Abstract
BACKGROUND: Irritable bowel syndrome with diarrhea (IBS-D) is characterized by abdominal pain and diarrhea and can affect people of all ages. Eluxadoline (ELX) is approved for the treatment of IBS-D in Canada, the U.S., and the E.U., based on Phase 3 trials in which it simultaneously improved abdominal pain and stool consistency. AIMS: To examine the efficacy and safety of ELX in patients aged <65 and ≥65 years in a post hoc analysis of Phase 3 clinical trials. METHODS: Two Phase 3 clinical trials randomized patients meeting Rome III criteria for IBS-D to twice-daily (BID) treatment with ELX (75 or 100 mg) or placebo for 26 weeks. Patients rated worst abdominal pain (0–10), stool consistency (Bristol Stool Form Scale [BSFS]; 1–7), and global symptom score (GSS; 0–4) daily. Patients with a decrease in abdominal pain (≥30%) and improvement in stool consistency (BSFS <5) on the same day for ≥50% of days were considered composite responders. A GSS score of 0 or 1 or an improvement of ≥2.0 indicated a GSS response. RESULTS: Overall, 9.9% of patients were aged ≥65 years. Significantly more patients aged <65 and ≥65 years were composite responders at both ELX doses compared to placebo (Table). The proportion of abdominal pain responders was significant only for patients <65 years, while the proportion of stool consistency responders was significantly greater than placebo at both ELX doses in both age groups (Table). In patients ≥65 years, only ELX 75 mg was associated with a significantly higher proportion of GSS responders vs. placebo. Among patients aged ≥65 years, the responder rate for each of these endpoints was greater with ELX 75 mg compared to ELX 100 mg. The proportion of patients with ≥1 adverse event was slightly higher among patients aged ≥65 years compared to younger patients (66.2% vs. 59.7% and 65.3% vs. 57.5% of patients receiving ELX 75 or 100 mg, respectively). In patients <65 years, constipation occurred in 7.3% and 8.4% of patients receiving ELX 75 or 100 mg, respectively, compared to 9.2% and 10.7% in patients ≥65. Of six total cases of pancreatitis, one occurred in a patient aged ≥65 years. CONCLUSIONS: ELX improved IBS-D symptoms in patients aged <65 and ≥65 years. While the data are limited by sample size, in patients aged ≥65 years, the lower approved ELX dose of 75 mg BID was associated with a greater response rate than the 100 mg BID dose. Hence, the lower approved dose is recommended for this population. FUNDING AGENCIES: Allergan plc