Intensity of Cyclophosphamide-Based Bridging Therapy Before Chimeric Antigen Receptor T Cell Therapy in Myeloma

• Published in: Transplantation and cellular therapy 2023-08, Vol.29 (8), p.504.e1-504.e7
• Main Authors: Zafar, Aneeqa, Huang, Chiung-Yu, Lo, Mimi, Arora, Shagun, Chung, Alfred, Wong, Sandy W., Wolf, Jeffrey, Martin, Thomas G., Shah, Nina, Banerjee, Rahul
• Format: Article
• Language: English
• Subjects: BCMA; Bridging therapy; CAR-T; Cyclophosphamide; Multiple myeloma
• ISSN: 2666-6367; 2666-6367
• DOI: 10.1016/j.jtct.2023.05.016

•Myeloma progression is common during pre-chimeric antigen receptor T cell bridging therapy (BT).•Hyperfractionated versus weekly BT regimens were used in comparable populations.•Hyperfractionated BT regimens were still associated with poorer survival. Patients receiving autologous chimeric antigen receptor T cell (CAR-T) therapy for multiple myeloma (MM) may require bridging therapy (BT) before CAR-T infusion to maintain some level of disease control. Alkylators, such as cyclophosphamide (Cy), are often used in regimens, either in high-intensity regimens, such as modified hyperCVAD (cyclophosphamide, vincristine, doxorubicin, and dexamethasone), or once-weekly regimens, such as KCd (carfilzomib, cyclophosphamide, and dexamethasone). However, there is no consensus regarding the optimal BT alkylator dose intensity in MM. We performed a single-center analysis of all instances of BT before planned autologous CAR-T for MM during a 5-year period ending in April 2022. We classified bridging regimens into 3 cohorts: (1) hyperfractionated Cy (HyperCy) with inpatient Cy every 12 to 24 hours or as a continuous i.v. infusion; (2) less intensive Cy dosing (WeeklyCy), such as KCd; and (3) NonCy, in which no alkylators were used in BT. Demographic, disease-related, and treatment-related characteristics were collected for all patients. The 3 BT cohorts were compared using the Fisher exact test, Kruskal-Wallis test, and log-rank test, as appropriate. We identified 70 discrete BT instances among 64 unique patients, including 29 (41%) with HyperCy, 23 (33%) with WeeklyCy, and 18 (26%) with NonCy. The median total Cy dosing during BT in the 3 groups were 2100 mg/m2, 615 mg/m2, and 0 mg/m2, respectively. Age, number of prior lines of therapy, triple-class refractory status, presence of high-risk cytogenetics, extramedullary disease, bone marrow plasma cell burden, involved free light chain (iFLC) kinetics before collection, and other measures of disease aggressiveness were comparable across the 3 cohorts. iFLC levels rose ≥25% and ≥100 mg/L during BT (approximating progressive disease) in comparable proportions (P = .25) among the cohorts: 52% for HyperCy, 39% for WeeklyCy, and 28% for NonCy. All BT instances without subsequent CAR-T were due to manufacturing failures. Among 61 instances of BT followed by CAR-T, vein-to-vein times were slightly longer (P = .03) with HyperCy (45 days) compared with WeeklyCy (39 days) and NonCy (46.5 days). Neutrophil recovery times were simila