Ironwood Pharmaceuticals Reports First Quarter 2024 Results - Reported positive topline results from global Phase III STARS trial of once-weekly apraglutide in adults with short bowel syndrome with intestinal failure (SB

Ironwood Pharmaceuticals Reports First

Quarter 2024 Results

- Reported positive topline results from

global Phase III STARS trial of once-weekly apraglutide in adults with short bowel syndrome with intestinal failure (SBS-IF) -

- Reported positive results from Phase

II exploratory STARGAZE trial of apraglutide in patients with steroid-refractory gastrointestinal acute Graft-versus-Host Disease (SR

- LINZESS (Iinaclotide)

EUTRx prescription demand growth of 10% year-over-year -

- Revises FY 2024 financial guidance due

to a LINZESS gross-to-net change in estimate -

BOSTON, Mass., May 9, 2024

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

today reported its first quarter 2024 results and recent business performance.

"In the first quarter of 2024, we made significant advancements

across our portfolio," said Tom McCourt, chief executive officer of Ironwood. "LINZESS maintained its strong demand momentum,

experiencing a rise in prescription volume by a robust 10% year-over-year, while continuing to generate meaningful cash flow. Particularly

noteworthy during the quarter was the positive Phase III clinical data for apraglutide, which validates its potential as the first and

only once-weekly GLP-2 analog for adult patients with short bowel syndrome who are dependent on parenteral support. The positive results

from the STARS trial, coupled with our proven track record of effective commercial execution, uniquely position Ironwood in the market

and reinforce our belief in the long-term value potential of apraglutide for patients and shareholders. We are working swiftly and plan

to file an NDA as soon as possible for apraglutide for adult SBS patients dependent on parenteral support. In addition, we remain focused

on executing across our strategic priorities by advancing our other GI pipeline assets, driving robust LINZESS demand growth, and delivering

sustained profits and cash flow."

First Quarter 2024 Financial

(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 Figures presented in Q1 2024 include a $30.0

million reduction to collaborative arrangements revenue due to a LINZESS gross-to-net change in estimate related to the year ended December 31,

First Quarter 2024 Corporate

2024 Financial Results

1 Adjusted EBITDA is calculated by subtracting restructuring

expenses, net interest expense, income taxes, depreciation and amortization, and acquisition-related costs from GAAP net income. For

purposes of the 2024 guidance, Ironwood has assumed it will not incur material expenses related to business development activities

in 2024 and excludes any costs associated with potential CNP-104 option exercise. 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.

2 Based on information provided by AbbVie, Ironwood estimates a $60.0 million LINZESS gross-to-net change related to the year ended December

31, 2023, and has recorded a $30.0 million reduction to collaborative arrangements revenue in its first quarter 2024 financial statements

to reflect this change in estimate.

3 2024 U.S. LINZESS Net Sales guidance presented as

year-over-year change relative to 2023 U.S. LINZESS Net Sales as reported by AbbVie of $1,073.2 million.

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, amortization of acquired intangible assets, restructuring expenses, and acquisition-related costs.

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 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 Thursday, May 9, 2024 to discuss its first quarter 2024 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 3416473. 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 May 9,

2024, running through 11:59 p.m. Eastern Time on May 23, 2024. To listen to the replay, dial (800) 770-2030 (U.S. and

Canada) or (609) 800-9909 (international) using conference ID number 3416473. 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), an S&P

SmallCap 600 company, is a leading 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 unmet

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