FDA Approves Linaclotide (Linzess) Capsules for Pediatric IBS-C

The US Food and Drug Administration (FDA) has approved Ironwood Pharmaceuticals' linaclotide (Linzess) capsules for pediatric patients ≥ 7 years of age with irritable bowel syndrome with constipation (IBS-C), making it the first treatment approved for IBS-C in this patient population.1

A guanylate cyclase C agonist, linaclotide increases intestinal fluid secretion, accelerates transit, and decreases the activity of pain-sensing nerves in the intestine. Its initial FDA approval dates back to 2012 for the treatment of chronic idiopathic constipation and IBS-C in adults.2

According to a November 5, 2025, release from the FDA, the approval for pediatric IBS-C was supported by extrapolation of efficacy from adequate and well-controlled studies in adults and a 12-week double-blind, randomized, parallel-group trial in pediatric patients 7-17 years of age who met modified Rome III criteria for child/adolescent IBS-C. The recommended dosage for this indication is 145 mcg orally once daily.1

In the trial, the primary endpoint was the proportion of patients who achieved ≥ 30% reduction in abdominal pain and an increase of ≥ 2 spontaneous bowel movements per week from baseline for ≥ 6 weeks of the 12-week treatment period. Of note, the efficacy results were consistent with results demonstrated in the adult IBS-C population.1

According to a release from the Agency, the safety of linaclotide in these clinical studies was similar in adult and pediatric patients. The most common side effect reported in pediatric patients 7-17 years of age with IBS-C was diarrhea.1

As described in the release, if severe diarrhea occurs, patients should discontinue linaclotide and be rehydrated. Of note, patients < 2 years of age can be at risk of serious dehydration and should not take linaclotide for any indication, nor should patients with known or suspected mechanical gastrointestinal obstruction.1

In 2023, the FDA approved linaclotide for the treatment of pediatric patients aged 6-17 years with functional constipation at a recommended dosage of 72 mcg orally once daily. Of note, the approval was accompanied by a boxed warning on linaclotide for patients < 2 years of age.3

The approval for this indication was based on topline results from a multicenter, double-blind, phase 3 study in which linaclotide showed a statistically significant and clinically meaningful improvement in 12-week spontaneous bowel movement frequency rate compared to placebo. Additionally, a statistically significant proportion of linaclotide-treated patients achieved > 2-fold least squares mean change from baseline in spontaneous bowel movement frequency rate compared to placebo (2.220 vs 1.050; P <.0001).3

References

1. US Food and Drug Administration. FDA approves 1st drug for children 7 years and older with irritable bowel syndrome with constipation. November 5, 2025. Accessed November 5, 2025. https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-1st-drug-children-7-years-and-older-irritable-bowel-syndrome-constipation

2. Brooks A. New Phase 3 Data Reinforces Safety, Efficacy of Linaclotide for Pediatric Functional Constipation. HCPLive. January 9, 2024. Accessed November 5, 2025. https://www.hcplive.com/view/new-phase-3-data-reinforces-safety-efficacy-linaclotide-pediatric-functional-constipation

3. Walter K. FDA Approves Linaclotide for Pediatric Patients With Functional Constipation. HCPLive. June 12, 2023. Accessed November 5, 2025. https://www.hcplive.com/view/fda-approves-linaclotide-pediatric-patients-functional-constipation