Ardelyx's Tenapanor (IBSRELA) Becomes a Relevant Player in the Irritable Bowel Syndrome with Constipation Market as the Company Awaits Important Regulatory News for the Drug in Hyperphosphatemia in Patients with Chronic Kidney Disease on Dialysis, Spherix Global Insights Reports

Surveyed nephrologists indicate enormous unmet need for new drugs to treat hyperphosphatemia and anticipate early adoption if the product is approved by the FDA

EXTON, Pa., Dec. 14, 2022 /PRNewswire/ -- After receiving an unexpected Complete Response Letter (CRL) from the FDA in July 2021 for tenapanor (marketed as XPHOZAH) to treat hyperphosphatemia, Ardelyx pivoted and elected to launch tenapanor (marketed as IBSRELA) in irritable bowel syndrome with constipation (IBS-C) in April 2022. IBSRELA was initially approved by the FDA in September 2019, but the company shifted gears of the drug's launch in favor of advancing the hyperphosphatemia indication.

As a newcomer to gastroenterology and a small player amidst some big pharma giants, making a dent in the IBS-C market, which is dominated by Ironwood/AbbVie's LINZESS, would be a challenge. In May 2022, Spherix began monthly tracking of the drug in their Launch Dynamix™: IBSRELA in IBS-C (US) report series.

The most recent results, gathered from the monthly pulse in December 2022 with 70 gastroenterologists, shows Ardelyx making significant headway with new patient starts and moving earlier in the treatment algorithm. Since September, the percent of gastroenterologists with clinical experience prescribing IBSRELA nearly doubled, with roughly two-thirds currently prescribing the drug. Familiarity with IBSRELA continues to climb and reached a new high in December, and gastroenterologists report higher satisfaction with the agent at the same point in launch than they had with Pfizer's XELJANZ and BMS' ZEPOSIA in ulcerative colitis. 

What unmet needs is IBSRELA addressing in the IBS-C market? Qualitative feedback from several of the respondents was captured as well:

• "Like I explained earlier, Ibsrela is a wonderful first, second, third, fourth option in the world of IBS-C that we didn't have just like in IBD. Now we're getting all these new drugs that really work well."
• "It is addressing the unmet needs with a different mechanism of action."
• There are quite a few patients who have done quite poorly or relatively poorly with the previous drugs. So, there is an unmet need for patients who are refractory to previously used over-the-counter and prescription laxatives. Having said that, newer MOAs with few side effects is an ideal situation. So, the answer is yes because of a new MOA."

Established competitors such as LNZESS and Salix Pharmaceuticals' TRULANCE are perceived to have better market access than IBSRELA, and out-of-pocket costs and reimbursement hassles are noted as top barriers along with familiarity. However, regarding efficacy and safety parameters, IBSRELA is rated similarly to competitors. Uptake in this market will continue to be tracked on a monthly basis throughout 2023.

Securing the hyperphosphatemia indication will be a major boost for tenapanor. To separate the indications, the company has branded tenapanor as XPHOZAH for the renal indication and hopes to have some clarity from the FDA this month regarding re-submission of its New Drug Application (NDA). Following the CRL in July 2021, the company was ultimately granted an audience with the Cardio-Renal Advisory Committee in November of this year. The committee recommended tenapanor by a vote of 10 to 2 for treatment in combination with phosphate binders, which is currently the only pharmacologic option patients have. The vote was still positive, but more reserved, for a monotherapy indication with the committee voting 9 to 4.

Should Ardelyx ultimately receive clearance to market XPHOZAH to the dialysis market, feedback gathered over time in Spherix's RealTime Dynamix™: Bone and Mineral Metabolism (US) suggests adoption would be rapid and widespread.  According to patient level data collected in RealWorld Dynamix™: Dialysis (US), where treatment patterns of nearly 1,000 dialysis patients were analyzed by Spherix, more than one-third of dialysis patients were above the target phosphorus level (5.5mg/dL) at the most recent measure.

Among the phosphate binder-treated patients, the collaborating nephrologists indicated that (assuming tenapanor was FDA approved) 24% of their binder-treated patients may be switched to tenapanor as the primary treatment for hyperphosphatemia, and 35% would have tenapanor added to their treatment regimen.

Importantly, more than half of the nephrologists (n=200) surveyed in the most recent  RealTime Dynamix™ studies in bone and anemia indicate they would prescribe the drug soon after approval. Put into context, only about one-quarter would be early prescribers of GSK's daprodustat, a novel anemia treatment also under FDA review, in the same timeframe – underscoring the high unmet need nephrologists see for new agents to treat hyperphosphatemia.

Launch Dynamix™ is an independent service providing monthly benchmarking of newly launched products for the first eighteen months of commercial availability, augmented by a quarterly deep dive into promotional activity, barriers to uptake, and patient types gravitating to the launch brand.

RealTime Dynamix™ is an independent service providing strategic guidance through quarterly or semiannual reports, which include market trending and a fresh infusion of event-driven and variable content with each wave. The reports provide an unbiased view of the competitive landscape within rapidly evolving specialty markets, fueled by robust HCP primary research and our in-house team of experts.

RealWorld Dynamix™ is an independent, data-driven service unveiling real patient management patterns through rigorous analysis of large-scale patient chart audits. Insights reveal the "why" behind treatment decisions, include year over year trending to quantify key aspects of market evolution, and integrate specialists' attitudinal & demographic data to highlight differences between stated and actual treatment patterns.

Spherix Global Insights is a leading provider of market research, business intelligence and advisory services to the global life sciences industry.

The company's unique service offerings are powered by deep therapeutic knowledge, the Spherix Network specialty physician panel, and commercially relevant analyses to enable strategic decision-making by our valued customers.

A trusted advisor and industry thought leader, Spherix Global Insights provides specialized market expertise in six (6) focused therapeutic areas including: dermatology, gastroenterology, nephrology, neurology, rheumatology and ophthalmology.

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Spherix Global Insights Contacts: 

Meghan Staudt
Insights Director, Nephrology
[email protected]

Scott Upham, Corporate Communications
[email protected] 

SOURCE Spherix Global Insights