The Patient Experience with Belantamab Mafodotin: Perspectives of Patients Receiving Treatment in Clinical Trials and in the Real-World

Introduction: Belantamab mafodotin (belamaf) has been available for treatment of patients with relapsed/refractory multiple myeloma (RRMM) in clinical practice since US approval in August 2020. Single-agent belamaf, a first-in-class B-cell maturation antigen-binding antibody-drug conjugate containing monomethyl auristatin F (MMAF) with a multimodal mechanism of action, showed deep and durable responses in the pivotal Phase II DREAMM-2 trial (NCT03525678). This study aimed to describe patients' perspectives of living with RRMM and their treatment with belamaf, based on interviews conducted in a real-world setting, supplemented by findings from interviews embedded into the DREAMM-2 trial.

Methods: Semi-structured interviews were conducted with adults with RRMM receiving belamaf in real-world clinical practice and those enrolled in the DREAMM-2 trial. Real-world interviews were conducted with eligible patients who had received commercially supplied belamaf in routine care, per label, for ≥3 months prior to recruitment or had discontinued treatment within the past year and had received treatment for ≥3 months. Eligible patients for the real-world study were identified by SparkCures, a patient engagement partner that works closely with patients to help identify and explore potential clinical trial options. In the real-world study, interviews were conducted at a single time-point with patients describing how their MM and treatment-related symptoms had changed over time since starting belamaf; patients recalled bothersomeness of symptoms before starting belamaf, "at symptom worst" and "at time of interview". In DREAMM-2, patients were interviewed at Cycle 4 (C4; 2.5 and 3.4 mg/kg Q3W) and at the end of treatment (EOT); at the EOT interview, patients recalled severity of symptoms "at symptom worst" and "at time of interview". Bothersomeness (real-world study) and severity (DREAMM-2) were rated using a numeric rating scale (0=no bother/not severe; 10=extremely bothersome/severe). The DREAMM-2 trial-embedded study included all eligible patients who agreed to participate in interviews. Patients' experiences with belamaf were also qualitatively explored. Real-world study interviews are ongoing; interim findings are reported.

Results: Patients who participated in real-world interviews (n=7; male 4 of 7; median 65 years; median 11 months of belamaf treatment) and patients enrolled in DREAMM-2 who participated in EOT interviews (n=38; male 20 of 38 patients; median 63.5 years) were included. Fatigue was the most frequently reported ongoing RRMM symptom in both studies (real-world: 6 of 7 patients; DREAMM-2 EOT: 22 of 38 patients). Within respective studies, mean bothersomeness/severity of most ongoing symptoms was substantially reduced "at time of interview" compared with "at worst" (Table 1). The type of ocular symptoms reported in both studies were similar and included sensitivity to light, blurred vision, and poor vision. Within respective studies, the bothersomeness/severity of patients' ocular symptoms was generally rated lower "at time of interview" compared with "at worst" occurrence (Table 2). To alleviate ocular symptoms, patients in both studies reported applying eye drops and wearing sunglasses. In the real-world study, 6 of 7 patients indicated that the benefits of belamaf treatment outweighed the treatment-related ocular changes, while 5 of 7 patients reported a preference for belamaf over past treatments. In DREAMM-2, 27 patients made ≥1 positive statement about belamaf treatment.

Conclusions: These qualitative interviews provide insights into the burden of disease-related symptoms experienced by patients with RRMM treated with belamaf. Insights from DREAMM-2 support the interim real-world findings that ongoing symptoms become less bothersome/severe over time with belamaf treatment. In both settings, patients described the benefits of belamaf and their positive opinion of its efficacy/safety profile. These findings suggest patients find belamaf an important treatment option for RRMM.

Funding: GSK 214290 and GSK 205678; drug linker technology licensed from Seagen Inc.; mAb produced using POTELLIGENT Technology licensed from BioWa.

Suvannasankha:Sutro Biopharma: Research Funding; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Oncology: Consultancy, Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; Regeneron: Research Funding. LeBlanc:BlueNote: Consultancy; Genentech: Consultancy; Astellas: Consultancy; GSK: Consultancy; Agios/Servier: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Flatiron: Consultancy; BMS/Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Consultancy; BeiGene: Honoraria; AstraZeneca: Consultancy, Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Seagen Inc: Research Funding; Novartis: Consultancy. Correll:Evidera: Consultancy, Current Employment, Research Funding. Carmichael:Clarivate: Consultancy, Current Employment, Current equity holder in publicly-traded company, Research Funding. Gorsh:GSK: Current Employment, Current equity holder in publicly-traded company. Martin:Evidera: Consultancy, Current Employment, Current equity holder in publicly-traded company, Research Funding. Kitchen:Clarivate: Consultancy, Current Employment, Current equity holder in publicly-traded company, Research Funding. Eliason:GSK: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Thursfield:Clarivate: Consultancy, Current Employment, Current equity holder in publicly-traded company, Research Funding. Boytsov:GSK: Current Employment, Current equity holder in publicly-traded company. Brown Hajdukova:Clarivate: Consultancy, Current Employment, Current equity holder in publicly-traded company, Research Funding. Lewis:GSK: Current Employment, Current equity holder in publicly-traded company. Mackay:GSK: Current Employment, Current equity holder in publicly-traded company. Paka:GSK: Current Employment, Current equity holder in publicly-traded company. O'Neill:GSK: Current Employment, Current equity holder in publicly-traded company. Perera:GSK: Current Employment, Current equity holder in publicly-traded company. Naine:GSK: Current Employment, Current equity holder in publicly-traded company. Molinari:GSK: Current Employment, Current equity holder in publicly-traded company. Hanna:GSK: Current Employment, Current equity holder in publicly-traded company. Kleinman:GSK: Consultancy; Calm Water Therapeutics LLC: Current equity holder in private company, Current holder of stock options in a privately-held company, Membership on an entity's Board of Directors or advisory committees; Triphase Accelerator Corp: Consultancy; Editas Medicine: Consultancy; Ascidian Therapeutics: Consultancy; Prime Medicine: Consultancy; ONL Therapeutics: Consultancy; Helixmith: Consultancy; AGTC: Consultancy; Emergent BioSolutions: Consultancy.