​ Forward-Looking Information ​ The following discussion of our financial condition and results of operations should be read in conjunction with our condensed consolidated financial statements and the notes to those financial statements appearing elsewhere in this Quarterly Report on Form 10-Q and the audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2025 which was filed with the U.S. Securities and Exchange Commission, or the SEC, on February 26, 2026, or the 2025 Annual Report on Form 10-K. This discussion contains forward-looking statements that involve significant risks and uncertainties. As a result of many factors, such as those set forth under “Note Regarding Forward-Looking Statements,” in this Quarterly Report on Form 10-Q, under “Part I, Item 1A—Risk Factors” in our 2025 Annual Report on Form 10-K and under “Risk Factors” in Part II, Item 1A of this Quarterly Report on Form 10-Q, our actual results may differ materially from those anticipated in these forward-looking statements. ​ Overview ​ We are a biotechnology company developing and commercializing life-changing therapies for people living with gastrointestinal, or GI, and rare diseases. We are focused on the development and commercialization of innovative product opportunities in areas of significant unmet need, leveraging our demonstrated expertise and capabilities in GI and rare diseases. ​ LINZESS® (linaclotide), our commercial product, is the first product approved by the United States Food and Drug Administration, or U.S. FDA, in a class of GI medicines called guanylate cyclase type C agonists, or GC-C agonists, and is indicated, in the U.S., for the treatment of irritable bowel syndrome with constipation, or IBS-C, in adults and pediatric patients 7 years of age and older, chronic idiopathic constipation, or CIC, in adults, and functional constipation, or FC, in pediatric patients ages 2-17 years-old. LINZESS is also available for the treatment of adults with IBS-C or CIC in Mexico and Kingdom of Saudi Arabia, adults with IBS-C or chronic constipation in Japan, and adults with IBS-C in China. Linaclotide is available under the trademarked name CONSTELLA® for the treatment of adults with IBS-C or CIC and pediatric patients ages 6-17 years old with FC in Canada, and to adults with IBS-C in certain European countries. ​ 24 Table of Contents We have strategic partnerships with leading pharmaceutical companies to support the development and commercialization of linaclotide throughout the world, including with our partner, AbbVie Inc., or together with its affiliates, AbbVie, in the U.S. and all countries worldwide other than China (including Hong Kong and Macau) and Japan, Grand Life Sciences (Beijing) Co., Ltd., or Grand Life Sciences, in China (including Hong Kong and Macau), and Astellas Pharma Inc., or Astellas, in Japan. In May 2026, AstraZeneca AB, our former partner in China (including Hong Kong and Macau), notified us that it assigned all its rights and obligations under the collaboration agreement to Grand Life Sciences. ​ We are also advancing apraglutide, a next-generation, synthetic long-acting peptide analog of glucagon-like peptide-2, or GLP-2, for short bowel syndrome, or SBS, patients who are dependent on parenteral support, or PS. In February 2024, we announced positive topline results from our pivotal Phase III clinical trial, STARS, which evaluated the efficacy and safety of once-weekly subcutaneous apraglutide in reducing parenteral support dependency in adult patients with short bowel syndrome with intestinal failure, or SBS-IF. We are also conducting an open-label extension study, STARS Extend, to further assess the safety of apraglutide in adult patients with SBS-IF. In April 2025, we announced that, based on discussions with the U.S. FDA, a confirmatory Phase III clinical trial is needed to seek approval of a new drug application or NDA, for apraglutide for patients with SBS-IF who are dependent on PS. We subsequently met with the U.S. FDA and aligned on key design elements of a confirmatory Phase III clinical trial, STARS-2, of apraglutide. STARS-2 is a 24-week global, randomized, double-blind, placebo-controlled trial. The clinical trial will consist of a primary endpoint measuring relative change from baseline in actual weekly PS as well as additional key secondary endpoints. In June 2026, we initiated STARS-2 and are actively recruiting patients. ​ To date, we have dedicated a majority of our activities to the research, development and commercialization of linaclotide, as well as other research and development programs, including apraglutide. For the three and six months ended June 30, 2026, we recorded net income of $51.3 million and $92.1 million, respectively. For the three and six months ended June 30, 2025, we recorded net income of $23.6 million and a net loss of $13.8 million, respectively. As of June 30, 2026, we had an accumulated deficit of approximately $1.6 billion. We are unable to predict the extent of any future losses or guarantee that our company will be able to generate and maintain positive cash flows. ​ We were incorporated in Delaware on January 5, 1998 as Microbia, Inc. On April 7, 2008, we changed our name to Ironwood Pharmaceuticals, Inc. We operate in one reportable business segment—human therapeutics. ​ Financial Operations Overview ​ Revenues. Our revenues are generated primarily through our collaborative arrangements and license agreements related to research and development and commercialization of linaclotide. ​ The majority of our revenues are generated from the sales of LINZESS in the U.S. We record our share of the net profits and losses from the sales of LINZESS in the U.S. less commercial expenses on a net basis and present the settlement payments to and from AbbVie as collaboration expense or collaborative arrangements revenue, as applicable. Net profits or losses consist of net sales to third-party customers and sublicense income in the U.S. less the cost of goods sold as well as selling, general and administrative expenses. Although we expect net sales to increase over time, the settlement payments between AbbVie and us, resulting in collaborative arrangements revenue or collaboration expense, are subject to fluctuation based on the ratio of selling, general and administrative expenses incurred by each party. In addition, our collaborative arrangements revenue may fluctuate as a result of the timing and amount of license fees and clinical and commercial milestones received and recognized under our current and future strategic partnerships as well as timing and amount of royalties from the sales of linaclotide in markets outside the U.S. where linaclotide is commercialized. ​ Research and Development Expenses. The core of our research and development strategy is to leverage our demonstrated expertise and capabilities in GI and rare diseases to bring medicines to patients. Research and development expenses consist of expenses incurred in connection with the research into and development of products and product candidates. These expenses consist primarily of compensation, benefits and other employee-related expenses, research and development related facility costs, third-party contract costs relating to nonclinical study and clinical trial activities, development of manufacturing processes, regulatory registration of third-party manufacturing facilities, and licensing fees for our product candidates. ​ Research and development expenses include amounts owed to AbbVie on an ongoing basis under cost-sharing 25 Table of Contents provisions in our collaboration agreement for linaclotide. Reimbursements received for research and development activities under this agreement are netted against research and development expenses. ​ Apraglutide. In February 2024, we announced positive topline results from our pivotal Phase III clinical trial, STARS, which evaluated the efficacy and safety of once-weekly subcutaneous apraglutide in reducing PS dependency in adult patients with SBS-IF. SBS-IF, a rare and severe organ failure condition in which patients are dependent on PS, affects an estimated 18,000 adult patients in the U.S., Europe, and Japan. We are also conducting an open-label extension study, STARS Extend, to further assess the safety of apraglutide in adult patients with SBS-IF. In April 2025, we announced that, based on discussions with the U.S. FDA, a confirmatory Phase III clinical trial is needed to seek approval of an NDA for apraglutide for patients with SBS-IF who are dependent on PS. We subsequently met with the U.S. FDA and aligned on key design elements of a confirmatory Phase III clinical trial, STARS-2, of apraglutide. In June 2026, we initiated STARS-2 and are actively recruiting patients. ​ Linaclotide. Our commercial product, LINZESS, is commercially available in the U.S. for the treatment of IBS-C in adults and pediatric patients 7 years of age and older, CIC in adults and FC in pediatric patients ages 2-17 years-old. Linaclotide is also available to adults suffering from IBS-C or CIC in certain countries of the world, including China, Japan, and in a number of European countries. ​ We and AbbVie continue to explore ways to enhance the clinical profile of LINZESS by studying linaclotide in additional indications, populations and formulations to assess its potential to treat various conditions. In September 2020, based on the Phase IIIb data of linaclotide 290 mcg on the overall abdominal symptoms of bloating, pain and discomfort in adult patients with IBS-C, the U.S. FDA approved our supplemental new drug application to include a more comprehensive description of the effects of LINZESS in its approved label. ​ In addition, we and AbbVie have established a nonclinical and clinical post-marketing plan with the U.S. FDA to understand the safety and efficacy of LINZESS in pediatric patients. In August 2021, the U.S. FDA approved a revised label for LINZESS based on clinical safety data that had been generated thus far in pediatric studies. The updated label modified the boxed warning for risk of serious dehydration and contraindication against use in children to those less than two years of age. The boxed warning and contraindication previously applied to all children less than 18 years of age and less than 6 years of age, respectively. In June 2023 and May 2026, the U.S. FDA approved LINZESS as a once-daily treatment for pediatric patients ages 6-17 years-old and 2-5 years-old with FC, respectively, making LINZESS the first and only U.S. FDA-approved prescription therapy for FC in this patient population. On October 15, 2025, the U.S. FDA granted us a pediatric exclusivity for studies conducted on linaclotide, and in November 2025, approved LINZESS for pediatric patients 7 years of age and older with IBS-C. ​ IW-3300. We were developing IW-3300, a GC-C agonist, for the potential treatment of visceral pain conditions, such as interstitial cystitis and bladder pain syndrome, or IC/BPS. In April 2025, based on analysis of the Phase II data, we decided to cease developing IW-3300 for IC/BPS. ​ CNP-104. Through a collaboration and license option agreement, or the COUR Collaboration Agreement, we and COUR Pharmaceutical Development Company, Inc., or COUR, were developing CNP-104 for the treatment of PBC, a rare autoimmune disease targeting the liver. In the third quarter of 2024, we received from COUR the topline data from COUR’s Phase II Clinical study for the treatment of PBC. In September 2024, we notified COUR of our decision not to exercise the option to acquire an exclusive license to CNP-104. As a result, the COUR Collaboration Agreement has terminated, and we retain no rights and have no obligations related to CNP-104. ​ Early research and development. Our early research and development efforts have been focused on supporting our development stage GI and rare diseases programs, including exploring strategic options for further development of certain of our internal programs, as well as evaluating external development-stage programs. ​ The following table sets forth our research and development expenses related to our product pipeline for the three and six months ended June 30, 2026 and 2025, respectively. These expenses relate primarily to compensation, benefits and other employee-related expenses and external costs associated with nonclinical studies and clinical trial costs for our product candidates. We allocate costs related to facilities, depreciation, share-based compensation, research and development support services and certain other costs directly to programs. ​ 26 Table of Contents ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ ​ June 30, ​ June 30, ​ ​ 2026 ​ ​ ​ 2025 ​ ​ ​ 2026 ​ ​ ​ 2025 ​ ​ (in thousands) ​ (in thousands) Apraglutide ​ $ 18,767 ​ $ 16,965 ​ $ 37,331 ​ $ 36,242 Linaclotide(1) ​ ​ ​ ​ 2,790 ​ ​ 3,467 ​ ​ 5,223 ​ ​ 7,396 IW-3300(2) ​ ​ (104) ​ ​ 2,051 ​ ​ (49) ​ ​ 4,327 CNP-104 ​ ​ — ​ ​ — ​ ​ — ​ ​ 75 Early research and development ​ 968 ​ ​ 890 ​ ​ 1,856 ​ ​ 2,765 Total research and development expenses ​ $ 22,421 ​ $ 23,373 ​ $ 44,361 ​ $ 50,805 (1) Includes linaclotide in all indications, populations and formulations. (2) Includes a net credit during the three and six months ended June 30, 2026 received upon the close-out of the development program. ​ We and AbbVie are exploring development opportunities to enhance the clinical profile of LINZESS by studying linaclotide in additional indications, populations and formulations to assess its potential to treat various conditions. We cannot currently estimate with any degree of certainty the amount of time or money that we will be required to expend in the future on linaclotide for additional indications, populations or formulations. ​ The lengthy process of securing regulatory approvals for product candidates, including apraglutide, requires the expenditure of substantial resources. Any failure by us to obtain, or any delay in obtaining, regulatory approvals would materially adversely affect our product development efforts and our business overall. Given the inherent uncertainties that come with the development of pharmaceutical products, we cannot estimate with any degree of certainty how our programs will evolve, and therefore the amount of time or money that would be required to obtain regulatory approval to market them. ​ As a result of these uncertainties surrounding the timing and outcome of any approvals, we are currently unable to estimate precisely when, if ever, linaclotide’s utility will be expanded within its currently approved indications; if or when linaclotide will be developed outside of its current markets, indications, populations or formulations; or when, if ever, apraglutide or any of our other product candidates will generate revenues and cash flows. ​ We invest carefully in our pipeline, and the commitment of funding for each subsequent stage of our development programs is dependent upon the receipt of clear, supportive data. In addition, we intend to access externally discovered drug candidates that fit within our core strategy. In evaluating these potential assets, we apply the same investment criteria as those used for investments in internally discovered assets. ​ The successful development of our product candidates is highly uncertain and subject to a number of risks including, but not limited to: ​ ● The duration of clinical trials may vary substantially according to the type, complexity and novelty of the product candidate; ​ ● The U.S. FDA and comparable foreign agencies impose substantial and varying requirements on the introduction of therapeutic pharmaceutical products, typically requiring lengthy and detailed laboratory and clinical testing procedures, sampling activities and other costly and time-consuming procedures; ​ ● Data obtained from nonclinical and clinical activities at any step in the testing process may be adverse and lead to discontinuation or redirection of development activity. Data obtained from these activities also are susceptible to varying interpretations, which could delay, limit or prevent regulatory approval; ​ ● The U.S. FDA and comparable foreign agencies may require additional clinical trials and other studies, which may be costly or delay, limit, prevent or otherwise impact regulatory submission or approval; ​ ● The duration and cost of early research and development, including nonclinical studies and clinical trials, may vary significantly over the life of a product candidate and are difficult to predict; ​ ● The costs, timing and outcome of regulatory review of a product candidate may not be favorable, and, even if approved, a product may face post-approval development and regulatory requirements; 27 Table of Contents ​ ● There may be substantial costs, delays and difficulties in successfully integrating externally developed product candidates into our business operations; and ​ ● The emergence of competing technologies and products and other adverse market developments may negatively impact us. ​ As a result of the factors discussed above, including the factors discussed under “Note Regarding Forward-Looking Statements” in this Quarterly Report on Form 10-Q, and under “Part I, Item 1A – Risk Factors” in our 2025 Annual Report on Form 10-K and under “Risk Factors” in Part II, Item 1A of this Quarterly Report on Form 10-Q, we are unable to determine the duration and costs to complete current or future nonclinical and clinical stages of our product candidates or when, or to what extent, we will generate revenues from the commercialization and sale of our product candidates. Development timelines, probability of success and development costs vary widely. We anticipate that we will make determinations as to which additional programs to pursue and how much funding to direct to each program on an ongoing basis in response to the data of each product candidate, the competitive landscape and ongoing assessments of such product candidate’s commercial potential. ​ We expect to invest in our development programs and incur substantial research and development expenses for the foreseeable future. We will continue to invest in linaclotide, including the investigation of ways to enhance the clinical profile within its currently approved indications, and the exploration of its potential utility in other indications, populations and formulations, and in apraglutide, as we advance it through clinical trials, in addition to funding research and development activities under our external collaboration and license agreements with respect to our products and product candidates. ​ Selling, General and Administrative Expense. Selling, general and administrative expense consists primarily of compensation, benefits and other employee-related expenses for personnel in our administrative, finance, legal, information technology, business development, commercial, sales, marketing, communications and human resource functions. Other costs include legal costs of pursuing patent protection of our intellectual property, general and administrative related facility costs, insurance costs and professional fees for accounting, tax, consulting, legal and other services. As we continue to invest in the development and commercialization of LINZESS, apraglutide and other product candidates, we expect our selling, general and administrative expenses will be substantial for the foreseeable future. ​ We include AbbVie’s selling, general and administrative cost-sharing payments in the calculation of the net profits and net losses from the sale of LINZESS in the U.S. and present the net payment to or from AbbVie as collaboration expense or collaborative arrangements revenue, respectively. ​ Restructuring Expenses. Restructuring expenses primarily pertain to a workforce reduction in January 2025 consisting primarily of field-based sales employees. The workforce reduction and restructuring initiatives are more fully described in Note 11, Workforce Reductions and Restructuring, to our condensed consolidated financial statements appearing elsewhere in this Quarterly Report on Form 10-Q. ​ Interest Expense and Other Financing Costs. Interest expense consists primarily of cash and non-cash interest costs related to the 1.50% convertible senior notes due 2026, or the 2026 Convertible Notes, which we repaid upon maturity in June 2026, and our $550.0 million secured revolving credit facility, or the Revolving Credit Facility. Non-cash interest expense consists of amortization of debt issuance costs. ​ Interest and Investment Income. Interest and investment income consists of interest earned on our cash and cash equivalents. ​ Income Taxes. We prepare our income tax provision based on our interpretation of the income tax accounting rules and each jurisdiction’s enacted tax laws and regulations. As of interim reporting dates, we record our income tax provision by applying our estimated annual effective tax rate to year-to-date pre-tax income, plus adjustments for significant discrete items. ​ 28 Table of Contents Critical Accounting Policies and Estimates ​ Our discussion and analysis of our financial condition and results of operations is based upon our condensed consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles. The preparation of these financial statements requires us to make certain estimates and assumptions that may affect the reported amounts of assets and liabilities, the disclosure of assets and liabilities as of the date of the condensed consolidated financial statements, and the amounts of revenues and expenses during the reported periods. We base our estimates on our historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ materially from our estimates under different assumptions or conditions. Changes in estimates are reflected in reported results in the period in which they become known. ​ During the three and six months ended June 30, 2026, there were no material changes to our critical accounting policies as reported in our 2025 Annual Report on Form 10-K. ​ Results of Operations ​ The following discussion summarizes the key factors our management believes are necessary for an understanding of our condensed consolidated financial statements. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ​ ​ ​ ​ 2026 ​ ​ ​ 2025 ​ ​ ​ 2026 ​ ​ ​ 2025 ​ ​ (in thousands) ​ (in thousands) Revenues: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaborative arrangements revenue ​ $ 113,041 ​ $ 85,239 ​ $ 219,547 ​ $ 126,382 Total revenues ​ ​ 113,041 ​ ​ 85,239 ​ ​ 219,547 ​ ​ 126,382 Costs and expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ 22,421 ​ 23,373 ​ 44,361 ​ 50,805 Selling, general and administrative ​ 11,313 ​ 16,795 ​ 23,346 ​ 41,055 Restructuring, net ​ ​ — ​ ​ (250) ​ ​ (40) ​ ​ 18,309 Total costs and expenses ​ 33,734 ​ 39,918 ​ 67,667 ​ 110,169 Income from operations ​ 79,307 ​ 45,321 ​ 151,880 ​ 16,213 Other income (expense): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest expense and other financing costs ​ (7,203) ​ (8,356) ​ (16,344) ​ (16,426) Interest and investment income ​ 1,585 ​ 818 ​ 3,283 ​ 1,687 Other ​ 42 ​ 39 ​ 84 ​ 76 Other income (expense), net ​ (5,576) ​ (7,499) ​ (12,977) ​ (14,663) Income before income taxes ​ ​ 73,731 ​ ​ 37,822 ​ ​ 138,903 ​ ​ 1,550 Income tax expense ​ ​ (22,440) ​ ​ (14,223) ​ ​ (46,839) ​ ​ (15,337) Net income (loss) ​ $ 51,291 ​ $ 23,599 ​ $ 92,064 ​ $ (13,787) ​ Three and six months ended June 30, 2026 compared to three and six months ended June 30, 2025 ​ Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ ​ Six Months Ended ​ ​ ​ ​ ​ June 30, ​ Change ​ June 30, ​ Change ​ ​ 2026 ​ 2025 ​ $ ​ 2026 ​ 2025 ​ $ ​ ​ (in thousands) ​ (in thousands) Revenues: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaborative arrangements revenue ​ ​ ​ $ 113,041 ​ ​ ​ $ 85,239 ​ ​ ​ $ 27,802 ​ $ 219,547 ​ ​ ​ $ 126,382 ​ ​ ​ $ 93,165 Total revenues ​ $ 113,041 ​ $ 85,239 ​ $ 27,802 ​ $ 219,547 ​ $ 126,382 ​ $ 93,165 ​ Collaborative arrangements revenue. The increase in collaborative arrangements revenue of $27.8 million for the three months ended June 30, 2026 compared to the three months ended June 30, 2025 was primarily related to a $24.4 million increase in our share of net profits from the sale of LINZESS in the U.S., which was driven primarily by increased net price and increased prescription demand. ​ 29 Table of Contents The increase in collaborative arrangements revenue of $93.2 million for the six months ended June 30, 2026 compared to the six months ended June 30, 2025 was primarily related to a $89.8 million increase in our share of net profits from the sale of LINZESS in the U.S., which was driven primarily by increased net price and increased prescription demand, as well as inventory channel fluctuations. ​ Costs and Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ ​ Six Months Ended ​ ​ ​ ​ ​ June 30, ​ Change ​ June 30, ​ Change ​ ​ ​ ​ 2026 ​ ​ ​ 2025 ​ ​ ​ $ ​ 2026 ​ ​ ​ 2025 ​ ​ ​ $ ​ ​ (in thousands) ​ (in thousands) Costs and expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ $ 22,421 ​ $ 23,373 ​ $ (952) ​ $ 44,361 ​ $ 50,805 ​ $ (6,444) Selling, general and administrative ​ 11,313 ​ 16,795 ​ (5,482) ​ 23,346 ​ 41,055 ​ (17,709) Restructuring, net ​ ​ — ​ ​ (250) ​ ​ 250 ​ ​ (40) ​ ​ 18,309 ​ ​ (18,349) Total costs and expenses ​ $ 33,734 ​ $ 39,918 ​ $ (6,184) ​ $ 67,667 ​ $ 110,169 ​ $ (42,502) ​ Research and development. The decrease in research and development expenses of $1.0 million for the three months ended June 30, 2026 compared to the three months ended June 30, 2025 was primarily related to a $1.6 million decrease in external costs associated with the IW-3300 development program and a $1.2 million decrease in external costs associated with the linaclotide program, partially offset by a $1.3 million increase in external costs associated with the apraglutide program. ​ The decrease in research and development expenses of $6.4 million for the six months ended June 30, 2026 compared to the six months ended June 30, 2025 was primarily related to a $3.0 million decrease in external costs associated with the IW-3300 development program and a $2.3 million decrease in external costs associated with the linaclotide program. ​ Selling, general and administrative. Selling, general and administrative expenses decreased by $5.5 million for the three months ended June 30, 2026 compared to the three months ended June 30, 2025, primarily due to a $3.1 million decrease in compensation, benefits, and other employee-related expenses and a $2.2 million decrease in professional services expenses. ​ Selling, general and administrative expenses decreased by $17.7 million for the six months ended June 30, 2026 compared to the six months ended June 30, 2025, primarily due to a $9.5 million decrease in compensation, benefits, and other employee-related expenses and a $7.4 million decrease in professional services expenses. ​ Restructuring, net. Restructuring expense for the three months ended June 30, 2025 were comprised of adjustments related to the workforce reduction in January 2025 consisting primarily of field-based employees. ​ The decrease in restructuring expense of $18.3 million for the six months ended June 30, 2026 compared to the six months ended June 30, 2025 was primarily related to the workforce reduction in January 2025 consisting primarily of field-based employees. ​ Other Income (Expense), Net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ ​ Six Months Ended ​ ​ ​ ​ ​ June 30, ​ Change ​ June 30, ​ Change ​ ​ ​ ​ 2026 ​ ​ ​ 2025 ​ ​ ​ $ ​ 2026 ​ ​ ​ 2025 ​ ​ ​ $ ​ ​ (in thousands) ​ (in thousands) Other income (expense): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest expense and other financing costs ​ $ (7,203) ​ $ (8,356) ​ $ 1,153 ​ $ (16,344) ​ $ (16,426) ​ $ 82 Interest and investment income ​ 1,585 ​ 818 ​ 767 ​ 3,283 ​ 1,687 ​ 1,596 Other ​ 42 ​ 39 ​ 3 ​ 84 ​ 76 ​ 8 Total other income (expense), net ​ $ (5,576) ​ $ (7,499) ​ $ 1,923 ​ $ (12,977) ​ $ (14,663) ​ $ 1,686 ​ Interest expense and other financing costs. Interest expense and other financing costs decreased by $1.2 million for the three months ended June 30, 2026 compared to the three months ended June 30, 2025, primarily due to lower interest rates on the Revolving Credit Facility throughout the period. ​ 30 Table of Contents Interest expense and other financing costs decreased by $0.1 million for the six months ended June 30, 2026 compared to the six months ended June 30, 2025, primarily due to lower interest rates on the Revolving Credit Facility throughout the period, partially offset by professional services incurred in connection with potential financing transactions. ​ Interest and investment income. Interest and investment income increased by $0.8 million for the three months ended June 30, 2026 compared to the three months ended June 30, 2025 due to an increase in cash and cash equivalents balances throughout the period prior to repayment of the 2026 Convertible Notes in June 2026, partially offset by a decrease in interest rates. ​ Interest and investment income increased by $1.6 million for the six months ended June 30, 2026 compared to the six months ended June 30, 2025 due to an increase in cash and cash equivalents balances throughout the period prior to repayment of the 2026 Convertible Notes in June 2026, partially offset by a decrease in interest rates. ​ Other. During the three and six months ended June 30, 2026 and 2025, we recorded a gain of an insignificant amount for pension-related activities. ​ Income taxes. For the three and six months ended June 30, 2026, we recorded income tax expense of $22.4 million and $46.8 million, respectively. For the three and six months ended June 30, 2025, we recorded income tax expense of $14.2 million and $15.3 million, respectively. Due to our ability to utilize our net operating losses and research and development credits to offset the majority of federal taxable income and taxable income in most states, the majority of our tax provision will be a non-cash expense. ​ Liquidity and Capital Resources As of June 30, 2026, we had $79.1 million of cash and cash equivalents. Our cash equivalents include amounts held in money market funds and commercial paper. We invest cash in excess of immediate requirements in accordance with our investment policy, which limits the amounts we may invest in certain types of investments and requires all investments held by us to be at least A- rated, with a remaining final maturity when purchased of less than twenty-four months, so as to primarily achieve liquidity and capital preservation objectives. ​ We anticipate our cash and cash equivalents balance, our expected net cash inflows from operations, our borrowing capacity on our Revolving Credit Facility, and/or additional capital sources to allow us to meet our short-term and long-term cash obligations, which are reflected in our condensed consolidated balance sheets. Our most significant fixed obligations are debt obligations and lease commitments, for which annual payments are disclosed in Note 8, Debt, and Note 6, Leases, respectively, to our condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q, as well as supply purchase commitments, for which the obligations are disclosed in Note 10, Commitments and Contingencies, in our 2025 Annual Report on Form 10-K. In June 2026, we repaid the outstanding aggregate principal amount of the 2026 Convertible Notes at their scheduled maturity using available cash on hand. No conversions were exercised by holders of the 2026 Convertible Notes, and the capped call transactions we have separately entered into in connection with the issuance of the 2026 Convertible Notes terminated upon expiry. ​ Sources of Liquidity ​ We have financed our operations to date primarily through both the private sale of our preferred stock and the public sale of our common stock, debt financings, and cash generated from our operations. As of June 30, 2026, our debt is comprised of $385.0 million aggregate principal amount outstanding under our Revolving Credit Facility, which we entered into in May 2023 to partially finance our acquisition of VectivBio Holding AG in June 2023. The Revolving Credit Facility provides for $550.0 million of borrowing capacity and includes a $10.0 million letter of credit subfacility. Refer to Note 8, Debt, to our condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q for information related to our debt obligations. ​ 31 Table of Contents Summary of Cash Flows The following table summarizes cash flows from operating, investing, and financing activities for the six months ended June 30, 2026 and 2025: ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ June 30, ​ ​ ​ ​ 2026 ​ ​ ​ 2025 ​ ​ (in thousands) Net cash provided by (used in): ​ ​ ​ ​ ​ ​ Operating activities ​ $ 63,397 ​ $ 4,886 Investing activities ​ ​ — ​ ​ (33) Financing activities ​ ​ (199,697) ​ ​ 94 Effect of exchange rate changes on cash and cash equivalents ​ ​ (29) ​ ​ (654) Net increase (decrease) in cash and cash equivalents ​ $ (136,329) ​ $ 4,293 ​ Cash Flows from Operating Activities Net cash provided by operating activities is derived by adjusting net income (loss) for non-cash items and changes in operating assets and liabilities, which reflect timing differences between the receipt and payment of cash associated with transactions and when they are recognized in the results of operations. Net operating cash inflows for the six months ended June 30, 2026 and 2025 totaled $63.4 million and $4.9 million, respectively, and were derived primarily from collaboration arrangements revenue related to sales of LINZESS in the U.S. ​ Cash Flows from Investing Activities Cash used in investing activities for the six months ended June 30, 2025 was insignificant and pertained to the purchase of property and equipment. ​ Cash Flows from Financing Activities Cash used in financing activities for the six months ended June 30, 2026 was $199.7 million, which was comprised primarily of a repayment of $200.0 million aggregate principal on the 2026 Convertible Notes upon their maturity in June 2026. Cash provided by financing activities for the six months ended June 30, 2025 was insignificant and was generated by employee equity transactions. Funding Requirements ​ We began commercializing LINZESS in the U.S. with our collaboration partner, AbbVie, in the fourth quarter of 2012, and we currently derive a significant portion of our revenue from this collaboration. Our goal is to generate and maintain positive cash flows, driven by increased revenue generated through sales of LINZESS and other commercial activities and financial discipline, while continuing to invest in the development and commercialization of linaclotide, apraglutide, and other product candidates. ​ Under our collaboration with AbbVie for North America, total net sales of LINZESS in the U.S., as recorded by AbbVie, are reduced by commercial costs incurred by each party, and the resulting amount is shared equally between us and AbbVie. Additionally, we receive royalties from AbbVie based on sales of linaclotide in its licensed territories outside of the U.S. We believe revenues from our LINZESS partnership for the U.S. with AbbVie will continue to constitute a significant portion of our total revenue for the foreseeable future and we cannot be certain that such revenues, as well as the revenues from our other commercial activities, will continue to enable us to generate positive cash flows, or to do so in the timeframes we expect. We also anticipate that we will continue to incur substantial expenses for the next several years as we further develop and commercialize linaclotide in the U.S., develop and commercialize other product candidates, including apraglutide, and invest in building our pipeline through internal or external opportunities. We believe that our cash and cash equivalents on hand as of June 30, 2026, our expected cash inflows from operations, and our borrowing capacity on our Revolving Credit Facility will be sufficient to meet our 32 Table of Contents projected operating needs at least through the next twelve months from the issuance of these financial statements. We have long-term debt obligations, which are disclosed in Note 8, Debt, to our condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q. There is no assurance we will have sufficient liquidity to meet our debt obligations when they become due. ​ Our forecast of the period of time through which our financial resources will be adequate to support our operations, including the underlying revenue expectations and estimates regarding the costs to continue to develop, obtain regulatory approval for, and commercialize linaclotide in the U.S., develop and commercialize other product candidates, including apraglutide, and our goal to generate and maintain positive cash flows, are forward-looking statements that involve risks and uncertainties. Our actual results could vary materially and negatively from these and other forward-looking statements as a result of a number of factors, including the factors discussed under the headings “Note Regarding Forward-Looking Statements” in this Quarterly Report on Form 10-Q under “Part I, Item 1A—Risk Factors” in our 2025 Annual Report on Form 10-K and under “Risk Factors” in Part II, Item 1A of this Quarterly Report on Form 10-Q. We have based our estimates on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we currently expect. ​ Due to the numerous risks and uncertainties associated with the development and commercialization of our product candidates, we are unable to estimate precisely the amounts of capital outlays and operating expenditures necessary to develop, obtain regulatory approval for, and commercialize linaclotide, apraglutide and our other product candidates, in each case, for all of the markets, indications, populations and formulations for which we believe each is suited. Our funding requirements will depend on many factors, including, but not limited to, the following: ​ ● the revenue generated by sales of LINZESS and CONSTELLA and from any other sources; ​ ● the rate of progress and cost of our commercialization activities, including the expense we incur in marketing and selling LINZESS in the U.S. and from any other sources; ​ ● the success of our third-party manufacturing activities; ​ ● the time and costs involved in developing, and obtaining regulatory approvals for, our product candidates, including apraglutide, as well as the timing and cost of any post-approval development and regulatory requirements; ​ ● the time and costs associated with commercial manufacturing, sales, marketing and distribution of apraglutide, if approved; ​ ● the success of our research and development efforts; ​ ● the emergence of competing or complementary products; ​ ● the costs of filing, prosecuting, defending and enforcing any patent claims and other intellectual property rights; ​ ● the terms and timing of any collaborative, licensing or other arrangements that we may establish, including milestones, royalties or other payments due or payable under such agreements; and ​ ● the acquisition of businesses, products and technologies and the impact of other strategic transactions, as well as the cost and timing of evaluating, acquiring, and, if completed, integrating into our business operations any such assets. ​ Financing Strategy ​ We may, from time to time, consider additional funding through a combination of new collaborative arrangements, strategic alliances, and additional equity and debt financings or from other sources. We will continue to manage our capital structure and to consider all financing opportunities, whenever they may occur, that could strengthen our long-term liquidity profile. Any such capital transactions may or may not be similar to transactions in which we have engaged in the past. There can be no assurance that any such financing opportunities will also be available on acceptable terms, if at all. ​ 33 Table of Contents New Accounting Pronouncements ​ For a discussion of recent accounting pronouncements, refer to Note 2, Summary of Significant Accounting Policies, to our consolidated financial statements in our 2025 Annual Report on Form 10-K and Note 2, Summary of Significant Accounting Policies, appearing elsewhere in this Quarterly Report on Form 10-Q. We did not otherwise adopt any new accounting pronouncements during the three and six months ended June 30, 2026 that had a material effect on our condensed consolidated financial statements included in this report. ​ ​