Factors influencing patient treatment selection among bispecific antibodies for relapsed/refractory multiple myeloma (RRMM): A mixed methods study

Abstract Background Novel immunotherapies such as bispecific antibodies (BsAbs) are rapidly changing the treatment landscape for RRMM, with improved outcomes for patients. As these treatments vary in efficacy, toxicity, dosing, and mode of administration, it is important to better understand how patients view such differences, and which factors they prioritize when selecting treatment. Objective This study aimed to identify factors that influence treatment decisions among patients with RRMM in the US and five European countries and how they prioritize attributes or outcomes associated with BsAbs. Methods From January to May 2025, one-on-one virtual interviews were conducted with patients who self-reported a diagnosis of MM and had completed 1 or more lines of treatment (LOT) in the United States, United Kingdom, France, Germany, Italy, and Spain. Open-ended questions were asked about factors that influence treatment decisions. Next, patients were asked to rate the meaningfulness of differences between the highest and lowest level of each treatment attribute related to administration, efficacy, and adverse events on a scale of 1 to 7 (1 = least meaningful, 7 = most meaningful). The attributes and levels were informed by clinical data available for elranatamab, linvoseltamab, talquetamab, and teclistamab. Finally, patients were asked to select the single most and single least meaningful attribute per category based on the difference in highest and lowest levels, reflecting their overall prioritization. A thematic analysis of responses to the open-ended questions was performed. Attribute wording was revised throughout the interview process in response to feedback. Summary statistics for patient characteristics, attribute ratings, and ranking outcomes were calculated. Results Thirty patients (5 per country) with a mean age of 56 years (range, 29-77) participated; 57% were female, and 57% had 3 or more LOTs. When asked about factors influencing treatment decision-making, most patients mentioned efficacy in some form. Key themes that emerged included achieving a “response” and “remission”, “that it works”, relieving symptoms and being able to perform daily activities, keeping the “disease under control”, “stop relapses”, and becoming treatment-free for as long as possible. Patients were willing to prioritize efficacy over toxicity risk, and a longer expected duration of response made side effects a lesser concern. Among the efficacy attributes, increased overall survival had the highest mean meaningfulness rating of 6.6. When asked to identify the single most meaningful efficacy attribute based on the difference between highest and lowest levels, the three efficacy attributes most often identified were related to response (n=24): chance of complete response, duration of response, or chance of any type of response. Among the side effects attributes, increased risk of grade 3-4 infections was most often identified as most meaningful (n=8), followed by the increased risks of immune effector cell-associated neurotoxicity syndrome (ICANS) (n=5) and of dysgeusia (n=4). When rating each side effect attribute independently based on the differences, the increased risk of skin-related side effects received a mean rating that was the same as the increased risk of grade 3-4 infections (6.2). Among the administration attributes, dosing schedule (n=10), mode of administration (n=8), and hospital stay at the beginning of treatment (n=6) were most often ranked as most meaningful. ConclusionsThis multi-country mixed methods study provides valuable information on what matters to patients when choosing among BsAbs for RRMM. Healthcare professionals should incorporate these insights into shared decision-making to better align treatment plans with patient values and priorities. The findings highlight the need for a large-scale quantitative study to more systematically assess patient preferences and quantify the trade-offs that patients are willing to make among key attributes in treatment selection. The results of this study will directly inform the design and selection of attributes for a discrete choice experiment (DCE). Based on the findings, a patient DCE focusing on BsAbs for treatment of RRMM should include attributes related to mode of administration, dosing schedule, survival, response rate, serious side effects like ICANS and grade 3-4 infections, and quality of life-related side effects, such as loss of taste and skin-related side effects.