May 27, 2026 -- Ironwood Pharmaceuticals, Inc. (Nasdaq: IRWD), a biotechnology company developing and commercializing life changing therapies for people living with gastrointestinal (GI) and rare diseases, today announced that the U.S. Food and Drug Administration (FDA) has approved the use of Linzess (linaclotide) in pediatric patients 2 years of age and older with functional constipation (FC). Linzess was previously approved for pediatric patients 6 years and older with FC. With this expanded indication, Linzess is now available for children ages 2-5 years with FC and remains the only FDA-approved prescription therapy for pediatric FC.
About Linzess (Linaclotide)
Linzess is the #1 prescribed brand in the U.S. for the treatment of patients with irritable bowel syndrome with constipation (“IBS-C”) or chronic idiopathic constipation (“CIC”), based on IQVIA data. Linzess is a once-daily capsule that helps relieve the abdominal pain and constipation associated with IBS-C in adults and pediatric patients 7 years of age and older. Linzess has also been shown to relieve constipation, infrequent stools, hard stools, straining and incomplete evacuation associated with CIC in adult patients. Linzess relieves constipation in children and adolescents aged 2 to 17 years with functional constipation.
Linzess is not a laxative; it is the first medicine approved by the FDA in a class called GC-C agonists. Linzess contains a peptide called linaclotide that activates the GC-C receptor in the intestine. Activation of GC-C is thought to result in increased intestinal fluid secretion and accelerated transit and a decrease in the activity of pain-sensing nerves in the intestine. The clinical relevance of the effect on pain fibers, which is based on nonclinical studies, has not been established.
In the United States, Ironwood and AbbVie co-develop and co-commercialize Linzess for the treatment of IBS-C in adults and pediatric patients 7 years of age and older, CIC in adults and functional constipation (FC) in pediatric patients 2 years of age and older. In Europe, AbbVie markets linaclotide under the brand name CONSTELLA for the treatment of adults with moderate to severe IBS-C. In Japan, Ironwood's partner, Astellas, markets linaclotide under the brand name Linzess for the treatment of adults with IBS-C or CIC. Ironwood also has partnered with AstraZeneca for development and commercialization of Linzess in China, and with AbbVie for development and commercialization of linaclotide in all other territories worldwide.
Linzess Important Safety Information
INDICATIONS AND USAGE
Linzess (linaclotide) is indicated for the treatment of irritable bowel syndrome with constipation (IBS-C) in adults and pediatric patients 7 years of age and older, chronic idiopathic constipation (CIC) in adults, and functional constipation (FC) in pediatric patients 2 years of age and older.
Contraindications
Linzess is contraindicated in patients less than 2 years of age due to the risk of serious dehydration.
Linzess is contraindicated in patients with known or suspected mechanical gastrointestinal obstruction.
Warnings and Precautions
Risk of Serious Dehydration in Pediatric Patients Less Than 2 Years of Age.
Linzess is contraindicated in patients less than 2 years of age. In neonatal mice, linaclotide increased fluid secretion as a consequence of age-dependent elevated guanylate cyclase (GC-C) agonism, which was associated with increased mortality within the first 24 hours due to dehydration. There was no age-dependent trend in GC-C intestinal expression in a clinical study of children 2 to less than 18 years of age; however, there are insufficient data available on GC-C intestinal expression in children less than 2 years of age to assess the risk of developing diarrhea and its potentially serious consequences in these patients.
Diarrhea
In adults, diarrhea was the most common adverse reaction in Linzess-treated patients in the pooled IBS-C and CIC double-blind placebo-controlled trials. The incidence of diarrhea was similar in the IBS-C and CIC populations. Severe diarrhea was reported in 2% of adult patients with IBS-C or CIC treated with Linzess 145 mcg or 290 mcg once daily, and in <1% of adult patients with CIC treated with Linzess 72 mcg once daily. In pediatric patients, diarrhea was also the most common adverse reaction in clinical trials of patients 7 to 17 years of age with IBS-C and 6 to 17 years of age with FC treated with Linzess. In two double-blind trials, diarrhea was reported in 4% of pediatric patients 6 to 17 years of age with FC treated with Linzess 72 mcg once daily, and 7% and 8% of pediatric patients 7 to 17 years of age with IBS-C treated with Linzess 145 mcg and 290 mcg once daily, respectively. In clinical trials, severe diarrhea was reported in one pediatric patient with FC treated with Linzess 72 mcg once daily and in one pediatric patient with IBS-C treated with Linzess at a dose higher than the recommended 145 mcg once daily dosage for IBS-C. If severe diarrhea occurs, dosing should be suspended and the patient rehydrated.
Common Adverse Reactions (incidence ≥2% and greater than placebo)
In adult patients with IBS-C or CIC: diarrhea, abdominal pain, flatulence and abdominal distension.
In pediatric patients 7 to 17 years of age with IBS-C and 6 to 17 years of age with FC: diarrhea.
Linzess and CONSTELLA are registered trademarks of Ironwood Pharmaceuticals, Inc. Any other trademarks referred to in this press release are the property of their respective owners. All rights reserved.
