Early response predicts a sustained response to eluxadoline in patients with irritable bowel syndrome with diarrhoea in two Phase 3 studies.

BACKGROUND: The mixed μ- and κ-opioid receptor agonist and δ-opioid receptor antagonist, eluxadoline, is licensed in the USA for the treatment of irritable bowel syndrome with diarrhoea (IBS-D), based on the results of two large Phase 3 clinical trials.

AIM: To understand the time course of treatment benefits with eluxadoline by comparing responder rates over the first month of treatment with responder rates over longer treatment intervals.

METHODS: In this post hoc analysis of two Phase 3 studies, composite and adequate relief (AR) responder rates were calculated over month 1 and patients were stratified by their responder status. Cumulative counts over subsequent intervals (months 1-3, months 1-6, months 2 through 6) were tallied.

RESULTS: The studies randomised 2428 patients. Over month 1, 24.6%, 22.8% and 12.5% of patients were composite responders with eluxadoline 100 mg, eluxadoline 75 mg and placebo respectively. For month 1 responders, 77.8% and 81.5% (over months 1-3) and 70.7% and 73.9% (over months 1-6) showed a continuous response with eluxadoline 100 mg and 75 mg respectively. [Correction added on 5 April 2017, after first online publication: The percentage for the responders over months 1-3 was previously wrong and has been corrected.] Of the month 1 nonresponders, <20% showed a response over months 1-3 or months 1-6. Similar results were seen for the analysis of proportions of AR responders over these time intervals.

CONCLUSIONS: Over two-thirds of patients who respond over the first month retain a positive response over 6 months of treatment with eluxadoline, indicating that early clinical response to eluxadoline is associated with sustained benefits for up to 6 months in patients with IBS-D.