GlaxoSmithKline: Research Funding; BMS: Research Funding; Janssen: Research Funding; J&J: Research Funding. Kumar: Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; Antengene: Consultancy, Honoraria; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Roche-Genentech: Consultancy, Research Funding; Beigene: Consultancy; BMS: Consultancy, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Consultancy; Oncopeptides: Consultancy; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Merck: Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Rodríguez-Otero: Regeneron: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kite: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel and other expenses. Cohen: BMS: Research Funding; GlaxoSmithKline: Other: Personal fees and other association with, Research Funding; Novartis: Research Funding; Celgene: Honoraria, Other: Personal fees and other association with; Janssen: Honoraria; Kite Pharma: Honoraria; Oncopeptides: Honoraria; Seattle Genetics: Honoraria; Takeda: Honoraria. Manier: Regeneron: Consultancy, Research Funding; Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnologies: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Research Funding; Celgene - Bristol Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Voorhees: Secura Bio: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: 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; Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Gay: Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Bluebird Bio: Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria. Rifkin: Takeda: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Fresenius-Kabi: Membership on an entity's Board of Directors or advisory committees; Coherus: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb (Celgene): Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; McKesson: Current Employment, Current equity holder in publicly-traded company; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Martin: Janssen: Research Funding; Sanofi: Research Funding; Oncopeptides: Consultancy; Amgen: Research Funding; GlaxoSmithKline: Consultancy. Chari: Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Research Funding; GlaxoSmithKline: Consultancy, Membership on an entity's Board of Directors or advisory committees; Secura Bio: Consultancy, Membership on an entity's Board of Directors or advisory committees; Shattuck Labs: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Antengene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding; Pharmacyclics: Research Funding; Millenium/Takeda: Consultancy, Research Funding; Sanofi Genzyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS/Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Weisel: Bristol Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: 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, Research Funding; Adaptive Biotechnologies: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy; Novartis: Honoraria; Pfizer: Honoraria. Farooq: Five Prime Therapeutics/Amgen: Consultancy; GlaxoSmithKline: Consultancy. Jeng: OysterPoint: Consultancy; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy; Eyegate: Current equity holder in publicly-traded company. Chng: Abbvie: Consultancy; GlaxoSmithKline: Consultancy; Takeda: Consultancy; BMS/Celgene: Consultancy, Research Funding; Sanofi: Consultancy; Novartis: Research Funding; Johnson & Johnson: Consultancy, Research Funding; Amgen: Consultancy; Antengene: Consultancy; Pfizer: Consultancy; Aslan: Research Funding. Lee: Takeda Pharmaceuticals: Consultancy, Research Funding; Oncopetides: Consultancy; Sanofi: Consultancy; GlaxoSmithKline: Consultancy, Research Funding; Legend Biotech: Consultancy; Karyopharm: Consultancy; Janssen: Consultancy, Research Funding; Genentech: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Amgen: Consultancy, Research Funding; Regeneron: Research Funding. Berdeja: BMS: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Celularity: Research Funding; CRISPR Therapeutics: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Kite Pharma: Consultancy; Legend Biotech: Consultancy; SecuraBio: Consultancy; EMD Serono: Research Funding; Genentech: Research Funding; GlaxoSmithKline: Research Funding; Ichnos Sciences: Research Funding; Incyte: Research Funding; Novartis: Research Funding; Poseida: Research Funding; Bluebird bio: Consultancy, Research Funding; Astex Pharmaceuticals: Research Funding; Amgen: Research Funding; Abbvie: Research Funding; Takeda: Consultancy; Sanofi: Research Funding; Acetylon: Research Funding; Teva: Research Funding; Lilly: Research Funding. Jadhav: GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Tosolini: GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Eliason: GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Palumbo: GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Dimopoulos: Beigene: Honoraria; BMS: Honoraria; Amgen: Honoraria; Janssen: Honoraria; Takeda: Honoraria. Lonial: Merck: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; AMGEN: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Trudel: Amgen: Consultancy, Honoraria, Research Funding; Takeda: Honoraria; Amgen Canada: Honoraria; Sanofi: Honoraria; Celgene: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Research Funding; Janssen: Honoraria, Research Funding; Genentech: Research Funding; Karyopharm: Honoraria. Richardson: Sanofi: Consultancy; Celgene/BMS: Consultancy, Research Funding; Protocol Intelligence: Consultancy; GlaxoSmithKline: Consultancy; Secura Bio: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy, Research Funding; Janssen: Consultancy; Oncopeptides: Consultancy, Research Funding; Regeneron: Consultancy; AstraZeneca: Consultancy; Takeda: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding. Terpos: Celgene: Consultancy, Honoraria, Research Funding; Genesis: Consultancy, Honoraria, Research Funding; GSK: Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; BMS: Honoraria; Janssen-Cilag: Consultancy, Honoraria, Research Funding; Novartis: Honoraria; Takeda: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding.

Introduction: IBER is an oral, potent novel cereblon E3 ligase modulator (CELMoD) agent with marked synergistic tumoricidal and immune-stimulatory effects in combination with BORT or DARA in preclinical models. CC-220-MM-001 is a phase 1/2 study evaluating dose escalations of IBER with different treatment combinations in independent cohorts, in patients (pts) with RRMM (NCT02773030); the IBER + DEX cohort showed a favorable safety profile with promising efficacy and a selected IBER RP2D of 1.6 mg 21/28 days (D). Here, we present results from the IBER + DARA + DEX (IberDd) and IBER + BORT + DEX (IberVd) cohorts. Methods: Eligible pts had received ≥ 2 prior regimens in the IberDd cohort, and ≥ 1 prior regimen in the IberVd cohort, containing at least lenalidomide or pomalidomide, and a proteasome inhibitor (PI), and had experienced disease progression on or within 60 days of last MM therapy. Escalating doses of IBER were given orally, in the IberDd cohort on D1-21, with DARA (16 mg/kg) on D1, D8, D15, and D22 (cycles [C]1-2), D1 and D15 (C3-6), and D1 (C ≥ 7), of each 28-day cycle; in the IberVd cohort, on D1-14, with BORT (1.3 mg/m2) on D1, D4, D8, and D11 (C1-8), and on D1 and D8 (C ≥ 9), of each 21-day cycle. In both cohorts DEX was given weekly. Primary objectives were to evaluate MTD, RP2D, and safety separately for each cohort; a key secondary objective was preliminary assessment of efficacy. Immune profiling was evaluated by flow cytometry from pt peripheral blood at C1D1, C2D15, C4D1, and C4D15. Results: As of June 18, 2020, 19 pts had received IberDd and 21 pts IberVd. Baseline characteristics for the 2 independent cohorts are shown in the table. All pts were refractory to their last prior regimen, and exposure to prior regimens was heterogeneous. IBER doses ranged from 1.0 to 1.6 mg; the MTD/RP2D has not been reached in either cohort. Median follow-up was 5 (0-14) and 3 (0-11) months, 10 (53%) and 13 (62%) pts continue on treatment, median cycles received was 5 (1-14) and 4.5 (1-17), with IberDd and IberVd, respectively. Grade (Gr) 3-4 treatment-emergent adverse events (TEAEs) were reported in 14 (78%) pts with IberDd, and in 13 (65%) pts with IberVd. Most frequent Gr 3-4 TEAEs of interest included neutropenia (50%), leukopenia (22%), and anemia (22%) with IberDd; and neutropenia (20%) and thrombocytopenia (20%) with IberVd. In both cohorts, neutropenia was managed with G-CSF. One pt (IberDd; 1.2 mg dose) had Gr 4 neutropenic sepsis. Occurrence of Gr 3-4 non-hematological TEAEs was low in both cohorts. One pt had Gr 2 infusion-related reaction with IberDd, and 3 pts had Gr 1-2 peripheral neuropathy with IberVd. Six (33%) and 4 (20%) pts had IBER dose reductions with IberDd and IberVd, respectively. In the IberDd cohort, with 12/19 (63%) DARA-refractory pts and 11 (58%) quad-class-refractory pts, the overall response rate (ORR) was 35% across all dosing groups (2 very good partial responses [VGPRs], 4 partial responses [PRs]); the clinical benefit rate (CBR) was 47% and disease control rate (DCR) was 88%. In the IberVd cohort, with 16/21 (76%) PI-refractory pts, 9 (43%) BORT-refractory pts, and 10 (48%) quad-class refractory pts, ORR was 50% (1 complete response, 3 VGPRs, 6 PRs); CBR was 65% and DCR was 85%. Responses with IberDd and IberVd were observed irrespective of DARA- and BORT-refractoriness, respectively. Median time to response was 4.1 (4.1-12.0) and 4.9 (3.0-13.1) weeks, in the IberDd and IberVd cohorts, respectively; median duration of response was not reached in both cohorts. Immune profiling showed dose-dependent decreases in B cells and increases in activated and differentiated T cells, in both cohorts. Except for reductions in CD38+ T cells in pts receiving IberDd, these observations were similar in pts treated with IBER + DEX. Conclusions: IberDd and IberVd showed a favorable tolerability profile in heavily pretreated RRMM pts, with promising clinical activity, even among pts refractory to the last prior regimen and previously exposed to IMiD agents, PIs, and CD38 antibodies. Immune-profiling data confirm that IBER + DEX was pharmacodynamically active in triplet combination and not augmented by the addition of DARA or BORT. The study is ongoing with continued enrollment at the 1.6 mg dose level for both cohorts. Updated results, including the MTD/RP2D, will be presented at the meeting. These results support the further development of IBER-based regimens in MM; phase 3 trials are planned to further evaluate these combinations. Disclosures van de Donk: Bristol Myers Squibb: 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; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Ferrer: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Popat:Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); AbbVie: Consultancy, Honoraria; GSK: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Larsen:Janssen Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Minnema:Servier: Consultancy; Kite, a Gilead Company: Speakers Bureau; Celgene: Other: travel support, Research Funding; Amgen: Consultancy. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy. Oriol:Sanofi: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Speakers Bureau. Zonder:Prothena: Consultancy; Intellia: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Celgene: Research Funding; BMS: Consultancy, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Oncopeptide: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Alnylam: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Janssen: Consultancy, Other: Personal fees; Caelum: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding. Rodriguez-Otero:Sanofi: Consultancy, Honoraria; Medscape: Membership on an entity's Board of Directors or advisory committees; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); GlaxoSmithKline: Consultancy, Current Employment, Current equity holder in publicly-traded company, Honoraria; Abbvie: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Amgen: Consultancy, Honoraria; Oncopeptides: Consultancy, Honoraria. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Stadtmauer:Sanofi: Consultancy; AbbVie: Research Funding; Takeda: Consultancy; Bristol Myers Squibb: Consultancy, Research Funding. Bringhen:Bristol-Myers Squibb: Honoraria; Amgen: 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; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Siegel:Takeda: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau; Merck: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Celulatiry: Consultancy; Karyopharma: Consultancy, Honoraria. Gamberi:Janssen: Consultancy, Honoraria; GSK: Consultancy; Amgen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria. Gironella Mesa:Janssen: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria, Speakers Bureau. Sonneveld:Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Skyline Dx: Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy. Nguyen:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Di Micco:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Sorrell:Children's Oncology Group: Other: Non-member; Previous Study Chair AAML08B1; Bristol Myers Squibb: Current Employment. Chen:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Amatangelo:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Kueenburg:Celgene International Sàrl, a Bristol Myers Squibb Company, Boudry, Switzerland: Current Employment. Lonial:Onyx: Honoraria; Novartis: Consultancy, Honoraria, Other: Personal fees; Genentech: Consultancy; Amgen: Consultancy, Honoraria, Other: Personal fees; Merck: Consultancy, Honoraria, Other: Personal fees; Abbvie: Consultancy; Millennium: Consultancy, Honoraria; Karyopharm: Consultancy; Sanofi: Consultancy; JUNO Therapeutics: Consultancy; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Other: Personal fees, Research Funding; Janssen: Consultancy, Honoraria, Other: Personal fees, Research Funding; BMS: Consultancy, Honoraria, Other: Personal fees, Research Funding; GSK: Consultancy, Honoraria, Other: Personal fees.

Background: Smoldering multiple myeloma (SMM) represents an intermediate stage between monoclonal gammopathy of undetermined significance and active myeloma with a high risk of progression to active MM, especially during the initial years after diagnosis. Available clinical risk factors have enabled development of risk stratification systems that allow for identification of patients at the highest risk of progression, opening opportunities for early intervention. Two phase 3 trials using lenalidomide with dexamethasone or lenalidomide alone have both shown benefit for early intervention by decreasing the risk of progression and improving the overall survival in the former. It remains unknown if an approach using a single active drug to delay progression, or one that uses therapies like active myeloma, represent a better approach; both are being studied in phase 3 trials. We designed this phase 2 trial to examine if an intense but limited duration therapy can possibly provide a significant elimination of the tumour burden that can potentially lead to long term responses. Patients and Methods: Patients with SMM (per updated IMWG definition of SMM) with high risk disease (defined by the IMWG updated risk stratification criteria- presence of any two of the following: Serum M spike > 2 gm/dL OR an involved to uninvolved FLC ratio > 20 OR bone marrow PC% > 20%) or a score of ≥9 using the risk scoring system using FLC ratio, serum M spike, marrow plasma cell% and presence of high risk FISH were enrolled provided they had adequate marrow and organ function. Patients with significant comorbidities such as heart disease were excluded from the trial. Treatment consisted of three phases: induction, consolidation and maintenance. Patients received carfilzomib (36 mg/m2 twice weekly or as per updated protocol 56mg/m2 weekly for 2 weeks), lenalidomide (25 mg daily for three weeks), daratumumab (weekly for 8 doses, every other week for 16 weeks) and dexamethasone 40 mg weekly, in 4 week cycles for 6 cycles as part of induction, the same regimen was administered with daratumumab every 4 weeks and dexamethasone 20 mg weekly for another 6 cycles for consolidation. This was followed by 12 cycles of maintenance therapy with lenalidomide (10 mg daily for three weeks), daratumumab (day 1 every other cycle) of a 4-week cycle. Appropriate antiviral, and thrombosis prophylaxis were mandated. The primary endpoint of this trial is the rate of confirmed sCR as best response across all cycles of treatment. We plan to accrue 83 patients to this trial with one-stage binomial trial design to test the null hypothesis that the true success (sCR) proportion is at most 65% and the alternate hypothesis of 80%. Results: Forty-six patients have been accrued to the trial as of July 14, 2020. The median age of the study population is 63 years (range 47 - 76); 70% are male. Overall, 2% have completed the maintenance, 50% have completed the consolidation, 80% have completed the induction and 15% are in the induction phase; only two patients have gone off treatment. The reasons for going off treatment were patient preference. At least one patient needed a dose modification for each drug; 17%, 2%, 13% and 7% required dose reductions for carfilzomib, daratumumab, lenalidomide and dexamethasone respectively. The relative median dose intensity for the drugs were 85%, 92%, 80% and 98% for carfilzomib, daratumumab, lenalidomide and dexamethasone respectively across the delivered cycles. The adverse events seen in at least 5% of the patients are as shown in the figure. A grade 3 or higher AE was seen in 52% of patients. There were no treatment related deaths observed. Response rate and depth have been as expected for this regimen in myeloma and analysis is pending completed accrual. Figure 1 Disclosures Kumar: Adaptive Biotechnologies: Consultancy; Sanofi: Research Funding; Cellectar: Other; Genecentrix: Consultancy; Novartis: Research Funding; Dr. Reddy's Laboratories: Honoraria; AbbVie: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Tenebio: Other, Research Funding; Merck: Consultancy, Research Funding; Amgen: Consultancy, Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments, Research Funding; Janssen Oncology: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Takeda: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Celgene/BMS: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Kite Pharma: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Karyopharm: Consultancy; MedImmune: Research Funding; Genentech/Roche: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Oncopeptides: Consultancy, Other: Independent Review Committee; IRC member; Carsgen: Other, Research Funding. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Dhakal:Celgene: Consultancy, Honoraria; Amgen: Consultancy, Other: AdvIsory Board, Research Funding; Janssen: Consultancy, Other: Advisory Board, Research Funding; Takeda: Consultancy, Other: Advisory Board; GSK: Consultancy, Research Funding, Speakers Bureau; Sanofi: Research Funding. Abonour:Celgene: Consultancy; Janssen: Honoraria, Research Funding; Takeda: Consultancy; BMS: Consultancy, Research Funding. Rosenbaum:Celgene: Honoraria; Akcea: Honoraria; Amgen: Research Funding; Janssen: Research Funding; GlaxoSmithKline: Research Funding. Bensinger:GSK: Consultancy, Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Research Funding, Speakers Bureau; Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau; Regeneron: Consultancy, Honoraria, Research Funding, Speakers Bureau. Bhutani:Prothena: Other: Clinical Trial Funding to Institute; Sanofi Genzyme: Consultancy; Janssen: Other: Clinical Trial Funding to Institute; BMS: Other: Clinical trial funding to institute, Speakers Bureau; Amgen: Speakers Bureau; MedImmune: Other: Clinical Trial Funding to Institute; Takeda: Other: Clinical trial funding to institute, Speakers Bureau. Jakubowiak:AbbVie, Amgen, BMS/Celgene, GSK, Janssen, Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive, Juno: Consultancy, Honoraria. Durie:Amgen, Celgene, Johnson & Johnson, and Takeda: Consultancy.

Introduction: Iberdomide (IBER; CC-220) is a potent, novel cereblon (CRBN) E3 ligase modulator (CELMoD) agent under investigation in a phase 1/2 dose-escalation study in relapsed/refractory multiple myeloma (MM) (CC-220-MM-001; NCT02773030). IBER modulates CRBN to induce ubiquitination and proteasome-dependent degradation of Ikaros/Aiolos, resulting in anti-myeloma and immunomodulatory activity. Compared with immunomodulatory drugs (IMiDs), IBER binds to CRBN with 20-fold higher affinity and is more efficient at degrading Ikaros/Aiolos. Additionally, IBER can overcome IMiD drug resistance. Here, we evaluate the preclinical activity of IBER in combination with monoclonal antibodies (mAbs) and assess immune pharmacodynamic changes of IBER + daratumumab (DARA) among patients in the CC-220-MM-001 study. Methods: Preclinical analyses were performed on MM cell lines and peripheral blood mononuclear cells (PBMCs) from healthy volunteers. In co-culture assays, cell lines and immune cells were treated with clinically relevant concentrations of lenalidomide (LEN; 1 μM), pomalidomide (POM; 300 nM), and IBER (20 nM) alone, and in combination with DARA or elotuzumab (ELO). Clinical biomarker data were obtained from blood samples of patients enrolled in IBER + dexamethasone (DEX) and IBER + DARA + DEX cohorts of the CC-220-MM-001 study. Immune profiling was evaluated by flow cytometry on Cycle (C) 1 Day (D) 1, C2D15, C4D1, and C4D15. Results: Treatment of CD3-stimulated PBMCs with IBER increased cytokine secretion more potently than with IMiD drugs, promoting natural killer (NK) cell proliferation and increasing NK cell numbers by > 30% in cultures. Treatment of CD3-stimulated PBMCs with IBER also promoted immune-mediated killing of MM cell lines, and pretreatment of MM cell lines for 48 h followed by washout sensitized cells to immune-mediated clearance. IBER treatment of MM cells increased protein expression of CD38, but had no discernable effect on SLAMF7 expression. IBER in combination with DARA or ELO enhanced the immune-mediated killing of MM cell lines and resulted in deeper cell killing compared with LEN or POM when combined with the same mAbs. Analogous to preclinical data, immune profiling of patients treated with IBER + DEX demonstrated an immune-stimulatory effect, including increased proliferating NK and T cells. Notably, patients coming on trial directly after a DARA-containing regimen showed depleted NK cell counts, which rebounded by nearly 2-fold after 1 cycle of IBER + DEX. Additionally, the effects of IBER on T and NK cell proliferation were similar in patients treated with IBER + DEX + DARA and IBER + DEX, except for overall reduction in CD38-expressing NK and T cells in patients receiving DARA. Conclusions: IBER induced immune-stimulatory activity more potently than LEN or POM, enhancing cytokine release and NK cell proliferation. MM cells treated with IBER were also sensitized to immune-mediated clearance. These data suggest that IBER may enhance the activity of biologics that exert anti-malignant activity through antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. Accordingly, IBER enhanced the activity of DARA and ELO in co-culture. IBER also induced an immune-stimulatory effect on NK and T cells in vivo, confirming immune-stimulatory effects of IBER in patients with MM. Notably, the effect of IBER on NK cells was more pronounced in patients whose last treatment regimen contained DARA, suggesting IBER treatment may contribute to NK cell recovery after DARA treatment. Furthermore, immune changes observed by the addition of DARA to IBER + DEX were similar, suggesting IBER was the primary agent promoting immunomodulation in this triplet therapy. Together, these data support continued clinical development of IBER in combination with CD38- and SLAMF7-directed mAbs as well as other immune-directed therapies for the treatment of MM. Disclosures Amatangelo: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Bjorklund:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ma:Bristol Myers Squibb: Current Employment. Wollerman:Bristol Myers Squibb: Current Employment. Pierceall:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Lonial:JUNO Therapeutics: Consultancy; Merck: Consultancy, Honoraria, Other: Personal fees; Abbvie: Consultancy; GSK: Consultancy, Honoraria, Other: Personal fees; BMS: Consultancy, Honoraria, Other: Personal fees, Research Funding; Novartis: Consultancy, Honoraria, Other: Personal fees; Takeda: Consultancy, Other: Personal fees, Research Funding; Genentech: Consultancy; Karyopharm: Consultancy; Sanofi: Consultancy; Amgen: Consultancy, Honoraria, Other: Personal fees; Janssen: Consultancy, Honoraria, Other: Personal fees, Research Funding; Onyx: Honoraria; Millennium: Consultancy, Honoraria; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. van de Donk:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Ferrer: Membership on an entity's Board of Directors or advisory committees. Popat:Celgene: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding; AbbVie: Consultancy, Honoraria; GSK: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy. Zonder:Intellia: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; BMS: Consultancy, Research Funding; Alnylam: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Celgene: Research Funding; Prothena: Consultancy; Janssen: Consultancy, Other: Personal fees; Oncopeptide: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Caelum: Consultancy; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees. Minnema:Kite, a Gilead Company: Speakers Bureau; Servier: Consultancy; Amgen: Consultancy; Celgene: Other: travel support, Research Funding. Oriol:Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy; Sanofi: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Larsen:Janssen Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Rodriguez-Otero:Sanofi: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); GlaxoSmithKline: Consultancy, Current Employment, Current equity holder in publicly-traded company, Honoraria; Medscape: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria; Oncopeptides: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Kite: Consultancy, Honoraria. Sonneveld:Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Skyline Dx: Honoraria, Research Funding; Sanofi: Consultancy; Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Nguyen:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Hong:Bristol Myers Squibb: Current Employment. Sorrell:Bristol Myers Squibb: Current Employment; Children's Oncology Group: Other: Non-member; Previous Study Chair AAML08B1. Thakurta:Bristol Myers Squibb: Current Employment; Oxford University: Other: Visiting professor.

Introduction: Iberdomide (IBER; CC-220) is a potent, novel cereblon (CRBN) E3 ligase modulator (CELMoD) agent under investigation in a phase 1/2 dose-escalation study for relapsed/refractory multiple myeloma (MM) (CC-220-MM-001; NCT02773030). IBER modulates CRBN to induce ubiquitination and proteasome-dependent degradation of Ikaros/Aiolos, resulting in antimyeloma and immunomodulatory activity. Compared with immunomodulatory drugs (IMiDs); IBER binds to CRBN with 20-fold higher affinity and is more efficient at degrading Ikaros/Aiolos. Additionally, IBER can overcome IMiD drug resistance. Here, we compare the preclinical activity of IBER versus IMiD drugs + proteasome inhibitors (PIs), and assess the pharmacodynamic (PD) activity of IBER in patients treated with IBER + dexamethasone (DEX), IBER + DEX + bortezomib (BORT), and IBER + DEX + carfilzomib (CFZ). Methods: MM cell lines and peripheral blood mononuclear cells (PBMCs) from healthy volunteers were analyzed. Cell lines treated with PIs (BORT and CFZ) were pulsed with drug for 1 h, and then treated with clinically relevant concentrations of lenalidomide (LEN; 1 μM), pomalidomide (POM; 300 nM), or IBER (20 nM). Biomarker data for PD analyses were obtained from blood samples of patients enrolled in the IBER + DEX, IBER + DEX + BORT, and IBER + DEX + CFZ cohorts of the CC-220-MM-001 study. Degradation of Ikaros/Aiolos in peripheral blood was analyzed on Cycle (C) 1 Day (D) 1, pre-dose, and post IBER/IBER + PI dose by flow cytometry. Immune profiling was evaluated by flow cytometry from peripheral blood at C1D1, C2D15, C4D1, and C4D15. Results : Proteasome inhibition in cell lines after 1 h pulse of PI was maintained after washout. However, substrate degradation by IBER was affected only minimally by combination with PIs, and was more potent than by LEN or POM. These results correlate with synergistic antiproliferative activity and more potent tumoricidal activity in cell lines treated with IBER + PI than IMiD + PI combinations. Furthermore, ex vivo treatment of PBMCs with IBER + PIs minimally affected cytokine induction by IBER. Analysis of patient samples from the CC-220-MM-001 study confirmed preclinical observations showing minimal inhibition of IBER PD with the addition of PIs to the treatment regimen. In patient T cells, Ikaros and Aiolos protein levels decreased by > 50% and > 70%, respectively, with IBER + DEX, and by > 30% and > 45% (at lower IBER doses) with IBER + DEX + BORT or IBER + DEX + CFX. In all cohorts, the nadir of substrate expression was determined to be 6 h. After repeated dosing (mid-C1) patients treated with IBER + PIs showed > 70% decreases in both Ikaros and Aiolos expression. Furthermore, immune profiling of patients showed that the addition of PIs to the IBER treatment regimen did not inhibit immune-stimulatory activity of IBER, including induction of NK and T cell proliferation. Conclusions: Preclinically, IBER induced substrate degradation in the presence of PIs, and treatment with IBER + PIs resulted in substantially increased tumoricidal activity. Deeper substrate degradation and increased apoptosis were also observed when PIs were combined with IBER versus IMiD drugs. Clinically, IBER led to rapid decreases in substrate levels, even in the presence of PIs, and levels were reduced further with repeated dosing, suggesting that concurrent administration of PIs minimally affects proteasomal degradation of substrates mediated by IBER. Furthermore, increases in NK and T cell proliferation in IBER-treated patients were consistent whether or not they also received a PI, further confirming that IBER has immune-stimulatory activity in combination with PIs. These data support continued clinical development of IBER in combination with PIs for the treatment of MM. Disclosures Amatangelo: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Bjorklund:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Kang:Bristol Myers Squibb: Current Employment. Mukhopadhyay:Bristol Myers Squibb: Other: Contract scientist, Research & Early Development. Jiménez Nuñez:CITRE, a Bristol-Myers Squibb Company: Current Employment. Wong:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Pierceall:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Lonial:Merck: Consultancy, Honoraria, Other: Personal fees; Genentech: Consultancy; Karyopharm: Consultancy; Sanofi: Consultancy; BMS: Consultancy, Honoraria, Other: Personal fees, Research Funding; Janssen: Consultancy, Honoraria, Other: Personal fees, Research Funding; Novartis: Consultancy, Honoraria, Other: Personal fees; Takeda: Consultancy, Other: Personal fees, Research Funding; Amgen: Consultancy, Honoraria, Other: Personal fees; GSK: Consultancy, Honoraria, Other: Personal fees; Abbvie: Consultancy; Millennium: Consultancy, Honoraria; JUNO Therapeutics: Consultancy; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Onyx: Honoraria. van de Donk:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; 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; Bayer: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Popat:GSK: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); AbbVie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy. Zonder:Caelum: Consultancy; Intellia: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Alnylam: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Oncopeptide: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Celgene: Research Funding; Janssen: Consultancy, Other: Personal fees; Prothena: Consultancy; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; BMS: Consultancy, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees. Minnema:Celgene: Other: travel support, Research Funding; Servier: Consultancy; Amgen: Consultancy; Kite, a Gilead Company: Speakers Bureau. Oriol:GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Amgen: Consultancy, Speakers Bureau; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Larsen:Janssen Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Rodriguez-Otero:Sanofi: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Current Employment, Current equity holder in publicly-traded company, Honoraria; Amgen: Consultancy, Honoraria; Medscape: Membership on an entity's Board of Directors or advisory committees; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Oncopeptides: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. Sonneveld:Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy; Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Skyline Dx: Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding. Nguyen:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Hong:Bristol Myers Squibb: Current Employment. Sorrell:Children's Oncology Group: Other: Non-member; Previous Study Chair AAML08B1; Bristol Myers Squibb: Current Employment. Thakurta:Oxford University: Other: visiting professor; Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company.