Plecanatide

In plain language

Plecanatide is an oral capsule for chronic constipation and IBS-C, sold as Trulance. It is a copy of uroguanylin, one of the body's own intestinal water-regulating hormones.

It works on the same intestinal water channel switch as linaclotide but is tuned to be most active in the mildly acidic upper intestine, matching where the natural hormone works. Its main side effect is diarrhea.

For students

Plecanatide is a 16-residue analogue of human uroguanylin (about 1,682 Da) with two disulfide bonds and an amino acid substitution (Asp3, Glu12 or equivalent stability changes) that resists proteolytic degradation. It activates GC-C like linaclotide, but its pH-dependent activity (maximal at pH 5-6, the proximal intestinal milieu) mirrors uroguanylin's physiological role and may produce a gentler secretion profile.

Like linaclotide it is minimally absorbed and acts locally, and the analgesic mechanism via extracellular cGMP on nociceptors is likewise proposed. Two Phase 3 trials in chronic idiopathic constipation (n=2,642 combined) met primary endpoints (spontaneous bowel movement improvement), and two IBS-C trials supported that indication.

For researchers and instructors

Biochemistry. The pH-tuning of GC-C agonism (plecanatide at acidic pH, STa-derived linaclotide constitutively) is the distinctive comparative lesson, a real example of designing for physiological microenvironment.

Pharmacology. 3 mg once daily with or without food; contraindicated under age 2; diarrhea incidence about 5% versus 1% placebo, otherwise well tolerated.

Human evidence. Phase 3 program (n=2,642 in chronic idiopathic constipation and 2,434 in IBS-C across replicate trials) met primary endpoints; no head-to-head trial versus linaclotide exists.

Teaching point. Teaches physiological mimicry as a design philosophy, and the evidence limits of same-mechanism competitor drugs without head-to-head trials.