Company Announcements

– Separate poster will feature long-term safety and tolerability data from STARS clinical trial program of apraglutide in adults with SBS who are dependent on parenteral support (PS) –

– Linaclotide data presentations highlight efficacy and safety insights in IBS-C, CIC and pediatric FC –

BOSTON--(BUSINESS WIRE)--Apr. 23, 2026-- Ironwood Pharmaceuticals, Inc.(Nasdaq: IRWD), a biotechnology company developing and commercializing life-changing therapies for people living with gastrointestinal (GI) and rare diseases, announced today that the company will present data from its LANDMARK survey during the 2026 Digestive Disease Week^® (DDW) meeting being held from May 2-5 in Chicago, IL. The data will spotlight healthcare professional (HCP) insights on the burden of total parenteral nutrition (TPN) for patients with short bowel syndrome (SBS), as well as preferred attributes for potential new therapies that reduce TPN dependence.

SBS is a serious and chronic condition characterized by reduced absorptive capacity for fluids and/or nutrients, often requiring long-term dependence on parenteral support (PS) (IV nutrition and/or IV hydration) to sustain life. Patients with SBS who are chronically dependent on PS, also referred to as SBS with intestinal failure (SBS-IF), frequently experience significant treatment burden, reduced quality of life and increased risk of severe complications such as infection. Despite current management approaches, substantial unmet need remains for therapies that reduce PS dependence and improve outcomes. An estimated 18,000 adult patients suffer from SBS-IF in the U.S., Europe and Japan, and have chronic dependence on PS.

Ironwood is advancing apraglutide, an investigational, next-generation, long-acting synthetic GLP-2 analog, for SBS patients dependent on PS.

“Short bowel syndrome remains a complex and underserved condition where patients and clinicians face significant challenges, particularly for those who rely on parenteral support, which is often life-sustaining but can be associated with substantial treatment burden,” said Michael Shetzline, M.D., Ph.D., chief medical officer, senior vice president and head of research and drug development at Ironwood Pharmaceuticals. “By bringing forward real-world healthcare professional perspectives, we aim to deepen understanding of current management and the factors that shape SBS-IF care in everyday practice and help inform future therapeutic approaches.”

In addition to the LANDMARK survey data, Ironwood will present long-term safety and tolerability data from the STARS clinical trial program of apraglutide in adults with SBS who are dependent on PS. Additional presentations include key findings from the company’s Phase 3 open-label safety extension study oflinaclotide in pediatric patients aged 2–5 years with functional constipation, as well as analyses in adults with irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC).

A full list of the poster presentations is below.

Short Bowel Syndrome

• “Burden of Total Parenteral Nutrition for Patients with Short Bowel Syndrome Dependent on Parenteral Support: Healthcare Professional Perspectives on Risks, Limitations, and Treatment Priorities” (Sunday, May 03, 12:30 pm CT) will be presented by Mena Boules, M.D., Ironwood Pharmaceuticals.
• “Long-Term Safety and Tolerability of Once-Weekly Apraglutide in Patients with Short Bowel Syndrome and Intestinal Failure (SBS-IF)” (Sunday, May 03, 12:30 pm CT) will be presented by Palle Bekker Jeppesen, M.D., Dr.med/Sci., Ph.D., dls., Rigshospitalet, Copenhagen.

IBS-C, CIC and Functional Constipation

• “Effect of pH-Modifying Agents on the Efficacy and Safety of Linaclotide in Adults with Chronic Idiopathic Constipation (CIC) or Irritable Bowel Syndrome with Constipation (IBS-C): A Post Hoc Analysis” (Saturday, May 02, 12:30 pm CT) will be presented by Satish SC Rao, M.D., Ph.D., FRCP (LON), FACG, AGAF, Augusta University.
• “Safety and Efficacy of Linaclotide in Pediatric Patients Aged 2–5 Years with Functional Constipation (FC): Results from an Open-Label Safety Extension of a Phase 3 Study” (Monday, May 04, 12:30 pm CT) will be presented by Carlo Di Lorenzo, M.D., Nationwide Children’s Hospital.
• “Efficacy and Safety of Linaclotide in Irritable Bowel Syndrome with Constipation (IBS-C): A Phase 3 Post Hoc Analysis by Race, Ethnicity and Age” (Saturday, May 02, 12:30 pm CT) will be presented by Aditya Ashok, M.D., Weill Cornell Medical College.
• “Linaclotide Efficacy in Adults with Severe Chronic Idiopathic Constipation (CIC): A Post Hoc Pooled Analysis of Phase 3 Studies” (Monday, May 04, 12:30 pm CT) will be presented by Anthony J. Lembo, M.D., Digestive Disease Institute, Cleveland Clinic.

About the LANDMARK Survey

The LANDMARK disease burden survey is a cross-sectional study of HCPs, patients and caregivers assessing the real-world burden of SBS and PS dependence. The HCP survey recruited 336 participants (U.S., n=123; Europe, n=213) with two or more years of experience treating patients with SBS-IF and actively managing one or more patients. Respondents included physicians (42.0%), pharmacists (23.0%) and dietitians (18.0%), practicing primarily in gastroenterology (45.2%), clinical nutrition/nutritional support (23.5%) and internal medicine (17.3%).

About Apraglutide

Apraglutide is an investigational, next-generation, long-acting synthetic GLP-2 analog with the potential to treat a range of rare gastrointestinal diseases where GLP-2 can play a central role in addressing disease pathophysiology. Ironwood is advancing apraglutide for short bowel syndrome (“SBS”) patients dependent on parenteral support (“PS”), a severe chronic malabsorptive condition. As the first and only GLP-2 to achieve a statistically significant reduction in weekly parenteral support volume with once-weekly administration, Ironwood believes apraglutide has the potential to improve the standard of care for adult patients with SBS who are dependent on PS.

About LINZESS (Linaclotide)

LINZESS^® is the #1 prescribed brand in the U.S. for the treatment of patients with irritable bowel syndrome with constipation (IBS-C) or chronic idiopathic constipation (CIC), based on IQVIA data. LINZESS is a once-daily capsule that helps relieve the abdominal pain and constipation, associated with IBS-C in adults and pediatric patients 7 years of age and older. LINZESS has also been shown to relieve constipation, infrequent stools, hard stools, straining and incomplete evacuation associated with CIC in adult patients. LINZESS relieves constipation in children and adolescents aged 6 to 17 years with functional constipation.

LINZESS is not a laxative; it is the first medicine approved by the FDA in a class called GC-C agonists. LINZESS contains a peptide called linaclotide that activates the GC-C receptor in the intestine. Activation of GC-C is thought to result in increased intestinal fluid secretion and accelerated transit and a decrease in the activity of pain-sensing nerves in the intestine. The clinical relevance of the effect on pain fibers, which is based on nonclinical studies, has not been established.

In the United States, Ironwood and AbbVie co-develop and co-commercialize LINZESS for the treatment of adults with IBS-C or CIC. In Europe, AbbVie markets linaclotide under the brand name CONSTELLA^® for the treatment of adults with moderate to severe IBS-C. In Japan, Ironwood's partner, Astellas, markets linaclotide under the brand name LINZESS for the treatment of adults with IBS-C or CIC. Ironwood also has partnered with AstraZeneca for development and commercialization of LINZESS in China, and with AbbVie for development and commercialization of linaclotide in all other territories worldwide.

LINZESS Important Safety Information

INDICATIONS AND USAGE

LINZESS^® (linaclotide) is indicated for the treatment of irritable bowel syndrome with constipation (IBS-C) in adults and pediatric patients 7 years of age and older and for the treatment of chronic idiopathic constipation (CIC) in adults and for the treatment of functional constipation (FC) in children and adolescents 6 to 17 years of age.

IMPORTANT SAFETY INFORMATION

WARNING: RISK OF SERIOUS DEHYDRATION IN PEDIATRIC PATIENTS LESS THAN 2 YEARS OF AGE
LINZESS is contraindicated in patients less than 2 years of age. In nonclinical studies in neonatal mice, administration of a single, clinically relevant adult oral dose of linaclotide caused deaths due to dehydration.

Contraindications

• LINZESS is contraindicated in patients less than 2 years of age due to the risk of serious dehydration.
• LINZESS is contraindicated in patients with known or suspected mechanical gastrointestinal obstruction.

Warnings and Precautions

• LINZESS is contraindicated in patients less than 2 years of age. In neonatal mice, linaclotide increased fluid secretion as a consequence of age-dependent elevated guanylate cyclase (GC-C) agonism, which was associated with increased mortality within the first 24 hours due to dehydration. There was no age dependent trend in GC-C intestinal expression in a clinical study of children 2 to less than 18 years of age; however, there are insufficient data available on GC-C intestinal expression in children less than 2 years of age to assess the risk of developing diarrhea and its potentially serious consequences in these patients.

Diarrhea

• In adults, diarrhea was the most common adverse reaction in LINZESS-treated patients in the pooled IBS-C and CIC double-blind placebo-controlled trials. The incidence of diarrhea was similar in the IBS-C and CIC populations. Severe diarrhea was reported in 2% of 145 mcg and 290 mcg LINZESS-treated patients and in <1% of 72 mcg LINZESS-treated CIC patients.
• In pediatric patients, diarrhea was also the most common adverse reaction of LINZESS-treated patients in IBS-C and FC clinical trials. In two double-blind trials, diarrhea was reported in 4% of pediatric patients 6 to 17 years of age with FC treated with LINZESS 72 mcg once daily, and 7% and 8% of pediatric patients 7 to 17 years of age with IBS-C treated with LINZESS 145 mcg and 290 mcg once daily, respectively. In clinical trials, severe diarrhea was reported in one pediatric patient with FC treated with LINZESS 72 mcg once daily and in one pediatric patient with IBS-C treated with LINZESS at a dosage higher than the recommended 145 mcg once daily dosage for IBS-C.

Common Adverse Reactions (incidence ≥2% and greater than placebo)

• In IBS-C or CIC adult patients: diarrhea, abdominal pain, flatulence and abdominal distension.
• Most common adverse reaction reported in pediatric patients with FC or IBS-C is diarrhea.

Please see full Prescribing Information including Boxed Warning: https://www.rxabbvie.com/pdf/linzess_pi.pdf

LINZESS^® and CONSTELLA^® are registered trademarks of Ironwood Pharmaceuticals, Inc. Any other trademarks referred to in this press release are the property of their respective owners. All rights reserved.

About Ironwood Pharmaceuticals

Ironwood Pharmaceuticals (Nasdaq: IRWD) is a biotechnology company developing and commercializing life-changing therapies for people living with gastrointestinal (GI) and rare diseases. Ironwood is advancing apraglutide, a next-generation, long-acting synthetic GLP-2 analog being developed for short bowel syndrome patients who are dependent on parenteral support. In addition, Ironwood has been a pioneer in the development of LINZESS^® (linaclotide), the U.S. branded prescription market leader for the treatment of irritable bowel syndrome with constipation (IBS-C) or chronic idiopathic constipation (CIC). Building upon our history of innovation, we keep patients at the heart of our R&D and commercialization efforts to reduce the burden of diseases and address significant unmet needs.

Founded in 1998, Ironwood Pharmaceuticals is headquartered in Boston, Massachusetts, with a site in Basel, Switzerland.

We routinely post information that may be important to investors on our website at www.ironwoodpharma.com. In addition, follow us on X and on LinkedIn.

About DDW

Digestive Disease Week^® (DDW) is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. Jointly sponsored by the American Association for the Study of Liver Diseases (AASLD), the American Gastroenterological Association (AGA), the American Society for Gastrointestinal Endoscopy (ASGE) and the Society for Surgery of the Alimentary Tract (SSAT), DDW is an in-person and online meeting.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Investors are cautioned not to place undue reliance on these forward-looking statements, including statements about Ironwood’s LANDMARK survey presentation; presentation of long-term safety and tolerability data from the apraglutide clinical program in adults with SBS who are dependent on PS and key findings from its Phase 3 open-label safety extension study of linaclotide in pediatric patients aged 2–5 years with FC, as well as analyses in adults with IBS-C and CIC; and the estimated adult population who suffer from SBS-IF in the U.S., Europe and Japan. These forward-looking statements speak only as of the date of this press release, and Ironwood undertakes no obligation to update these forward-looking statements. 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 those related to the effectiveness of development and commercialization efforts by us and our partners; preclinical and clinical development, manufacturing and formulation development of linaclotide, apraglutide, and our other product candidates; the risk of uncertainty relating to pricing and reimbursement policies in the U.S., which, if not favorable for our products, could hinder or prevent our products’ commercial success; the risk that clinical programs and studies, including for linaclotide pediatric programs and apraglutide, may not progress or develop as anticipated, including that studies are delayed or discontinued for any reason, such as safety, tolerability, enrollment, manufacturing, economic or other reasons; the risk that findings from our completed nonclinical studies and clinical trials may not be replicated in later trials and earlier-stage clinical trials may not be predictive of the results we may obtain in later-stage clinical trials or of the likelihood of regulatory approval; the risk that apraglutide will not be approved by the FDA or other regulatory agencies; the risk of competition or that new products may emerge that provide different or better alternatives for treatment of the conditions that our products are approved to treat; the risk that we are unable to execute on our strategy to in-license externally developed products or product candidates; the risk that we are unable to successfully partner with other companies to develop and commercialize products or product candidates; the risk that healthcare reform and other governmental and private payor initiatives may have an adverse effect upon or prevent our products’ or product candidates’ commercial success; the efficacy, safety and tolerability of linaclotide and our product candidates; the risk that the commercial and therapeutic opportunities for LINZESS, apraglutide or our other product candidates are not as we expect; decisions by regulatory and judicial authorities; the risk we may never get additional patent protection for linaclotide, apraglutide and other product candidates, that patents for linaclotide, apraglutide or other products may not provide adequate protection from competition, or that we are not able to successfully protect such patents; the risk that we are unable to manage our expenses or cash use, or are unable to commercialize our products as expected; the risk that the development of any of our linaclotide pediatric programs and/or apraglutide is not successful or that any of our product candidates does not receive regulatory approval or is not successfully commercialized; outcomes in legal proceedings to protect or enforce the patents relating to our products and product candidates, including abbreviated new drug application litigation; the risk that financial and operating results may differ from our projections; developments in the intellectual property landscape; challenges from and rights of competitors or potential competitors; the risk that our planned investments do not have the anticipated effect on our company revenues; developments in accounting guidance or practice; Ironwood’s or AbbVie’s accounting practices, including reporting and settlement practices as between Ironwood and AbbVie; the risk that our indebtedness could adversely affect our financial condition or restrict our future operations; and the risks listed under the heading “Risk Factors” and elsewhere in our Annual Report on Form 10-K for the year ended December 31, 2025, and in our subsequent Securities and Exchange Commission filings.

View source version on businesswire.com: https://www.businesswire.com/news/home/20260423319236/en/

Company Contact:
Greg Martini
Chief Financial Officer
gmartini@ironwoodpharma.com

Investors:
Precision AQ (formerly Stern Investor Relations)
Stephanie Ascher
Stephanie.Ascher@precisionaq.com

Source: Ironwood Pharmaceuticals, Inc.