ABSTRACT
Background: The bortezomib, lenalidomide, and dexamethasone (VRd) regimen is a standard of care for newly diagnosed multiple myeloma (NDMM). Belantamab mafodotin (belamaf) is a B-cell maturation antigen-binding antibody-drug conjugate that eliminates myeloma cells by a multimodal mechanism: direct cell kill and anti-myeloma tumor immune response. Belamaf has demonstrated deep and durable responses as a monotherapy in the DREAMM-2 study of patients (pts) with relapsed/refractory multiple myeloma (RRMM). Preclinical evidence of belamaf in combination with bortezomib or lenalidomide suggests enhanced anti-myeloma activity, providing rationale for this treatment combination. Aims: To evaluate the safety and tolerability of this combination in adult pts with transplant-ineligible (TI) NDMM and establish the recommended Phase III dose. Methods: DREAMM-9 (NCT04091126) is an ongoing Phase I, open-label, randomized study of belamaf + VRd. The belamaf dose cohorts currently being evaluated are Cohort 1 (1.9 mg/kg Q3/4W), Cohort 2 (1.4 mg/kg Q6/8W), Cohort 3 (1.9 mg/kg Q6/8W), Cohort 4 (1.0 mg/kg Q3/4W), and Cohort 5 (1.4 mg/kg Q3/4W). Belamaf is given with VRd Q3W until Cycle 8, and with Rd Q4W thereafter. After evaluation of safety data for Cohort 1, Cohorts 2-5 were opened in parallel and enrolled pts were randomized 1:1:1:1. Primary endpoint is safety. Secondary endpoints include efficacy, tolerability, and pharmacokinetics (PK). Results: As of data cutoff (07 Dec 2021), 64 pts were analyzed across all cohorts. Median age (range) was 73.0 (51- 88) years, 55% were male, 80% were white, 8% had extramedullary disease, 59% were International Staging System stage II or III, 20% had amp1q, and 17% had high-risk cytogenetics (≥1 of: t(4;14), t(14;16), del17p). The median duration of follow-up varied: Cohort 1 (17.4 months [mo]), Cohort 2 (5.9 mo), Cohort 3 (6.1 mo), Cohort 4 (4.7 mo), Cohort 5 (5.8 mo). Median number of belamaf cycles were: Cohort 1 (6), Cohort 2 (3), Cohort 3 (3.5), Cohort 4 (4.5), and Cohort 5 (5). Most common adverse events (AEs) across cohorts included thrombocytopenia (49%), constipation (43%), diarrhea (32%), and peripheral sensory neuropathy (30%). AEs related to study treatment were experienced by 61 (97%) pts. Belamaf-related grade 3/4 AEs occurred in 24 (38%) pts. Belamaf dose reductions occurred in 11 (18%) pts, with dose delays in 10 (16%) pts. Three pts experienced a fatal severe AE (unrelated to study treatment);2 due to COVID-19 infection, 1 due to pancreatic adenocarcinoma. Early deep responses were observed;67-92% pts achieved ≥very good partial response (VGPR) (Table), with median time to VGPR of 2.1-2.9 months across cohorts. Of pts with ≥VGPR, 17 were minimal residual disease (MRD) negative, 10 in Cohort 1. As of data cutoff, 8-75% of pts achieved best response of complete response (CR) or stringent CR (sCR). Grade 3 corneal exam findings were reported in 25-58% of pts;grade 3 visual acuity changes were reported in 21-75% of pts. No grade 4 corneal exam findings or visual acuity changes were reported in pts receiving belamaf Q6/8W, compared with 0-17% and 0-8%, respectively, in the Q3/4W cohorts. Belamaf PK profile was similar to that in pts with RRMM, accounting for baseline characteristics. Image: Summary/Conclusion: Belamaf + VRd demonstrated high response rates in pts with TI NDMM, with a high rate of MRD negativity indicating deep responses. No new safety signals were observed relative to DREAMM-2. Study is ongoing to evaluate the safety and efficacy of variable dose intensities of belamaf in combination with VRd.
ABSTRACT
Background: The bortezomib, lenalidomide, and dexamethasone (VRd) regimen is a SoC for NDMM. Belamaf, a B-cell maturation antigen (BCMA)-targeting antibody-drug conjugate, demonstrated durable responses in patients with relapsed/refractory multiple myeloma. Preclinical studies of belamaf in combination with bortezomib/ lenalidomide suggest enhanced antimyeloma activity. We report preliminary findings of belamaf + VRd for patients with TI NDMM. Materials and Methods: DREAMM-9 (NCT04091126) is an ongoing Phase I, open label, randomized, dose and schedule evaluation trial. Adults with TI NDMM and ECOG status 0-2 are eligible. VRd is administered Q3W until Cycle 8, followed by lenalidomide + dexamethasone (Rd) Q4W. Belamaf + VRd is administered until Cycle 8, and with Rd thereafter. The currently evaluated belamaf dose cohorts are: Cohort 1 (1.9 mg/kg Q3/4W), Cohort 2 (1.4 mg/kg Q6/8W), Cohort 3 (1.9 mg/ kg Q6/8W), Cohort 4 (1.0 mg/kg Q3/4W), and Cohort 5 (1.4 mg/kg Q3/4W). Primary endpoint is safety. Secondary endpoints include efficacy, tolerability, and pharmacokinetics (PK). Results: Overall 36 patients were treated across the 5 cohorts. The median (range) age was 74.0 (63-80) years;56% patients were male, 17 (47%) had stage 2 disease, 3 (8%) had extramedullary disease, 6 (17%) patients had high risk cytogenetic abnormalities;the median number of belamaf cycles ranged from 1-9. No new safety signals were observed. Across Cohorts 1-5, all patients experienced AEs related to study treatment;1 patient in Cohort 1 died due to COVID-19 infection. The most common AEs leading to dose modification were thrombocytopenia, neutropenia, and corneal events. Patients in Cohort 2 and 3 had the lowest number of Grade ≥3 corneal events (3 and 2 events, respectively). All 12 patients in Cohort 1, all 6 in Cohorts 3 and 5, and 5/6 patients in Cohorts 2 and 4 have responded to the treatment;≥half of patients in each cohort achieved very good partial response or better. As of data cut-off, 3/12 patients in Cohort 1, 2/6 in Cohort 4, and 1/6 patients each in Cohorts 3 and 5 remained in complete response. Belamaf PK profile was similar to that observed in patients with RRMM taking into consideration baseline patients characteristics. Conclusions: Preliminary data suggest addition of belamaf to VRd did not reveal new safety signals and demonstrates high response rates, albeit with short follow-up. The trial is ongoing to confirm safety and evaluate the efficacy of belamaf + VRd. .
ABSTRACT
Introduction: The bortezomib, lenalidomide, and dexamethasone (VRd) regimen is an acceptable standard of care (SoC) for both transplant-eligible and transplant-ineligible newly diagnosed multiple myeloma (TI NDMM). Ongoing development of novel therapies and combinations strive to improve survival outcomes beyond what is expected from SoC. Belantamab mafodotin (belamaf) is a B-cell maturation antigen-binding antibody-drug conjugate that eliminates myeloma cells by a multimodal mechanism and has demonstrated durable responses in patients with relapsed/refractory multiple myeloma (RRMM). Preclinical evidence of belamaf in combination with bortezomib or lenalidomide suggests enhanced anti-myeloma activity, providing rationale for this treatment combination. We report the preliminary findings of belamaf + VRd for TI NDMM patients. Methods: DREAMM-9 (NCT04091126) is an ongoing Phase I, open-label, randomized, dose and schedule evaluation study of belamaf + VRd in patients with TI NDMM. Eligible patients include those ≥18 years old with ECOG status 0-2 and adequate organ system functions. The study evaluates safety and tolerability of belamaf + VRd in up to 8 cohorts, up to 144 patients, to establish the recommended phase 3 dose (RP3D). VRd is administered Q3W until cycle 8, followed by lenalidomide + dexamethasone (Rd) Q4W. Belamaf + VRd is administered until cycle 8, and then in combination with Rd thereafter. The belamaf dose cohorts currently being evaluated are: cohort 1 (1.9 mg/kg Q3/4W), cohort 2 (1.4 mg/kg Q6/8W), cohort 3 (1.9 mg/kg Q6/8W), cohort 4 (1.0 mg/kg Q3/4W), and cohort 5 (1.4 mg/kg Q3/4W). After evaluation of safety data for cohort 1, cohorts 2-5 were opened in parallel and enrolled patients were randomized 1:1:1:1. Safety data, clinical activity, and drug concentrations will be assessed, and used to determine the belamaf RP3D. This analysis reports the preliminary results from cohort 1. Primary endpoints include number of patients with adverse events (AEs). Secondary endpoints include establishing relative dose intensity of lenalidomide and bortezomib in combination with belamaf, cumulative dose of belamaf, pharmacokinetics (PK) profile of belamaf when combined with VRd, overall response rate (ORR), complete response (CR), stringent complete response (sCR), complete response rate ([CRR];% of patients with a confirmed CR or better), and rate of very good partial response or better (≥VGPR). Exploratory endpoints include assessing minimal residual disease (MRD) in patients who achieve ≥VGPR, and safety and efficacy exposure-response relationships. Results: Twelve patients in cohort 1 were included in this preliminary analysis. Eight patients (67%) were male;median age (range) was 72.5 years (63-77). Ten patients (83%) were white and 2 (17%) were Asian. Nine patients (75%), were ISS stage II or III, and 4 (33%) patients had high-risk cytogenetics (consisting of one or more of the following: t(4;14), t(14;16), del17p, 17p13del). AEs related to study treatment were experienced by all 12 patients. Dose reductions occurred in 12 (100%) patients, all of whom also experienced a dose delay. Most common AEs leading to dose modification were thrombocytopenia, neutropenia, and corneal events. Grade 3 or 4 AEs related to belamaf occurred in 9 (75%) patients. During the trial, one patient experienced a fatal severe AE due to COVID-19 infection (unrelated to study treatment;Table). All patients, 100% (n=12;95% CI: 73.5-100) achieved ≥VGPR. Early deep responses were observed;2 (17%) patients achieved VGPR as early as 4 weeks. As of data cut-off, 5 (42%) remain in CR and 3 (25%) in sCR. Based on real-time data captured in the clinical database, 7 out of 9 patients achieved MRD-negative status at the first test after VGPR. Belamaf PK profile was similar to that observed in patients with RRMM taking into consideration baseline patients characteristics. Conclusion: Preliminary data suggest addition of belamaf to VRd did not reveal new safety signals and demonstrates high response rates, albeit with short follow up. The study is ongoing to confirm safety and evaluate the efficacy of belamaf + VRd. Updated data for cohort 1 will be reported at the congress. Funding: GSK (Study 209664);belamaf drug linker technology licensed from Seagen;belamaf monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. [Formula presented] Disclosures: Usmani: Pharmacyclics: Consultancy, Research Funding;Seattle Genetics: Consultancy, Research Funding;Takeda: Consultancy, Research Funding, Speakers Bureau;Merck: Consultancy, Research Funding;SkylineDX: Consultancy, Research Funding;Sanofi: Consultancy, Research Funding, Speakers Bureau;Janssen: Consultancy, Research Funding, Speakers Bureau;Janssen Oncology: Consultancy, Research Funding;Bristol-Myers Squibb: Research Funding;EdoPharma: Consultancy;GSK: Consultancy, Research Funding;Celgene/BMS: Consultancy, Research Funding, Speakers Bureau;Array BioPharma: Consultancy, Research Funding;Abbvie: Consultancy;Amgen: Consultancy, Research Funding, Speakers Bureau. Quach: Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Janssen/Cilag: 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, Research Funding;Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding;Bristol Myers Squibb: Consultancy, 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;Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees;CSL: Consultancy, Membership on an entity's Board of Directors or advisory committees. Koh: Pfizer: Consultancy;Jassen: Honoraria;AstraZeneca: Honoraria;Novartis: Honoraria;GSK: Honoraria;Roche: Honoraria;Takeda: Honoraria. Guenther: Novartis: Consultancy;Celgene: Consultancy, Honoraria;Roche: Consultancy;Takeda: Consultancy, Honoraria;Amgen: Consultancy, Honoraria;AbbVie: Consultancy;Jazz Pharmaceuticals: Honoraria;Janssen Pharmaceuticals: Consultancy, Honoraria. Zhou: GlaxoSmithKline: Current Employment. Kaisermann: GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Mis: GlaxoSmithKline: Current Employment. Williams: GlaxoSmithKline: Current Employment. Yeakey: GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Ferron-Brady: GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Figueroa: GlaxoSmithKline: Current Employment. Kremer: GlaxoSmithKline: Current Employment. Gupta: Novartis: Current equity holder in publicly-traded company;GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Janowski: Celgene: Consultancy;AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees;Janssen: 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;BMS: Membership on an entity's Board of Directors or advisory committees.