Form 8-K

8-K — ARDELYX, INC.

Accession: 0001437402-26-000021

Filed: 2026-04-30

Period: 2026-04-30

CIK: 0001437402

SIC: 2834 (PHARMACEUTICAL PREPARATIONS)

Item: Results of Operations and Financial Condition

Item: Regulation FD Disclosure

Item: Financial Statements and Exhibits

Documents

8-K — ardx-20260430.htm (Primary)

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8-K

8-K (Primary)

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ardx-20260430

0001437402false00014374022026-04-302026-04-30

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 30, 2026

ARDELYX, INC.

(Exact name of registrant as specified in its charter)

Delaware 001-36485 26-1303944

(State or other jurisdiction

of incorporation) (Commission

File Number) (IRS Employer

Identification Number)

400 FIFTH AVE., SUITE 210, WALTHAM, MASSACHUSETTS 02451

(Address of principal executive offices, including Zip Code)

Registrant’s telephone number, including area code: (617) 675-2739

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol(s) Name of each exchange on which registered

Common Stock, par value $0.0001 per share ARDX The Nasdaq Global Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Item 2.02 Results of Operations and Financial Condition.

On April 30, 2026, Ardelyx, Inc. (the “Company”) announced its financial results for the quarter ended March 31, 2026. The full text of the press release issued in connection with the announcement is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

The information furnished under this Item 2.02, including Exhibit 99.1 hereto, shall not be considered “filed” under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), nor shall it be incorporated by reference into any future filing under the Securities Act of 1933, as amended (the “Securities Act”), or under the Exchange Act, unless the Company expressly sets forth in such future filing that such information is to be considered “filed” or incorporated by reference therein.

Item 7.01 Regulation FD Disclosure.

On April 30, 2026, the Company will host a conference call to discuss its financial results for the quarter ended March 31, 2026. A copy of the earnings presentation that will be used during this conference call is furnished as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated herein by reference.

The information furnished under this Item 7.01, including Exhibit 99.2 hereto, shall not be considered “filed” under the Exchange Act nor shall it be incorporated by reference into any future filing under the Securities Act, or under the Exchange Act, unless the Company expressly sets forth in such future filing that such information is to be considered “filed” or incorporated by reference therein.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No.

Description

99.1

Press Release of Ardelyx, Inc.

99.2

Earnings Presentation of Ardelyx, Inc.

104 Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: April 30, 2026 ARDELYX, INC.

By: /s/ Susan Hohenleitner

Susan Hohenleitner

Chief Financial Officer

EX-99.1

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Document

Exhibit 99.1

Ardelyx Reports First Quarter 2026 Financial Results and Provides Business Update

Q1 2026 total product revenue of $93.4 million, reflecting 38% growth year-over-year

IBSRELA Q1 2026 revenue growth of 58% year-over-year to $70.1 million; Reiterating guidance of $410-$430 million

Strong financial position with $238.1 million in cash, cash equivalents and investments as of March 31, 2026

Conference call scheduled for 4:30 PM Eastern Time

WALTHAM, Mass., April 30, 2026 – Ardelyx Inc. (Nasdaq: ARDX), (“Ardelyx” or the “Company”) a commercial-stage biopharmaceutical company focused on the development and commercialization of innovative medicines that meet significant unmet medical needs, today reported financial results for the first quarter ended March 31, 2026, and provided a business update.

“In the first quarter of 2026, Ardelyx continued our strong commercial execution which coupled with our strengthening cash position allows us to conduct multiple IBSRELA clinical trials, advance development of our next-generation NHE3 inhibitor, RDX10531, and purposefully explore various avenues to build a significant and sustainable pipeline of important medicines,” said Mike Raab, President and Chief Executive Officer of Ardelyx. “IBSRELA is the cornerstone for the company we’re building and is on the path to becoming a blockbuster by achieving at least one billion dollars in revenue in 2029 with continued strong growth thereafter. We are in a position of financial strength, providing flexibility to allocate capital across the business, accelerate commercial momentum, and drive intrinsic long-term value for the Company, our patients, and our shareholders.”

Product Revenue

Revenue for IBSRELA® (tenapanor) during the first quarter of 2026 was $70.1 million, reflecting year-over-year growth of approximately 58%. The growth was driven by increases across key demand indicators, including total writers and new and refill prescriptions and continued improvement to prescription pull-through.

Revenue for XPHOZAH® (tenapanor) during the first quarter of 2026 was $23.3 million driven by a strong increase in paid prescriptions.

2026 Revenue Guidance

Ardelyx reiterates its full-year 2026 revenue guidance:

•IBSRELA revenue between $410.0 and $430.0 million

•XPHOZAH revenue between $110.0 and $120.0 million

Advancing a Pipeline of Important Medicines

•IBSRELA is being evaluated for the treatment of chronic idiopathic constipation (CIC) in adults in a Phase 3 clinical trial, ACCEL. In January 2026, the Company dosed the first patient in ACCEL and has initiated all pre-identified sites. The Company expects to complete enrollment by the end of 2026 with topline data read out in the second half of 2027.

•IBSRELA is also being evaluated in multiple pediatric clinical trials which could potentially provide six months of additional patent life for tenapanor.

•RDX10531, the Company’s next-generation NHE3 inhibitor is currently being tested in IND-enabling studies. If successful, RDX10531 has potential for broad applications across multiple therapeutic areas.

Other Corporate Developments

•In February, Ardelyx announced a multi-year partnership with the LPGA to serve as an official corporate pharmaceutical marketing partner, focusing on digestive health education and patient empowerment throughout the 2026 season.

•In April, the Company expanded its executive leadership team with the appointment of Rajani Dinavahi, M.D. as Chief Medical Officer and Felecia W. Ettenberg, Esq. as Chief Legal Officer.

•In April, the Company and SLR Investment Corp refinanced their existing debt, resulting in better overall terms. Morgan Stanley & Co. LLC acted as financial advisor to Ardelyx.

•The Company’s abstracts containing additional tenapanor data were accepted for poster presentations at the upcoming Digestive Disease Week conference (May 2-5, 2026) and National Kidney Foundation’s Spring Clinical Meeting (May 6-10, 2026).

First Quarter 2026 Financial Results

• Cash Position: As of March 31, 2026, the Company had total cash, cash equivalents and short-term investments of $238.1 million, compared to total cash, cash equivalents and short-term investments of $264.7 million as of December 31, 2025.

• Revenues: Total product revenue for the quarter ended March 31, 2026 was $93.4 million, compared to $67.8 million for the quarter ended March 31, 2025, reflecting 38% growth, driven by increased demand.

• R&D Expenses: Research and development expenses were $20.2 million for the quarter ended March 31, 2026, compared to $14.9 million for the quarter ended March 31, 2025. The increase was primarily related to investments in the ACCEL Phase 3 trial for CIC.

• SG&A Expenses: Selling, general and administrative expenses were $102.3 million for the quarter ended March 31, 2026, compared to $83.2 million for the quarter ended March 31, 2025. The increase was related to ongoing investments to drive adoption of IBSRELA.

• Net Loss: Net loss for the quarter ended March 31, 2026 was $37.6 million, or $(0.15) per share, compared to net loss of $41.1 million, or $(0.17) per share, for the quarter ended March 31, 2025. The net loss for the first quarter of 2026 included share-based compensation expense of $14.2 million.

Conference Call Details

The company will host a conference call today, April 30, 2026, at 4:30 PM ET to discuss today’s announcement. To participate in the conference call, please dial (877) 346-6112 (domestic) or +1 (848) 280-6350 (international) and ask to be joined into the Ardelyx call. A webcast of the call can also be accessed by visiting the Investor page of the company’s website, https://ardelyx.com/, and will be available on the website following the call.

IMPORTANT SAFETY INFORMATION (IBSRELA)

WARNING: RISK OF SERIOUS DEHYDRATION IN PEDIATRIC PATIENTS

IBSRELA is contraindicated in patients less than 6 years of age; in nonclinical studies in young juvenile rats administration of tenapanor caused deaths presumed to be due to dehydration. Avoid use of IBSRELA in patients 6 years to less than 12 years of age. The safety and effectiveness of IBSRELA have not been established in patients less than 18 years of age.

CONTRAINDICATIONS

•IBSRELA is contraindicated in patients less than 6 years of age due to the risk of serious dehydration.

•IBSRELA is contraindicated in patients with known or suspected mechanical gastrointestinal obstruction.

WARNINGS AND PRECAUTIONS

Risk of Serious Dehydration in Pediatric Patients

•IBSRELA is contraindicated in patients below 6 years of age. The safety and effectiveness of IBSRELA in patients less than 18 years of age have not been established. In young juvenile rats (less than 1 week old; approximate human age equivalent of less than 2 years of age), decreased body weight and deaths occurred, presumed to be due to dehydration, following oral administration of tenapanor. There are no data available in older juvenile rats (human age equivalent 2 years to less than 12 years).

•Avoid the use of IBSRELA in patients 6 years to less than 12 years of age. Although there are no data in older juvenile rats, given the deaths in younger rats and the lack of clinical safety and efficacy data in pediatric patients, avoid the use of IBSRELA in patients 6 years to less than 12 years of age.

Diarrhea

Diarrhea was the most common adverse reaction in two randomized, double-blind, placebo-controlled trials of IBS-C. Severe diarrhea was reported in 2.5% of IBSRELA-treated patients. If severe diarrhea occurs, suspend dosing and rehydrate patient.

MOST COMMON ADVERSE REACTIONS

The most common adverse reactions in IBSRELA-treated patients (incidence ≥2% and greater than placebo) were: diarrhea (16% vs 4% placebo), abdominal distension (3% vs <1%), flatulence (3% vs 1%) and dizziness (2% vs <1%).

INDICATION

IBSRELA (tenapanor) is indicated for the treatment of Irritable Bowel Syndrome with Constipation (IBS-C) in adults.

Please see full Prescribing Information, including Boxed Warning, for additional risk information.

IMPORTANT SAFETY INFORMATION (XPHOZAH)

CONTRAINDICATIONS

XPHOZAH is contraindicated in:

•Pediatric patients under 6 years of age

•Patients with known or suspected mechanical gastrointestinal obstruction

WARNINGS AND PRECAUTIONS

Diarrhea

Patients may experience severe diarrhea. Treatment with XPHOZAH should be discontinued in patients who develop severe diarrhea.

MOST COMMON ADVERSE REACTIONS

Diarrhea, which occurred in 43-53% of patients, was the only adverse reaction reported in at least 5% of XPHOZAH-treated patients with CKD on dialysis across trials. The majority of diarrhea events in the XPHOZAH-treated patients were reported to be mild-to-moderate in severity and resolved over time, or with dose reduction. Diarrhea was typically reported soon after initiation but could occur at any time during treatment with XPHOZAH. Severe diarrhea was reported in 5% of XPHOZAH-treated patients in these trials.

INDICATION

XPHOZAH (tenapanor), 30 mg BID, is indicated to reduce serum phosphorus in adults with chronic kidney disease (CKD) on dialysis as add-on therapy in patients who have an inadequate response to phosphate binders or who are intolerant of any dose of phosphate binder therapy.

For additional safety information, please see full Prescribing Information.

About Ardelyx

Ardelyx is a commercial-stage biopharmaceutical company focused on the development and commercialization of innovative medicines that meet significant unmet medical needs. Ardelyx has two commercial products approved in the United States, IBSRELA® (tenapanor) and XPHOZAH® (tenapanor). The company’s pipeline includes the Phase 3 development of IBSRELA for chronic idiopathic constipation (CIC) and RDX10531, a next-generation NHE3 inhibitor with potential application across multiple therapeutic areas. Ardelyx works with partners to develop and commercialize our products outside of the United States. For more information, please visit https://ardelyx.com/ and connect with us on X (formerly known as Twitter), LinkedIn and Facebook.

Forward Looking Statements

To the extent that statements contained in this press release are not descriptions of historical facts regarding Ardelyx, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor of the Private Securities Reform Act of 1995, including Ardelyx’s current expectations regarding: the long term potential for Ardelyx’s existing commercial products; opportunities for continued IBSRELA growth, including our expectations and timing for achieving one billion in revenue; our U.S. net product sales revenue guidance for IBSRELA and XPHOZAH for full year 2026; and our expectations and timing regarding pipeline development activities, including enrollment in and expected topline readout of the Phase 3 ACCEL trial, the potential for additional patent life for IBSRELA as a result of ongoing pediatric clinical trials and RDX10531’s potential across multiple therapeutic areas. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that are in some cases beyond our control, that could cause actual outcomes or results to differ materially from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, uncertainties associated with the development of, regulatory process for, and commercialization of drugs in the U.S. and internationally. Ardelyx undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to Ardelyx’s business in general, please refer to Ardelyx’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on April 30, 2026, and its future current and periodic reports to be filed with the Securities and Exchange Commission.

Investor Contact:

Lisa Caperelli

lcaperelli@ardelyx.com

Ardelyx, Inc.

Condensed Balance Sheets

(Unaudited)

(in thousands)

March 31, 2026 December 31, 2025

Assets

Cash and cash equivalents $ 31,209 $ 67,999

Short-term investments 206,865 196,690

Accounts receivable 82,840 71,848

Prepaid commercial manufacturing 18,873 14,479

Inventory 128,025 123,107

Property and equipment, net 2,002 2,184

Right-of-use assets 4,433 4,795

Prepaid and other assets 30,260 20,502

Total assets $ 504,507 $ 501,604

Liabilities and stockholders’ equity

Accounts payable $ 28,195 $ 19,235

Accrued compensation and benefits 9,382 19,108

Current portion of operating lease liability 1,510 1,479

Deferred revenue 16,947 14,905

Accrued expenses and other liabilities 70,470 51,218

Long-term debt 203,517 202,834

Deferred royalty obligation related to the sale of future royalties 25,864 25,876

Total stockholders’ equity 148,622 166,949

Total liabilities and stockholders’ equity $ 504,507 $ 501,604

Ardelyx, Inc.

Condensed Statements of Operations

(Unaudited)

(in thousands, except share and per share amounts)

Three Months Ended March 31,

2026 2025

Revenues

Product sales, net

IBSRELA $ 70,074 $ 44,403

XPHOZAH 23,299 23,411

Total product sales, net 93,373 67,814

Product supply revenue 354 254

Licensing revenue 51 5,020

Non-cash royalty revenue related to the sale of future royalties 695 1,026

Total revenues 94,473 74,114

Costs and operating expenses

Cost of sales(1)

4,811 12,303

Research and development 20,188 14,938

Selling, general and administrative 102,267 83,222

Total costs and operating expenses 127,266 110,463

Loss from operations (32,793) (36,349)

Interest expense (5,599) (4,191)

Non-cash interest expense related to the sale of future royalties (1,317) (2,071)

Other income, net 2,112 2,326

Loss before provision for income taxes (37,597) (40,285)

Provision for income taxes 8 859

Net loss $ (37,605) $ (41,144)

Net loss per share of common stock - basic and diluted $ (0.15) $ (0.17)

Shares used in computing net loss per share - basic and diluted 245,855,082 238,624,145

(1) Prior year amounts have been reclassified to conform to the current year presentation.

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Q1 2026 Earnings Call April 30, 2026 This presentation is intended for investor purposes only and is not intended for promotional purposes.

2Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Introduction Lisa Caperelli Senior Vice President, Investor Relations & Corporate Communications

Participants Mike Raab President & Chief Executive Officer Eric Foster Chief Commercial Officer Sue Hohenleitner, CPA, CMA Chief Financial Officer 3This presentation is intended for investor purposes only and is not intended for promotional purposes. Q1 2026 Earnings

4Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Forward-Looking Statements To the extent that statements contained in this presentation are not descriptions of historical facts regarding Ardelyx, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor of the Private Securities Reform Act of 1995, including Ardelyx’s current expectations regarding: the company’s 2026 strategic priorities; our U.S. net product sales revenue guidance for IBSRELA and XPHOZAH for full year 2026; opportunities for continued product revenue growth, including the year in which IBSRELA will achieve annual U.S. net product sales revenue of $1 billion; our current capital allocation strategy and expectations for future operating expenses, including plans for field force expansion; and our expectations and timing regarding pipeline development activities, including enrollment in and expected topline readout of the Phase 3 ACCEL trial of IBSRELA in CIC. Such forward-looking statements involve substantial risks and uncertainties that could cause Ardelyx's future results, performance or achievements to differ significantly from those expressed or implied by the forward- looking statements. Such risks and uncertainties include, among others, uncertainties associated with the commercialization of drugs and uncertainties regarding the FDA and foreign regulatory processes. Ardelyx undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to Ardelyx's business in general, please refer to Ardelyx’s quarterly report on Form 10-Q filed with the Securities and Exchange Commission on April 30, 2026, and its future current and periodic reports to be filed with the Securities and Exchange Commission.

5Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Opening Remarks Mike Raab President and CEO

This presentation is intended for investor purposes only and is not intended for promotional purposes. Significantly grow IBSRELA demand Maintain XPHOZAH momentum Build and expand our pipeline of innovative medicines Continue delivering strong financial performance Well-Positioned to Execute on Our Priorities 2026 Strategic Priorities 6Q1 2026 Earnings Building an innovative pipeline of medicines for patients to address unmet medical needs

7Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Grew IBSRELA Demand YoY Maintained XPHOZAH Momentum Q1 Demonstrated Strength of Fundamentals Driving Business $70.1M Q1 2026 Revenue 58% YoY Growth $23.3M Q1 2026 Revenue

8Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. PRECLINICAL PHASE I PHASE II PHASE III APPROVED Our Development Pipeline The safety and efficacy of the agents for the indications under investigation have not been established. Building a pipeline of important medicines to address areas of unmet patient need PRODUCT DISEASE RDX10531 TBD End Stage Renal Disease on Dialysis with Hyperphosphatemia Irritable Bowel Syndrome with Constipation (IBS-C) Chronic Idiopathic Constipation (CIC) IBS-C in pediatric patients ages 6 to <18 Functional Constipation (FC) in pediatric patients ages 2 to <18 Pediatric Program

9Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Expanding Leadership Team Rajani Dinavahi, MD Chief Medical Officer Felecia Ettenberg Chief Legal Officer

This presentation is intended for investor purposes only and is not intended for promotional purposes. Well-Positioned for 2026 Growth 10Q1 2026 Earnings $410 - $430M Reiterating 2026 Revenue Guidance $110 - $120M

11Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Commercial Update Eric Foster Chief Commercial Officer

12Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes.This presentation is intended f r investor purposes o ly and is not intended for prom tional purposes.

13Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Strong Commercial Performance Large and Growing Market Significant Unmet Need Q1 2026 IBSRELA Highlights 1. IQVIA NPA Audit 2025. Market basket defined as Rx products with indication for treatment of IBS-C which includes Linzess, Amitiza, Trulance, Zelnorm and IBSRELA. Linzess, Amitiza and Trulance are also indicated for CIC. IQVIA NPA audit data reflects all RXs irrespective of indication. IBSRELA is indicated for the treatment of IBS-C and is not indicated for CIC 2. Quigley EMM, Horn J, Kissous-Hunt M, Crozier RA, Harris LA. Better understanding and recognition of the disconnects, experiences, and needs of patients with irritable bowel syndrome with constipation (BURDEN IBS-C) study: results of an online questionnaire. Adv Ther. 2018;35(7):967-980. 77% of patients on a secretagogue continue to experience residual abdominal and stool-related symptoms2 TRxs for IBS-C Indicated Products1 (Millions) 2020 2021 2022 2023 2024 2025 6.9 11% growth IBSRELA TRxEq Demand Since Launch Q1 2026 Revenue $70.1M +58% YoY 2022 2023 2024 2025

14Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. IBSRELA Value Proposition Unlocks Significant Growth Potential Growth Drivers * Projected $158.3M $80.1M $15.6M $274.2M $410-430M* $1B* 2022 2023 2024 2025 2026 2029 Continued growth until loss of exclusivity Breath and depth of writers • Increase in number of writers and depth of prescribing • Focus on high-writing HCPs who represent ~50% of IBS-C total scripts Patient activation • Robust engagement across digital & social channels to expand reach • Partnership with LPGA Prescription pull-through • Focused sales team to support HCPs with script fulfillment • Higher fulfillment rates when scripts go through IBSRELA specialty pharmacy Significant Long-Term Growth Potential Annual Revenue Opportunity

15Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes.This presentation is intended for investor purposes only and is not intended for pro otional purposes.

16Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Q1 2026 Highlights XPHOZAH Differentiation is Driving Momentum in High Unmet-Need Market Growth Drivers  Targeted sales execution  Broaden reach via cross- channel engagement  Continued evidence generation and scientific engagement Significant Unmet Need 70% of CKD patients on dialysis are unable to consistently achieve and maintain target phosphorus levels over a 6-month period2 1. Represents growth vs. Q1 2025 taking into account $3.8 million favorable adjustment related to product returns. 2. Data on file Q1 2026 Revenue $23.3M +19% YoY  Improved patient access  Increased total dispenses by 32% and paid prescriptions by 19% YoY1  Increased total writers, new & refill scripts, refills & total scripts across non-Medicare market 1

17Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Financial Performance Sue Hohenleitner, CPA, CMA Chief Financial Officer

18Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. First Quarter 2026 Financial Highlights $ in millions, excluding EPS Q1 2026 Q1 2025 % Change IBSRELA Revenue $70.1 $44.4 58% XPHOZAH Revenue $23.3 $23.4 19%* Total Product Revenue $93.4 $67.8 38% Other Revenue $1.1 $6.3 (83)% Total Revenue $94.5 $74.1 27% R&D Expenses $20.2 $14.9 35% SG&A Expenses $102.3 $83.2 23% Total Operating Expenses1 $122.5 $98.1 25% Net Loss $(37.6) $(41.1) (9)% EPS $(0.15) $(0.17) (12)% Stock-Based Compensation $14.2 $12.1 17% 1. Includes R&D and SG&A expenses 2. Includes total cash, cash equivalents and short-term investments $238.1M Cash & Investments2 as of Mar 31, 2026 Compared to $264.7M on Dec 31, 2025 * Represents growth vs. Q1 2025 taking into account $3.8 million favorable adjustment related to product returns. Refinanced Debt 2-year extension to maturity and interest-only period Lowered overall cost of capital & annual interest expenses Financially Strong

19Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. 2025 2026 2029 Poised to Deliver Meaningful Growth in 2026 and Beyond Revenue growth continues to outpace operating expenses $ in millions Guidance Range* YoY Change IBSRELA Revenue $410-430 50-57% XPHOZAH Revenue $110-120 6-16% Product Revenue $520-550 38-46% Operating Expenses up to $520 ~25% Long-Term IBSRELA Growth Expectations 38% CAGR Reiterating 2026 Financial Guidance * Projected $1B* $274.2M Continued growth until loss of exclusivity Product Revenue Growth Operating Expenses Growth 38 – 46% 25% $410 - $430M*

20Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Capital Allocation Strategy Looking ahead: as IBSRELA scales toward $1B and we approach sustained profitability, capital allocation priorities may evolve. Disciplined investment for durable growth Pr i or i ty 1 Accelerate IBSRELA o Commercial investment to grow IBS-C opportunity in IBSRELA— highest ROI use of capital today o Field force expansion + specialty pharmacy shift o Path to $1B annual revenue by 2029 Pr i or i t y 2 Fund pipeline opportunities o CIC Phase 3 (ACCEL) —anticipate complete enrollment in 2026 & topline data in H2 2027 o RDX10531 – IND-enabling studies underway o Pediatric program – multiple clinical trials in IBS-C and FC o Opportunistic business development Pr i or i ty 3 Maintain financial strength o Cash balance anticipated to grow YoY o Revenue growth funds existing operations o Opportunistic refinancing to extend debt maturity, reduce cost of capital, and maintain our existing draw options o Build toward sustainable profitability

21Q1 2026 EarningsThis presentation is intended for investor purposes only and is not intended for promotional purposes. Closing Remarks Mike Raab President and CEO

22Q1 2026 Earnings Q&A This presentation is intended for investor purposes only and is not intended for promotional purposes.

Thank You This presentation is intended for investor purposes only and is not intended for promotional purposes.

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Apr. 30, 2026

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400 FIFTH AVE.

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