Post-infusion Costs Associated with Idecabtagene Vicleucel Treatment for Patients with Relapsed/Refractory Multiple Myeloma in the KarMMa Trial.

Introduction: Patients with triple-class exposed relapsed/refractory multiple myeloma (RRMM) have poor outcomes with substantial healthcare costs. Idecabtagene vicleucel (ide-cel), a B-cell maturation antigen (BCMA)-directed chimeric antigen receptor (CAR) T cell therapy, showed deep, durable responses in patients with RRMM in the pivotal phase 2 KarMMa trial (NCT03361748). Healthcare resource utilization (HCRU) and costs were estimated for ide-cel-treated patients in the KarMMa trial.

Methods: Post-infusion costs were estimated based on HCRU data, including facility care, diagnostics, medications, and procedures. Length of stay (LOS) was extracted for inpatient and intensive care unit (ICU) care. All patients had a 14-day post-infusion inpatient stay per trial protocol. Analyses were conducted for patients treated in the United States (US), who received the ide-cel target dose of 450 × 10 CAR + T cells and assuming a 7-day inpatient stay.

Results: Overall, 128 patients received ide-cel and were included in this analysis. Mean age was 60 years, 59% were men, and 81% were white. Mean total LOS was 23.9 days. Total estimated costs over 24 months post-infusion were US$115,614 per patient, driven by facility costs (75%; $86,385). Most costs were incurred in the first month (58%; $67,259). The scenario analysis assuming a 7-day inpatient stay showed estimated 24-month costs of $92,294. For the 54 (42%) patients who received ide-cel high dose, total costs over 24 months were $113,298 per patient.

Conclusions: Extrapolation of costs based on HCRU data from patients receiving single-infusion of ide-cel in the KarMMa trial showed substantially reduced HCRU and costs over 2 years after initial treatment. Most costs were incurred during the first month after ide-cel infusion, likely attributable to the 14-day inpatient stay required by the trial protocol. These findings suggest a nominal, incremental monthly cost of care immediately after treatment, which may be lower in routine clinical practice.