AstraZeneca, a global biopharmaceutical company, and Ironwood Pharmaceuticals, a Cambridge, Mass.-based entrepreneurial pharmaceutical company, have signed an agreement to co-develop and co-commercialize Ironwood’s linaclotide in China.

Linaclotide is the first and only guanylate cyclase-C (GC-C) agonist approved by the FDA, in August 2012, for irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC).

AstraZeneca will make an upfront payment of $25 million to Ironwood and will share the net profits and losses associated with linaclotide in China, with AstraZeneca carrying 55% of each until a certain specified milestone is achieved, moving to a 50/50 split thereafter. Ironwood will also be eligible for $125 million in additional commercial milestone payments contingent on the achievement of certain sales targets.

AstraZeneca and Ironwood are jointly responsible for strategic oversight of the development and commercialization of linaclotide in China. AstraZeneca will have primary responsibility for the local operational execution.

In addition, the companies also agreed that Ironwood’s sales force of approximately 160 experienced clinical sales specialists will promote AstraZeneca’s Nexium (esomeprazole magnesium) in the U.S. This agreement will provide Ironwood with an opportunity to increase its presence with the key gastrointestinal physicians in the U.S.

“A large percentage of adult patients who have IBS-C or who have CIC, may also suffer from GERD,” said Thomas McCourt, chief commercial officer, senior vice-president, marketing and sales, Ironwood Pharmaceuticals. “This agreement provides our experienced clinical sales specialists with the opportunity to bring two different and effective therapies to physicians for managing their patients who have these prevalent and troublesome gastrointestinal disorders.”

In May 2012, Ironwood filed a clinical trial application with the State FDA in China for a phase III clinical trial to assess the efficacy and safety of linaclotide in adult patients suffering from irritable bowel syndrome with constipation (IBS-C).