Duration of Treatment with Linaclotide

Orlando—Patients with irritable bowel syndrome (IBS) whose symptoms improved after 4 weeks of treatment with linaclotide were highly likely to continue feeling better at week 12. In addition, at least 30% of patients who did not improve through week 4 saw improvement after 12 weeks of treatment, according to data from 2, randomized, double-blind, phase 3 trials.

Results were presented during a poster session at DDW. The poster was titled Determining the Minimum Duration for Initial Treatment with Linaclotide in IBS-C Patients: Results from Pooled Phase 3 Trials.

In August 2012, the FDA approved linaclotide to treat chronic idiopathic constipation and IBS with constipation. Linaclotide, a minimally absorbed guanylate cyclase-C agonist, is a capsule taken on an empty stomach once daily at least 30 minutes before the first meal of the day. People with IBS with constipation have abdominal pain as well as hard or lumpy stools at least 25% of the time and loose or watery stools <25% of the time.

In this analysis, the authors were interested in determining whether physicians should continue to prescribe linaclotide if patients do not experience symptom improvement during the early weeks of treatment. They used data from the 2 randomized trials and evaluated the degree of relief of IBS symptoms, the degree of relief of abdominal pain, and the frequency of spontaneous bowel movements (SBMs) at week 4.

The categories for the degree of relief for IBS symptoms and abdominal pain were complete relief, considerable relief, somewhat relief, unchanged, somewhat worse, considerably worse, or as bad as the patient can imagine. For SBMs, the authors determined if the patients had an increase of at least 2 SBMs from baseline.

The analysis included 1602 patients: 805 received linaclotide and 797 took a placebo pill. The mean age of patients was 44 years, 90% were females, and 77% were white.

At week 4, 76% of the patients in the linaclotide group showed improvement in the degree of relief of IBS symptoms. Of that group, 86% continued to show improvement at week 12. In addition, 35% of patients in the linaclotide group who did not improve at week 4 showed improvement at week 12.

Further, 75% of the patients in the linaclotide group showed improvement in the degree of relief of abdominal pain at week 4. Of that group, 87% continued to show improvement at week 12. In addition, 36% of patients in the linaclotide group who did not improve at week 4 showed improvement at week 12.

Also, 62% of the patients in the linaclotide group showed improvement in SBMs at week 4. Of that group, 74% continued to show improvement at week 12. In addition, 30% of patients in the linaclotide group who did not improve at week 4 showed improvement at week 12.

Of the patients in the placebo group whose symptoms had not improved at week 4, 20% had improved in the degree of relief of IBS symptoms at week 12, 20% had improved in the degree of relief of abdominal pain at week 12, and 17% had improved in SBMs at week 12.

This study was sponsored by Forest Laboratories, Inc. and Ironwood Pharmaceuticals, Inc.