Treatment-Free Interval: A Novel Approach to Assessing Real-World Treatment Effectiveness and Economic Impact Among Patients with Irritable Bowel Syndrome with Diarrhea

Brian E Lacy; Patrick Gagnon-Sanschagrin; Zeev Heimanson; Rebecca Bungay; Remi Bellefleur; Annie Guérin; Brock Bumpass; Danellys Borroto; George Joseph; Ankur A Dashputre

doi:10.1007/s12325-024-02832-x

Treatment-Free Interval: A Novel Approach to Assessing Real-World Treatment Effectiveness and Economic Impact Among Patients with Irritable Bowel Syndrome with Diarrhea

Adv Ther. 2024 Apr 15. doi: 10.1007/s12325-024-02832-x. Online ahead of print.

Authors

Affiliations

¹ Division of Gastroenterology, Mayo Clinic, Jacksonville, FL, USA.
² Analysis Group, Inc., 1190 Avenue Des Canadiens-de-Montréal, Suite 1500, Montréal, QC, H3B 0G7, Canada.
³ Salix Pharmaceuticals, Bridgewater Township, NJ, USA.
⁴ Analysis Group, Inc., 1190 Avenue Des Canadiens-de-Montréal, Suite 1500, Montréal, QC, H3B 0G7, Canada. Rebecca.Bungay@analysisgroup.com.
⁵ Bausch Health, Bridgewater Township, NJ, USA.
⁶ BioNTech US Inc., 40 Erie St, Cambridge, MA, 02139, USA.

PMID: 38619720
DOI: 10.1007/s12325-024-02832-x

Abstract

Introduction: Objective assessment of treatment effectiveness using real-world claims data is challenging. This study assessed treatment-free intervals (TFI) as a proxy for treatment effectiveness, and all-cause healthcare costs among adult patients with irritable bowel syndrome with diarrhea (IBS-D) treated with rifaximin or eluxadoline in the USA.

Methods: Adult patients (18-64 years) with IBS-D and ≥ 1 rifaximin or eluxadoline prescription were identified in the IQVIA PharMetrics^® Plus database (10/01/2015-12/31/2021) and classified into two mutually exclusive cohorts (i.e., rifaximin and eluxadoline). Index date was the date of rifaximin or eluxadoline initiation. Entropy-balanced baseline characteristics, TFI (periods of ≥ 30 consecutive days without IBS-D treatment), and healthcare costs were reported. Healthcare costs were compared between cohorts using mean cost differences.

Results: There were 7094 and 2161 patients in the rifaximin and eluxadoline cohorts, respectively. After balancing, baseline characteristics (mean age 44.1 years; female 72.4%) were similar between cohorts. A higher proportion of patients treated with rifaximin achieved a TFI of ≥ 30 days (76.2% vs. 66.7%), ≥ 60 days (67.0% vs. 47.0%), ≥ 90 days (61.0% vs. 38.7%), ≥ 180 days (51.7% vs. 31.0%), and ≥ 240 days (47.7% vs. 27.9%) compared to eluxadoline. Among patients with a TFI ≥ 30 days, mean TFI durations were 8.3 and 6.0 months for the rifaximin and eluxadoline cohorts. Mean all-cause healthcare costs were lower for rifaximin vs. eluxadoline ($18,316 vs. $23,437; p = 0.008), primarily driven by pharmacy costs ($7348 vs. $10,250; p < 0.001). In a simulated health plan of one million commercially insured lives, initiating 50% of patients on rifaximin instead of eluxadoline resulted in total cost savings of $2.1 million per year or $0.18 per-member-per-month.

Conclusions: This real-world study suggests that TFI is a meaningful surrogate measure of treatment effectiveness in IBS-D. Patients treated with rifaximin had longer treatment-free periods and lower healthcare costs than patients treated with eluxadoline.

Keywords: Eluxadoline; Irritable bowel syndrome; Real-world; Rifaximin; Treatment-free interval.