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

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.

AGA Clinical Practice Guideline on the Pharmacological Management of Irritable Bowel Syndrome With Diarrhea

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder associated with significant disease burden. This American Gastroenterological Association Guideline is intended to support practitioners in decisions about the use of medications for the pharmacological management of IBS with predominant diarrhea (IBS-D) and is an update of a prior technical review and guideline.

METHODS

The Grading of Recommendations Assessment, Development and Evaluation framework was used to assess evidence and make recommendations. The technical review panel prioritized clinical questions and outcomes according to their importance for clinicians and patients and conducted an evidence review of the following agents: eluxadoline, rifaximin, alosetron, loperamide, tricyclic antidepressants, selective serotonin reuptake inhibitors, and antispasmodics. The guideline panel reviewed the evidence and used the Evidence-to-Decision Framework to develop recommendations.

CONCLUSIONS

The panel agreed on 8 recommendations for the management of patients with IBS-D. The panel made conditional recommendations for eluxadoline, rifaximin, alosetron, (moderate certainty), loperamide (very low certainty), tricyclic antidepressants, and anstispasmodics (low certainty). The panel made a conditional recommendation against the use of selective serotonin reuptake inhibitors (low certainty).

Management of irritable bowel syndrome with diarrhea: focus on eluxadoline

OBJECTIVE

We sought to summarize current recommendations for the diagnosis of diarrhea-predominant irritable bowel syndrome (IBS-D) and describe available management options, highlighting a newer US Food and Drug Administration (FDA)-approved agent, eluxadoline.

METHODS

Literature on IBS-D was assessed up to January 2020 using PubMed, with key search terms including "IBS-D diagnosis", "IBS-D management", and "eluxadoline".

RESULTS

IBS is a common gastrointestinal disorder affecting up to 14% of US adults and is particularly prevalent in women and those aged under 50. Symptoms include abdominal pain associated with altered bowel habits (i.e. diarrhea and/or constipation subtyped based on the predominant stool pattern). As IBS-D is challenging to manage with varying symptom severity, effective treatment requires a personalized management approach. Evidence-based therapeutic options endorsed by the American Gastroenterological Association and the American College of Gastroenterology can be used to effectively guide treatment. Dietary and lifestyle modifications, including adequate hydration, reducing caffeine and alcohol intake, and increasing soluble fiber intake may lead to symptom improvement. Over-the-counter medications such as loperamide are frequently recommended and may improve stool frequency and rectal urgency; however, for the outcome of abdominal pain, mixed results have been observed. Several off-label prescription medications are useful in IBS-D management, including tricyclic antidepressants, bile acid sequestrants, and antispasmodics. Three prescription medications have been approved by the FDA for IBS-D: alosetron, eluxadoline, and rifaximin.

CONCLUSIONS

IBS-D can be effectively managed in the primary care setting in the absence of alarm features. Benefits and risks of pharmacologic interventions should be weighed during treatment selection.

Current US Food and Drug Administration-Approved Pharmacologic Therapies for the Treatment of Irritable Bowel Syndrome with Diarrhea

Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by abdominal pain and alterations in stool form and/or frequency, leading to reduced quality of life. Pharmacologic agents currently approved by the US Food and Drug Administration for treatment of IBS with diarrhea (IBS-D) in adults are the nonsystemic antibiotic rifaximin, the mixed µ- and κ-opioid receptor agonist/δ-opioid antagonist eluxadoline, and the selective serotonin 5-HT₃ antagonist alosetron (the last of which is indicated only in women with severe IBS-D refractory to conventional therapy). Both eluxadoline and alosetron are administered as chronic daily therapies; rifaximin is given as a 2-week course of treatment with repeat courses administered as needed for symptom recurrence. Presumed mechanisms of action of rifaximin include modulation of the gut microbiota, anti-inflammatory activity, normalization of visceral hypersensitivity, and reduction in intestinal permeability. Eluxadoline targets opioid receptors in the gastrointestinal (GI) tract, resulting in decreased GI motility, fluid secretion, and visceral pain perception. Alosetron antagonizes serotonergic afferent neural signals and also slows GI motility. The efficacy and safety of these agents have been investigated in several rigorous clinical trials, and it has been demonstrated that they improve global and individual IBS symptoms. This review highlights the pivotal efficacy and safety data of the three pharmacologic agents currently indicated in the USA for the management of IBS-D in adults.Funding: Salix Pharmaceuticals.

The impact of treatment with eluxadoline on health-related quality of life among adult patients with irritable bowel syndrome with diarrhea

Purpose

Irritable bowel syndrome with diarrhea (IBS-D) significantly impacts health-related quality of life (HRQOL). This post hoc analysis of two phase III trials evaluated the effects of eluxadoline treatment on disease-specific HRQOL among patients with IBS-D.

Methods

Adult patients meeting Rome III criteria for IBS-D were randomized to oral eluxadoline (75 mg or 100 mg) or placebo twice daily in two phase III clinical trials for 52 weeks (IBS-3001) and 26 weeks (IBS-3002). The Irritable Bowel Syndrome Quality of Life (IBS-QOL) questionnaire assessed disease-specific HRQOL throughout the study. Changes from baseline to Week 26 in IBS-QOL total and subscale scores were analyzed using an analysis of covariance model. Percentages of IBS-QOL responders with ≥ 14- and 20-point changes were evaluated for IBS-QOL total and subscale scores. A longitudinal mixed-effects model was fitted to evaluate mean IBS-QOL total scores. A cumulative distribution function for change from baseline to Week 26 in IBS-QOL total score was plotted.

Results

Mean changes from baseline to Week 26 for the IBS-QOL total and all subscale scores were significantly higher for patients treated with eluxadoline (both doses) compared to placebo. A significantly greater proportion of eluxadoline-treated patients were responders compared to placebo. Mean and mixed-effects model estimated mean IBS-QOL total scores were consistently higher for eluxadoline versus placebo over 52 weeks.

Conclusions

Compared to placebo, twice-daily eluxadoline treatment significantly improved HRQOL among patients with IBS-D in two phase III trials.

Eluxadoline for the treatment of diarrhoea-predominant irritable bowel syndrome

INTRODUCTION

Irritable bowel syndrome (IBS) treatment is challenging physicians because of its multifactorial physiopathology. In particular, abdominal pain and diarrhea management lack one unique effective pharmacological remedy. Opioid receptors, present in the central nervous system (CNS) and the enteric nervous system (ENS), are involved in visceral sensitivity and gastrointestinal motility control. To date only a few opioid receptor modulators are currently in use for the treatment of IBS but with dosage limitations due to the early development of severe constipation.

AREAS COVERED

In this drug evaluation manuscript we review the irritable bowel syndrome therapeutic needs and chemistry, pharmacokinetics and -dynamics, clinical study results with the new opioid receptor ligand eluxadoline for the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D).

EXPERT OPINION

Eluxadoline shows a peculiar pharmacological profile with μ-opioid agonism and δ-opioid antagonism actions. Its efficacy over placebo for the treatment of abdominal pain and diarrhea in IBS-D has been demonstrated in short- and long-term clinical studies in humans. Its safety has been evaluated in the same studies. Interestingly, eluxadoline showed a low rate of constipation development in IBS patients in comparison with known effects of other opioid receptor modulators. Patients with a history of acute pancreatitis should not be treated with eluxadoline.

Novel Therapies in IBS-D Treatment

OPINION STATEMENT

Irritable bowel syndrome (IBS) is a common gastrointestinal disease characterized by abdominal pain and change in bowel habits. IBS diarrhea predominant (IBS-D), which is arguably the most common subset of IBS, is also associated with rectal urgency, increased frequency, abdominal bloating, and loose to watery stools. Current treatments for diarrhea include mu-opioid agonists (i.e., loperamide, lomotil) and bile acid sequestrants (i.e., cholestyramine) while treatments for abdominal pain include antispasmodics (i.e., hyoscyamine, dicyclomine) and tricyclic antidepressants (i.e., amitriptyline). There are currently 3 FDA-approved treatments for IBS-D, which have been shown to improve both abdominal pain and diarrhea. Alosetron was initially approved by FDA 2000; however, its use is now limited to women with severe IBS-D symptoms refractory to other treatment. Eluxadoline, a mixed mu-opioid agonist, and rifaximin, a broad spectrum gut specific antibiotic, were both FDA approved in 2015. Eluxadoline has been shown to relieve abdominal pain and stool consistency in appropriate candidates. While large trials already showed the efficacy of rifaximin in treating non-constipated IBS for bloating, stool consistency, and abdominal pain, the recent TARGET 3 trial demonstrates that retreatment is also effective. While these new treatments significantly expand options for patients suffering from IBS-D, there is likely to remain a need for additional safe and effective therapies.

Molecular characterization of eluxadoline as a potential ligand targeting mu-delta opioid receptor heteromers

Eluxadoline, an orally active mixed μ opioid receptor (μOR) agonist δ opioid receptor (δOR) antagonist developed for the treatment of diarrhea-predominant irritable bowel syndrome, normalizes gastrointestinal (GI) transit and defecation under conditions of novel environment stress or post-inflammatory altered GI function. Furthermore, compared to loperamide, which is used to treat non-specific diarrhea, the effects of eluxadoline on GI transit occur over a wider dosage range. However, the mechanisms of action of eluxadoline are unclear. In this study, we compared the ability of eluxadoline and loperamide to activate G-protein- and β-arrestin-mediated signaling at μOR homomers or μOR-δOR heteromers in heterologous cells. We also examined the ability of both compounds to reduce castor oil induced diarrhea in wild type (WT) and mice lacking δOR. We find that eluxadoline is more potent than loperamide in eliciting G-protein activity and β-arrestin recruitment in μOR expressing cells. However, in cells expressing μOR-δOR heteromers, the potency of eluxadoline is higher, but its maximal effect is lower than that of loperamide. Moreover, in these cells the signaling mediated by eluxadoline but not loperamide is reduced by μOR-δOR heteromer-selective antibodies. We find that in castor oil-induced diarrhea eluxadoline is more efficacious compared to loperamide in WT mice, and δOR appears to play a role in this process. Taken together these results indicate that eluxadoline behaves as a potent μOR agonist in the absence of δOR, while in the presence of δOR eluxadoline's effects are mediated through the μOR-δOR heteromer.