CRS, Neurologic Events Increase Costs, Health Care Utilization in Patients Receiving CAR T-Cell Therapy for Multiple Myeloma

Idecabtagene vicleucel (ide-cel) is a chimeric antigen receptor (CAR) T-cell therapy in development for patients with relapsed/refractory multiple myeloma (MM) who are triple-class exposed to immunomodulatory drugs, proteasome inhibitors, and anti-CD38 antibodies. Researchers found that among patients with relapsed/refractory MM who were treated with ide-cel in the KarMMA clinical trial, increased health care resource utilization and costs were associated with higher-grade toxicities, including cytokine release syndrome (CRS) and neurologic events. The results were presented at the 2020 ASH Annual Meeting.

Researchers assessed the KarMMa clinical trial database and applied a micro-costing methodology to estimate costs. Health care resource utilization included hospital length of stay (LOS), diagnostics (e.g., lab work and imaging), procedures (dialysis and intubation), and medications. Researchers only included health care resource utilization that was consistent with trial management guidelines. Unit costs were applied to each health care resource utilization from the U.S. provider perspective and adjusted to 2020 U.S. dollars.

Cost per inpatient day was estimated from Healthcare Cost and Utilization Project databases, and cost per intensive care unit (ICU) day was sourced from the literature. Medication costs were obtained from REDBOOK™using wholesale acquisition costs and were uniformly applied across sites of care. Diagnostic, transfusion, and procedure costs were taken from the Centers for Medicare & Medicaid Services lab fee schedule, physician fee schedule, or outpatient prospective payment system.

Among 128 patients treated with ide-cel in the KarMMa trial, 107 (83.6%) experienced CRS with or without neurologic events; 84 patients (65.6%) had CRS only, and 23 (18.0%) had both CRS and neurologic events. No patients had isolated neurologic events. Most cases (n=96/107; 89.7%) of CRS and/or neurologic events were grade ≤2. No patients experienced both grade ≥3 CRS and neurologic events.

CRS occurred before or on the same day as neurologic events in most patients experiencing both adverse events (AEs; 95.6%). Among the 15 patients in whom CRS occurred first, neurologic events developed a median of two days after CRS onset.

Of patients with CRS with or without neurologic events, 67 (62.6%) received tocilizumab, 26 (24.3%) received both tocilizumab and corticosteroids, seven (6.5%) received vasopressors, and 19 (17.8%) were admitted to the ICU for AE management. Five patients (4.7%) required dialysis or intubation; all had grade ≥3 events.

Median total LOS ranged from six to 30 days, with inpatient stay accounting for the majority. Median costs ranged from $18,497 to $23,285 for grade ≤2 CRS; from $33,183 for CRS grade ≤2 with neurologic events; and from $60,588 to $121,535 for grade ≥3 CRS with or without neurologic events.

Costs were mostly related to hospitalization—particularly inpatient and ICU LOS, which ranged from $15,252 to $106,346. Median overall costs for patients with grade ≤2 CRS with or without neurologic events were $21,693 versus $99,894 for grade ≥3 CRS with or without neurologic events.

“More severe CRS or neurologic events was associated with increased health care resource utilization and management costs, particularly grade ≤2 versus grade ≥3,” the researchers concluded.

Reference

Hari P, Nguyen A, McGarvey N, et al. Healthcare Resource Utilization and Cost of Cytokine Release Syndrome and Neurotoxicity in Patients with Relapsed and Refractory Multiple Myeloma Receiving the BCMA-Directed Chimeric Antigen Receptor T Cell Therapy Idecabtagene Vicleucel (ide-cel, bb2121) in the KarMMa Trial. Abstract 1598. Presented at the 62nd American Society of Hematology Annual Meeting & Exposition, Dec. 2-11, 2020.