What changed in this filing

/stocks — the workspaceLOADING

Item 1. Financial Statements

2026-04-30 compared with 2025-10-30 · 171 added, 198 removed, 378 unchanged (49% of the section changed)

3 unchanged sentences

(in thousands, except share and per share amounts)

September 30, 2025 December 31, 2024

March 31, 2026 December 31, 2025

Current assets

8 unchanged sentences

Inventory, non-current 105,280 105,372

Prepaid commercial manufacturing, non-current 4,238 —

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

16 unchanged sentences

Stockholders’ equity

Common stock, $ 0.0001 par value;

Common stock, $ 0.0001 par value per share;

500,000,000 shares authorized;

242,971,838 and 238,015,825 shares issued and outstanding as of September 30, 2025 and December 31, 2024, respectively

246,973,414 and 244,351,501 shares issued and outstanding as of March 31, 2026 and December 31, 2025, respectively

Additional paid-in capital 1,133,265 1,113,666

Accumulated deficit ( 984,544 ) ( 946,939 )

Accumulated other comprehensive income 124 57

Accumulated other comprehensive (loss) income ( 124 ) 198

Total stockholders’ equity 148,622 166,949

4 unchanged sentences

(in thousands, except share and per share amounts)

Three Months Ended September 30, Nine Months Ended September 30,

2025 2024 2025 2024

Three Months Ended March 31,

Product sales, net $ 93,373 $ 67,814

3 unchanged sentences

Total revenues 94,473 74,114

Cost of goods sold

Cost of product sales 2,662 1,715 8,247 4,133

Other cost of revenue 1,320 14,013 20,441 28,159

Total cost of goods sold 3,982 15,728 28,688 32,292

Operating expenses

Costs and operating expenses

Cost of sales 4,811 12,303

Research and development 20,188 14,938

Selling, general and administrative 102,267 83,222

Total operating expenses 101,679 80,280 299,493 221,269

Income (loss) from operations 4,668 2,233 ( 46,076 ) ( 36,075 )

Total costs and operating expenses 127,266 110,463

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

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

8 unchanged sentences

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

Unrealized gains (losses) on available-for-sale securities 162 286 67 ( 39 )

Unrealized losses on available-for-sale securities ( 322 ) ( 39 )

Comprehensive loss $ ( 37,927 ) $ ( 41,183 )

2 unchanged sentences

CONDENSED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY

(in thousands, except shares)

Three Months Ended September 30, 2025

(in thousands, except share amounts)

Three Months Ended March 31, 2026

Common Stock Additional Paid-In Capital

Accumulated Deficit

Accumulated Other Comprehensive (Loss) Income

Total Stockholders’ Equity

Shares Amount

Balance as of June 30, 2025 240,765,516 $ 24 $ 1,085,108 $ ( 945,563 ) $ ( 38 ) $ 139,531

Issuance of common stock under employee stock purchase plan 162,859 — 703 — — 703

Issuance of common stock upon exercise of options 860,811 — 2,111 — — 2,111

Issuance of common stock upon vesting of restricted stock units 1,182,652 — — — — —

Stock-based compensation — — 12,742 — — 12,742

Unrealized gains on available-for-sale securities — — — — 162 162

Net loss — — — ( 969 ) — ( 969 )

Balance as of September 30, 2025 242,971,838 $ 24 $ 1,100,664 $ ( 946,532 ) $ 124 $ 154,280

Nine Months Ended September 30, 2025

Common Stock Additional Paid-In Capital Accumulated Deficit Accumulated Other Comprehensive Income

Accumulated Other Comprehensive Income (Loss)

Total Stockholders’ Equity

2 unchanged sentences

Issuance of common stock under employee stock purchase plan 136,480 — 742 — — 742

Issuance of common stock for services 87,256 — 315 — — 315

Issuance of common stock upon exercise of options 1,100,306 1 4,699 — — 4,700

1 unchanged sentence

Stock-based compensation — — 14,158 — — 14,158

Unrealized gains on available-for-sale securities — — — — 67 67

Net loss — — — ( 61,192 ) — ( 61,192 )

Balance as of September 30, 2025 242,971,838 $ 24 $ 1,100,664 $ ( 946,532 ) $ 124 $ 154,280

Three Months Ended September 30, 2024

Common Stock Additional Paid-In Capital Accumulated Deficit Accumulated Other Comprehensive (Loss) Income

Total Stockholders’ Equity

Shares Amount

Balance as of June 30, 2024 235,401,398 $ 23 $ 1,036,244 $ ( 889,176 ) $ ( 101 ) $ 146,990

Issuance of common stock under employee stock purchase plan 226,297 — 1,189 — — 1,189

Issuance of common stock upon exercise of options 663,358 1 1,507 — — 1,508

Issuance of common stock upon vesting of restricted stock units 599,378 — — — — —

Stock-based compensation — — 9,133 — — 9,133

Unrealized gains on available-for-sale securities — — — — 286 286

Unrealized losses on available-for-sale securities — — — — ( 322 ) ( 322 )

Net loss — — — ( 37,605 ) — ( 37,605 )

Balance as of September 30, 2024 236,890,431 $ 24 $ 1,048,073 $ ( 889,985 ) $ 185 $ 158,297

Nine Months Ended September 30, 2024

Balance as of March 31, 2026 246,973,414 $ 25 $ 1,133,265 $ ( 984,544 ) $ ( 124 ) $ 148,622

Three Months Ended March 31, 2025

Common Stock Additional Paid-In Capital Accumulated Deficit Accumulated Other Comprehensive Income (Loss)

3 unchanged sentences

Issuance of common stock under employee stock purchase plan 222,734 — 1,015 — — 1,015

Issuance of common stock for services 40,549 — 257 — — 257

Issuance of common stock upon exercise of options 389,963 — 467 — — 467

3 unchanged sentences

Net loss — — — ( 41,144 ) — ( 41,144 )

Balance as of September 30, 2024 236,890,431 $ 24 $ 1,048,073 $ ( 889,985 ) $ 185 $ 158,297

Balance as of March 31, 2025 239,201,256 $ 24 $ 1,072,118 $ ( 926,484 ) $ 18 $ 145,676

The accompanying notes are an integral part of these condensed financial statements.

2 unchanged sentences

(in thousands)

Nine Months Ended September 30,

Three Months Ended March 31,

Operating activities

23 unchanged sentences

Net cash (used in) provided by investing activities ( 9,995 ) 2,851

( 12,735 ) 23,302

Financing activities

Proceeds from 2022 Loan Agreement, net of costs 48,668 49,750

Proceeds from issuance of common stock under equity incentive and stock purchase plans 5,284 7,526

Proceeds from issuance of common stock under equity incentive plans 5,442 1,482

Net cash provided by financing activities 5,442 1,482

Net (decrease) increase in cash and cash equivalents

( 22,217 ) 25,959

Net decrease in cash and cash equivalents ( 36,790 ) ( 34,124 )

Cash and cash equivalents at beginning of period 67,999 64,932

Cash and cash equivalents at end of period $ 31,209 $ 30,808

Supplementary disclosure of cash flow information

Supplemental disclosure of cash flow information

Cash paid for interest $ 3,114 $ 2,454

Cash paid for income taxes $ 491 $ 272

Supplementary disclosure of non-cash activities

Cash (refunded) paid for income taxes $ ( 69 ) $ 2

Supplemental disclosure of non-cash activity

Right-of-use assets obtained in exchange for lease obligations $ — $ 2,213

Issuance of common stock for services $ 315 $ 257

The accompanying notes are an integral part of these condensed financial statements.

2 unchanged sentences

NATURE OF OPERATIONS

We are a biopharmaceutical company founded with a mission to discover, develop and commercialize innovative, first-in-class medicines that meet significant unmet medical needs.

We developed a unique and innovative platform that enabled the discovery of new biological mechanisms and pathways to develop potent and efficacious therapies that minimize the side effects and drug-drug interactions frequently encountered with traditional, systemically absorbed medicines.

The first molecule we discovered and developed was tenapanor, a minimally absorbed, first-in-class, oral, small molecule therapy.

We are a commercial-stage biopharmaceutical company focused on the development and commercialization of innovative medicines that meet significant unmet medical needs.

We currently market two therapies from the active ingredient tenapanor, a sodium/hydrogen exchanger (NHE3) inhibitor that was discovered and developed by Ardelyx.

NHE3 is an antiporter expressed on the apical surface of the small and large intestines.

Tenapanor is a minimally absorbed, small molecule therapy.

Tenapanor, branded as IBSRELA ® , is approved in the U.S.

for the treatment of adults with IBS-C.

for the treatment of adults with irritable bowel syndrome with constipation (IBS-C).

We are seeking to further expand the IBSRELA eligible patient population to include patients with chronic idiopathic constipation (CIC), and have initiated a Phase 3 clinical trial evaluating tenapanor in adult CIC patients.

Tenapanor, branded as XPHOZAH ® , is approved in the U.S.

to reduce serum phosphorus in adults with 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.

to reduce serum phosphorus in adults with chronic kidney disease 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.

We are also developing a next-generation NHE3 inhibitor, RDX10531, which has demonstrated in preclinical models to have improved solubility and potency compared to tenapanor.

We believe that RDX10531 can have application across multiple therapeutic areas.

We operate in one business segment, which is the development and commercialization of biopharmaceutical products.

Refer to Note 12.

Segment Reporting for further discussion on our segment reporting.

Segment Reporting for further segment reporting information.

Basis of Presentation

4 unchanged sentences

These condensed financial statements have been prepared on the same basis as our most recent annual financial statements and, in the opinion of management, reflect all normal and recurring adjustments necessary to present fairly our financial position, results of operations, changes in stockholders’ equity and cash flows for the interim periods presented.

Certain prior year amounts have been reclassified to conform to the current year presentation on the condensed statements of operations and comprehensive loss to include the “cost of product sales” and the “other cost of revenue” captions within the “cost of sales” caption.

Certain prior year amounts have also been reclassified to conform to the current year presentation in Note 12.

Segment Reporting .

These reclassifications had no effect on the previously reported results of operations.

The accompanying condensed financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto included in our 2025 Form 10-K.

The results for the three and nine months ended September 30, 2025 are not necessarily indicative of results to be expected for the entire year ending December 31, 2025, or for any other interim period or future year.

The results for the three months ended March 31, 2026 are not necessarily indicative of results to be expected for the entire year ending December 31, 2026, or for any other interim period or future year.

Refer to the Summary of Abbreviated Terms at the end of this Quarterly Report on Form 10-Q for definitions of terms used throughout the document.

Use of Estimates

Critical Accounting Policies and Estimates

The preparation of financial statements requires management to make estimates, judgments and assumptions.

2 unchanged sentences

Actual results could materially differ from those estimates.

Our critical accounting policies and estimates are discussed in our 2025 Form 10-K.

Concentration of Credit Risk

Financial instruments that potentially subject us to significant concentrations of credit risk consist primarily of cash, cash equivalents, short-term investments and accounts receivable.

We are exposed to credit risks in the event of default by the counterparties to the extent of the amount recorded in our balance sheets.

Cash, cash equivalents and short-term investments are invested through banks and other financial institutions in the U.S.

Recent Accounting Pronouncements

Recent Accounting Pronouncements Not Yet Adopted

In December 2023, the FASB issued ASU No.

2023-09, Income Taxes (Topic 740) - Improvements to Income Tax Disclosures .

The ASU provides additional transparency within the income tax disclosures, primarily related to the rate reconciliation and income taxes paid information.

The Company anticipates that the adoption of ASU 2023-09 will result in modifications to its income tax disclosures, including an enhanced effective tax rate reconciliation using both percentages and currency amounts, broken out into defined categories, with certain reconciling items further disaggregated by nature and jurisdiction to the extent those items exceed a specified threshold.

In addition, the Company will disclose income taxes paid, net of refunds received disaggregated by jurisdiction if the amount is at least five percent of total income taxes paid, net of refunds received.

The new disclosure requirements will be included in the Company’s Form 10-K for the fiscal year ending December 31, 2025 and will be applied retrospectively.

Recent Accounting Pronouncement Not Yet Adopted

In November 2024, the FASB issued ASU No.

4 unchanged sentences

The following table summarizes our cash, cash equivalents and short-term investments:

September 30, 2025 December 31, 2024

March 31, 2026 December 31, 2025

Gross Unrealized Gross Unrealized

6 unchanged sentences

treasury securities $ 94,379 $ 11 $ ( 38 ) $ 94,352 $ 95,052 $ 105 $ — $ 95,157

government-sponsored agency bonds 27,100 32 — 27,132 45,960 29 ( 27 ) 45,962

Commercial paper 48,958 3 ( 68 ) 48,893 46,421 32 ( 3 ) 46,450

government-sponsored agency bonds 35,266 5 ( 18 ) 35,253 27,330 36 — 27,366

Corporate bonds 23,274 3 ( 15 ) 23,262 22,557 25 — 22,582

Asset-backed securities 2,752 — — 2,752 2,983 2 — 2,985

Yankee bonds 5,112 — ( 7 ) 5,105 5,132 3 — 5,135

1 unchanged sentence

Total cash, cash equivalents and investments $ 238,198 $ 22 $ ( 146 ) $ 238,074 $ 264,491 $ 201 $ ( 3 ) $ 264,689

Realized gains or losses have not been significant and are included in other income, net, in the condensed statements of operations and comprehensive loss.

Unrealized losses as of September 30, 2025 and December 31, 2024 were not material.

All of the short-term available-for-sale securities held as of September 30, 2025 and December 31, 2024 had contractual maturities of less than one year.

We determined that none of our available-for-sale securities were other-than-temporarily impaired as of September 30, 2025 and December 31, 2024, and no investment was in a continuous unrealized loss position for more than one year.

Realized gains or losses have not been significant and are included in other income, net in our condensed statements of operations and comprehensive loss.

Unrealized losses as of March 31, 2026 and December 31, 2025 were not material.

All of the short-term available-for-sale securities held as of March 31, 2026 and December 31, 2025 had contractual maturities of less than one year, and no investment was in a continuous unrealized loss position for more than one year.

Therefore, we believe that it is more likely than not that the investments will be held until maturity or a forecasted recovery of fair value.

Based on our procedures under the expected credit loss model, including an assessment of unrealized losses in our portfolio, we concluded that any unrealized losses on our marketable securities were not attributable to credit and, therefore, we have not recorded an allowance for credit losses for these securities as of September 30, 2025 and December 31, 2024.

See “Cash and Cash Equivalents” and “Short-Term Investments” captions of Note 2.

Summary of Significant Accounting Policies of our 2024 Form 10-K for more information on our accounting policies for cash, cash equivalents and short-term investments.

See “Cash Equivalents” and “Short-Term Investments” captions of Note 2.

Summary of Significant Accounting Policies of our 2025 Form 10-K for more information on our accounting policies for cash equivalents and short-term investments.

FAIR VALUE MEASUREMENTS

7 unchanged sentences

The following table sets forth the fair value of our financial assets that are measured or disclosed on a recurring basis by level within the fair value hierarchy:

September 30, 2025 December 31, 2024

March 31, 2026 December 31, 2025

(in thousands) Total

3 unchanged sentences

treasury securities 94,352 — 94,352 — 95,157 — 95,157 —

government-sponsored agency bonds 27,132 — 27,132 — 45,962 — 45,962 —

Commercial paper 48,893 — 48,893 — 46,450 — 46,450 —

government-sponsored agency bonds 35,253 — 35,253 — 27,366 — 27,366 —

Corporate bonds 23,262 — 23,262 — 22,582 — 22,582 —

Asset-backed securities 2,752 — 2,752 — 2,985 — 2,985 —

Yankee bonds 5,105 — 5,105 — 5,135 — 5,135 —

1 unchanged sentence

Fair Value of Debt

The principal outstanding under our 2022 Loan Agreement is subject to a variable interest rate and therefore, we believe the carrying amount of the term loan approximates fair value as of September 30, 2025 and December 31, 2024.

The outstanding principal under our 2022 Loan Agreement is subject to a variable interest rate and therefore, we believe the carrying amount of the term loan facility approximated its fair value as of March 31, 2026 and December 31, 2025.

Borrowing for a description of the Level 2 inputs used to estimate the fair value of the liability.

The carrying value of the deferred royalty obligation related to the sale of future royalties approximates its fair value as of September 30, 2025 and December 31, 2024 and is based on our current estimates of future royalties and commercialization milestones expected to be paid to us by Kyowa Kirin over the life of the agreement.

Deferred Royalty Obligation Related to the Sale of Future Royalties for a description of the Level 3 inputs used to estimate the fair value of the liability.

The carrying value of the deferred royalty obligation related to the sale of future royalties approximated its fair value as of March 31, 2026 and December 31, 2025, and is based on our current estimates of future royalties and commercialization milestones expected to be received by HCR over the life of the HCR Agreement.

Deferred Royalty Obligation Related to the Sale of Future Royalties .

Inventory consisted of the following:

(in thousands) September 30, 2025 December 31, 2024

(in thousands) March 31, 2026 December 31, 2025

Raw materials $ 27,941 $ 28,009

5 unchanged sentences

Total $ 128,025 $ 123,107

Prepaid commercial manufacturing with third-party CMOs not included in inventory was $ 8.1 million and $ 16.4 million as of September 30, 2025 and December 31, 2024, respectively.

There were no prepayments expected to be converted into inventory after 12 months as of September 30, 2025 and December 31, 2024.

Prepaid commercial manufacturing with third-party CMOs not included in inventory was $ 18.9 million and $ 14.5 million as of March 31, 2026 and December 31, 2025, respectively.

There were $ 4.2 million prepayments expected to be converted into inventory after 12 months as of March 31, 2026, compared to none as of December 31, 2025.

Disaggregation of total revenues by nature is as follows:

Three Months Ended September 30, Nine Months Ended September 30,

Three Months Ended March 31,

(in thousands)

2025 2024 2025 2024

Product sales, net $ 93,373 $ 67,814

$ 105,515 $ 92,090 $ 263,406 $ 208,193

Product supply revenue 354 254

4 unchanged sentences

Total product sales, net was as follows:

Three Months Ended September 30, Nine Months Ended September 30,

Three Months Ended March 31,

(in thousands)

2025 2024 2025 2024

Product sales, net

6 unchanged sentences

Gross product sales from Customers accounting for more than 10% of total revenues were as follows:

Three Months Ended September 30, Nine Months Ended September 30,

2025 2024 2025 2024

Three Months Ended March 31,

Customers (1)

BioRidge Pharma, LLC 85.5 % 63.8 %

Cardinal Health 25.5 % 12.4 % 23.9 % 14.6 %

Cencora, Inc.

17.2 % 18.2 %

McKesson Corporation 15.7 % 16.9 %

Cencora (formerly AmerisourceBergen Drug Corporation)

Cardinal Health, Inc.

12.8 % 22.2 %

Caremark, LLC 12.1 % — %

(1) The total of the above percentages exceeds 100% as the numerators used in the calculations represent gross product sales for each Customer, as opposed to product sales, net as presented in our condensed statements of operations and comprehensive loss.

9 unchanged sentences

Credits/payments ( 7,753 ) ( 25,012 ) ( 12,475 ) ( 45,240 )

Balance as of September 30, 2025 $ 1,854 $ 29,630 $ 11,709 $ 43,193

(1) Provisions included approximately $ 3.8 million of favorable adjustment in the 2025 first quarter, resulting from changes in prior periods’ estimated product returns for XPHOZAH.

Balance as of March 31, 2026 $ 2,145 $ 39,413 $ 11,870 $ 53,428

(1) Adjustments to prior period provisions recorded in the current period were not material.

COLLABORATION AND LICENSING AGREEMENTS

We out-license to external partners for the development and commercialization of tenapanor outside of the U.S.

We recognize revenue from our agreements with Kyowa Kirin, Fosun Pharma and Knight as licensing revenue, product supply revenue or non-cash royalty revenue related to the sale of future royalties.

Collaboration and Licensing Agreements and “Licensing Revenue Recognition” caption of Note 2.

We have out-licensed to external partners for the development and commercialization of tenapanor outside of the U.S.

We recognize revenue from our collaboration partnerships as licensing revenue, product supply revenue or non-cash royalty revenue related to the sale of future royalties.

Collaboration and Licensing Agreements and “Collaboration and Licensing Revenue” caption of Note 2.

Summary of Significant Accounting Policies of our 2025 Form 10-K for more information on the nature, purpose, significant rights and obligations of the parties, as well as our accounting policies for such revenue streams.

The following table summarizes total revenues by collaboration partner:

Three Months Ended September 30, Nine Months Ended September 30,

Three Months Ended March 31,

(in thousands) 2026 2025

Licensing revenue

$ — $ — $ 5,000 $ —

Total licensing revenue

$ 25 $ 20 $ 5,065 $ 56

Product supply revenue

$ — $ 5,322 $ 6,185 $ 7,461

Total supply revenue

$ — $ 5,322 $ 6,439 $ 7,461

Non-cash royalty revenue related to the sale of future royalties

$ 695 $ 1,026

The following table presents changes in our current and non-current deferred revenue balances, which are primarily attributable to Kyowa Kirin:

(in thousands) Current Non-Current Current Non-Current

The following table presents changes in our current deferred revenue balances by collaboration partner:

(in thousands) 2026 2025

Kyowa Kirin Fosun Pharma Total Kyowa Kirin Fosun Pharma Total

Deferred revenue balance as of January 1, $ — $ 1,206 $ 1,206 $ 10,686 $ — $ 10,686

$ 10,686 $ 7,232 $ 7,182 $ 8,644

Prepaid product supply — 2,391 2,391 227 — 227

Product supply delivered — ( 349 ) ( 349 ) — — —

Reclassify amounts to be recognized in the next twelve months — — 4,086 ( 4,086 )

Deferred revenue balance as of September 30, $ 6,581 $ 13,699 $ 7,272 $ 12,770

Significant developments and updates related to our collaboration and licensing agreements in the nine months ended September 30, 2025 and 2024 are discussed below.

In February 2024, Kyowa Kirin announced the launch of tenapanor, marketed as PHOZEVEL ® , for patients with CKD with hyperphosphatemia in Japan.

Following the launch, we began to recognize earned royalties and commercialization milestones from sales of tenapanor in Japan, which are remitted to HCR in accordance with the HCR Agreement.

The first commercialization milestone was achieved in the 2025 third quarter, triggering a ¥ 500.0 million payment to us under the terms of the Kyowa Kirin Agreement, or approximately $ 3.4 million at the currency exchange rate as of September 30, 2025.

This milestone was recorded as non-cash royalty revenue related to the sale of future royalties and will be remitted to HCR upon receipt.

In February 2025, we announced the approval of an NDA for tenapanor for the control of hyperphosphatemia in adult patients with CKD undergoing hemodialysis by China’s Center for Drug Evaluation of the NMPA.

This approval triggered a $ 5.0 million milestone to us under the terms of the Fosun Agreement, which was recorded as licensing revenue on our condensed statement of operations and comprehensive loss when earned during the 2025 first quarter and was received in April 2025.

In connection with the AstraZeneca Termination Agreement, we recognized royalty expense as other cost of revenue in our condensed statements of operations and comprehensive loss of zero and $ 12.7 million in the three and nine months ended September 30, 2025, and $ 10.0 million and $ 22.7 million in the three and nine months ended September 30, 2024, respectively.

As of the 2025 second quarter, we had fully recognized the $ 75.0 million royalty obligation, which had been fully remitted as of September 30, 2025.

Reclassify amounts to be recognized in the next 12 months — — — — — —

Deferred revenue balance as of March 31, $ — $ 3,248 $ 3,248 $ 10,913 $ — $ 10,913

The following table presents changes in our non-current deferred revenue balances by collaboration partner:

(in thousands) 2026 2025

Non-current Kyowa Kirin Fosun Pharma Total Kyowa Kirin Fosun Pharma Total

Deferred revenue balance as of January 1, $ 13,699 $ — $ 13,699 $ 7,232 $ — $ 7,232

Prepaid product supply — — — 1,118 — 1,118

Product supply delivered — — — — — —

Reclassify amounts to be recognized in the next 12 months — — — — — —

Deferred revenue balance as of March 31, $ 13,699 $ — $ 13,699 $ 8,350 $ — $ 8,350

Significant developments and updates related to our collaboration partnerships in the three months ended March 31, 2026 and 2025 are discussed below.

In March 2026, Fosun Pharma reported the first commercial sales of tenapanor, marketed under the Chinese trade name Wan Ti Le, for patients with CKD on hemodialysis with hyperphosphatemia in China.

Pursuant to the terms of the license and manufacturing services agreements with Fosun Pharma, we are eligible to receive reimbursement of cost plus a reasonable overhead for the supply of product and tiered royalties on net sales ranging from the mid-teens to 20 %.

In February 2025, we announced the NDA approval by China’s Center for Drug Evaluation of the NMPA for tenapanor in the control of serum phosphorus in adult patients with CKD on hemodialysis.

This approval triggered a $ 5.0 million milestone to us, which was recorded as licensing revenue in our condensed statements of operations and comprehensive loss in the 2025 first quarter.

Knight - Former Collaboration Partner

Effective as of March 13, 2026, we entered into a termination agreement with Knight, pursuant to which we and Knight agreed to mutually terminate our exclusive license agreement for the development, commercialization and distribution of tenapanor in Canada for hyperphosphatemia and IBS-C.

The decision was not related to any concerns regarding the safety, efficacy or quality of the product.

Sales of IBSRELA in Canada were discontinued effective March 31, 2026.

The termination did not have a material effect on our operations or financial results, and we do not expect it to adversely impact our operations or financial results in the future.

In connection with the AstraZeneca Termination Agreement, we recognized royalty expense as cost of sales in our condensed statements of operations and comprehensive loss of $ 8.8 million in the three months ended March 31, 2025.

As of the end of the 2025 second quarter, we had fully recognized the maximum $ 75.0 million royalty obligation, which had been fully remitted as of the end of the 2025 third quarter.

DEFERRED ROYALTY OBLIGATION RELATED TO THE SALE OF FUTURE ROYALTIES

We and HCR have an agreement in which HCR agreed to pay up to $ 20.0 million in exchange for royalty and commercialization milestone payments that we may receive under our Kyowa Kirin Agreement.

We and HCR have an agreement in which HCR paid $ 15.0 million in exchange for royalty and commercialization milestone payments that we may receive under our Kyowa Kirin Agreement.

Deferred Royalty Obligation Related to the Sale of Future Royalties of our 2025 Form 10-K for further discussion on the nature, purpose, significant rights and obligations of the parties, as well as our accounting policies regarding the HCR Agreement.

Payments received from HCR are recorded as a deferred royalty obligation on our balance sheets, which is being amortized as non-cash interest expense over the estimated life of the HCR Agreement using the effective interest method.

The deferred royalty obligation will be effectively repaid over the life of the HCR Agreement as we remit to HCR royalties and commercialization milestones paid to us by Kyowa Kirin.

We periodically assess the estimated amounts and timing of future royalties and commercialization milestone payments from Kyowa Kirin and, to the extent that the amount or timing of such payments is materially different than our original estimates, we prospectively adjust the imputed interest rate and the related amortization of the deferred royalty obligation.

A summary of financial information related to the HCR Agreement is as follows:

Three Months Ended September 30, Nine Months Ended September 30,

Three Months Ended March 31,

($ in thousands)

2025 2024 2025 2024

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

3 unchanged sentences

$ 25,876 $ 25,527

Non-cash interest expense related to sale of future royalties

Royalty distributed to HCR

( 3,379 ) ( 1,009 )

Deferred royalty obligation balance as of September 30, $ 28,626 $ 24,372

The following table presents our long-term borrowing under the 2022 Loan Agreement:

(in thousands) September 30, 2025 December 31, 2024 Interest rate

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

Royalty and commercialization milestone payments remitted to HCR ( 1,329 ) ( 1,076 )

Deferred royalty obligation balance as of March 31, $ 25,864 $ 26,522

The following table presents our outstanding term loans under the 2022 Loan Agreement:

(in thousands) March 31, 2026 December 31, 2025 Interest Rates

Term A Loan $ 27,500 $ 27,500 7.95 % + 0.022 % + SOFR (subject to a floor of 1.0 %)

11 unchanged sentences

Long-term debt, net of current portion $ 203,517 $ 202,834

On June 30, 2025, we entered into an amendment to our 2022 Loan Agreement (the Fifth Amendment), by and among the Company, as borrower, SLR, as collateral agent and the lenders party thereto.

The Fifth Amendment, among other things, (1) provided for the immediate draw of the principal amount of $ 50.0 million (the Term E Loan) on the closing date of the Fifth Amendment and (2) provides us with the option to draw an additional $ 100.0 million of committed senior secured term loans, consisting of two separate term loans, each in a principal amount of $ 50.0 million:

(a) the first of which is available at the Company’s election through June 30, 2026 (the Term F Loan) and (b) the second of which is available at the Company’s election through December 20, 2026 (the Term G Loan and, together with the Term F Loan, the Incremental Term Loans).

We concluded that the Fifth Amendment was a modification to the 2022 Loan Agreement and is accounted for accordingly.

The interest rate for each of the Incremental Term Loans, if drawn, will be 4.95 % plus the 1-month CME Term SOFR reference rate as published by the CME Term SOFR Administrator on the CME Term SOFR Administrator’s Website, subject to a SOFR floor of 3.50 %.

On the closing date of the Fifth Amendment, we paid (i) a fee of $ 0.3 million in connection with the funding of the Term E Loan, and (ii) a facility fee of $ 1.0 million with respect to the Incremental Term Loans.

Under the Fifth Amendment, the maturity date for the Term E Loan (and the other outstanding term loans) remains July 1, 2028.

We are permitted to make interest-only payments on the Term E Loan (and the other outstanding term loans) through July 1, 2028.

The maturity date for each of the Incremental Term Loans will be July 1, 2030.

We will be permitted to make interest-only payments on the Incremental Term Loans from the date each of the Incremental Term Loans is drawn through July 1, 2030.

We will be obligated to pay a final fee equal to 3.45 % of the aggregate original principal amount of the Incremental Term Loans, to the extent such loans are funded, upon the earliest of any final termination, acceleration, prepayment or July 1, 2030.

The 2022 Loan Agreement contains certain covenants, including a single financial covenant that the sum of our net product revenue, calculated on a trailing six ( 6 ) month basis, plus unrestricted cash and cash equivalents that are subject to a first-priority perfected lien in favor of SLR, shall be greater than or equal to 100 % of the principal amount outstanding under the 2022 Loan Agreement.

In addition, the 2022 Loan Agreement contains subjective acceleration clauses to accelerate the maturity of outstanding principal amount in the event that a material adverse change has occurred within the business, operations or financial condition of the Company.

As of September 30, 2025, the Company believes that the likelihood of the acceleration of the maturity due to subjective acceleration clauses is remote.

The total unaccreted final fee was $ 6.5 million and $ 5.4 million as of September 30, 2025 and December 31, 2024, respectively.

As of September 30, 2025, our total future payment obligation related to the outstanding balance of the term loans, excluding interest payments, was $ 209.9 million, which is due on July 1, 2028.

The total unaccreted final fee was $ 5.4 million and $ 5.9 million as of March 31, 2026 and December 31, 2025, respectively.

As of March 31, 2026, our total future payment obligation related to the outstanding balance of the term loans, excluding interest payments, was $ 209.9 million, which is due on July 1, 2028.

As of March 31, 2026, there have been no changes to the principal, maturity, interest rates, interest payment terms and debt covenants since December 31, 2025.

Borrowing of our 2025 Form 10-K for additional information regarding our 2022 Loan Agreement.

Effective as of April 28, 2026, we entered into the Sixth Amendment with SLR as collateral agent and the lenders party thereto.

For additional information, refer to Note 15.

Subsequent Events .

The following table provides additional details of our facility leases presented in our condensed balance sheets:

($ in thousands)

Facilities September 30, 2025 December 31, 2024

Facilities March 31, 2026 December 31, 2025

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

4 unchanged sentences

Weighted-average discount rate 5.6 % 5.6 %

The lease costs, which are included in operating expenses in our condensed statements of operations and comprehensive loss, were as follows:

Three Months Ended September 30, Nine Months Ended September 30,

The following table presents the lease costs, which are included in our condensed statements of operations and comprehensive loss, and the supplemental cash flow information related to the leases:

Three Months Ended March 31,

(in thousands)

2025 2024 2025 2024

Operating lease expense $ 432 $ 977

Cash paid for operating leases $ 442 $ 1,047

The following table summarizes our undiscounted cash payment obligations for our operating lease liabilities as of September 30, 2025:

The following table summarizes our undiscounted cash payment obligations for our operating lease liabilities as of March 31, 2026:

(in thousands)

7 unchanged sentences

STOCKHOLDERS’ EQUITY

In January 2023, we filed a registration statement on Form S-3, which became effective in January 2023, containing (i) a base prospectus for the offering, issuance and sale by us of up to a maximum aggregate offering price of $ 250.0 million of our common stock, preferred stock, debt securities, warrants and/or units, from time to time in one or more offerings;

and (ii) a prospectus supplement for the offering, issuance and sale by us of up to a maximum aggregate offering price of $ 150.0 million of our common stock that may be issued and sold, from time to time, under a sales agreement with Jefferies, deemed to be “at-the-market offerings” (2023 Open Market Sales Agreement).

Pursuant to the 2023 Open Market Sales Agreement, Jefferies, as sales agent, may receive a commission of up to 3.0 % of the gross sales price for shares of common stock sold under the 2023 Open Market Sales Agreement.

In the nine months ended September 30, 2025, we completed no sales pursuant to the 2023 Open Market Sales Agreement.

As of September 30, 2025, we have completed sales pursuant to the 2023 Open Market Sales Agreement, resulting in the issuance of 16.8 million shares of our common stock and receipt of gross proceeds of $ 70.0 million at a weighted average sales price of approximately $ 4.17 .

In November 2025, we filed an automatic shelf registration statement on Form S-3ASR, which became effective upon filing, containing (i) a base prospectus, which covers the offering, issuance and sale from time to time in one or more offerings of our common stock, preferred stock, debt securities, warrants and/or units;

and (ii) a prospectus supplement for the offering, issuance and sale of up to a maximum aggregate offering price of $ 100.0 million of our common stock that may be issued and sold from time to time under the 2025 Open Market Sales Agreement, deemed to be “at-the-market offerings.” Pursuant to the 2025 Open Market Sales Agreement, Jefferies, as sales agent, may receive a commission of up to three percent of the gross sales price for shares of our common stock sold under the 2025 Open Market Sales Agreement.

As of March 31, 2026, there have been no sales of our common stock under the 2025 Open Market Sales Agreement.

EQUITY INCENTIVE PLANS

Stock-Based Compensation Expense

Stock-based compensation expense recognized for stock options, RSUs and our ESPP is recorded as operating expenses in our condensed statements of operations and comprehensive loss, as follows:

Three Months Ended September 30, Nine Months Ended September 30,

Stock-based compensation expense for stock options, RSUs and our ESPP included in our condensed statements of operations and comprehensive loss was as follows:

Three Months Ended March 31,

(in thousands)

2025 2024 2025 2024

Selling, general and administrative $ 11,556 $ 8,484

1 unchanged sentence

Total $ 14,158 $ 12,088

A summary of our total unrecognized stock-based compensation expense, net of estimated forfeitures, as of September 30, 2025 is as follows:

A summary of our total unrecognized stock-based compensation expense, net of estimated forfeitures, as of March 31, 2026 is as follows:

Unrecognized Compensation Expense

5 unchanged sentences

Stock Options

A summary of our stock option activity and related information for the nine months ended September 30, 2025 is as follows:

A summary of our stock option activity and related information for the three months ended March 31, 2026 is as follows:

Number of Shares

(in thousands) Weighted-Average Exercise Price per Share

(in thousands)

Weighted-Average Exercise Price

Balance as of December 31, 2025 28,977 $ 5.54

2 unchanged sentences

Options forfeited or canceled ( 1,014 ) $ 9.03

Balance as of September 30, 2025 30,143 $ 5.52

Exercisable as of September 30, 2025 17,039 $ 5.42

Balance as of March 31, 2026 29,811 $ 5.69

Exercisable as of March 31, 2026 17,718 $ 5.31

Restricted Stock Units

A summary of our RSUs activity and related information for the nine months ended September 30, 2025 is as follows:

A summary of our RSU activity and related information for the three months ended March 31, 2026 is as follows:

Number of RSUs

(in thousands) Weighted-Average Grant Date Fair Value per Share

(in thousands) Weighted-Average Grant Date Fair Value

Non-vested restricted stock units as of December 31, 2025 12,583 $ 5.71

2 unchanged sentences

Forfeited ( 540 ) $ 6.10

Non-vested restricted stock units as of September 30, 2025 13,824 $ 5.72

Non-vested restricted stock units as of March 31, 2026 15,932 $ 6.28

Employee Stock Purchase Plan

During the nine months ended September 30, 2025, we issued approximately 0.4 million shares of our common stock under the ESPP.

During the three months ended March 31, 2026, we issued approximately 0.1 million shares of our common stock under the ESPP.

The shares were purchased by employees at an average purchase price of $ 5.44 per share, resulting in proceeds to us of approximately $ 0.7 million.

Issuance of Common Stock for Services

During the nine months ended September 30, 2025, we issued 0.1 million shares of our common stock to members of the board of directors who elected to receive stock in lieu of their cash fees under our Non-Employee Director Compensation Program.

SEGMENT REPORTING

We operate in a single reportable segment.

The CODM primarily uses aggregated net loss as reported on the condensed statements of operations and comprehensive loss to measure segment loss, supplemented by certain additional significant expense details reflected in the table below.

The Chief Executive Officer is our Chief Operating Decision Maker, who primarily uses aggregated net loss as reported on the condensed statements of operations and comprehensive loss to measure segment loss, supplemented by certain additional significant expense details reflected in the table below.

There have been no changes in the determination of segmentation or the measurements used to determine reported segment loss discussed in our 2025 Form 10-K.

1 unchanged sentence

Detailed information regarding our single operating segment’s significant revenues, expenses and operating loss is as follows:

Three Months Ended September 30, Nine Months Ended September 30,

Three Months Ended March 31,

(in thousands) 2026 2025

1 unchanged sentence

Other revenues (1)

4,814 6,151 18,699 9,293

Total revenues 94,473 74,114

1 unchanged sentence

Other cost of revenue (3)

Total cost of goods sold 3,982 15,728 28,688 32,292

Research and development (4)

4 unchanged sentences

Stock-based compensation 14,158 12,088

Other segment expenses (3)

3,622 4,462 12,098 13,364

Total operating expenses 101,679 80,280 299,493 221,269

Consolidated income (loss) from operations 4,668 2,233 ( 46,076 ) ( 36,075 )

Total costs and operating expenses 127,266 110,463

Consolidated loss from operations ( 32,793 ) ( 36,349 )

Other reconciliation items (5)

2 unchanged sentences

(1) Other revenues includes revenues from our collaboration partnerships, including licensing revenue, product supply revenue and non-cash royalty revenue related to the sale of future royalties.

(2) Research and development, selling and general and administrative expenses herein do not include certain allocated items, such as stock-based compensation expenses.

(3) Other segment expenses primarily consists of allocated facilities, information technology and employee costs of approximately $ 3.2 million and $ 11.1 million for the three and nine months ended September 30, 2025, and $ 3.9 million and $ 12.2 million for the three and nine months ended September 30, 2024, respectively.

(2) Cost of product sales includes the cost of commercial goods sold to our Customers, such as the cost of materials, third-party contract manufacturing, third-party packaging services, freight, labor costs for personnel involved in the manufacturing process and indirect overhead costs.

(3) Other cost of revenue includes the cost of materials sold to our collaboration partners under product supply agreements, certain costs related to capacity expansion at current and future CMOs and payments due to AstraZeneca.

As of the end of the 2025 second quarter, the maximum $ 75.0 million royalty obligation under the AstraZeneca Termination Agreement had been fully recognized.

(4) Research and development, selling and general and administrative expenses herein do not include stock-based compensation expenses.

(5) Other reconciliation items includes interest expense, non-cash interest expense related to the sale of future royalties, provision for income taxes and other income, net.

2 unchanged sentences

Diluted net loss per common share is computed giving effect to all potential dilutive common shares, including common stock issuable upon exercise of stock options, unvested restricted stock units and ESPP shares issuable pursuant to the current purchase period.

As we had net losses for the nine months ended September 30, 2025 and 2024, all potential common shares were determined to be anti-dilutive during those periods.

As we had net losses for the three months ended March 31, 2026 and 2025, all potential common shares were determined to be anti-dilutive during those periods.

The following table sets forth the computation of net loss per common share:

Three Months Ended March 31,

(in thousands, except per share amounts)

Three Months Ended September 30, Nine Months Ended September 30,

2025 2024 2025 2024

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

3 unchanged sentences

The total numbers of securities that could potentially dilute net income per share in the future that were not considered in the diluted net loss per share calculations because the effect would have been anti-dilutive were as follows:

Three Months Ended September 30, Nine Months Ended September 30,

Three Months Ended March 31,

(in thousands) 2026 2025

4 unchanged sentences

COMMITMENTS AND CONTINGENCIES

On December 7, 2021 and March 29, 2022, two verified shareholders derivative lawsuits were filed in the U.S.

On December 7, 2021 and March 29, 2022, two verified shareholder derivative lawsuits were filed in the U.S.

District Court for the Northern District of California purportedly on behalf of Ardelyx against certain of Ardelyx’s executive officers and members of our board of directors, captioned Go v.

3 unchanged sentences

4:22-cv-01988-JSC (together, the Go and Morris actions).

The complaints allege that the defendants’ violations of Section 14(a) of the Securities Exchange Act of 1934, as amended, breaches of fiduciary duties, unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets for personally making and/or causing Ardelyx to make materially false and misleading statements regarding the Company’s business, operations and prospects.

The complaint seeks contribution under Sections 10(b) and 21D of the Securities Exchange Act of 1934 from two executive officers.

The complaints allege that the defendants’ violations of Section 14(a) of the Exchange Act, breaches of fiduciary duties, unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets for personally making and/or causing Ardelyx to make materially false and misleading statements regarding the Company’s business, operations and prospects.

The complaint seeks contribution under Sections 10(b) and 21D of the Exchange Act from two executive officers.

On January 19, 2022 and April 27, 2022, the court granted the parties’ stipulation to stay the Go and Morris actions, respectively, until resolution of the motion(s) to dismiss in the lawsuits captioned Strezsak v.

3 unchanged sentences

5:21-cv-06228-HSG (together, the Securities Class Actions).

On October 25, 2022, the parties filed a stipulation to consolidate and stay the Go and Morris actions, and on October 27, 2022, the court consolidated the Go and Morris action and stayed the consolidated action pending resolution of the anticipated motion(s) to dismiss in the Securities Class Action.

On October 25, 2022, the parties filed a stipulation to consolidate and stay the Go and Morris actions, and on October 27, 2022, the court consolidated the Go and Morris actions and stayed the consolidated action pending resolution of the anticipated motion(s) to dismiss in the Securities Class Action.

The Securities Class Actions were voluntarily dismissed on March 5, 2025.

9 unchanged sentences

Appellees filed an initial brief on March 6, 2025;

and Appellants filed a reply brief March 27, 2025.

and Appellants filed a reply brief on March 27, 2025.

Both Appellees and Appellants filed a final brief on April 10, 2025.

4 unchanged sentences

24-cv-12119 (D.

The complaint names the Company, Mike Raab, and Justin Renz as defendants and alleges violations of Sections 10(b) and 20(a) the Exchange Act and Rule 10b-5 promulgated thereunder, related to the our announcement on July 2, 2024 that it had chosen not to file an application for Transitional Drug Add-on Payment Adjustment for XPHOZAH (the “Yarborough Action”).

The complaint names the Company, Michael Raab, and Justin Renz as defendants and alleges violations of Sections 10(b) and 20(a) of the Exchange Act and Rule 10b-5 promulgated thereunder, related to our announcement on July 2, 2024 that it had chosen not to file an application for Transitional Drug Add-on Payment Adjustment for XPHOZAH (the Yarborough Action).

The plaintiffs seek damages and interest, and an award of costs, including attorneys’ fees.

5 unchanged sentences

Defendants filed a reply in support of their motion to dismiss on June 23, 2025.

There is no hearing currently scheduled on the motion to dismiss, and the Court has not yet issued a decision on the motion.

We believe the plaintiffs’ claims are without merit.

On September 6 and 13, 2024, certain Ardelyx shareholders filed two verified derivative complaints purportedly on behalf of the Company in the United States District Court for the District of Massachusetts alleging violations of Sections 10(b) and/or 14(a) of the Exchange Act, breaches of fiduciary duty, unjust enrichment, waste, and aiding and abetting breaches of fiduciary duty against certain members of our board of directors and management based on substantially the same factual allegations in the Yarborough Action.

A hearing on the motion to dismiss was held on September 25, 2025, and on December 24, 2025, the Court granted defendants’ motion to dismiss and issued an order dismissing the case with prejudice.

On January 21, 2026, Plaintiffs appealed the District Court’s decisions to the United States Court of Appeals for the First Circuit.

On March 26, 2026, the Court granted the Parties’ stipulated voluntary dismissal of Plaintiffs’ appeal.

duty against certain members of our board of directors and management based on substantially the same factual allegations in the Yarborough Action.

The complaints seek unspecified damages and corporate governance reforms, as well as costs and attorneys’ fees.

3 unchanged sentences

On November 7, 2024, the Court stayed the consolidated derivative action pending resolution of any and all motion(s) to dismiss in the Yarborough Action.

We believe the plaintiffs’ claims are without merit.

On April 9, 2026, the Court dismissed the consolidated derivative action pursuant to the parties’ stipulation of dismissal.

From time to time, we may be involved in legal proceedings arising in the ordinary course of business.

As of September 30, 2025, there is no litigation pending that would reasonably be expected to have a material adverse effect on our results of operations and financial condition.

As of March 31, 2026, there is no litigation pending that would reasonably be expected to have a material adverse effect on our results of operations and financial condition.

SUBSEQUENT EVENTS

On April 28, 2026, we entered into an amendment to our 2022 Loan Agreement (the Sixth Amendment), by and among the Company, as borrower, SLR, as collateral agent and the lenders party thereto.

Pursuant to the Sixth Amendment, among other things, (i) a portion of $ 200.0 million in outstanding principal previously allocated among the outstanding Term A through C Loans (collectively, the Revised Loans) was refinanced with a new Term H Loan;

(ii) the maturity date for the Revised Loans has been extended from July 1, 2028 to July 1, 2030 (the New Maturity Date), which is the maturity date applicable for each other term loan;

(iii) the interest-only payment period for the Revised Loans has been extended until the New Maturity Date;

(iv) the interest rates for the Revised Loans, the Term H Loan, and the Term F and Term G Loans will have a collectively reduced interest rate, at the sum of 4.55 % plus the greater of (a) the 1-month SOFR reference rate or (b) 3.5 %;

(v) the Company will retain the option to draw the Term F and Term G Loans, each in the amount of $ 50.0 million, at the Company’s election by June 30, 2026 and December 20, 2026, respectively;

and (vi) certain negative covenants and other conditions were amended to provide additional flexibility to the Company.

On the closing date of the Sixth Amendment, the Company paid approximately $ 1.9 million in final fees and prepayment fees in connection with the partial paydown of the Term A through C Loans.

The Company is obligated to pay a final fee with respect to each of the outstanding amounts under each of the term loans, upon the earliest to occur of (i) the New Maturity Date, (ii) the acceleration of the applicable term loan or (iii) the prepayment, refinancing, substitution or replacement of the applicable term loan.

This final fee is 4.95 % for the Term A through E loans, 3.45 % for the Term F and Term G Loans and 2.50 % for the new Term H Loan.

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-Q

Item 1. Financial Statements