DREAMM-6: Safety, Tolerability and Clinical Activity of Belantamab Mafodotin (Belamaf) in Combination with Bortezomib/Dexamethasone (BorDex) in Relapsed/Refractory Multiple Myeloma (RRMM)

Abstract

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.

Molecular Profiling Practices in Pancreatic Adenocarcinoma: Academic vs Community Physicians

“…Median PFS was 86 months, and only 24% of patients underwent radical treatment. 21 Overall, PDT is effective in delaying the progression of low-risk cancer compared with AS. Potential drawbacks to PDT include the need to avoid direct sunlight following the procedure for 48 hours to reduce AEs and the potential of an allergic reaction to the photosensitized agent.…”

“…20 Notably, a single agent, olaparib, achieved an 82% response rate in 11 patients with germline PALB2 mutation in the recent proof-of-principle study. 21 The comparison of efficacy and safety of a PARP inhibitor vs platinum-based treatment in patients with TNBC and germline BRCA1/2 mutation has not yet been done.…”

“…In this trial, keratopathy occurred in all 18 patients and led to dose reductions in 7 (39%) and dose delay in 15 (83%), with no discontinuations. 21 As a BCMA-targeted therapy, belamaf avoids the off-target AEs and potential cytotoxicity associated with treatments such as chemotherapy. "CD38, while it is clearly effective, is expressed on a number of different cells that may potentially result in some chronic long-term immunosuppression through the use of CD38-targeted therapy," explained Lonial.…”

“…In grade 2 HFSR, painful skin changes (eg, blisters, erythema, hyperkeratotic plaques) limit instrumental daily life activities, and grade 3 HFSR is characterized by severe skin changes (eg, moist desquamation, ulceration, blistering, fissures, or local injury causing infectious complications) and pain that limits self-care activities of daily life. 5,16,21 Treatment of grade 2 and 3 HFSR involves pain control with systemic medications, including nonsteroidal anti-inflammatory drugs and opioids or γ-aminobutyric acid antagonists. 7,17 Superpotent topical steroids, such as clobetasol propionate ointment 0.05% or fluocinonide 0.05%, are recommended for treatment of the inflamed, erythematous areas.…”

Immunotherapy with Antibodies in Multiple Myeloma: Monoclonals, Bispecifics, and Immunoconjugates

“…Based on the activity observed in advanced MM, several combination studies with belantamab mafodotin are ongoing, also in earlier stages of the disease. This includes the DREAMM-6 study, which evaluates the combination of belantamab mafodotin with lenalidomide-dexamethasone or bortezomib-dexamethasone in patients with at least one prior line of therapy [62]. Preliminary data show an acceptable safety profile of belantamab mafodotin (2.5 mg/kg) plus bortezomib-dexamethasone, with keratopathy and thrombocytopenia as the most common adverse events.…”