Ardelyx Q4 Earnings Call Highlights

Key Points

• IBSRELA strength: IBSRELA revenue grew 73% in 2025 to $274.2M, helping drive total revenue to $407.3M; Ardelyx reaffirmed 2026 guidance for IBSRELA of $410–$430M while planning ~25% higher operating spend to support growth.
• XPHOZAH access shift: XPHOZAH revenue fell 36% to $103.6M after loss of Medicare Part D reimbursement on Jan 1, 2025, and management is focusing on non‑Medicare segments and expanded pull‑through/specialty pharmacy efforts to sustain dispenses.
• Pipeline progress: Ardelyx started the ACCEL Phase III trial for tenapanor in CIC (≈700 patients) with top‑line data expected H2 2027 and plans an sNDA thereafter, while advancing a next‑generation NHE3 inhibitor (RDX10531) toward an IND in H2 2026 and a Phase I study.

Ardelyx NASDAQ: ARDX executives used the company’s fourth-quarter and full-year 2025 earnings call to highlight sharp growth in IBSRELA, continued momentum for XPHOZAH despite a major Medicare reimbursement change, and the launch of new development programs designed to expand the tenapanor franchise and advance a next-generation NHE3 inhibitor.

Management frames 2025 as a year of execution

President and CEO Mike Raab said 2025 was “an extraordinary year” in which the company delivered on four strategic priorities: accelerating IBSRELA growth, executing its XPHOZAH strategy, building a pipeline focused on unmet need, and delivering strong financial performance. He said the company will continue to “significantly” grow IBSRELA while maintaining XPHOZAH’s momentum in 2026.

Raab also noted the issuance of a new patent covering the commercial formulations of IBSRELA and XPHOZAH. The patent expires in 2042 and is listed in the FDA’s Orange Book, which he said supports Ardelyx’s effort to build “a comprehensive IP portfolio” around both products.

IBSRELA: demand growth, market opportunity, and 2026 investments

Chief Commercial Officer Eric Foster said IBSRELA delivered 73% revenue growth in 2025 compared to 2024, and the fourth quarter marked the product’s highest net revenue and strongest demand quarter since launch. Raab added that IBSRELA revenue grew 61% year-over-year in the fourth quarter, and said the medicine is now helping “tens of thousands of patients.”

Foster described the IBS-C market as “robust,” citing nearly 7 million prescriptions written in 2025, up 11% versus 2024. He also pointed to internal dynamics supporting IBSRELA’s positioning as an option for patients who remain symptomatic on secretagogues, noting that “as much as 77%” of patients on a secretagogue report continuing symptoms.

To capture more of the market in 2026 and beyond, Foster said the company is investing in three areas:

• Prescribers: Continued optimization of the field sales team to increase reach and frequency among high-writing healthcare providers, who Ardelyx said represent about 50% of the IBS-C total prescription market.
• Prescription pull-through: Expanded use of field reimbursement managers and encouragement for prescribers to route prescriptions through the IBSRELA Pharmacy Network, a limited specialty pharmacy network designed to better handle prior authorizations and payer hurdles. Foster said fulfillment rates are higher through specialty pharmacy and the company sees “on average, an additional prescription per year for patients.”
• Patients: Increased direct-to-patient engagement intended to educate and mobilize patients. Foster said research shows that when patients request IBSRELA, “the majority of the time” a provider is willing to write a prescription.

During Q&A, management reiterated confidence in 2026 guidance, with Foster emphasizing continued sales force optimization and an expansion of pull-through initiatives, including doubling the field reimbursement manager team. Executives also said IBSRELA is not being positioned as a frontline therapy from a commercial objective standpoint, despite being described as a first-line therapeutic in its label; they pointed to payer dynamics as a key source of access hurdles.

XPHOZAH: access strategy and growth outside Medicare

Foster said XPHOZAH posted consistent quarter-over-quarter growth in 2025, with improved patient access “to its highest point since launch.” He reported total dispenses increased 9% year over year, and paid dispenses increased 41% excluding Medicare, compared to 2024.

Chief Financial Officer Sue Hohenleitner explained that as of January 1, 2025, Ardelyx no longer receives Part D reimbursement for Medicare patients, who represent roughly 60% of the total XPHOZAH patient base. She said the company’s focus on access and pull-through supported the year-over-year increase in total dispenses and the growth in paid dispenses outside Medicare.

In response to an analyst question about potential Medicare base-rate adjustments for phosphate binders, Raab said such changes are “not relevant” to Ardelyx’s business because the company does not benefit from that framework. He reiterated that the company’s objective is ensuring that any appropriate patient who is prescribed XPHOZAH receives it, regardless of coverage, while the “revenue-generating” business is focused on non-Medicare segments.

Pipeline updates: CIC Phase III trial and next-generation NHE3 inhibitor

Chief Patient Officer and Interim Chief Medical Officer Dr. Laura Williams outlined two newer development initiatives in addition to ongoing pediatric studies in IBS-C that began in late 2022 as part of post-approval commitments for IBSRELA.

Chronic idiopathic constipation (CIC) label expansion: Williams said Ardelyx has had “very productive discussions” with the FDA and believes that the safety package from prior IBS clinical studies, combined with results from a single Phase III trial, could support a supplemental NDA. The company has begun ACCEL, a randomized, double-blind, placebo-controlled Phase III trial evaluating tenapanor in adults with CIC.

ACCEL is planned to enroll about 700 patients across 110 U.S. sites, with more than half of sites already active. Patients are randomized to one of four groups: three tenapanor doses and placebo, with each active dose group randomized 3:1 versus placebo. The study includes a two-week screening period, a 26-week randomized treatment period, and a four-week follow-up safety period. The primary endpoint at week 12 is the proportion of patients achieving a durable complete spontaneous bowel movement (CSBM) response, defined by increases from baseline in weekly CSBM frequency and a threshold of at least three CSBMs in the same week.

Williams said Ardelyx expects full enrollment by the end of 2026, with top-line results expected in the second half of 2027 and an sNDA filing “shortly thereafter.” In Q&A, management said the trial is powered at 95% and is designed to detect roughly an 18% to 20% difference between placebo and active drug for the 25 mg and 50 mg doses. Executives also said the lowest dose is included to evaluate dose response and that the company will “follow the data” when selecting a dose for potential commercialization.

RDX10531 (531): Williams said Ardelyx is advancing a next-generation NHE3 inhibitor that was approximately 10 times more potent and 30 times more soluble than tenapanor in preclinical studies. She said the profile may support once-daily dosing and could create opportunities in additional therapeutic areas. Ardelyx is finalizing preclinical studies to support an IND submission in the second half of 2026, with plans to begin a Phase I first-in-human safety trial shortly thereafter.

Financial results and 2026 guidance

Hohenleitner reported full-year 2025 total revenue of $407.3 million, up 22% from $333.6 million in 2024. She attributed the growth to increased IBSRELA demand, which she said rose to $274.2 million, a 73% increase compared to 2024 and at the upper end of the company’s most recent guidance range. She also reported XPHOZAH revenue of $103.6 million in 2025, down 36% from $160.9 million in 2024, reflecting the Medicare Part D reimbursement change.

R&D expenses were $71.5 million in 2025 versus $52.3 million in 2024, driven by pediatric trials, the ACCEL trial, preclinical work for 531, and increased medical engagement. SG&A expenses were $337.2 million versus $258.7 million, primarily due to investments to drive IBSRELA demand and adoption.

Net loss for 2025 was $61.6 million, or $0.26 per share, compared with a net loss of $39.1 million, or $0.17 per share, in 2024. The 2025 net loss included $49.0 million of non-cash share-based compensation, compared to $37.4 million in 2024.

Ardelyx ended 2025 with $264.7 million in cash, cash equivalents, and short-term investments, up from $250.1 million at the end of 2024. Hohenleitner said the company generated positive cash flow in each of the last two quarters, though she said the company is not formally guiding to sustained cash flow positivity “at the moment.”

For 2026, Ardelyx reaffirmed prior guidance for IBSRELA revenue of $410 million to $430 million and guided XPHOZAH revenue of $110 million to $120 million. Hohenleitner said IBSRELA growth is expected to be driven by quarter-over-quarter demand increases and improved pull-through, while noting that the IBS-C market historically contracts in the first quarter due to co-pay resets, insurance changes, and prior authorization renewals. She said the company expects similar dynamics in Q1 2026, along with impacts from a winter storm referenced on the call.

The company expects 2026 operating expenses (R&D plus SG&A) to increase about 25% to up to $520 million, reflecting continued investment in both commercial initiatives and pipeline programs, including ACCEL and planning for a Phase I trial for 531.

About Ardelyx NASDAQ: ARDX

Ardelyx, Inc NASDAQ: ARDX is a clinical‐stage biopharmaceutical company focused on discovering, developing and commercializing targeted small molecule drugs for cardio‐renal and gastrointestinal diseases. The company's lead marketed product, tenapanor (sold under the brand name XPHOZAH in the United States), is approved for the treatment of hyperphosphatemia in patients with chronic kidney disease on dialysis. Ardelyx's proprietary approach targets epithelial transporters in the gastrointestinal tract, offering localized activity with limited systemic exposure.

Beyond tenapanor, Ardelyx's development pipeline includes treatments designed to address other complications in kidney disease and related metabolic disorders.

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