COSTS PER RESPONSE AND REMISSION OF MIRIKIZUMAB VS RISANKIZUMAB IN THE MAINTENANCE PHASE FOR MODERATELY TO SEVERELY ACTIVE CROHN’S DISEASE TREATMENT IN THE UNITED STATES

Abstract BACKGROUND Mirikizumab (MIRI) and risankizumab (RZB) are interleukin-23p19 inhibitors effective in treating moderately to severely active Crohn’s disease (CD). Both the clinical and economic value of a therapy should be demonstrated. We estimated the cost per response and remission of MIRI and RZB among patients with CD during the maintenance phase in the United States. METHODS In VIVID-1 and FORTIFY Phase-3 studies, patients received subcutaneous MIRI (300mg every 4 weeks) or RZB (360mg every 8 weeks) during the maintenance phase, respectively. This analysis includes patients who responded to MIRI or RZB during the induction phase and continued the same treatment during the maintenance phase. In both studies, clinical response was defined as at least a 30% decrease in stool frequency and/or abdominal pain, and neither score worse than baseline, while clinical remission was defined as a Crohn’s Disease Activity Index (CDAI) score less than 150 at the end of the maintenance phase. The cost per response and cost per remission were estimated using the proportion of patients achieving clinical response and clinical remission. Cost per response or cost per remission was calculated by multiplying the drug acquisition cost per dose with the total number of doses administered during the maintenance phase and dividing this product by the clinical response rate or clinical remission rate. RESULTS Data were included from 403 and 141 patients enrolled in VIVID-1 and FORTIFY, respectively. The mean age (SD) of patients was 36.0 (13.2) years in VIVID-1 and 37.0 (12.8) years in FORTIFY. More than 57.0% of patients enrolled in these studies were male (VIVID-1: 57.6%, FORTIFY: 57.4%). The clinical remission rate (65.3% vs 52.5%) and clinical response rate (81.9% vs 59.6%) were numerically higher for MIRI vs RZB at the end of the maintenance phase. The maintenance cost per remission was numerically lower for MIRI than RZB ($217K vs $298K). The maintenance cost per response also was numerically lower for MIRI than RZB ($173K vs $263K). CONCLUSIONS Our findings indicate that the maintenance cost per remission and maintenance cost per response were substantially lower for MIRI than for RZB. Additionally, MIRI had a higher response rate than RZB at the end of the maintenance phase. This analysis offers valuable insights into the prospective economic impact of these treatments to assist formulary and reimbursement decisions for CD.