Ironwood Pharmaceuticals Reports First Quarter 2025 Results - On track to achieve FY 2025 financial guidance; raised adjusted EBITDA guidance to greater than $105 million for 2025 - - LINZESS (Iinac

Pharmaceuticals Reports First Quarter 2025 Results

- On track to achieve

FY 2025 financial guidance; raised adjusted EBITDA guidance to greater than $105 million for 2025 -

- LINZESS (Iinaclotide) EUTRx prescription

demand growth of 8% year-over-year; in line with full-year expectations -

strategic alternatives to maximize stockholder value -

BOSTON, Mass., May 7, 2025 - 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 2025 results and recent business performance.

"LINZESS demand continues to be strong, and we remain on track

to meet our full-year 2025 guidance and further, recently raised our adjusted EBITDA guidance. We are making a concerted effort to maximize

stockholder value across all areas of the business, including advancing plans for a confirmatory Phase 3 trial for apraglutide and exploring

strategic alternatives," said Tom McCourt, chief executive officer of Ironwood.

First Quarter 2025 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 Loss to Adjusted EBITDA table at the end of this press release. Refer to

Non-GAAP Financial Measures for additional information.

2 Total revenue for three months ended March 31, 2025

reflects a change in estimate of AbbVie gross-to-net rebate reserves, which was refined to reflect rebates owed for units dispensed in

the first quarter of 2025. Ironwood does not expect first quarter LINZESS U.S. net sales results or this change in estimate to impact

the full-year results.

3 Adjusted EBITDA is calculated by subtracting restructuring

expenses, net interest expense, income taxes, depreciation and amortization, and stock-based compensation, from GAAP net income. The exclusion

of stock-based compensation from Adjusted EBITDA represents an update to our definition of Adjusted EBITDA, effective in the first quarter

of 2025. For comparison purposes, first quarter 2024 Adjusted EBITDA has also been updated to reflect this updated definition.

2025 Corporate Highlights

First Quarter 2025 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. The FY2025 total revenue guidance accounts for the impact of the reduction to Ironwood's commercial

expenses and corresponding reimbursement from AbbVie due to Ironwood's strategic reorganization announced in

2 Adjusted EBITDA is calculated by subtracting restructuring

expenses, net interest expense, income taxes, depreciation and amortization and stock-based compensation, from GAAP net income. The exclusion

of stock-based compensation from Adjusted EBITDA represents an update to our definition of Adjusted EBITDA, effective in the first quarter

of 2025. For purposes of this guidance, we have assumed that Ironwood will not incur material expenses related to business development

activities in 2025. 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

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, restructuring expenses, and acquisition-related costs, all net

of tax effect. Non-GAAP adjustments are further detailed below:

Ironwood also presents adjusted EBITDA, a non-GAAP measure, as well

as guidance on adjusted EBITDA. Adjusted EBITDA is calculated by subtracting stock-based compensation, restructuring expenses, net interest

expense, income taxes, depreciation and amortization, and acquisition-related costs from GAAP net income. The adjustments are made on

a similar basis as described above related to non-GAAP net income (loss), as applicable.

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 and GAAP net income per share, respectively, and for a reconciliation of adjusted EBITDA to

GAAP net income, 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.

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 adults with irritable bowel syndrome with constipation (IBS-C) or chronic idiopathic constipation

(CIC). LINZESS is also approved for the treatment of functional constipation in pediatric patients ages 6-17 years old. 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.

routinely post information that may be important to investors on our website at www.ironwoodpharma.com.

About LINZESS (Linaclotide)

LINZESS is the #1 prescribed brand in the U.S. for the treatment

of adult 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,

constipation, and overall abdominal symptoms of bloating, discomfort and pain associated with IBS-C, as well as the constipation, infrequent

stools, hard stools, straining, and incomplete evacuation associated with CIC. LINZESS relieves constipation in children and adolescents

aged 6 to 17 years with functional constipation. The recommended dose is 290 mcg for IBS-C patients and 145 mcg for CIC patients, with

a 72 mcg dose approved for use in CIC depending on individual patient presentation or tolerability. In children with functional constipation

aged 6 to 17 years, the recommended dose is 72 mcg.

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