Ironwood and AbbVie Secure FDA Expansion for LINZESS in Young Children for FC

The U.S. Food and Drug Administration (FDA) has expanded approval of LINZESS® (linaclotide) to include pediatric patients aged 2–5 years with functional constipation (FC). The decision, granted under priority review, broadens the drug’s label beyond its previous indication for children aged 6 years and older and addresses a significant treatment gap in preschool-aged patients.

Functional constipation is a chronic gastrointestinal disorder characterized by infrequent, hard, and often painful bowel movements. The condition commonly affects preschool-aged children and can persist despite dietary changes and over-the-counter therapies. Linaclotide is a guanylate cyclase-C (GC-C) agonist that increases intestinal fluid secretion and accelerates gastrointestinal transit.

Clinical Trial Evidence

Approval was supported by a 12-week Phase 3 randomized, placebo-controlled trial in children aged 2–5 years with FC (NCT05652205). Once-daily LINZESS 72 mcg improved spontaneous bowel movement (SBM) frequency compared with placebo, meeting the study’s primary endpoint. Secondary measures, including stool consistency and symptom relief, also favored treatment.

Investigators reported a safety profile consistent with adult chronic idiopathic constipation (CIC) and pediatric FC studies. Diarrhea was the most common adverse event, while serious adverse events and treatment discontinuations were uncommon.

 Safety Considerations

LINZESS carries a boxed warning and is contraindicated in children younger than 2 years due to risk of serious dehydration. This warning is based on neonatal mouse studies in which exposure to clinically relevant doses resulted in fatal dehydration.

The capsules may be opened and mixed with applesauce or water, which may help administration in preschool‑aged patients who have difficulty swallowing capsules.

Expert and Industry Perspectives

Julie Khlevner, M.D., pediatric gastroenterologist at Columbia University Vagelos College of Physicians and Surgeons, highlighted the limited treatment options available for younger children with persistent constipation and noted the potential for improved adherence through flexible administration options.

Ironwood CEO Tom McCourt described the approval as a continuation of LINZESS’ established role in gastrointestinal care and said the FDA’s priority review reflects the unmet need in younger pediatric patients with FC.

Regulatory Trajectory

Since its 2012 launch, LINZESS has been prescribed to more than 5.5 million patients and remains a leading therapy for irritable bowel syndrome with constipation (IBS‑C) and chronic idiopathic constipation (CIC) in the United States. In November 2025, the FDA approved LINZESS for the treatment of pediatric IBS‑C in patients aged 7 years and older, marking the first‑ever FDA‑approved therapy for pediatric IBS‑C. The latest expansion to children aged 2–5 years with functional constipation builds on this milestone, further broadening the drug’s pediatric label and reinforcing its established role in gastrointestinal care.

Ironwood and AbbVie co-commercialize LINZESS in the U.S., while AbbVie, Astellas, and AstraZeneca manage commercialization across international markets. The expanded pediatric approval further strengthens the drug’s role in pediatric gastrointestinal care.

Reference

Ironwood Pharmaceuticals, Inc. – FDA Approves Use of LINZESS® (linaclotide) in Pediatric Patients Two Years of Age and Older with Functional Constipation (FC)