Ironwood Pharmaceuticals Reports Strong First

Ironwood Pharmaceuticals Reports Strong First

Quarter 2026 Results with 97% year-over-year LINZESS U.S. Net Sales Growth; Maintains Full-Year 2026 Financial Guidance

- LINZESS (linaclotide)

U.S. net sales of $273 million in Q1 2026, primarily driven by improved net price and 5% EUTRx demand growth year-over-year -

- Total revenue of $107 million,

GAAP net income of $41 million and adjusted EBITDA of $77 million in Q1 2026 -

- On track to begin site initiations for Phase 3 confirmatory trial of apraglutide in short bowel syndrome with intestinal failure (SBS-IF) in the second quarter of 2026 -

- sNDA for LINZESS treatment of functional constipation (FC) in patients 2 to 5 years of age accepted and granted priority review by FDA; PDUFA date set for May 24th -

BOSTON, Mass., May 7, 2026 -

Ironwood Pharmaceuticals, Inc. (Nasdaq: IRWD), a biotechnology company developing and commercializing

life-changing therapies for people living with gastrointestinal (GI) and rare diseases, today reported its first quarter 2026 results

and recent business performance.

"Our first quarter of 2026 delivered strong financial performance,

driven by significantly improved net price and mid-single digit prescription growth for LINZESS, positioning us well to achieve our full-year

2026 financial guidance," said Tom McCourt, chief executive officer of Ironwood. "We expect strong first quarter revenue to

result in significant operating cash flows in the second quarter of 2026, which will help support repayment of our 2026 convertible notes

at maturity in June."

"We remain on track for site initiation for the confirmatory

STARS-2 Phase 3 clinical trial in the second quarter," said Michael Shetzline, chief medical officer, senior vice president and

head of research and drug development at Ironwood. "Building on the positive results from STARS, we believe that the highly potent,

selective, and long-acting pharmacologic properties of apraglutide have the potential to drive best-in-class efficacy and tolerability

with once-weekly dosing and redefine the standard of care in SBS-IF. Importantly, the long-term data generated to date show compelling

enteral autonomy outcomes, with rapid and sustained reductions in parenteral support over time."

First Quarter 2026 Financial Highlights1

(in thousands, except for per share amounts)

1 Refer to the Reconciliation of GAAP Results to Non-GAAP

Financial Measures table and to the Reconciliation of GAAP Net Income (Loss) to Adjusted EBITDA table at the end of this press release.

Refer to Non-GAAP Financial Measures for additional information.

2 Adjusted EBITDA is calculated by subtracting stock-based compensation, net restructuring expenses, net interest expense,

income taxes, depreciation and amortization, from GAAP net income (loss).

First Quarter and Full Year 2026 Corporate Highlights

First Quarter 2026 Financial Results

1 Ironwood's U.S. collaborative arrangements

revenue includes reimbursement from AbbVie for a portion of Ironwood's commercial expenses related to sales of LINZESS in the U.S.

2 Adjusted EBITDA is calculated by subtracting stock-based compensation, net restructuring expenses, net interest expense,

income taxes, and depreciation and amortization from GAAP net income (loss). For purposes of this guidance, we have assumed that Ironwood

will not incur material expenses related to business development activities in 2026. Ironwood does not provide guidance on GAAP net income

or a reconciliation of expected adjusted EBITDA to expected GAAP net income because, without unreasonable efforts, it is unable to predict

with reasonable certainty the non-GAAP adjustments used to calculate adjusted EBITDA. These adjustments are uncertain, depend on various

factors and could have a material impact on GAAP net income for the guidance period. Management believes this non-GAAP information is

useful for investors, taken in conjunction with Ironwood's GAAP financial statements, because it provides greater transparency and

period-over-period comparability with respect to Ironwood's operating performance. These measures are also used by management to

assess the performance of the business. Investors should consider these non-GAAP measures only as a supplement to, not as a substitute

for or as superior to, measures of financial performance prepared in accordance with GAAP. In addition, these non-GAAP financial measures

are unlikely to be comparable with non-GAAP information provided by other companies.

Non-GAAP Financial Measures

Ironwood presents non-GAAP net income (loss) and non-GAAP net income

(loss) per share to exclude amortization of acquired intangible assets, and net restructuring expenses, all net of tax effect. Non-GAAP

adjustments are further detailed below:

Management believes this non-GAAP information is useful for investors,

taken in conjunction with Ironwood's GAAP financial statements, because it provides greater transparency and period-over-period

comparability with respect to Ironwood's operating performance. These measures are also used by management to assess the performance

of the business. Investors should consider these non-GAAP measures only as a supplement to, not as a substitute for or as superior to,

measures of financial performance prepared in accordance with GAAP. In addition, these non-GAAP financial measures are unlikely to be

comparable with non-GAAP information provided by other companies. For a reconciliation of non-GAAP net income (loss) and non-GAAP net

income (loss) per share to GAAP net income (loss) and GAAP net income (loss) per share, respectively, and for a reconciliation of adjusted

EBITDA to GAAP net income (loss), please refer to the tables at the end of this press release.

Ironwood does not provide guidance on GAAP net income or a reconciliation

of expected adjusted EBITDA to expected GAAP net income because, without unreasonable efforts, it is unable to predict with reasonable

certainty the non-GAAP adjustments used to calculate adjusted EBITDA. These adjustments are uncertain, depend on various factors and could

have a material impact on GAAP net income for the guidance period.

Conference Call Information

Ironwood will host a conference call and webcast at 8:30 a.m. Eastern

Time on Thursday, May 7th, 2026 to discuss its first quarter results and recent business activities. Individuals interested

in participating in the call should dial (888) 596-4144 (U.S. and Canada) or (646) 968-2525 (international) using conference ID number

and event passcode 3647053. To access the webcast, please visit the Investors section of Ironwood's website at www.ironwoodpharma.com.

The call will be available for replay via telephone starting Thursday, May 7th, 2026, at approximately 11:30 a.m. Eastern Time, running

through 11:59 p.m. Eastern Time on Thursday, May 21st, 2026. To listen to the replay, dial (800) 770-2030 (U.S. and Canada) or (609)

800-9909 (international) using conference ID number 3647053. The archived webcast will be available on Ironwood's website for 1

year beginning approximately one hour after the call has completed.

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

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.