Plecanatide

Plecanatide is a 16-amino acid synthetic peptide analog of uroguanylin, a naturally occurring peptide hormone produced in the small intestine that helps regulate fluid and electrolyte balance. Developed by Synergy Pharmaceuticals and marketed as Trulance, plecanatide was approved by the FDA in 2017 for chronic idiopathic constipation (CIC) and in 2018 for irritable bowel syndrome with constipation (IBS-C).

Like linaclotide, plecanatide activates guanylate cyclase-C (GC-C) receptors on intestinal epithelial cells, stimulating chloride and bicarbonate secretion into the intestinal lumen to increase fluid content and accelerate transit. However, plecanatide was designed to more closely mimic the structure of endogenous uroguanylin, which naturally activates GC-C in a pH-dependent manner. Uroguanylin is most active in the mildly acidic environment of the proximal small intestine (pH 5-6), and plecanatide shares this pH-dependent activation profile.

This pH-dependent activity is hypothesized to provide a more physiologically targeted effect, primarily stimulating fluid secretion in the upper GI tract where absorption and secretion are most actively regulated. Proponents suggest this may translate to a potentially lower incidence of diarrhea compared to pH-independent GC-C agonists, though direct comparative clinical data between plecanatide and linaclotide is limited.

Phase 3 clinical trials demonstrated that plecanatide significantly improved spontaneous bowel movement frequency, stool consistency, and straining in CIC patients, and improved abdominal pain and bowel function in IBS-C patients. The peptide acts locally in the gut with minimal systemic absorption, contributing to its safety profile.