ALBERT

Description: Background: Patients with RRMM who have relapsed through multiple prior lines of therapy need novel, effective, targeted agents. B-cell maturation antigen (BCMA) is a cell-surface receptor required for plasma cell survival that is ubiquitously expressed on MM cells, but virtually absent on naïve and memory B cells. Belantamab mafodotin (GSK2857916) is a BCMA-directed immuno-conjugate with an afucosylated, humanized anti-BCMA monoclonal antibody (mAb) conjugated by a protease-resistant cysteine linker to a microtubule disrupting agent, monomethyl auristatin F (MMAF). Belantamab mafodotin specifically binds to BCMA, eliminating MM cells by a multimodal mechanism including delivering MMAF to BCMA-expressing malignant cells, enhancing antibody-dependent cellular cytotoxicity, and leveraging immunogenic cell death. In an open-label, phase 1 study (DREAMM-1), belantamab mafodotin monotherapy had a manageable safety profile and demonstrated rapid, deep and durable clinical response (60% overall response rate, 14.3 months duration of response) with significant progression free-survival (PFS; 12 months) in patients with heavily pretreated MM. Belantamab mafodotin is being evaluated in clinical trials in various lines of MM therapy, either as monotherapy or in combination. The DREAMM-5 platform trial is a phase 1/2 study that incorporates an efficient design with 1 master protocol, wherein multiple belantamab mafodotin-containing combinations will be evaluated in separate substudies to identify effective doublet combinations versus a shared belantamab mafodotin monotherapy control arm. Initial substudies will include combinations with the T-cell activating checkpoint mAbs GSK3359609 (an IgG4 inducible T-cell costimulatory [ICOS] agonist antibody that is Fc optimized to selectively enhance T-cell function to enable antitumor responses), GSK3174998 (a humanized wild-type IgG1 anti-OX40 agonistic mAb), and a gamma-secretase inhibitor, Nirogacestat (PF-03084014, SpringWorks Therapeutics). Furthermore, as treatment paradigms evolve, including potential genomic subsets of patients with RRMM and actionable mutations, other control arms may be introduced. The combination agent for evaluation in each substudy will be selected based on scientific rationale and/or results of preclinical experiments with the selected agent in combination with belantamab mafodotin. Methods: Patients with RRMM will be eligible if they have received ≥3 prior lines of therapy (consisting of an immunomodulatory drug, proteasome inhibitor, and an anti-CD38 mAb), have measurable disease (as measured by M-protein and free light chain), and acceptable hematologic and vital organ functions. Participants previously treated with an anti-BCMA targeted therapy are eligible except for prior belantamab mafodotin treatment and chimeric antigen receptor (CAR) T-cell therapy within 3 months of screening. Each substudy will have 2 sequential phases to evaluate safety and efficacy (Figure). The dose exploration (DE) phase will evaluate the safety and tolerability of belantamab mafodotin administered in combination with a partner agent. Each DE phase will consist of multiple dosing cohorts (N≤10 per cohort), 1 cohort per doublet combination. The primary objective is to identify a recommended phase 2 dose for each doublet combination based on safety and preliminary efficacy. Once a substudy is selected for the cohort expansion (CE) phase (N=35 per substudy), the objective is to compare the response rate between the doublet combination and the shared belantamab mafodotin monotherapy control arm. Secondary objectives in CE are to assess AEs, durability of response, PFS, and overall survival. Exploratory objectives include assessment of PK for belantamab mafodotin with each partner agent, bone marrow minimal residual disease status, and plasma soluble BCMA levels as candidate prognostic and predictive biomarkers. DREAMM-5 is designed to efficiently identify novel, highly effective belantamab mafodotin-containing doublet combinations for evaluation in pivotal trials against current standard-of-care MM agents. Acknowledgments: Editorial assistance provided by Sarah Hauze, PhD, at Fishawack Indicia Ltd and funded by GSK. Study funded by GSK (208887); drug linker technology licensed from Seattle Genetics; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. Figure Disclosures Richardson: Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Celgene: 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, Research Funding; Bristol-Myers Squibb: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Biswas:GSK: Employment, Equity Ownership. Holkova:GlaxoSmithKline: Employment, Equity Ownership. Jackson:GlaxoSmithKline: Employment, Equity Ownership. Netherway:GlaxoSmithKline: Employment, Equity Ownership. Bao:GSK: Employment, Equity Ownership. Ferron-Brady:GlaxoSmithKline: Employment, Equity Ownership. Yeakey:GlaxoSmithKline: Employment, Equity Ownership. Shelton:GlaxoSmithKline: Employment, Equity Ownership. Montes De Oca:GlaxoSmithKline: Employment. Ahlers:GlaxoSmithKline: Employment, Equity Ownership. Franco:GlaxoSmithKline: Employment, Equity Ownership. Ballas:GlaxoSmithKline: Employment, Equity Ownership; Bristol-Myers Squibb: Equity Ownership; AstraZeneca: Patents & Royalties: Uncompensated copyrights. Paul:GlaxoSmithKline: Employment, Equity Ownership. Luptakova:GlaxoSmithKline: Employment, Equity Ownership. Gupta:GlaxoSmithKline: Employment, Equity Ownership. Opalinska:GSK: Employment, Equity Ownership.

Description: Introduction: Single-agent belamaf (GSK2857916), a B-cell maturation antigen-targeting antibody-drug conjugate, demonstrated deep and durable responses with a manageable safety profile in patients with heavily pretreated RRMM (median 7 lines of prior therapy) refractory to an immunomodulatory agent (IMiD), a proteasome inhibitor (PI), and refractory and/or intolerant to an anti-CD38 monoclonal antibody in the pivotal Phase II DREAMM-2 study (NCT03525678). At 13-month follow-up, the overall response rate (ORR) was 32% and the median duration of response (DoR) was 11.0 months in the belamaf 2.5 mg/kg arm (Lonial. ASCO 2020 Poster 436). The multimodal mechanism of action, efficacy and safety profile of belamaf, as well as preclinical data suggest possible synergy with standard of care agents and a potential benefit in combination with IMiDs and PIs. DREAMM-6 (NCT03544281) is an ongoing Phase I/II, two-part study of belamaf in combination with lenalidomide/dexamethasone (Arm A) or BorDex (Arm B) in patients with RRMM who had received ≥1 prior therapy (bortezomib-refractory patients were not excluded); preliminary results from Arm B have been reported (Nooka. ASCO 2020 Oral 8502). Methods: Part 1 (dose escalation) and Part 2 (dose expansion) of Arm B in DREAMM-6 evaluated belamaf (2.5 and 3.4 mg/kg intravenously (IV) every 3 weeks [Q3W]) administered as SINGLE (Day 1) or SPLIT dose (divided equally on Days 1 and 8) plus BorDex (Bor 1.3 mg/m2 [subcutaneously] and Dex 20 mg [IV or orally]). Combination treatment continued for up to 8 cycles, with single-agent belamaf maintenance therapy thereafter. Primary objectives were safety, tolerability, and efficacy (ORR [≥ partial response, PR] per investigator-assessed best confirmed response). We report safety and efficacy results from the 2.5 mg/kg SINGLE dose cohort from Arm B. Results: As of March 30, 2020, 18 patients had received belamaf 2.5 mg/kg SINGLE + BorDex in Parts 1 and 2 of Arm B. The median age was 67 years, 61% were male, and 33% had high-risk cytogenetics; patients had received a median of 3 (range, 1-11) prior lines of therapy. All 18 patients had treatment-related adverse events (AEs), of whom 16 (89%) had Grade 3/4 events (see Table). Treatment-related serious AEs occurred in 5 (28%) patients. There were no Grade 5 AEs of interest. Thirteen (72%) patients had dose reductions (8/13 belamaf) and all patients had dose delays (16/18 belamaf) to manage AEs. Five (28%) patients discontinued a study treatment due to AEs: 4 bortezomib, 2 dexamethasone, no patients discontinued belamaf. Of the AEs of interest, thrombocytopenia occurred in 12 patients (67%; maximum Grade 4 in 8 patients and Grade 3 in 3 patients) and led to dose reduction in 6 (33%) patients, dose delay in 7 (39%) patients, and no discontinuations. Three (17%) patients had Grade 2 infusion-related reactions (with no dose modifications or discontinuations). Changes in the corneal epithelium (keratopathy/microcyst-like epithelial changes [MECs], an eye exam finding with or without symptoms), an anticipated AE associated with monomethyl auristatin F, the payload in belamaf, occurred in all 18 patients (maximum Grade 3 in 10 patients, Grade 2 in 7 patients, and Grade 1 in 1 patient), and led to dose reduction in 7 (39%) patients, dose delay in 15 (83%) patients, with no discontinuations. Response was evaluable in all patients; ORR was 78% (95% CI 52.4-93.6), with very good partial response (VGPR) in 9 (50%) and PR in 5 (28%) patients. One (6%) patient had minimal response, and 3 (17%) patients had stable disease. Clinical benefit rate was 83% (95% CI 58.6-96.4). After a median of 18.2 weeks (range 6.0-46.4 weeks) on treatment, median DoR was not reached. Conclusions: The combination of belamaf 2.5 mg/kg Q3W with standard-of care BorDex demonstrated an acceptable safety profile in patients with RRMM who had received a median of 3 prior lines of therapy, with AEs as expected, and no new safety signals to date. Corneal events were common but manageable with belamaf dose modifications. At interim follow-up, best response data indicate a high ORR of 78%, VGPR of 50%, and clinical benefit rate of 83%. Final data for the 2.5 mg/kg SINGLE + BorDex cohort will be reported at the congress. Funding: GSK (Study 207497); drug linker technology licensed from Seattle Genetics; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. Disclosures Popat: 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); Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Nooka:Karyopharm Therapeutics, Adaptive technologies: Consultancy, Honoraria, Research Funding; Oncopeptides: Consultancy, Honoraria; Spectrum Pharmaceuticals: Consultancy; Takeda: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria; Adaptive Technologies: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria, Other: Personal Fees: Travel/accomodations/expenses, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding. Stockerl-Goldstein:Celgene: Consultancy; Abbott Laboratories: Current equity holder in publicly-traded company; Abbvie: Current equity holder in publicly-traded company; GSK: Research Funding; Takeda: Research Funding; BiolineRx: Research Funding; Janssen: Research Funding; Cellerant: Other: Other relationship. Abonour:Takeda: Consultancy; Janssen: Honoraria, Research Funding; Celgene: Consultancy; BMS: Consultancy, Research Funding. Khot:Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Other: Speaker fees; Novartis: Other: Travel grant. Lee:Janssen: Consultancy; Amgen: Consultancy; Celgene/BMS: Consultancy. Augustson:Roche: Other: Support of parent study and funding of editorial support. Spencer:AbbVie, Amgen, Celgene, Haemalogix, Janssen, Sanofi, SecuraBio, Specialised Therapeutics Australia, Servier and Takeda: Honoraria; Amgen, Celgene, Haemalogix, Janssen, Servier and Takeda: Research Funding; AbbVie, Celgene, Haemalogix, Janssen, Sanofi, SecuraBio, Specialised Therapeutics Australia, Servier and Takeda: Consultancy; Celgene, Janssen and Takeda: Speakers Bureau. Mateos:Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Regeneron: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Consultancy, Honoraria; PharmaMar-Zeltia: Consultancy; Abbvie/Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy, 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; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy; Takeda: 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; Janssen: 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. Chopra:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Rogers:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Smith:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Davidge:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Montes de Oca:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Ferron-Brady:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Yeakey:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Talekar:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Kremer:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Gupta:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company; Novartis: Current equity holder in publicly-traded company. Quach:Sanofi: Consultancy, Research Funding; Janssen Cilag: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria, Research Funding; Glaxo Kline Smith: Consultancy, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding.

Description: Introduction: Single-agent belamaf (GSK2857916), a B-cell maturation antigen-targeting antibody-drug conjugate, induced deep and durable responses in patients with RRMM, with a manageable safety profile with 13 months of follow-up (DREAMM-2; NCT03525678; Lonial et al, ASCO 2020, Poster 436). A platform trial design allows efficient evaluation of belamaf in combination with other anti-myeloma agents, such as a humanized wild-type IgG1 anti-OX40 agonist, an IgG4-inducible T-cell co-stimulator (ICOS) agonist, a gamma-secretase inhibitor, and a humanized programmed cell death (PD)-1 antagonist. The unique, multimodal mechanisms of action (MoAs) of belamaf, in combination with MoAs of these agents, has the potential to achieve synergistic effects in RRMM to further enhance anti-myeloma activity without compromising safety. Methods: DREAMM-5 (NCT04126200) is a Phase I/II study that utilizes a master protocol with separate substudies comprised of sequential dose-exploration (DE) and cohort-expansion (CE) phases, to identify promising, effective belamaf combinations when compared with a shared single-agent belamaf control arm (CE phase only). The DE phase consists of multiple dosing cohorts with belamaf combinations in which patients are assigned to treatment slots by a predetermined algorithmic approach (N≤10 per cohort). A recommended Phase II dose (RP2D) for each combination treatment will be identified based on the safety and preliminary efficacy in the DE phase. At the end of the DE phase, an interim analysis of safety, pharmacokinetic, and efficacy data will also be performed for each substudy treatment combination to determine whether the combination should move forward at the RP2D to the CE phase. Patients in the CE phase (N≥35 per cohort) will be randomized to a substudy and within a substudy to either combination treatment or the belamaf monotherapy control arm; patients will also be stratified by number of prior therapies). Eligible patients will have RRMM and will have received ≥3 prior therapy lines, which includes a prior immunomodulatory agent, proteasome inhibitor, and anti-CD38 antibody; all patients will provide informed consent for participation. The primary objectives of the study are to identify the RP2D (DE phase) and the overall response rate (≥partial response, CE phase), along with safety and tolerability, for each combination treatment. Substudies 1 (combination with GSK3174998, OX40 agonist antibody), 2 (combination with GSK3359609, ICOS agonist antibody), and 3 (combination with nirogacestat [PF-03084014; SpringWorks Therapeutics], gamma-secretase inhibitor) are currently open to enrollment. Substudy 4 (combination with dostarlimab; PD-1 antagonist antibody) is under review. Additional substudies will be explored based on scientific rationale and/or preclinical combination study results. Funding: GSK (Study 208887); belamaf drug linker technology licensed from Seattle Genetics; belamaf monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa; nirogacestat gamma-secretase inhibitor produced by and used in collaboration with SpringWorks Therapeutics. Figure: DREAMM-5 study design Figure 1 Disclosures Richardson: Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding. Nooka:GlaxoSmithKline: Consultancy, Honoraria, Other: Personal Fees: Travel/accomodations/expenses, Research Funding; Karyopharm Therapeutics, Adaptive technologies: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Spectrum Pharmaceuticals: Consultancy; Adaptive Technologies: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Oncopeptides: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding. Quach:Amgen, sanofi, celgene, Karyopharm, GSK: Research Funding; Amgen, Celgene, karyopharm, GSK, Janssen Cilag, Sanofi.: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Consultancy; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Honoraria. Trudel:Celgene, Janssen, Takeda, Sanofi, Karyopharm, Amgen Canada: Honoraria; Celgene, Amgen, GSK: Consultancy, Research Funding; GSK, Celgene, Janssen, Amgen, Genentech: Research Funding. Routledge:Celgene, Sandoz: Consultancy; Amgen, BMS, Celgene, Sandoz: Honoraria. Song:Otsuka: Honoraria; Janssen: Honoraria, Research Funding; Amgen, Celgene,Takeda: Consultancy, Honoraria; Sanofi: 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; Gilead: 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; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Paul:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Khan:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Brouch:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Ferron-Brady:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Yeakey:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Shelton:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Montes de Oca:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Smith:SpringWorks: Current Employment, Current equity holder in publicly-traded company. Im:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Ahlers:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Paul:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Holkova:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Gupta:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company; Novartis: Current equity holder in publicly-traded company. Kremer:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Rodriguez-Otero:GlaxoSmithKline: Consultancy, Current Employment, Current equity holder in publicly-traded company, Honoraria; Kite: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Oncopeptides: Consultancy, 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); Sanofi: Consultancy, Honoraria.