Ironwood reports positive results for IBS-C drug

Ironwood Pharmaceuticals announce positive data from a phase 3b study to determine the efficacy of Linzess for the treatment of multiple abdominal symptoms in patients with constipation-predominant irritable bowel syndrome, according to a press release.

Lin Chang, MD, professor of medicine at the Vatche and Tamar Manoukian Division of Digestive Diseases at the University of California Los Angeles, said pain is traditionally used as the primary endpoint in IBS-C trials, but patients often experience other abdominal symptoms, as well.

“This study was trying to look at the other abdominal symptoms,” she told Healio Gastroenterology and Liver Disease. “Not just pain, but also discomfort and bloating... looking at the three of them separately, but the primary endpoint was the average of all three together.”

Researchers conducted a randomized, controlled, parallel-group study to evaluate the efficacy and safety of Linzess (linaclotide, Ironwood, Allergan) in adult patients with IBS-C. They randomly assigned 614 patients to receive either placebo or linaclotide 290 μg once daily for 12 weeks, followed by a 4-week randomized withdrawal period.

The primary endpoint of the study was the change from baseline in abdominal score based on patient assessment of abdominal bloating, pain and discomfort using an 11-point rating scale. Researchers also assessed the impact on bowel habits from baseline.

Chang said patients in the linaclotide group reported a 29.7% mean decrease from baseline in the composite primary endpoint compared with an 18.3% decrease among patients in the placebo group (P < .0001). Additionally, 40.5% of patients in the Linzess group demonstrated a clinically meaningful response based on abdominal symptom score compared with 23.4% in the placebo group (P < .0001).

In their evaluation of the drug’s safety, researchers found that linaclotide was well-tolerated. While diarrhea was the most commonly reported adverse event at 4.6% in the linaclotide group, Chang said that percentage was actually lower than they had anticipated.

Ironwood expects to present additional data from this study at future scientific meetings and in publication.

Chang said their findings show that linaclotide is effective in treating a range of abdominal symptoms in patients with IBS-C.

“This provides information on the efficacy of linaclotide on several different abdominal symptoms,” Chang said. “It’s not just that it improves pain... it also significantly improves discomfort and bloating.” – by Alex Young

Disclosures: Chang reports serving on the scientific advisory board for Ironwood Pharmaceuticals.