Ironwood Pharmaceuticals Reports Second Quarter 2023 Results; Raises Full Year 2023 LINZESS U.S. Net Sales and Ironwood Revenue Guidance - LINZESS (Iinaclotide) EUTRx prescription demand growth incr

Ironwood Pharmaceuticals

Reports Second Quarter 2023 Results; Raises Full Year 2023 LINZESS U.S. Net Sales and Ironwood Revenue Guidance

(Iinaclotide) EUTRx prescription demand growth increased 9% year-over-year; LINZESS U.S. net sales of $270 million, an increase of 9%

- Expands clinical utility of LINZESS

with FDA approval for pediatric patients ages 6-17 years-old suffering from functional constipation (FC) -

- Strengthens GI development portfolio

with acquisition of VectivBio Holding AG and its lead investigational asset, apraglutide, for the potential treatment of short bowel

syndrome with intestinal failure -

- Completes STARS Phase III clinical

trial enrollment; now expects topline data in March of 2024 -

BOSTON, Mass., August 8, 2023

- Ironwood Pharmaceuticals, Inc. (Nasdaq: IRWD), a GI-focused healthcare company, today reported its second

quarter 2023 results and updated its full year 2023 financial guidance.

"We made significant progress towards the goal of becoming the

leading GI healthcare company, as the second quarter was truly transformative for Ironwood," said Tom McCourt, chief executive

officer of Ironwood. "LINZESS continued its strong momentum with another quarter of impressive performance. As a result, we are

raising our full-year 2023 U.S. net sales and Ironwood revenue guidance. Furthermore, we are thrilled that in June the FDA approved

LINZESS for the treatment of pediatric patients ages 6 to 17 years-old with functional constipation, expanding its clinical utility and

adding another potential growth driver for the brand. Also in the second quarter, we strengthened our GI portfolio with the acquisition

of VectivBio, including its lead investigational asset, apraglutide, which we believe is poised to become the new standard of care for

patients with short bowel syndrome with intestinal failure if successfully developed and approved, with the potential to achieve $1 billion

in peak net sales. Looking ahead, we are excited about continuing to maximize LINZESS, advance our clinical programs, strengthen our

financial position, and grow Ironwood's leadership within GI."

Second Quarter 2023 Financial Highlights1

(in thousands, except for per share amounts)

Second Quarter 2023 Corporate Highlights

FDA Approval of New Indication for LINZESS

Acquisition of VectivBio Holding AG ("VectivBio")

Workforce Reductions and Restructuring

Second Quarter 2023 Financial Results

1 Adjusted EBITDA is calculated by subtracting mark-to-market

adjustments on derivatives related to Ironwood's 2022 Convertible Notes, restructuring expenses, net interest expense, income taxes,

depreciation and amortization, and acquisition-related costs from GAAP net income.

2 Updated 2023 adjusted EBITDA guidance includes a one-time

charge of approximately $1.1 billion related to acquired in-process research and development from the acquisition of VectivBio in the

second quarter of 2023. For purposes of this guidance, Ironwood has assumed that it will not incur material expenses related to

additional business development activities in 2023.

Non-GAAP Financial Measures

Ironwood presents non-GAAP net income and non-GAAP net income per

share to exclude the impact, net of tax effects, of net gains and losses on derivatives related to Ironwood's 2022 Convertible

Notes that are required to be marked-to-market, restructuring expenses, and acquisition-related costs. Non-GAAP adjustments are further

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

as guidance on adjusted EBITDA. Adjusted EBITDA is calculated by subtracting mark-to-market adjustments on derivatives related to Ironwood's

2022 Convertible Notes, 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, 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 and non-GAAP net income

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.

Conference Call Information

Ironwood will host a conference call

and webcast at 8:30 a.m. Eastern Time on Tuesday, August 8, 2023 to discuss its second quarter 2023 results and recent business

activities. Individuals interested in participating in the call should dial (888) 330-2384 (U.S. and Canada) or (240) 789-2701 (international)

using conference ID number and event passcode 4671230. To access the webcast, please visit the Investors section of Ironwood's

website at www.ironwoodpharma.com at least 15 minutes prior to the start of the call to ensure adequate time for any software downloads

that may be required. The call will be available for replay via telephone starting at approximately 11:30 a.m. Eastern Time on August 8,

2023, running through 11:59 p.m. Eastern Time on August 22, 2023. To listen to the replay, dial (800) 770-2030 (U.S.

and Canada) or (647) 362-9199 (international) using conference ID number 4671230. The archived webcast will be available on Ironwood's

website for 14 days beginning approximately one hour after the call has completed.

About Ironwood Pharmaceuticals

Ironwood Pharmaceuticals (Nasdaq: IRWD), an S&P

SmallCap 600 company, is a leading global gastrointestinal (GI) healthcare company on a mission to advance the treatment of GI diseases

and redefine the standard of care for GI patients. We are pioneers 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. Ironwood is also advancing

apraglutide, a next-generation, long-acting synthetic GLP-2 analog being developed for rare gastrointestinal diseases, including short

bowel syndrome with intestinal failure (SBS-IF) as well as several earlier stage assets. Building upon our history of GI innovation,

we keep patients at the heart of our R&D and commercialization efforts to reduce the burden of GI diseases and address significant

Founded in 1998, Ironwood Pharmaceuticals

is headquartered in Boston, Massachusetts, and has additional operations 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