Ironwood steps up to challenge Valeant with Allergan's IBS med Viberzi

The partnership that brought constipation med Linzess to the GI world is back to promote Allergan's ($AGN) new treatment for irritable bowel syndrome with diarrhea (IBS-D), Viberzi.

Allergan EVP Bill Meury

Ironwood Pharmaceuticals ($IRWD) has signed on to help the Dublin drugmaker with its U.S. launch. Under the agreement, Ironwood's sales reps will detail Viberzi to the 25,000 prescribers they already reach with Linzess and colon cancer at-home test Cologuard. Allergan will pay Ironwood based on the volume of calls its sales force delivers, among other factors, the company said.

"Allergan and Ironwood have an established and successful partnership co-promoting Linzess in the U.S. market, and we have demonstrated the strength of our combined commercial teams in accessing and educating both gastroenterologists and primary care physicians," Bill Meury, Allergan EVP of North American brands, said in a statement.

The partnership could help Allergan compete with Valeant ($VRX), which won an IBS-D nod for its newly acquired Xifaxan--a former Salix drug--the same day Allergan got the FDA's green light for Viberzi. Xifaxan's IBS launch is already underway, with GI expert Salix's specialty sales force--which Valeant promised to keep intact upon buying out the company earlier this year--spearheading the rollout.

Allergan and Ironwood will have to wait before they can get to work playing catch-up, however. Because Viberzi is an opioid receptor agonist--read: potentially addictive--it's subject to Drug Enforcement Agency (DEA) scheduling. That could mean a launch delay until as late as next year's Q1, Evercore ISI analyst Umer Raffat wrote in June in a note to clients.

Still, Allergan's ability to promote Linzess and Viberzi side by side will help Viberzi pick up half the peak share levels of Linzess, Leerink Partners analyst Jason Gerberry wrote earlier this summer. He forecasts about $400 million for the new med by 2020.

- read Ironwood's release

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