Plecanatide

Background

Plecanatide is a synthetic guanylate cyclase-C (GC-C) agonist and second-in-class intestinal secretagogue approved for the treatment of chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C) in adults.[1][3][5][6] It is marketed under the brand name Trulance.

Plecanatide is a 16–amino acid peptide structurally modeled on the endogenous gastrointestinal hormone uroguanylin, differing by a single amino acid substitution (Asp→Glu at position 3) that enhances stability at intestinal pH while preserving receptor activity.[1][2][5] The peptide was developed to mimic physiologic regulation of fluid secretion in the small intestine with pH-sensitive activation, in contrast to linaclotide, which is modeled on the heat-stable enterotoxin and is active across a broader pH range.[1][5]

The US Food and Drug Administration (FDA) first approved plecanatide in 2017 for adult CIC, followed by an expanded indication for IBS-C in adults.[3][5][6] As of current published reviews, marketing is primarily in the United States; development and/or approval status in the European Union remains limited and plecanatide is not widely listed as an authorized medicinal product by major EU regulators.[3][5]

Mechanism of action

Plecanatide is a selective agonist of guanylate cyclase-C (GC-C) receptors located on the luminal surface of epithelial cells throughout the small intestine and colon.[1][5][7] GC-C is the receptor for endogenous uroguanylin and guanylin and for certain bacterial heat-stable enterotoxins.[1][5]

After oral administration, plecanatide acts locally in the intestinal lumen with minimal systemic absorption.[1][3][5] Binding to GC-C activates the enzyme to convert guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP).[1][5][7] Elevated intracellular cGMP activates cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels, increasing chloride and bicarbonate secretion into the intestinal lumen and concurrently reducing sodium absorption.[1][5][7]

These ion fluxes lead to enhanced luminal fluid secretion and accelerated intestinal transit, which in turn soften stools and increase bowel movement frequency.[1][5] Increased extracellular cGMP may also reduce activation of colonic sensory neurons, potentially attenuating visceral pain and contributing to improvements in abdominal pain and bloating reported in IBS-C trials.[4][5]

Plecanatide’s activity is pH-sensitive, with higher activity in the slightly acidic environment of the proximal small intestine, reflecting its uroguanylin-based design.[1][5] This may restrict activity to the upper small intestine and reduce distal hypersecretion relative to non–pH-dependent GC-C agonists, which has been proposed as a contributor to a relatively low rate of severe diarrhea in trials.[1][5]

Evidence summary

Preclinical data

In vitro and animal studies demonstrate that plecanatide activates GC-C, increases cGMP, and stimulates CFTR-dependent chloride and bicarbonate secretion, leading to increased intestinal fluid and accelerated transit.[1][5][7] Rodent models of constipation showed increased stool water content and improved stool frequency following plecanatide administration.[1][5] Plecanatide exhibited low systemic bioavailability with plasma levels generally below quantifiable limits in preclinical species, supporting a primarily local mechanism.[1][5]

Phase 3 trials in chronic idiopathic constipation

Two large, randomized, double-blind, placebo-controlled phase 3 trials evaluated plecanatide in adults with CIC.[1][5][8]

• In a pivotal phase 3 trial by Schwartz et al. (American Journal of Gastroenterology 2017), 1350 patients with CIC were randomized to plecanatide 3 mg, plecanatide 6 mg, or placebo once daily for 12 weeks.[8] The primary endpoint was the proportion of durable overall complete spontaneous bowel movement (CSBM) responders, defined by an increase of ≥1 CSBM/week over baseline and ≥3 CSBMs/week for at least 9 of 12 treatment weeks including ≥3 of the last 4 weeks.[2][8]

  Plecanatide significantly increased durable overall CSBM responder rates versus placebo: 21.0% (3 mg) and 19.5% (6 mg) vs 10.2% for placebo (P<0.001 for both doses).[8] Mean weekly CSBM frequency increased by 2.5 (3 mg) and 2.2 (6 mg) from baseline vs 1.2 for placebo (P<0.001).[8] Improvements were also observed in spontaneous bowel movements (SBMs), stool consistency, and straining scores.[2][8]

• A second identically designed phase 3 study (data summarized in premarketing reviews) showed similar results, with durable overall CSBM responder rates of approximately 20% with plecanatide (3 or 6 mg) vs ~13% with placebo, and consistent improvements in stool frequency and related symptoms.[1][2][5] Across both trials, treatment benefits appeared within the first week and were maintained over 12 weeks.[1][2][8]

A pooled analysis of both CIC phase 3 trials further confirmed efficacy and safety, reinforcing 3 mg once daily as the recommended dosage.[1][5]

Phase 3 trials in irritable bowel syndrome with constipation

Two multicenter, randomized, double-blind, placebo-controlled phase 3 trials evaluated plecanatide 3 mg and 6 mg once daily in adults with IBS-C over 12 weeks, followed by an open-label extension period.[4][5]

An integrated efficacy and safety analysis of these two trials (Schoenfeld et al., 2023) included 2189 patients (plecanatide 3 mg: 724; 6 mg: 725; placebo: 740).[4] The primary responder endpoint followed US FDA IBS-C guidance, requiring a ≥30% reduction in worst abdominal pain and an increase of ≥1 CSBM/week on the same week for at least 6 of 12 treatment weeks.[4][5]

Both plecanatide doses significantly increased the proportion of combined pain and stool responders vs placebo, with early and sustained improvements in stool frequency, stool consistency, straining, and abdominal symptoms including fullness, bloating, and cramping.[4] Diarrhea was the most common adverse event but occurred in <5% of plecanatide recipients and led to discontinuation in approximately 1%.[4]

Systematic review and meta-analysis

A systematic review and meta-analysis by Ahmed et al. included 7 studies and 6316 participants (4349 plecanatide; 1967 placebo) across CIC and IBS-C indications, evaluating plecanatide doses from 0.3 to 9 mg once daily.[6] Plecanatide significantly improved global response and bowel function outcomes compared with placebo, with the 3 mg dose consistently demonstrating favorable efficacy–safety balance.[6] Diarrhea was more frequent with plecanatide than placebo but was generally mild to moderate; serious adverse events were rare and comparable between groups.[6]

Clinical and research uses

Approved indications

• Chronic idiopathic constipation (CIC) in adults: Plecanatide is FDA‑approved in the United States for this indication.[1][3][5][6]
• Irritable bowel syndrome with constipation (IBS-C) in adults: Plecanatide is also FDA‑approved for IBS-C in adults.[3][4][5][6]

Off-label and investigational contexts

Preclinical and early mechanistic work has suggested potential benefits in other gastrointestinal disorders associated with impaired mucosal barrier function or inflammation, such as ulcerative colitis, based on GC-C–mediated enhancement of epithelial integrity and anti-inflammatory effects; however, robust clinical data are lacking.[5][7] As of the most recent systematic and narrative reviews, there are no large phase 3 trials published for plecanatide outside CIC and IBS-C.[1][5][6][7]

Dosing context

Plecanatide is administered orally once daily, with or without food.[3][5][7]

• For CIC, phase 3 trials evaluated 3 mg and 6 mg once daily; efficacy and safety were similar, and regulatory labeling and reviews designate 3 mg once daily as the recommended dose for adults.[1][2][3][5][8]
• For IBS-C, phase 3 trials also evaluated 3 mg and 6 mg once daily; the 3 mg once-daily regimen is the approved dose.[3][4][5]

Lower (0.3–1 mg) and higher (up to 9 mg) doses have been studied in early-phase trials and in meta-analysis, but these are not widely used clinically; 3 mg once daily has emerged as the standard dose based on efficacy–safety balance.[2][6][7]

Plecanatide tablets may be swallowed whole or, in individuals with swallowing difficulties, crushed and mixed with certain liquids or soft foods per product instructions; administration via certain enteral feeding tubes has also been described in labeling and reviews, though this is based on limited data.[3][5][7]

Safety profile

Common adverse effects

Across CIC and IBS-C phase 3 trials and pooled analyses, diarrhea is the most frequently reported adverse event.[1][3][4][5][6][8]

• In CIC phase 3 trials, diarrhea occurred in approximately 4–6% of plecanatide-treated patients vs ~1–2% of placebo recipients, and led to discontinuation in about 0.5–1% of treated patients.[1][2][5][8]
• In the IBS-C integrated analysis, diarrhea occurred in 4.3% (3 mg), 4.0% (6 mg), and 1.0% (placebo) of patients, leading to study discontinuation in 1.2%, 1.4%, and 0%, respectively.[4]

Other relatively common adverse events (mostly mild to moderate) include abdominal distension, flatulence, abdominal pain, and nausea, with incidences generally similar to placebo.[1][3][5][6]

Serious adverse events and special populations

Serious adverse events were infrequent and occurred at rates similar to placebo in phase 3 trials.[1][3][5][8] The most clinically significant safety concern is severe diarrhea, which can lead to dehydration, hypotension, and electrolyte disturbances; discontinuation is recommended if severe diarrhea occurs.[3][5][7]

Systemic exposure to plecanatide and its active metabolites is negligible, with plasma concentrations typically below quantifiable limits in adults, including older adults, suggesting a low potential for systemic toxicity and drug–drug interactions.[1][3][5][7] However, clinical experience in certain populations (e.g., severe hepatic or renal impairment) remains limited.[1][3][5]

In juvenile animal studies, GC-C agonism led to increased mortality due to dehydration, which informs pediatric contraindications.[3][5][7]

Contraindications and precautions

Plecanatide is contraindicated in:

• Pediatric patients <6 years of age due to the risk of serious dehydration observed in young juvenile animals.[3][5][7]
• Patients with known or suspected mechanical gastrointestinal obstruction, based on its prosecretory and motility effects and the absence of safety data in this setting.[3][5][7]

Use is not recommended in patients 6 to <18 years because of insufficient safety and efficacy data and the dehydration signal from juvenile animal models.[3][5][7]

Caution is advised in individuals at risk for severe diarrhea or dehydration (e.g., frail or very elderly patients, those on diuretics), with monitoring and prompt discontinuation if severe diarrhea develops.[3][5][7]

Regulatory status

In the United States, plecanatide (Trulance) is FDA‑approved for the treatment of:

• Chronic idiopathic constipation (CIC) in adults, and
• Irritable bowel syndrome with constipation (IBS-C) in adults.[3][5][6][7]

Plecanatide is classified as a prescription-only GC-C agonist intestinal secretagogue.[3][5][7] Postmarketing surveillance continues to monitor for rare adverse events, but published reviews up to 2023 report a safety profile consistent with phase 3 trials.[3][5][6]

In the European Union, as summarized in recent reviews, plecanatide has not been widely reported as an EMA-authorized medicinal product, and no major EU-wide approvals for CIC or IBS-C have been detailed in the peer-reviewed literature; GC-C agonist therapy for these indications in Europe currently centers primarily on linaclotide.[1][3][5] Thus, plecanatide’s availability outside the US appears limited and may be region- or country-specific, with no large body of EU regulatory documentation cited in contemporary clinical reviews.[1][3][5]