Ardelyx Focuses Resources on Late-Stage Programs and Reports Second Quarter 2017 Operational Results Restructuring Aligns Resources on Execution of Late-Stage Program Milestones T3MPO-2 Phase 3 Trial Results of Tenapanor

Ardelyx Focuses Resources on Late-Stage Programs and Reports Second Quarter 2017 Operational Results

Restructuring Aligns Resources on Execution of Late-Stage Program Milestones

T3MPO-2 Phase 3 Trial Results of Tenapanor for IBS-C on

Track for Early Fourth Quarter;

Onset-of-Action Data Planned for Fourth Quarter

Conference Call to be Held at 8:00 a.m. ET Today

FREMONT, Calif., Aug. 9, 2017 Ardelyx, Inc. (NASDAQ: ARDX), a late-stage clinical company focused on enhancing the treatment of patients

with cardiorenal and gastrointestinal (GI) diseases, today announced an update of its business operations and clinical programs, as well as reported financial results for the second quarter ended June 30, 2017.

At Ardelyx, we have advanced a unique, late-stage pipeline of programs, led by our

first-in-class drug candidate, tenapanor, in Phase 3 development for both IBS-C and hyperphosphatemia, and RDX7675, our

proprietary binder for the treatment of hyperkalemia, which is also in Phase 3 development, said Mike Raab, president and chief executive officer of Ardelyx. Based on the clinical data we ve generated to date, we are highly

confident in both the registration and commercial potential for tenapanor and RDX7675. In order to fully focus on the execution of our late-stage pipeline, we have implemented a plan designed to align our resources to deliver on these programs,

while also creating strategic optionality and reinforcing our financial strength.

Mr. Raab continued, As a result of a comprehensive

strategic review, we have chosen to reduce our workforce, an inherently difficult endeavor. I am proud of everything the Ardelyx team has accomplished over the years, and am incredibly grateful for the hard work, dedication and innovations

contributed by each person impacted by this decision. As we look ahead, we are confident that the changes we are making now, and the extraordinary team that remains at Ardelyx, will best position us to efficiently execute on our near-term milestones

and to create value in the future.

Strategic Restructuring and Updated Financial Guidance

Ardelyx completed a comprehensive strategic review of its operations, assessing several core areas, to optimally position the company to advance towards

delivering on multiple significant opportunities with its late-stage portfolio and execute on its strategic objectives. This review resulted in the prioritization of resources to focus on the upcoming milestones for the late-stage programs, a delay

in the development of a number of earlier-stage programs and a reduction in workforce of 28 percent, resulting in a remaining team of 76 employees.

Ardelyx believes that with this, and other cost-saving activities, the company is positioned to extend its operating runway to the end of 2018, excluding any

revenues generated through potential partnerships. The company expects to incur approximately $0.8 million in one-time, cash-related restructuring expenses, which will be recorded predominantly in the

third quarter of 2017. Ardelyx will continue to evaluate all pathways, both internal and external, to maintain a strong balance sheet and ensure it has the necessary resources to fund its operations.

Clinical Progress and Prioritized Pipeline Activities

Second Quarter 2017 Financial Results

Conference Call Information

The company will host a

conference call today, August 9, 2017 at 8:00 a.m. ET to discuss the company s strategic review and second quarter financial results. To participate in the conference call, please dial (855) 296-9612

(toll-free) or (920) 663-6277 (toll) and reference call ID number 47784045. A webcast of the call, and reference slides, can also be accessed by visiting the Investor page of the company s website

www.ardelyx.com, and will be available on the website for 60 days following the call.

Ardelyx is focused on enhancing the way patients with cardiorenal and gastrointestinal (GI) diseases are treated by using the gut as the gateway to delivering

medicines that matter. The company has established unique cardiorenal and GI business portfolios aimed at bringing new, effective medicines with distinct safety and dosing advantages to underserved patients. Ardelyx s cardiorenal portfolio

includes the Phase 3 development of tenapanor for the treatment of hyperphosphatemia in people with end-stage renal disease who are on dialysis and the Phase 3 development of RDX7675 for the treatment of

people with hyperkalemia. The company s GI portfolio includes the Phase 3 development of tenapanor for the treatment of people with irritable bowel syndrome with constipation (IBS-C), and RDX8940, the

company s TGR5 agonist. For more information, please visit http://www.ardelyx.com/ and connect with us on Twitter @Ardelyx.

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 the potential for Ardelyx s product candidates in treating the diseases and conditions for

which they are being developed; Ardelyx s future development plans for tenapanor and its other product candidates and the expected timing thereof; Ardelyx s expectations regarding the timing of its initiation of, and receipt of results

from its clinical trials evaluating its product candidates and for the completion of its T3MPO program; the potential of Ardelyx s drug discovery and design platform; Ardelyx s ability to generate revenues in the future; and Ardelyx s

expectations regarding the exhaustion of its current capital resources. Such forward-looking statements involve substantial risks and uncertainties that could cause the development of Ardelyx s product candidates or 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, the uncertainties inherent in research and the clinical development

process, including the regulatory approval process, and the uncertainties in the manufacture of clinical trial material, including process development and the scale up of manufacturing processes, and uncertainties in the drug commercialization

process. 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 August 9,

2017, and its future current and periodic reports to be filed with the Securities and Exchange Commission.

Monique Allaire, THRUST IR

Alicia Davis, THRUST IR

Consolidated Condensed Balance Sheets

Consolidated Condensed Statements of Operations

(In thousands, except share and per share amounts)