Linaclotide

Linaclotide (Linzess) — Guanylate Cyclase-C Agonist

Evidence & Status

  • FDA Approved
  • Strong Human Evidence
  • Established

At a Glance

An FDA-approved oral peptide drug that acts mainly inside the intestine through GC-C/cGMP signaling to increase fluid secretion and bowel transit. It is used for IBS-C in adults and pediatric patients 7 years of age and older, CIC in adults, and functional constipation in pediatric patients 2 years of age and older.

Plain English

Linaclotide works mainly inside the gut, where it activates a receptor on intestinal lining cells that increases fluid secretion and helps move stool through the bowel. It has very low systemic availability and is used for IBS-C, adult CIC, and pediatric functional constipation under the current approved age ranges. Its IBS-C benefit includes reduced abdominal pain, although the detailed pain-signaling mechanism is supported primarily by animal-model evidence.

Overview

Linaclotide is a 14-amino-acid peptide agonist of guanylate cyclase-C (GC-C), structurally related to human guanylin and uroguanylin. After oral administration, linaclotide and its active metabolite act mainly on the luminal surface of the intestinal epithelium. GC-C activation increases cGMP and stimulates chloride and bicarbonate secretion largely through CFTR, increasing intestinal fluid and accelerating transit. LINZESS is approved for IBS-C in adults and pediatric patients 7 years of age and older, CIC in adults, and functional constipation in pediatric patients 2 years of age and older. It is minimally absorbed systemically; extracellular cGMP is implicated in the visceral-pain benefit in IBS-C, with mechanistic support in animal models.

Research Summary

In the 26-week randomized, double-blind, placebo-controlled Phase III IBS-C trial, 804 patients received linaclotide 290 mcg once daily or placebo. The FDA combined responder definition over the first 12 weeks required both at least 30% improvement from baseline in average daily worst abdominal pain and at least 1 additional complete spontaneous bowel movement from baseline in the same week for at least 6 of 12 weeks. Response was 33.7% with linaclotide versus 13.9% with placebo (P < 0.0001). The trial also showed statistically significant improvements in abdominal pain, bloating, and bowel symptoms versus placebo. Current FDA labeling provides the indication and safety context, including pediatric functional constipation in patients 2 years of age and older.

Research Areas

  • IBS with constipation
  • Chronic idiopathic constipation
  • Visceral pain
  • GCC receptor pharmacology
  • Gut epithelial physiology

Safety & Risks

Serious Risks

  • Pediatric serious dehydration — LINZESS carries a boxed warning for risk of serious dehydration in pediatric patients less than 2 years of age and is contraindicated in this age group
  • Severe diarrhea can occur; if it occurs, suspend dosing and rehydrate the patient
  • Mechanical gastrointestinal obstruction — LINZESS is contraindicated in patients with known or suspected mechanical gastrointestinal obstruction

Reported Side Effects

  • Diarrhea
  • Abdominal pain
  • Flatulence
  • Abdominal distension
United States
LINZESS is FDA-approved for 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 in pediatric patients 2 years of age and older
United Kingdom
EMA-approved (Constella) for moderate-to-severe IBS-C in adults
Australia
TGA-approved (Linzess) for IBS-C and CIC
Canada
Health Canada-approved for IBS-C and CIC

Citations & Sources