Short-Term Costs Associated with Outpatient Use of Axicabtagene Ciloleucel in Second-Line Relapsed/Refractory Large B-Cell Lymphoma Based on Zuma-24 Clinical Trial
Authors: Oluwole Olalekan O. , Wade Sally W. , Smith Nathaniel J , Spousta Tomas , Kim Jenny J. , Zheng Yan , Best Timothy , Ray Markqayne , Leslie Lori A. 
Published: December 2024

INTRODUCTION
Axicabtagene ciloleucel (axi-cel) is an autologous chimeric antigen receptor T-cell (CAR T) therapy approved for adults with relapsed/refractory (R/R) large B-cell lymphoma (LBCL), based on significant clinical benefit demonstrated in second line (ZUMA-7) and third or later lines (ZUMA-1) of therapy. Recently, the ZUMA-24 study evaluated the safety and efficacy of outpatient administration of axi-cel with prophylactic corticosteroid use and early adverse event (AE) intervention in patients with R/R LBCL after ≥1 prior line of therapy (Leslie et al, 2024). With these strategies, in ZUMA-24 to date, no patients have experienced grade 3+ cytokine release syndrome and 3 of 30 total infused patients had ongoing neurologic events at data cutoff (median follow-up 7 months). Numerically lower intensive care unit (ICU) admission rates and median duration of hospitalizations than in previous R/R LBCL axi-cel trials were reported. The objective of the analysis presented here was to evaluate the short-term costs associated with outpatient use of axi-cel in 2L+ LBCL based on the results of the ZUMA-24 clinical trial.

METHODS
A cost calculator was developed in Microsoft Excel to evaluate the short-term cost of outpatient use of axi-cel in 2L+ LBCL patients based on a median follow-up of 7 months from the ZUMA-24 trial. Healthcare resource utilization (HRU) data were sourced from the ZUMA-24 clinical trial. HRU including infusion-related treatments (i.e., conditioning chemotherapy and leukapheresis), laboratory tests, diagnostic and imaging procedures, hospitalizations (including both standard room and ICU for patients admitted to hospital after axi-cel infusion), and supportive medications (tocilizumab and prophylactic steroids) were included in the analysis. Analyses are underway to add cost of bridging therapies. The proportions of patients utilizing each healthcare resource were combined with the average number of units per healthcare resource utilized in the trial. Unit costs for HRU were sourced from the 2024 Centers for Medicare and Medicaid Services fees schedules, RedBook, the Healthcare Cost and Utilization Project, and published literature; costs are presented in 2024 USD. It was assumed that costs of adverse event management (beyond steroid and tocilizumab use) would be included as part of the inpatient hospitalization costs. Drug acquisition costs (i.e., cost of axi-cel) were not included in the analysis.

RESULTS
The estimated mean short-term cost of outpatient use of axi-cel in 2L+ LBCL was $71,377 per patient, including $1,963 in leukapheresis and conditioning chemotherapy costs and post-infusion costs of $28 in laboratory testing, $1,397 in diagnostic and imaging, $52,299 in inpatient hospitalization, and $15,682 in supportive medication. Costs for inpatient hospitalization were driven by all-cause hospital stays for the 93% of study patients who had inpatient care (mean length of stay per admission of 8.1 days) and 13% of patients requiring ICU (mean length of stay per admission of 6.0 days). The most common reason for first inpatient hospitalization was Grade 1 CRS (60%).

CONCLUSION
As previously reported, in the ZUMA-24 study, axi-cel use in the outpatient setting with prophylactic steroids and early intervention strategies was associated with efficacy similar to prior clinical trials. Using ZUMA-24 HRU data (including ICU days and inpatient hospital days), this costing analysis reports manageable short-term cost with axi-cel administered in the outpatient setting for 2L+ LBCL patients.