Chimeric antigen receptor (CAR) modified T cell therapies targeting BCMA have displayed impressive activity in the treatment of multiple myeloma. There are currently two FDA licensed products, ciltacabtagene autoleucel and idecabtagene vicleucel, for treating relapsed and refractory disease. Although correlative analyses performed by product manufacturers have been reported in clinical trials, there are limited options for reliable BCMA CAR T detection assays for physicians and researchers looking to explore it as a biomarker for clinical outcome. Given the known association of CAR T cell expansion kinetics with toxicity and response, being able to quantify BCMA CAR T cells routinely and accurately in the blood of patients can serve as a valuable asset. Here, we optimized an accurate and sensitive flow cytometry test using a PE‐conjugated soluble BCMA protein, with a lower limit of quantitation of 0.19% of CD3+ T cells, suitable for use as a routine assay for monitoring the frequency of BCMA CAR T cells in the blood of patients receiving either ciltacabtagene autoleucel or idecabtagene vicleucel.

中文翻译：

---

优化流式细胞术检测外周血中 B 细胞成熟抗原靶向 CAR 的常规监测

针对 BCMA 的嵌合抗原受体 (CAR) 修饰 T 细胞疗法在治疗多发性骨髓瘤中表现出令人印象深刻的活性。目前有两种FDA许可的产品，ciltacabtagene autoleucel和idecabtagene vicleucel，用于治疗复发和难治性疾病。尽管产品制造商进行的相关分析已在临床试验中得到报告，但对于希望探索其作为临床结果生物标志物的医生和研究人员来说，可靠的 BCMA CAR T 检测分析的选择有限。鉴于 CAR T 细胞扩增动力学与毒性和反应之间的已知关联，能够常规、准确地量化患者血液中的 BCMA CAR T 细胞可以作为一项宝贵的资产。在这里，我们使用 PE 缀合的可溶性 BCMA 蛋白优化了准确、灵敏的流式细胞术测试，定量下限为 0.19% CD3+ T 细胞，适合用作监测 BCMA CAR T 细胞频率的常规检测接受 ciltacabtagene autoleucel 或 idecabtagene vicleucel 治疗的患者的血液中。