Survey Reveals Real-World Bridging Therapy Practices for CAR T-Cell Therapy in Multiple Myeloma
A multinational survey shows bridging therapy is used for over 85% of multiple myeloma patients awaiting CAR T-cell therapy, with proteasome inhibitors being the most common approach. Most centers lack standardized protocols and typically bridge patients for 1-2 months, with regimen selection driven primarily by prior therapy history and disease burden.
A multinational survey of 48 centers across 11 countries reveals that bridging therapy is common but highly individualized for multiple myeloma patients awaiting CAR T-cell therapy, with most centers bridging over 85% of their patients. The survey found limited protocol standardization, with 40% of centers reporting "not standardized at all" and only 4% selecting "very standardized" on a 5-point scale. Most centers described a typical bridging duration of 1–2 months, with 81% beginning immediately within one week after apheresis.
Proteasome inhibitors were the most frequently reported bridging option at 90%, followed by immunomodulatory drugs at 85%. Chemotherapy-based regimens and bispecific antibodies were each selected by 75%, while monoclonal antibodies were used by 69% and radiation by 63%. Importantly, all centers with experience using bispecific antibodies responded that these agents should be standard for most patients, showing superior efficacy specifically for bridging.
Regimen selection was driven primarily by prior therapy and refractory patterns at 92%, followed by baseline disease burden at 77% and extramedullary disease at 69%. Less emphasis was placed on cytogenetic risk at 31%, biochemical markers at 21%, and bone marrow involvement at 21%. During bridging, monitoring relied predominantly on free light chains at 96% and serum M-protein at 94%, with frequent use of imaging at 75% and clinical symptom assessment at 67%.
Most centers would still proceed to CAR-T after progression on bridging, with more than 95% continuing toward infusion. About four in ten centers opt to pause and reassess timing when progression occurs. Decision-making during bridging most often reflected achievement of targeted serum marker reductions at 75%, signals of rapid disease progression at 73%, treatment-related toxicities at 54%, imaging improvements at 52%, and less commonly reductions in marrow plasma cell burden at 21%.
Product availability was uneven across centers, with cilta-cel reported by 60% and ide-cel by 38%. A notable 16% indicated no access outside clinical trials, underscoring an access bottleneck that persists across parts of Europe. Most centers infused 10–30 multiple myeloma patients per year, and 65% were not currently enrolled in trials or registries focused on bridging therapy.
The heterogeneity of approaches, the paucity of multiple myeloma-specific prospective data, and evolving indications for earlier referral all argue for consensus-building and practice-informing evidence. The survey was conducted to characterize current practice patterns, rationales for regimen selection, and perceived risks and benefits of bridging prior to CAR-T for multiple myeloma.