Effects of treatment with eluxadoline on abdominal pain in patients with IBS-D: Additional post hoc analyses of Phase 3 trials

BACKGROUND

Recurring abdominal pain is a characteristic and often unpredictable and debilitating symptom of irritable bowel syndrome with diarrhea (IBS-D). Measuring the effects of IBS-D treatments on abdominal pain remains a significant challenge in clinical trials. Here, we aimed to examine the effect of eluxadoline through various post hoc analyses.

METHODS

Data from two eluxadoline Phase 3 trials were pooled over 26 weeks, comparing eluxadoline 100 mg twice daily to placebo. Worst abdominal pain (WAP) was measured daily on a 0-10 scale. WAP responder criteria were prospectively defined as a ≥30% improvement in daily WAP score on ≥50% of days. Pairwise, two-sided Cochran-Mantel-Haenszel tests assessed treatment effects. Cumulative distribution functions were used to plot WAP response rates using variations on the response criteria.

KEY RESULTS

Of 1615 patients with IBS-D (66% female, mean age 46 years), 806 received eluxadoline and 809 received placebo; 48.3% and 44.0% were WAP responders (≥30% improvement), respectively (P value not significant). When the response threshold was increased to 50% daily WAP improvement from baseline, a significantly greater percentage of eluxadoline-treated patients versus placebo-treated patients were WAP responders (38.7% vs 32.5%, respectively; P = .009). At Week 26, average WAP changes from baseline were -3.4 and -3.0 points, respectively (P = .002).

CONCLUSIONS AND INFERENCES

Despite small effect sizes, eluxadoline demonstrated consistent and sustained improvement in WAP compared to placebo across a range of prospective and post hoc analyses. Assessing WAP response across a range of measures is important for fully understanding a treatment's efficacy.

Impact of patient and disease characteristics on the efficacy and safety of eluxadoline for IBS-D: a subgroup analysis of phase III trials

BACKGROUND

Irritable bowel syndrome with diarrhea (IBS-D) is a prevalent gastrointestinal (GI) disorder with a varied presentation, often overlapping with other GI and non-GI disorders. Eluxadoline is a locally active mixed µ- and κ-opioid receptor agonist and δ-opioid receptor antagonist approved for the treatment of IBS-D in adults. As IBS-D is a heterogeneous disease, factors such as patient demographics, symptom severity, and symptom pattern history can potentially inform treatment selection.

METHODS

Here, we report additional prospectively planned analyses of two large double-blind, placebo-controlled studies (IBS-3001 and IBS-3002) enrolling patients meeting Rome III criteria for IBS-D. Patients were randomized 1:1:1 to receive placebo or eluxadoline 75 mg or 100 mg twice daily. Efficacy (abdominal pain, stool consistency, and composite, simultaneous improvement in both) and safety were assessed for prospectively defined patient subgroups stratified by age, sex, race, presence of comorbidities, and baseline disease characteristics.

RESULTS

Across all age, sex, race, comorbidity, and disease characteristic subgroups, a greater proportion of patients were composite responders with both eluxadoline doses as compared with placebo, including patients with a history of depression or a history of gastroesophageal reflux disease. Among patients aged ⩾65 years, a greater proportion of patients receiving eluxadoline 75 mg were composite, abdominal pain, and stool consistency responders compared with those receiving 100 mg. The proportion of patients with at least one adverse event was slightly higher in patients aged ⩾65 years and also in female patients.

CONCLUSIONS

This analysis suggests that eluxadoline is effective in treating IBS-D across a range of commonly encountered patient types. In contrast to the overall population, patients aged ⩾65 years demonstrated a greater proportion of responders at the lower approved 75 mg eluxadoline dose.

Evaluation of Eluxadoline Effect on Cardiac Repolarization

This study evaluated the effects of eluxadoline, a mixed μ‐opioid receptor (OR) and κ‐OR agonist and δ‐OR antagonist, on cardiac repolarization. This evaluator‐blinded, placebo‐ and positive‐controlled, 4‐period crossover study randomized healthy men and women to single oral doses of eluxadoline (therapeutic dose 100 mg or supratherapeutic dose 1000 mg), moxifloxacin 400 mg, or placebo. QT data were corrected using individual custom correction (QTcI). The primary endpoint was the change from baseline in QTcI intervals (ΔQTcI) between eluxadoline and placebo (ΔΔQTcI). An upper bound of the 95% confidence interval around ΔΔQTcI of 10 milliseconds was considered clinically significant. Concentration–QTc data were analyzed using a repeated‐measures, mixed‐effects linear model. Sixty‐four volunteers were treated, and 58 completed the study. Assay sensitivity was demonstrated with moxifloxacin (noted by ΔΔQTcI of 11.94 milliseconds). The maximum ΔΔQTcI for eluxadoline 1000 mg was 4.10 milliseconds 1 hour postdose (1‐sided 95% upper confidence bound, 5.81 milliseconds), and for eluxadoline 100 mg was 1.20 milliseconds at 0.5 hours postdose (1‐sided 95% upper confidence bound, 2.91 milliseconds). Primary ΔΔQTcI results were confirmed using Fridericia's formula for QTc. Categorical, morphological, and concentration–QTc analyses were consistent with the primary and secondary findings. There were no significant gender effects on ΔΔQTcI values. The most common adverse events were contact dermatitis and nausea (12.5% each) and dizziness (10.9%); adverse events were more frequent in the eluxadoline 1000 mg group. In conclusion, eluxadoline, at therapeutic or supratherapeutic doses, did not significantly prolong QT intervals, and was safe and generally well tolerated in this study population.

Radar plots: A novel modality for displaying disparate data on the efficacy of eluxadoline for the treatment of irritable bowel syndrome with diarrhea

BACKGROUND

Patients with irritable bowel syndrome with diarrhea (IBS-D) experience a range of abdominal and bowel symptoms; successful management requires alleviation of this constellation of symptoms. Eluxadoline, a locally active mixed μ- and κ-opioid receptor agonist and δ-opioid receptor antagonist, is approved for the treatment of IBS-D in adults based on the results of 2 Phase 3 studies. Radar plots can facilitate comprehensive, visual evaluation of diverse but interrelated efficacy endpoints.

METHODS

Two double-blind, placebo-controlled, Phase 3 trials (IBS-3001 and IBS-3002) randomized patients meeting Rome III criteria for IBS-D to twice-daily eluxadoline 75 or 100 mg or placebo. Radar plots were prepared showing pooled Weeks 1-26 response rates for the primary efficacy composite endpoint (simultaneous improvement in abdominal pain and stool consistency), stool consistency, abdominal pain, urgency-free days, and adequate relief, and change from baseline to Week 26 in IBS-D global symptom score, abdominal discomfort, abdominal pain, abdominal bloating, and daily number of bowel movements.

KEY RESULTS

The studies enrolled 2428 patients. Eluxadoline increased Weeks 1-26 responder proportions vs placebo for the composite endpoint, stool consistency, abdominal pain, urgency-free days, and adequate relief. Changes from baseline to Week 26 in IBS-D global symptom score, abdominal discomfort, abdominal pain, abdominal bloating, and number of bowel movements were greater with eluxadoline vs placebo.

CONCLUSIONS AND INFERENCES

Data presentation in radar plot format facilitates interpretation across multiple domains, demonstrating that eluxadoline treatment led to improvements vs placebo across 13 endpoints representing the range of symptoms experienced by patients with IBS-D.

Eluxadoline Demonstrates a Lack of Abuse Potential in Phase 2 and 3 Studies of Patients With Irritable Bowel Syndrome With Diarrhea

BACKGROUND & AIMS

Eluxadoline is approved by the Food and Drug Administration for the treatment of adults with irritable bowel syndrome with diarrhea (IBS-D). Eluxadoline is a locally acting mixed μ-opiod and κ-opioid receptor agonist and δ-opioid receptor antagonist. The abuse potential of eluxadoline was evaluated as part of the Phase 2 and 3 clinical trials assessing the efficacy, safety, and tolerability of the drug.

METHODS

One Phase 2 (IBS-2001) and two Phase 3 (IBS-3001 and IBS-3002) randomized controlled trials enrolled patients meeting Rome III criteria for IBS-D. Patients received oral twice-daily double-blind treatment with eluxadoline or placebo for 12, 26, or 52 weeks. The primary end point of these studies was the proportion of patients who had a composite response of decrease in abdominal pain and improvement in stool consistency on the same day for at least 50% of days. Safety data were pooled, and specific adverse event terms potentially related to abuse were assessed descriptively. Adverse events reported during a 2-week post-treatment period (IBS-3001) and a 4-week single-blind washout period (IBS-3002) were assessed for signs of opioid withdrawal. Potential withdrawal effects were assessed by using the Subjective Opiate Withdrawal Scale.

RESULTS

Overall, 807 and 1032 patients received 1 or more doses of eluxadoline (75 or 100 mg, respectively), and 975 patients received placebo. The overall incidence of adverse events potentially related to abuse did not differ significantly among the groups given placebo, eluxadoline 75 mg, or eluxadoline 100 mg (2.8%, 2.7%, and 4.3%, respectively). The most common adverse events potentially related to abuse were anxiety and somnolence, which occurred in less than 2% of patients in each group. Median overall Subjective Opiate Withdrawal Scale scores did not differ significantly among the groups given placebo, eluxadoline 75 mg, or eluxadoline 100 mg (3.0, 2.0, and 3.0, respectively).

CONCLUSIONS

In an analysis of data from Phase 2 and Phase 3 trials of eluxadoline (75 or 100 mg) for patients with IBS-D, data revealed no signs of abuse potential for eluxadoline. ClinicalTrials.gov numbers: NCT01130272, NCT01553591, NCT01553747.

Corrigendum: Eluxadoline Efficacy in IBS-D Patients Who Report Prior Loperamide Use

This corrects the article DOI: 10.1038/ajg.2017.72.

Abuse Potential and Pharmacodynamic Characteristics of Oral and Intranasal Eluxadoline, a Mixed μ- and κ-Opioid Receptor Agonist and δ-Opioid Receptor Antagonist

Drugs with μ-opioid receptor (OR) activity can be associated with abuse and misuse. The peripherally acting mixed μ-OR and κ-OR agonist and δ-OR antagonist eluxadoline is approved in the United States for the treatment of irritable bowel syndrome with diarrhea. In two separate crossover studies, we evaluated the oral and intranasal abuse potential of eluxadoline versus placebo and the active control oxycodone. Healthy recreational opioid users received eluxadoline 100, 300, and 1000 mg, oxycodone 30 and 60 mg, and placebo (oral study), or eluxadoline 100 and 200 mg, oxycodone 15 and 30 mg, and placebos matched to eluxadoline and oxycodone (intranasal study). In the oral study, Drug Liking Visual Analog Scale (VAS) peak (maximum) effect (E_max) score (primary endpoint) was significantly greater with eluxadoline 300 and 1000 mg versus placebo, but scores were significantly lower versus oxycodone. Following intranasal insufflation of eluxadoline, Drug Liking VAS E_max scores were not statistically different versus placebo, and were significantly lower versus oxycodone. Across other subjective measures, eluxadoline was generally similar to or disliked versus placebo. Pupillometry indicated no or minimal central effects with oral and intranasal eluxadoline, respectively. Adverse events of euphoric mood were reported with oral and intranasal eluxadoline but at a far lower frequency versus oxycodone. These data demonstrate that eluxadoline has less abuse potential than oxycodone in recreational opioid users.

Eluxadoline for Irritable Bowel Syndrome with Diarrhea

Background Effective and safe treatments are needed for patients who have irritable bowel syndrome (IBS) with diarrhea. We conducted two phase 3 trials to assess the efficacy and safety of eluxadoline, a new oral agent with mixed opioid effects (μ- and κ-opioid receptor agonist and δ-opioid receptor antagonist), in patients with IBS with diarrhea. Methods We randomly assigned 2427 adults who had IBS with diarrhea to eluxadoline (at a dose of 75 mg or 100 mg) or placebo twice daily for 26 weeks (IBS-3002 trial) or 52 weeks (IBS-3001 trial). The primary end point was the proportion of patients who had a composite response of decrease in abdominal pain and improvement in stool consistency on the same day for at least 50% of the days from weeks 1 through 12 and from weeks 1 through 26. Results For weeks 1 through 12, more patients in the eluxadoline groups (75 mg and 100 mg) than in the placebo group reached the primary end point (IBS-3001 trial, 23.9% with the 75-mg dose and 25.1% with the 100-mg dose vs. 17.1% with placebo; P=0.01 and P=0.004, respectively; IBS-3002 trial, 28.9% and 29.6%, respectively, vs. 16.2%; P<0.001 for both comparisons). For weeks 1 through 26, the corresponding rates in IBS-3001 were 23.4% and 29.3% versus 19.0% (P=0.11 and P<0.001, respectively), and the corresponding rates in IBS-3002 were 30.4% and 32.7% versus 20.2% (P=0.001 and P<0.001, respectively). The most common adverse events associated with 75 mg of eluxadoline and 100 mg of eluxadoline, as compared with placebo, were nausea (8.1% and 7.5% vs. 5.1%), constipation (7.4% and 8.6% vs. 2.5%), and abdominal pain (5.8% and 7.2% vs. 4.1%). Pancreatitis developed in 5 (2 in the 75-mg group and 3 in the 100-mg group) of the 1666 patients in the safety population (0.3%). Conclusions Eluxadoline is a new therapeutic agent that reduced symptoms of IBS with diarrhea in men and women, with sustained efficacy over 6 months in patients who received the 100-mg dose twice daily. (Funded by Furiex Pharmaceuticals, an affiliate of Allergan; IBS-3001 and IBS-3002 ClinicalTrials.gov numbers, NCT01553591 and NCT01553747 , respectively.).

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.

Eluxadoline benefits patients with irritable bowel syndrome with diarrhea in a phase 2 study

BACKGROUND & AIMS

Simultaneous agonism of the μ-opioid receptor and antagonism of the δ-opioid receptor can reduce abdominal pain and diarrhea in patients with irritable bowel syndrome with diarrhea (IBS-D) without constipating side effects. We evaluated the efficacy and safety of a minimally absorbed, μ-opioid receptor agonist and δ-opioid receptor antagonist (eluxadoline) in a phase 2 study in patients with IBS-D.

METHODS

We randomly assigned 807 patients to groups that received oral placebo twice daily or 5, 25, 100, or 200 mg oral eluxadoline for 12 weeks. The primary end point was clinical response at week 4, defined by a mean reduction in daily pain score from baseline of ≥ 30%, and of at least 2 points on 0-10 scale, as well as a stool consistency score of 3 or 4 on the Bristol Stool Scale (1-7) for at least 66% of daily diary entries during that week.

RESULTS

Significantly more patients receiving 25 mg (12.0%) or 200 mg (13.8%) eluxadoline met the primary end point of clinical response than patients given placebo (5.7%; P < .05). Patients receiving eluxadoline at 100 mg and 200 mg also had greater improvements in bowel movement frequency and urgency, global symptoms, quality of life, and adequate relief assessments (P < .05). Additionally, patients receiving 100 mg (28.0%) or 200 mg (28.5%) eluxadoline were significantly more likely than those receiving placebo (13.8%; P < .005) to meet the US Food and Drug Administration response end point during the full 12 weeks of the study. Eluxadoline was well tolerated with a low incidence of constipation.

CONCLUSIONS

In a phase 2 study of the mixed μ-opioid receptor agonist/δ-opioid receptor antagonist eluxadoline vs placebo in patients with IBS-D, patients given eluxadoline were significantly more likely to be clinical responders, based on a composite of improvement in abdominal pain and stool consistency. Further study of eluxadoline is warranted to assess its potential as a treatment for IBS-D.

Homeostatic compensation maintains Ca2+ signaling functions in Purkinje neurons in the leaner mutant mouse

Several human neurological disorders have been associated with mutations in the gene coding for the alpha1 subunit of the P/Q type voltage-gated calcium channel (alpha1A/Ca(v)2.1). Mutations in this gene also occur in a number of neurologically affected mouse strains, including leaner (tg(la)/tg(la)). Because the P-type calcium current is very prominent in cerebellar Purkinje neurons, these cells from mice with alpha1 subunit mutations make excellent models for the investigation of the functional consequences of native mutations in a voltage-gated calcium channel of mammalian central nervous system. In this review, we describe the impact of altered channel function on cellular calcium homeostasis and signaling. Remarkably, calcium buffering functions of the endoplasmic reticulum and calcium-binding proteins appear to be regulated in order to compensate for altered calcium influx through the mutant channels. Although this compensation may serve to maintain calcium signaling functions, such as calcium-induced calcium release, it remains uncertain whether such compensation alleviates or contributes to the behavioral phenotype.

Altered calcium homeostasis in cerebellar Purkinje cells of leaner mutant mice

The leaner (tg(la)) mouse mutation occurs in the gene encoding the voltage-activated Ca(2+) channel alpha(1A) subunit, the pore-forming subunit of P/Q-type Ca(2+) channels. This mutation results in dramatic reductions in P-type Ca(2+) channel function in cerebellar Purkinje neurons of tg(la)/tg(la) mice that could affect intracellular Ca(2+) signaling. We combined whole cell patch-clamp electrophysiology with fura-2 microfluorimetry to examine aspects of Ca(2+) homeostasis in acutely dissociated tg(la)/tg(la) Purkinje cells. There was no difference between resting somatic Ca(2+) concentrations in tg(la)/tg(la) cells and in wild-type (+/+) cells. However, by quantifying the relationship between intracellular Ca(2+) elevations and depolarization-induced Ca(2+) influx, we detected marked alterations in rapid calcium buffering between the two genotypes. Calcium buffering values (ratio of bound/free ions) were significantly reduced in tg(la)/tg(la) (584 +/- 52) Purkinje cells relative to +/+ (1,221 +/- 80) cells. By blocking the endoplasmic reticulum (ER) Ca(2+)-ATPases with thapsigargin, we observed that the ER had a profound impact on rapid Ca(2+) buffering that was also differential between tg(la)/tg(la) and +/+ Purkinje cells. Diminished Ca(2+) uptake by the ER apparently contributes to the reduced buffering ability of mutant cells. This report constitutes one of the few instances in which the ER has been implicated in rapid Ca(2+) buffering. Concomitant with this reduced buffering, in situ hybridization with calbindin D28k and parvalbumin antisense oligonucleotides revealed significant reductions in mRNA levels for these Ca(2+)-binding proteins (CaBPs) in tg(la)/tg(la) Purkinje cells. All of these results suggest that alterations of Ca(2+) homeostasis in tg(la)/tg(la) mouse Purkinje cells may serve as a mechanism whereby reduced P-type Ca(2+) channel function contributes to the mutant phenotype.

Whole-cell and single-channel analysis of P-type calcium currents in cerebellar Purkinje cells of leaner mutant mice

The leaner (tgla) mutation in mice results in severe ataxia and an overt neurodegeneration of the cerebellum. Positional cloning has revealed that the tgla mutation occurs in a gene encoding the voltage-activated calcium channel alpha1A subunit. The alpha1A subunit is highly expressed in the cerebellum and is thought to be the pore-forming subunit of P- and Q-type calcium channels. In this study we used both whole-cell and single-channel patch-clamp recordings to examine the functional consequences of the tgla mutation on P-type calcium currents. High-voltage-activated (HVA) calcium currents were recorded from acutely dissociated cerebellar Purkinje cells of homozygous leaner (tgla/tgla) and age-matched wild-type (+/+) mice. In whole cell recordings, we observed a marked reduction of peak current density in tgla/tgla Purkinje cells (-35.0 +/- 1.8 pA/pF) relative to that in +/+ (-103.1 +/- 5.9 pA/pF). The reduced whole-cell current in tgla/tgla cells was accompanied by little to no alteration in the voltage dependence of channel gating. In both genotypes, HVA currents were predominantly of the omega-agatoxin-IVA-sensitive P-type. Cell-attached patch-clamp recordings revealed no differences in single-channel conductance between the two genotypes and confirmed the presence of three distinct conductance levels (9, 13-14, and 17-18 pS) in cerebellar Purkinje cells. Analysis of patch open-probability (NPo) revealed a threefold reduction in the open-probability of channels in tgla/tgla patches (0.04 +/- 0.01) relative to that in +/+ (0.13 +/- 0.02), which may account for the reduced whole-cell current in tgla/tgla Purkinje cells. These results suggest that the tgla mutation can alter native P-type calcium channels at the single-channel level and that these alterations may contribute to the neuropathology of the leaner phenotype.