Plecanatide & Linaclotide are two drugs made by two different companies but both target Irritable Bowel Syndrome in a similar way.
Plecanatide is being developed by Synergy Pharmaceuticals while Linaclotide is being developed by Ironwood Pharmaceuticals. These drugs are targeted towards those with constipation predominant IBS with associated IBS related abdominal pain.
Both drugs are agonists that stimulates the GC-C(guanylate cyclase C) receptor within the mucosa lining of the intestinal tract. When this receptor is stimulated it triggers the release of CFTR(cystic fibrosis transmembrane conductance regulator) proteins. These CFTR proteins improve the flow of the intestinal contents by increase secretions of water & chloride, while reducing water absorption. They appear to help with reducing inflammation as well. The end result is similar to the only currently available IBS drug Lubiprostone(Amitiza), Lubiprostone operates in a a different way, it still results in an increase of chloride & water secretions within the gut.
As far as the efficacy, Linaclotide is further along in FDA trials. During Phase III(final phase) trials of Linaclotide, of which 800 patients participated in, 34% of participants who received Linaclotide had relief of pain & constipation compared to 21% who took a placebo. 50% saw at least a reduction in pain compared to 37% with placebo. 6% of the participants experienced diarrhea that was severe enough that they left the study entirely.
Currently Plecanatide is getting ready for advanced Phase II trials. It has not yet had a major study done on it’s efficacy, but I wouldn’t be surprised to see similar results to those found in Linaclotide. While these numbers do point towards these drugs having positive benefit for some, it’d be nice if they were a little bit better. I gave Rifaxamin a hard time for having a similar margin over placebo.
In the end these drugs appear to be more advanced forms of laxatives with the added benefit of possible pain relief & a reduced chance of tolerance being built up over time, which causes the more typical stimulant based laxatives to become ineffective. Their most likely usage scenario would when typical laxatives and/or dietary changes fail to improve constipation symptoms. The cost associated may be as high as a few dollars per dosage. What with these drugs being targeted as daily maintenance drugs, using them could get rather pricey over the long haul.
There is no firm date for when Plecanatide & Linaclotide might be available from your doctor. What with Linaclotide having a seemingly successful Phase II trial, we may see it hitting the market sooner than later. Plecanatide still has a bit of a ways to go, but we may see it follow up shortly after Linaclotide hits the market.