Health Care Resource Utilization (HCRU) and Cost of Management of Cytokine Release Syndrome (CRS) and Neurological Events (NEs) in Patients with R/R CLL/SLL Receiving Lisocabtagene Maraleucel (liso-cel) Treatment in the TRANSCEND CLL 004 Study

Background:Liso-cel is an autologous, CD19-directed, 4-1BB CAR T cell product administered at equal target doses of CD8 ⁺ and CD4 ⁺ CAR ⁺ T cells, which is currently being evaluated for treatment of patients with R/R CLL/SLL in the TRANSCEND CLL 004 study (NCT03331198). Initial study results suggested that a single infusion induced CRs or remission in patients with R/R CLL/SLL and had a manageable safety profile, with low to moderate incidence of severe CRS and NEs (Siddiqi T, et al. Lancet 2023). While the clinical consequences of CRS/NEs associated with CAR T cell therapies are well understood, limited data are available on the cost of management of these AEs. This analysis evaluated HCRU and estimated costs of managing CRS/NEs by grade in patients with R/R CLL/SLL who received liso-cel treatment in TRANSCEND CLL 004.

Methods: Case report forms were analyzed from the trial database, capturing patient-level HCRU related to the management of CRS/NEs. Only patients that received liso-cel at a dose level of 100 × 10 ⁶ CAR ⁺ T cells (dose level 2 [DL2]) and subsequently experienced treatment-emergent CRS and/or NEs were included in this study. Treatment-emergent AEs were defined as those initiated within a 90-day period of liso-cel administration. Costs for management of CRS/NEs were estimated using microcosting methodology. Relevant HCRU observed from the day of AE onset through resolution that was associated with the management of CRS/NEs per protocol management guidelines was identified; unit costs sourced from public databases were applied to each HCRU. Included HCRU categories were: facility (standard inpatient admission, ICU stay), diagnostics (laboratory, imaging), medications (tocilizumab, corticosteroids, vasopressors), and procedures (dialysis, intubation). Cost analyses were conducted from the United States (US) health care system perspective and adjusted to 2023 US dollars. Unit costs were obtained from the US Centers for Medicare & Medicaid Services Hospital Outpatient Prospective Payment System, laboratory and physician fee schedules, IBM ® Micromedex ® RED BOOK ®, and literature. Descriptive statistical analyses stratified by AE severity grade and type of AE experienced were performed.

Results: Ninety-four of 108 (87%) patients who received liso-cel at DL2 experienced CRS and/or NEs; 68 (72%) were grade ≤ 2 and 26 (28%) were grade ≥ 3. Overall, 44 (47%) patients had CRS only, 1 (1%) had NEs only, and 49 (52%) experienced both CRS and NEs. The study sample had a mean (standard deviation) age of 64.5 y (7.9) and were predominantly male (69%), White (84%), and non-Hispanic or Latino (90%). HCRU and total length of stay (LOS; the sum of inpatient and ICU stay days) are shown in the Table. All patients had an inpatient stay. ICU admissions only occurred among patients who experienced both CRS and NEs (10/49 [20%]) and were more common among patients with grade ≥ 3 (29%) compared with grade ≤ 2 (12%) AEs. Among patients who had an ICU admission, the median duration of an ICU stay was 5 days. Median total LOS increased with increasing AE severity for patients who had CRS only (grade 1, 5 days; grade 2, 9 days; grade 3, 15 days) and for patients who experienced both CRS and NEs (grade ≤ 2, 12 days; grade ≥ 3, 15 days). Overall, 68% and 62% of patients received tocilizumab and corticosteroids, respectively. Patients with grade ≥ 3 CRS and/or NEs had higher rates of utilization of medications, diagnostics, and procedures than those with grade ≤ 2 (Table). Additionally, patients who experienced both CRS and NEs had higher rates of utilization across all HCRU categories compared with those who experienced CRS or NEs only (Table). Estimated median management costs for CRS or NEs ranged from $14,638 (CRS only grade 1) to $46,802 (experienced both CRS and NEs with CRS or NEs grade ≥ 3) (Figure). Facility-related costs were the largest contributor to median total costs.

Conclusions: While most patients treated with liso-cel at DL2 in TRANSCEND CLL 004 experienced CRS and/or NEs, they were primarily of low severity. HCRU and associated costs for management of CRS and/or NEs after liso-cel infusion increased with AE severity.Although everyone in this study required hospitalization, ICU admissions were rare and only observed among patients who experienced both CRS and NEs. Overall, costs of managing CRS and/or NEs were modest.