CAMBRIDGE, Mass.--(BUSINESS WIRE)--

Ironwood Pharmaceuticals, Inc. (NASDAQ: IRWD) today announced the initiation of a Phase Ib clinical study of IW-1973 and a Phase Ia clinical study of IW-1701, both of which are investigational soluble guanylate cyclase (sGC) stimulators from within a broad, pharmacologically-distinct library of sGC compounds discovered by Ironwood. Data from the Phase Ia study with IW-1701 are expected in the first half of 2016 and data from the Phase Ib study with IW-1973 are expected in the second half of 2016; these data are expected to inform the selection of doses and priority indications for the planned Phase II sGC program, which will focus on diseases with the highest unmet need and optimal path to market.

"Soluble guanylate cyclase is a fundamental regulator of blood flow, inflammation and fibrosis, which endows sGC stimulators with broad therapeutic potential in cardiovascular diseases, fibrotic diseases, muscular dystrophy and other disorders," said Mark Currie, Ph.D., chief scientific officer and president of research and development at Ironwood. "Ironwood has developed significant pharmacologic expertise in guanylate cyclase pathways through our discovery of the GC-C agonist, linaclotide, and we have applied this GC expertise to discover multiple promising sGC stimulators."

The Phase Ib clinical study of IW-1973 includes two stages: an open-label, single dose, crossover stage and a randomized, double-blind, placebo-controlled, multiple-ascending-dose stage. The study is designed to assess the safety, tolerability, pharmacokinetic profile and pharmacodynamic effects of IW-1973 repeat-doses administered orally to healthy subjects. The Phase Ia clinical study of IW-1701 is a randomized, double-blind, placebo-controlled, single-ascending-dose study that will evaluate the safety, tolerability, pharmacokinetic profile and pharmacodynamic effects of IW-1701 administered orally to healthy subjects.

About Ironwood's sGC Platform

IW-1973 and IW-1701 are investigational clinical compounds from Ironwood's library of pharmacologically distinct soluble guanylate cyclase (sGC) stimulators. The stimulation of sGC is a clinically validated approach with broad therapeutic potential. Found throughout the body, sGC is an enzyme that is activated by the key regulator nitric oxide (NO) to increase levels of the second messenger cyclic guanosine monophosphate (cGMP), a signaling molecule that regulates blood flow, inflammation and fibrosis. As fundamental regulators of such core physiological processes, sGC stimulators may be relevant in the treatment of a broad range of diseases including cardiovascular diseases such as pulmonary arterial hypertension and congestive heart failure, as well as fibrotic diseases, muscular dystrophy, and other disorders. Ironwood established its expertise in the cGMP signaling pathway through the discovery and development of linaclotide, a guanylate cyclase C (GC-C) agonist that also modulates cGMP; the company has leveraged its GC-C expertise to discover its broad library of sGC stimulators.

About Ironwood Pharmaceuticals

Ironwood Pharmaceuticals (NASDAQ: IRWD) is focused on creating medicines that make a difference for patients, building value to earn the continued support of our fellow shareholders, and empowering our team to passionately pursue excellence. We discovered, developed and are commercializing linaclotide, which is approved in the United States and a number of other countries. Our pipeline priorities include exploring further opportunities for linaclotide, as well as leveraging our therapeutic expertise in gastrointestinal disorders and our pharmacologic expertise in guanylate cyclases to address patient needs across the upper and lower gastrointestinal tract. Ironwood was founded in 1998 and is headquartered in Cambridge, Mass. Connect with us at www.ironwoodpharma.com or on Twitter at www.twitter.com/ironwoodpharma; information that may be important to investors will be routinely posted in both these locations.

This press release contains forward-looking statements. Investors are cautioned not to place undue reliance on these forward-looking statements, including, but not limited to, statements about the clinical programs for IW-1973 and IW-1701, including the design of the Phase I studies and the completion thereof; the data to be generated from these Phase I studies, the timing that these data are expected to be available and the impact thereof on future development plans for our sGC program; the focus of our planned sGC Phase II clinical program and the goals thereof; the therapeutic opportunities for sGC stimulators; the design, breath, scope and potential of our library of sGC stimulators, their pharmacological distinctness, and our development plans and activities with respect thereto, including the diseases and dosing schedules we intend to pursue; and the results of our clinical and preclinical studies of IW-1973 and our preclinical studies of IW-1701 and our other sGC stimulators and the impact thereof. Each forward-looking statement is subject to risks and uncertainties that could cause actual results to differ materially from those expressed or implied in such statement. Applicable risks and uncertainties include, but are not limited to, the risk that we are unable to complete the Phase I clinical studies for IW-1973 and IW-1701 on the same timelines or with the same results as we currently anticipate, or we are otherwise unable to effectively execute on our sGC clinical program; the risk that the data from such clinical studies are not available when we currently anticipate them or do not demonstrate the results we expect, including with respect to safety, tolerability, pharmacokinetic profile or pharmacodynamic effects; the risk that the Phase I clinical studies need to be discontinued for any reason, including safety, tolerability, enrollment, manufacturing or economic reasons; the risk that the data from non-clinical or previous clinical studies do not support the data from these clinical studies; the risk that the therapeutic opportunities for sGC stimulators and the potential for our library of sGC stimulators is not as we expect; those related to decisions made by regulatory authorities; those related to decisions made by the U.S. Patent and Trademark Office and its foreign counterparts, intellectual property rights of competitors or potential competitors, and the risk that we may never get sufficient patent protection for IW-1973, IW-1701 and our other sGC stimulators; and those risks related to competition and future business decisions made by us and our competitors or potential competitors. Applicable risks also include those that are listed in Ironwood's Quarterly Report on Form 10-Q for the quarter ended June 30, 2015, in addition to the risk factors that are listed from time to time in Ironwood's Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and any subsequent SEC filings. Ironwood undertakes no obligation to update these forward-looking statements to reflect events or circumstances occurring after this press release. These forward-looking statements speak only as of the date of this press release. All forward-looking statements are qualified in their entirety by this cautionary statement.

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