Linzess Approved as First Drug for Children with IBS with Constipation

The FDA has approved Linzess (linaclotide) capsules for the treatment of irritable bowel syndrome with constipation (IBS-C) in pediatric patients seven years of age and older, marking the first FDA-approved therapy in this age group for the condition.

IBS-C is characterized by chronic abdominal pain, bloating and infrequent, hard or difficult‐to-pass stools, symptoms that significantly affect children’s quality of life, social participation and school attendance.

In the US, the drug is co-developed and co-commercialized by Ironwood Pharmaceuticals (the originator and patent holder) and AbbVie. The two companies equally share collaboration profits for the US branding. In Asia, the treatment is marketed by Astellas.

Until now, no treatment had been formally approved for pediatric IBS-C, leaving children and adolescents to rely on adult‐labelled off-label prescribing or symptomatic measures.

Related: Kygevvi Becomes First FDA-Approved Treatment for Rare Mitochondrial Disorder TK2d

The FDA’s expanded approval of Linzess was supported by adult efficacy data, combined with a 12-week, double-blind, randomized, placebo-controlled trial in children aged seven to 17 who met modified Rome III criteria for IBS-C.

The primary endpoint required both a ≥30% reduction in abdominal pain and an increase of at least two spontaneous bowel movements (SBMs) per week for at least six of the 12 treatment weeks. The pediatric results were consistent with those seen in adults.

Safety findings in the pediatric cohort were similar to those in adult populations; the most common side effect was diarrhea, and a boxed warning remains for children under two years due to dehydration risk.

Earlier this year, the primary analysis of LIN-MD-64 showed responder rates of 22.6% with linaclotide 145 µg and 23.4% with 290 µg, higher than the 16% adult placebo benchmark for the composite endpoint, but short of statistical superiority. In a sensitivity analysis that accounted for missing diary entries, however, both doses did achieve superiority, with responder rates of 34.1% and 38.9%, respectively.

XTALKS WEBINAR: Riding the data wave: How pharma can navigate disruptions in open claims

Live and On-Demand: Monday, December 8, 2025, at 12pm EST (6pm CET/EU-Central)

Register for this free webinar to learn how to manage disruptions in open claims data and preserve analytical value proactively.

With no approved pediatric therapy for IBS-C until now, the approval meets an important unmet need in GI pediatrics.

Approving therapy for a younger demographic opens the door to treating earlier in disease progression, potentially improving long-term outcomes and mitigating psychosocial impact.

The FDA nod makes the guanylate cyclase-C agonist the first FDA-approved therapy for pediatric IBS-C, with a recommended dose of 145 µg orally once daily per linaclotide’s updated label.

First cleared in 2012, linaclotide is already indicated for chronic idiopathic constipation (CIC) and IBS-C in adults. In 2023, the FDA also approved the capsules for functional constipation in children aged six and older.

Linzess holds a leading position in the constipation treatment market, particularly for adults with CIC and IBS-C.

In 2024, it led in the market, capturing an estimated 37.3% revenue share, driven by strong efficacy in IBS-C.

Adoption has been broad across the US, Europe and Japan, where the therapy is recognized for reducing abdominal pain and increasing bowel movement frequency. Its recent approval in China further extends market reach.