Plecanatide

Plecanatide is a 16-amino-acid synthetic peptide that is a structural analog of human uroguanylin, the endogenous activator of guanylate cyclase-C (GC-C) in the intestine. The peptide differs from native uroguanylin by a single amino acid substitution (replacement of the third position aspartate with glutamate) that provides enhanced stability and oral bioavailability while preserving GC-C agonism. Plecanatide is administered orally as a 3 mg tablet once daily, taken with or without food. The molecule has minimal systemic absorption (less than 0.5 percent) and acts locally in the intestinal lumen. It is FDA-approved for chronic idiopathic constipation (January 19, 2017) and irritable bowel syndrome with constipation (January 24, 2018).

The molecule was developed by Synergy Pharmaceuticals with the clinical hypothesis that a uroguanylin-based GC-C agonist would offer advantages over the bacterial enterotoxin-derived linaclotide. The pH-dependent activity profile (more active in proximal intestine where the pH is slightly acidic and uroguanylin is physiologically active) was hypothesized to provide better tolerability and potentially reduced diarrhea rates.

The commercial development was challenging. Synergy Pharmaceuticals filed for bankruptcy in December 2018, less than two years after the original FDA approval. Bausch Health acquired Trulance in March 2019 through the bankruptcy proceedings. Trulance is now marketed by Bausch Health and its Salix Pharmaceuticals subsidiary. The commercial position has been more constrained than the strong clinical efficacy would have predicted.

The Approved Indications

Plecanatide has two FDA-approved indications.

Chronic idiopathic constipation (CIC, FDA approval January 19, 2017). Adults with CIC. Dose: 3 mg orally once daily, with or without food. Approved based on two Phase 3 trials in 2,791 patients with CIC.

Irritable bowel syndrome with constipation (IBS-C, FDA approval January 24, 2018). Adults with IBS-C. Dose: 3 mg orally once daily, with or without food. Approved based on two Phase 3 trials in 2,191 patients with IBS-C.

No pediatric indication. Unlike linaclotide (which has FDA approval for pediatric functional constipation since 2023), plecanatide is approved only for adults.

The narrower indication breadth (no pediatric approval) is one of the commercial differentiators between plecanatide and linaclotide.

The Phase 3 Clinical Evidence

The plecanatide Phase 3 program was substantial.

CIC Phase 3 trials. Two large randomized placebo-controlled trials in 2,791 patients with CIC. 12-week treatment duration. Both doses tested (3 mg and 6 mg) significantly improved primary endpoints versus placebo. The 3 mg dose was selected for the FDA submission and approval based on superior tolerability with similar efficacy.

IBS-C Phase 3 trials. Two large randomized placebo-controlled trials in 2,191 patients with IBS-C. 12-week treatment duration. Plecanatide 3 mg met primary endpoints for both bowel symptoms and abdominal pain.

Systematic review and meta-analysis (Shah et al., 2018). Seven plecanatide trials (4 CIC, 3 IBS-C) evaluating patients in head-to-head efficacy and tolerability assessments versus linaclotide. Similar efficacy and tolerability between the two GC-C agonists. Diarrhea occurred in excess of placebo at similar rates between linaclotide and plecanatide.

Long-term safety extension trials. Multi-year extension trials documented sustained efficacy and acceptable safety over extended treatment durations.

The clinical evidence is strong and supports plecanatide as a well-characterized therapy for the approved indications. The efficacy is broadly comparable to linaclotide, which is the principal commercial challenge.

Plecanatide has a GC-C agonist mechanism that is fundamentally similar to linaclotide but with pH-dependent activity.

GC-C receptor activation. Plecanatide binds GC-C on intestinal epithelial cells and triggers cGMP increase, the same intracellular second messenger increase produced by linaclotide. The downstream pathway is identical: cGMP activates CFTR, driving chloride and bicarbonate efflux into the intestinal lumen with osmotically drawn water.

Uroguanylin analog structure. Plecanatide differs from native uroguanylin (a 16-amino-acid endogenous peptide produced by intestinal cells) by a single conservative amino acid substitution. The substitution preserves GC-C agonism while providing slightly improved stability.

pH-dependent activity. This is the principal mechanistic distinction from linaclotide. Plecanatide has maximum GC-C agonism at slightly acidic pH (approximately 5 to 6) and reduced activity at neutral or alkaline pH. The proximal small intestine (duodenum and proximal jejunum) has slightly acidic pH where plecanatide is most active. The distal small intestine and colon have more alkaline pH where plecanatide activity is reduced. This pH profile may concentrate the secretory effect in the proximal small intestine and may reduce distal effects (which could otherwise produce more diarrhea).

Reduced visceral pain. Like linaclotide, plecanatide produces local cGMP increase that may reduce visceral hypersensitivity, contributing to the IBS-C indication efficacy.

Local intraluminal action. Less than 0.5 percent systemic absorption. The action is essentially entirely local in the intestinal lumen. This is even less systemic absorption than linaclotide and supports the favorable safety profile.

Once-daily dosing. The pharmacokinetic profile supports once-daily oral dosing.

The mechanistic similarity to linaclotide is the principal commercial challenge for plecanatide. With nearly identical mechanism, similar efficacy, and similar tolerability, plecanatide must compete on dosing convenience (with or without food) and prescriber preference rather than fundamental mechanism advantages.

Plecanatide has two FDA-approved indications.

Chronic idiopathic constipation (CIC, FDA approval January 19, 2017). Adults with CIC. Dose: 3 mg orally once daily, with or without food. Approved based on two Phase 3 trials in 2,791 patients with CIC.

Irritable bowel syndrome with constipation (IBS-C, FDA approval January 24, 2018). Adults with IBS-C. Dose: 3 mg orally once daily, with or without food. Approved based on two Phase 3 trials in 2,191 patients with IBS-C.

No pediatric indication. Unlike linaclotide (which has FDA approval for pediatric functional constipation since 2023), plecanatide is approved only for adults.

The narrower indication breadth (no pediatric approval) is one of the commercial differentiators between plecanatide and linaclotide.

Regulatory status

United States (FDA). Approved for CIC (January 19, 2017) and IBS-C (January 24, 2018). Active marketing authorization. NDA held by Bausch Health.

European Union (EMA). Plecanatide is not approved in EU as of May 2026. Commercial focus has been on US market.

Other markets. Limited international approvals.

Commercial status. Originally developed by Synergy Pharmaceuticals. Acquired by Bausch Health in March 2019 through Synergy's bankruptcy proceedings. Now marketed by Bausch Health and Salix Pharmaceuticals. Commercial position has been constrained by competition with linaclotide (with stronger commercial position under AbbVie/Ironwood).

Generic status. Patent protection extends through approximately 2030 to 2032. Generic competition is not anticipated in the near term.

Compounding status. Plecanatide is not on the FDA Category 2 bulks list.

WADA status. Plecanatide is not on the WADA Prohibited List.

Plecanatide has two FDA-approved indications.

Chronic idiopathic constipation (CIC, FDA approval January 19, 2017). Adults with CIC. Dose: 3 mg orally once daily, with or without food. Approved based on two Phase 3 trials in 2,791 patients with CIC.

Irritable bowel syndrome with constipation (IBS-C, FDA approval January 24, 2018). Adults with IBS-C. Dose: 3 mg orally once daily, with or without food. Approved based on two Phase 3 trials in 2,191 patients with IBS-C.

No pediatric indication. Unlike linaclotide (which has FDA approval for pediatric functional constipation since 2023), plecanatide is approved only for adults.

The narrower indication breadth (no pediatric approval) is one of the commercial differentiators between plecanatide and linaclotide.

The plecanatide safety profile is broadly similar to linaclotide.

Diarrhea. The most common adverse event and the dose-limiting effect. Mechanism-related. Approximately 5 percent of adult patients on plecanatide 3 mg versus 1 percent on placebo. Severe diarrhea in approximately 0.4 percent. The diarrhea rates are similar to or slightly lower than linaclotide rates, supporting the hypothesis that pH-dependent activity may reduce distal diarrhea effects.

Abdominal pain, abdominal distension, flatulence. Common GI effects. Generally mild.

Pediatric contraindication. Plecanatide is contraindicated in patients younger than 6 years of age due to risk of serious dehydration. The drug is approved only for adults (18 years and older).

Hypersensitivity reactions. Rare. Standard peptide hypersensitivity profile.

Pregnancy and lactation. Minimal systemic absorption supports use during pregnancy, though specific safety data is limited.

Long-term safety. Cumulative experience over 8+ years has not identified significant long-term safety concerns.

The safety profile is favorable. The pH-dependent activity profile may produce slightly better tolerability than linaclotide in some patient populations, though the head-to-head data does not show significant clinical differences.

The comparison with linaclotide is the central commercial reality for plecanatide.

Plecanatide vs Linaclotide. Same mechanism class (GC-C agonist). Plecanatide is derived from uroguanylin while linaclotide is derived from bacterial enterotoxin. Plecanatide can be taken with or without food, while linaclotide requires empty-stomach administration. Linaclotide has pediatric indication (6 years and older), but plecanatide is adult-only. The 2018 meta-analysis showed similar efficacy and tolerability between the two. The choice between the two often depends on prescriber preference, payer coverage, and food-timing convenience.

Plecanatide vs Lubiprostone (Amitiza). Lubiprostone is a chloride channel type 2 activator. Different mechanism class. Approved for CIC, IBS-C in women, and opioid-induced constipation in certain patients.

Plecanatide vs Prucalopride (Motegrity). Prucalopride is a selective 5-HT4 receptor agonist (prokinetic). Different mechanism class. Approved for CIC.

Plecanatide vs Tenapanor (Ibsrela). Tenapanor is a sodium/hydrogen exchanger 3 (NHE3) inhibitor that reduces sodium absorption, drawing water into the intestine. Different mechanism class. FDA-approved for IBS-C in 2019. The first non-GC-C peptide secretagogue for constipation.

Plecanatide vs PEG (MiraLAX). Osmotic laxative, over-the-counter, much less expensive. Often first-line therapy before prescription options.

Plecanatide vs Senna, Bisacodyl (stimulant laxatives). Different mechanism. Over-the-counter. Generally used for occasional rather than chronic constipation.

The constipation pharmacotherapy class in 2026 has multiple options. Plecanatide's commercial position has been moderate, reflecting the strong head-to-head competition from linaclotide and the broader availability of effective over-the-counter alternatives.