Nakajima A, et al. – The physicians conducted this randomized, double–blind, placebo–controlled, dose–finding phase IIb study to determine the optimal clinical dose of elobixibat in Japanese patients with chronic constipation. They proposed that for Japanese patients with chronic constipation, 10 mg of elobixibat was a clinically optimal dose.

• The physicians randomized Japanese patients with chronic constipation to receive elobixibat (5, 10, or 15 mg) or placebo once daily for 2 weeks.
• The change from baseline in frequency of spontaneous bowel movements at Week 1 of treatment was the primary efficacy endpoint.
• They also examined secondary endpoints and adverse events.

• 163 patients were randomized among 226 patients who provided informed consent and included in the full analysis set.
• Compared with 2.6 ± 2.9 times per week in the placebo group [P = 0.0005, P = 0.0001, respectively]), in the 10- and 15-mg groups, frequency of spontaneous bowel movements (±standard deviation) were significantly higher than baseline (5.7 ± 4.2 and 5.6 ± 3.5 times per week, respectively.
• Subgroup analysis demonstrated that in patients with or without constipation-predominant irritable bowel syndrome, elobixibat was equally effective.
• In the elobixibat groups, common adverse events included mild abdominal pain and diarrhea.
• No serious or severe adverse events occurred.
• At once-daily oral doses up to 15 mg for 2 weeks, elobixibat was well tolerated.