Ironwood Pharmaceuticals Reports Second Quarter 2020 Results; Delivered GAAP Net Income of $25 Million and Adjusted EBITDA of $33 Million - Grew LINZESS (Iinaclotide) total prescription demand by 9%

Pharmaceuticals Reports Second Quarter 2020 Results; Delivered GAAP Net

of $25 Million and Adjusted EBITDA of $33 Million

Grew LINZESS (Iinaclotide) total prescription demand by 9% year-over-year; new-to-brand prescription demand

grew >15% in June 2020 compared to March 2020 -

Made important updates designed to strengthen IW-3718 Phase III program; FDA indicated that long-term safety study for

IW-3718 is not required for an NDA submission -

Reinstating full year 2020 total revenue and LINZESS net sales growth guidance; reiterating adjusted EBITDA guidance -

Mass., August 6, 2020 - Ironwood Pharmaceuticals, Inc. (Nasdaq: IRWD), a GI-focused

healthcare company, today provided an update on its second quarter 2020 results and recent business performance, as well as an

update related to the impact of the COVID-19 pandemic on its business.

execution resulted in another solid quarter, highlighting the fundamental strength and resiliency of our business as we

continue to advance our mission of advancing GI diseases and redefining the standard of care for millions of GI patients,

despite the challenges posed by the COVID-19 pandemic," said Mark Mallon, chief executive officer of Ironwood.

"We are disappointed by the Phase II results for MD-7246; however, our strategy remains clear and we believe we are

well-positioned for long-term growth, evidenced by continued LINZESS performance, the updates we made designed to strengthen

our IW-3718 Phase III program, and our fifth consecutive profitable quarter."

COVID-19 Business Impact

The impact of the COVID-19 pandemic

continues to be far-reaching and unpredictable in the U.S. and around the world. Ironwood is taking important actions designed

to help mitigate the impacts of the COVID-19 pandemic on its business and is following applicable federal, state and local health

Second Quarter 2020 Financial

(in thousands, except for

Second Quarter 2020 Corporate

Global Collaborations and

U.S. Promotional Partnerships

Second Quarter Financial Results

EBITDA is calculated by subtracting net interest expense, taxes, depreciation, amortization, mark-to-market adjustments on derivatives

related to Ironwood's 2022 Convertible Notes, restructuring expenses, separation expenses, and loss on extinguishment of

debt from GAAP net income (loss) from continuing operations.

Ironwood presents non-GAAP net

income (loss) and non-GAAP net income (loss) per share to exclude the impact of net gains and losses on derivatives related to

our 2022 Convertible Notes that are required to be marked-to-market. Ironwood also excludes restructuring, and separation-related

expenses from non-GAAP net income (loss), if any. These adjustments, as applicable, are reflected in the non-GAAP net income (loss)

in the second quarter 2020 presented in this press release. 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 net interest

expense, taxes, depreciation, amortization, mark-to-market adjustments on derivatives related to Ironwood's 2022 Convertible

Notes, restructuring expenses, and separation expenses from GAAP net income (loss) from continuing operations. 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 (loss) and GAAP

net income (loss) per share, respectively, and for a reconciliation of adjusted EBITDA to net income (loss) from continuing operations

on a GAAP basis, please refer to the tables at the end of this press release.

Ironwood does not provide

guidance on GAAP net income (loss) from continuing operations or a reconciliation of expected adjusted EBITDA to expected

GAAP net income (loss) from continuing operations because, without unreasonable efforts, it is unable to predict with

reasonable certainty the non-GAAP adjustments used to calculate adjusted EBITDA including, without limitation, the

mark-to-market adjustments on the derivatives related to its 2022 Convertible Notes. These adjustments are uncertain,

depend on various factors and could have a material impact on GAAP net income (loss) from continuing operations for the

Conference Call Information

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

Eastern Time on Thursday, August 6, 2020 to discuss its second quarter 2020 results and recent business activities. Individuals

interested in participating in the call should dial (866) 324- 3683 (U.S. and Canada) or (509) 844-0959 (international) using conference

ID number 6183913. 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 6, 2020 running through

11:59 p.m. Eastern Time on August 20, 2020. To listen to the replay, dial (855) 859-2056 (U.S. and Canada) or (404) 537-4306 (international)

using conference ID number 6183913. 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) is a GI-focused healthcare

company dedicated to creating medicines that make a difference for patients living with GI diseases. We discovered, developed and

are commercializing linaclotide, the U.S. branded prescription market leader for adults with irritable bowel syndrome with constipation

(IBS-C) or chronic idiopathic constipation (CIC). We are also advancing IW-3718, a gastric retentive formulation of a bile acid

sequestrant being developed for the potential treatment of refractory gastroesophageal reflux disease. IW-3718 is first-in-category

product candidate currently in Phase III clinical trials.

Ironwood was founded in 1998 and is headquartered in Boston,

Mass. For more information, please visit our website at www.ironwoodpharma.com or www.twitter.com/ironwoodpharma;

information that may be important to investors will be routinely posted in both these locations.

About LINZESS (linaclotide)

prescribed brand for the treatment of adult patients with irritable bowel syndrome with constipation (IBS-C) and 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, as well as the constipation, infrequent stools,

hard stools, straining, and incomplete evacuation associated with CIC. 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.

LINZESS should be taken at least 30 minutes before the first meal of the day.

contraindicated in pediatric patients less than 6 years of age. The safety and effectiveness of LINZESS in pediatric patients

less than 18 years of age have not been established. In neonatal mice, linaclotide increased fluid secretion as a consequence

of GC-C agonism resulting in mortality within the first 24 hours due to dehydration. Due to increased intestinal expression

of GC-C, patients less than 6 years of age may be more likely than patients 6 years of age and older to develop severe

diarrhea and its potentially serious consequences. In adults with IBS-C or CIC treated with LINZESS, the most commonly

reported adverse event was diarrhea.

LINZESS is not a laxative; it is the first medicine approved

by the FDA in a class called guanylate cyclase-C (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