S990 Cost Analysis of Inpatient Originator Infliximab (Remicade) vs Biosimilar Infliximab (Renflexis) for Acute Severe Ulcerative Colitis: A Cost Minimization Study

Abstract

Introduction: Infliximab (IFX) is a standard, inpatient salvage therapy for treatment of refractory acute severe ulcerative colitis (ASUC). Inpatient IFX, as the originator Remicade, significantly increases colectomy-free survival in this population. The biosimilar Renflexis offers reduced cost as compared to Remicade. We performed a cost-minimization analysis to compare costs with Remicade and Renflexis for inpatient treatment of ASUC. Methods: Retrospective clinical and financial data was obtained from 34 inpatients with refractory ASUC who had received treatment with Renflexis (17) or Remicade (17) between 2019-2021. Clinical data included admission and discharge serum albumin (alb), hemoglobin (Hgb), C-reactive protein (CRP), and colectomy rate within 30 days of treatment (CR-30). Financial data included a decision support drug cost (DSDC), depicting the total cost associated with inpatient infliximab administration, and total inpatient care cost, depicting the full cost of the inpatient admission. The following equation generated a ratio (rDSDC) which represents the percentage of how much the DSDC accounts for the total inpatient care cost, after controlling for dose of infliximab and length of stay. [DSDC of IFX/Number of Units of IFX] ÷ [Total Inpatient Cost of Care/Length of Stay in Days] Mean and unpaired T-test (parametric test) were used for clinical data analysis. Median and non-parametric test called Wilcoxon ranked sum test were used for financial data analysis. (Figure) Results: No differences were found in baseline or discharge clinical parameters including baseline CRP (P=0.64), alb (P=0.1294), Hgb (P=0.5051), discharge CRP (P=0.1244), alb (P=0.8728), Hgb (P=0.4875), or CR-30 (23.53% vs. 29.41%, p=0.6975) (Table). Median rDSDC was 0.387 vs. 0.241 in the Remicade vs. Renflexis groups, respectively (Figure, p = 0.0025) representing a difference of ∼14%. Conclusion: A 14% reduction in cost attributed to DSDC was found using Renflexis, as compared to Remicade, treating inpatient ASUC. Our calculation included median decision support drug cost as a percentage of the total inpatient care cost, controlling for dose of infliximab and length of stay. Such a reduced cost structure promotes use of Renflexis for ASUC inpatients, which may result in improved utilization, improved health outcomes, and reduced costs for patients and hospitals. Further studies may confirm non-inferiority and demonstrate cost-effectiveness.Figure 1 Table 1. - Remicade (n=17) Renflexis (n=17) P- Value Admission C-reactive protein 117.73 mg/L 103.98 mg/L 0.6400 Albumin 2.74 g/dL 2.45 g/dL 0.1294 Hgb 11.34 g/dL 10.82 g/dL 0.5051 Discharge C-reactive protein 17.18 mg/L 30.99 mg/L 0.1244 Albumin 2.36 g/dL 2.4 g/dL 0.8728 Hgb 10.11 g/dL 9.71 g/dL 0.4875 Colectomy rate within 30 days of Treatment 23.53% (n=4) 29.41% (n=5) 0.6975 Median ratio of decision support drug cost to total inpatient cost of care after accounting for number of units of IFX administered and length of inpatient stay in days 0.387 0.241 0.0025