Facility-Related Healthcare Resource Utilization (HCRU) for Patients Treated with Idecabtagene Vicleucel (Ide-Cel, bb2121) in a Real-World (RW) Setting: A Single-Center Experience
Authors: Peres Lauren C. , Patwardhan Pallavi , Huggar David , De Avila Gabriel , Oswald Laura B. , Grajales-Cruz Ariel F. , Blue Brandon , Abraham Miranda Julieta , Reid Kayla , Liu Hien , Nishihori Taiga , Shain Kenneth H. , Baz Rachid , Alsina Melissa , Castaneda Omar , Locke Frederick L. , Freeman Ciara Louise L. , Tiwana Simrandeep , Botros Afraim , Hansen Doris K. 
Published: December 2023

Introduction: Ide-cel is a B-cell maturation antigen (BCMA)-directed chimeric antigen receptor (CAR) T cell therapy associated with deep and durable responses and improved quality of life among triple-class exposed (TCE) patients with relapsed/refractory multiple myeloma (RRMM) (Munshi NC, et al. N Engl J Med 2021;384:705-716; Delforge M, et al. Blood Adv 2022;6:1309-1318). An analysis of 2-year post-infusion facility-related HCRU (fHCRU) associated with ide-cel treatment in the phase 2 KarMMa clinical trial (NCT03361748) found that most facility costs were incurred within the first month following infusion where the median hospital length of stay (LOS) was 19.5 days which included the clinical trial requirement of hospitalization for monitoring and 20% of the patients had intensive care unit (ICU) stays (McGarvey N, et al. Blood 2022;140(suppl 1):10947-10948). In this study, we estimated fHCRU and associated costs for patients with TCE RRMM receiving ide-cel in RW clinical practice.

Methods: This was a retrospective chart review of adults (≥ 18 years of age) with TCE RRMM who received an ide-cel infusion in RW clinical practice at H. Lee Moffitt Cancer Center, Tampa, FL, USA from May 25, 2021 to December 27, 2022. Costs were estimated using a two-step micro-costing methodology. Unit costs were sourced from public databases or literature, adjusted to 2022 US dollars and then applied to fHCRU. Patient characteristics and fHCRU were characterized using descriptive statistics, and the distribution of fHCRU was examined by key characteristics using Wilcoxon rank sum or chi-square tests. fHCRU and total facility costs included LOS and ICU stays obtained from the National Inpatient Sample and peer-reviewed literature, inflated to 2022 US dollars (USD); LOS days included readmissions. Unit costs (2022) were applied to post-index hospitalizations at the rate of USD 3001.80 per inpatient day and USD 9351.52 per ICU day.

Results: A total of 109 patients were included. Median age was 65 years, 61% were male, 67% were non-Hispanic White, 14% had extramedullary disease, and 28% had high-risk cytogenetics. Patients had a median (range) of 6.0 (4.0-13.0) prior lines of MM therapy; 75% and 30% of patients were triple- and penta-class refractory, respectively. Median (range) follow-up was 9.2 months (0.2-24.4). Any grade cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in 82% and 17% of patients, respectively. Moderate or worse CRS and ICANS (grade ≥ 2) occurred in 19% and 10% of patients, respectively. A total of 71% of patients received tocilizumab, 34% received steroids, and 2% received anakinra for toxicity management. Only 26% of patients would have been eligible for the KarMMa trial. In the overall cohort, median LOS was 8.0 days (interquartile range [IQR], 7.0-10.0) and total median hospital costs were USD 24,014 (IQR, USD 21,013-30,018). Five (5%) patients had an ICU stay (median 8.0 days; IQR, 8.0-12.0) with total median costs of USD 76,252 (IQR, USD 76,252-114,378). fHCRU was comparable when analyzed by extramedullary disease, high-risk cytogenetics, penta-class refractory status, age at infusion (&lt; 65 vs ≥ 65 years), and KarMMa clinical trial eligibility criteria ( P &gt; 0.05). LOS and total costs were significantly lower among those with grade &lt; 2 versus grade ≥ 2 CRS (both P &lt; 0.05) or ICANS (both P &lt; 0.01). Patients with more severe toxicity (grade ≥ 2) had a longer median LOS (CRS: 9 vs 8 days, P = 0.017; ICANS: 14 vs 8 days, P = 0.0026, respectively), were more likely to have an ICU stay (CRS: 24% vs 0%, P &lt; 0.001; ICANS: 36% vs 1%, P &lt; 0.001, respectively), and had higher median hospital costs (CRS: USD 27,016 vs USD 24,014, P = 0.0069; ICANS: USD 51,031 vs USD 24,014, P = 0.002, respectively) than patients with less severe toxicity (grade &lt; 2) (Figure).

Conclusion: This is the first study to characterize fHCRU and associated costs for patients with TCE RRMM who received ide-cel in a RW single-center practice. Median LOS was only 8 days and few patients (5%) had an ICU stay. fHCRU and associated costs were higher among patients who experienced moderate or worse CRS and neurologic toxicity. A limitation of this study is that fHCRU does not consider drug costs, including that of ide-cel. Additional studies with larger sample sizes and detailed cost analyses are needed to further quantify RW HCRU and pre-infusion and post-infusion costs in this patient population.