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What happened

After announcing positive results in phase 3 trials evaluating plecanatide for the treatment of irritable bowel syndrome with constipation (IBS-C), shares in Synergy Pharmaceuticals (NASDAQ:SGYP) rallied 10% this morning.

So what

Plecanatide is already under review by the FDA for approval in treating patients with chronic idiopathic constipation (CIC). That review is being based upon previously reported phase 3 successes that include a relatively low incidence rate of severe diarrhea when compared to other treatment options.

Today, the company rolled out final phase 3 results showing that plecanatide may also address IBS-C, a condition that affects millions of people. 

Preliminary overall response rates in the 3 mg and 6 mg plecanatide arms and placebo arm were 30.2%, 29.5%, and 17.8%, respectively, with a p-value of <0.001.

Unsurprisingly, the most common adverse event was diarrhea, which occurred in 5.4% of patients in 3 mg and 4.3% of patients in 6 mg dose groups versus 0.6% of patients in the placebo arm of the study.

Now what

A FDA decision on plecanatide in CIC is anticipated on Jan. 29. Management expects to file a supplemental approval application for plecanatide's use in IBS-C in the first quarter.

If approved, plecanatide will face off against Ironwood Pharmaceuticals (NASDAQ:IRWD) and Allergan's (NYSE:AGN) Linzess. Linzess' U.S. net sales increased 34% year over year to $150.5 million in Q2 2016, and U.S. net sales increased 40% year over year to $164 million in Q3 2016.