Between Real-World Decisions: Selecting GPRC5D vs BCMA-Targeting Bispecific
Panelists discuss how clinical decision-making between GPRC5D and BCMA-targeting bispecific antibodies involves considering prior treatment history, target switching strategies, and patient-specific factors, with Karen explaining her preference for talquetamab's targeted approach that spares healthy cells, subcutaneous administration convenience, and the advantage of switching to a different antigen target after previous BCMA therapy.
Patient Decision-Making Factors
Karen's decision to pursue talquetamab treatment was influenced by several key factors beyond medical recommendations. Having just completed an unsuccessful Pomalidomide regimen, she was encouraged that talquetamab was no longer in clinical trial phase, meaning there was established data from other patients showing proven results. Her willingness to try new treatments stems from a positive outlook and recognition that previous patients' participation in clinical trials made her current options possible. Karen emphasizes the convenience of subcutaneous administration over intravenous infusions, which significantly reduces time spent at the hospital. The transition from every-other-week to once-monthly dosing has been particularly beneficial given her 2-hour travel distance, allowing her to maintain a normal life with minimal medical appointments.
Clinical Decision-Making Strategy
The physician's treatment selection was strategically based on Karen's prior exposure to BCMA-targeted bispecific antibody therapy. Rather than retreating the same target antigen, the decision was made to pursue a different mechanism by targeting GPRC5D with talquetamab. This approach proved successful partly due to the significant time gap between her first bispecific treatment in 2021 and starting talquetamab, allowing for target switching. Clinical trial data suggests that patients transitioning directly between different bispecific antibodies typically respond for only 4-5 months, but Karen's extended treatment-free interval likely contributed to her sustained 19-month response. This strategic sequencing demonstrates the importance of target diversification in heavily pretreated patients.
Treatment Advantages and Targeted Approach
A particularly appealing aspect of bispecific antibody therapy for Karen was its targeted mechanism of action. Unlike traditional chemotherapy that destroys both healthy and cancerous cells throughout the body, bispecific antibodies specifically direct immune cells to attack only cancer cells. This precision approach significantly reduces recovery time and systemic toxicity, allowing patients to maintain better quality of life during treatment. This targeted therapy represents a major advancement for patients like Karen, who has undergone 19 different treatment lines since her 2009 diagnosis, multiple transplants, and numerous therapies over more than a decade of disease management.
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