Pablo Pergola, MD, PhD, is the research director of the Clinical Advancement Center at Renal Associates PA.

Pablo Pergola, MD, PhD

“Remarkable” Phase 2 Oxylanthanum Carbonate Data, With Pablo Pergola, MD, PhD

Hyperphosphatemia remains a common and clinically important challenge for individuals with 

 undergoing dialysis. Although phosphate binders play a critical role in helping regulate phosphate levels, their utility is often hampered by large pill sizes, high daily pill counts, strict dosing requirements, and gastrointestinal intolerance. These barriers frequently lead to poor adherence, limiting their effectiveness in long-term disease management.

“When you talk about efficacy… there are several things that affect how you can get that done. One is the potency, so how well the medication works in binding the phosphate from the intestine. But a very potent drug that you cannot take doesn't work. If it sits on the counter or on your table, then the efficacy is zero,” Pablo Pergola, MD, PhD, research director of the Clinical Advancement Center at Renal Associates PA, explained to 

. “You need to have something that's potent that the patients can take, so it relates to that pill burden, availability, and accessibility, so the patient can take it, they tolerate it, and it works. Then you get the efficacy that you need.”

Oxylanthanum carbonate (OLC), an investigational lanthanum-based phosphate binder, has been developed using nanoparticle technology designed to minimize pill size and reduce overall pill burden. Findings from a phase 2, open-label, single-arm, multicenter trial published in the 

Clinical Journal of the American Society of Nephrology

 point to OLC’s potential as a promising new therapy for managing hyperphosphatemia in patients with CKD receiving dialysis.1

For more on the shortcomings of current phosphate binders, check out part 1 of the interview with Pergola 

The trial enrolled patients with serum phosphate (sP) ≥4.0 and ≤7.0 mg/dl for ≥ 8 weeks before screening while receiving thrice weekly hemodialysis and a stable phosphate binder regimen. The primary objective was to evaluate the tolerability of OLC at clinically effective doses with a goal sP concentration ≤5.5 mg/dl.

The trial included washout, titration, and maintenance periods. Patients started titration when sP was >5.5 mg/dl and entered maintenance once sP was ≤5.5 mg/dl. The starting dose of OLC during titration was 1500 mg/d (500 mg thrice daily).

A total of 86 patients were treated with OLC during the study. At screening, sP was ≤5.5 mg/dl in 59% of patients. Among the cohort, 91% of patients entered maintenance and 71 achieved sP ≤5.5 mg/dl on a median OLC dose of 500 mg 3 times a day. Of note, two-thirds of patients required ≤ 3 OLC tablets per day to achieve target sP levels, with most requiring no more than one tablet with each meal.

“This is not trivial. I've done multiple studies with phosphate bindings in the past, and I had never seen a drug performed this way. It's really remarkable,” Pergola said. “It's a small study, I understand, but finding this kind of efficacy is unheard of.”

Editors’ note: Pergola has relevant disclosures with Alexion, Ardelyx, AstraZeneca, Bayer, CSL, DISC, Novo Nordisk, Renibus, Unicycive, and Vera.

Unicycive Therapeutics. Unicycive Therapeutics Announces the Publication of Oxylanthanum Carbonate Pivotal Trial Data in Clinical Journal of the American Society of Nephrology. July 24, 2025. Accessed August 28, 2025. 

https://ir.unicycive.com/news/detail/107/unicycive-therapeutics-announces-the-publication-of

Brooks A. Oxylanthanum Carbonate May Offer Desirable Alternative to Current Phosphate Binders. 

. April 10, 2025. Accessed August 28, 2025. 

https://www.hcplive.com/view/oxylanthanum-carbonate-may-offer-desirable-alternative-current-phosphate-binders

Videos

Pergola breaks down findings from a phase 2 trial of OLC for managing hyperphosphatemia in patients with chronic kidney disease receiving dialysis.

Improving Phosphate Binder Adherence With Oxylanthanum Carbonate, With Pablo Pergola, MD, PhD

Hyperphosphatemia is a persistent and clinically significant complication in patients with 

 receiving dialysis. While phosphate binders are an essential adjunct to dialysis in maintaining phosphate balance, their effectiveness is frequently limited by high pill burden, large tablet size, inconvenient administration requirements, and gastrointestinal side effects, all of which contribute to poor adherence and undermine long-term management.

An investigational next-generation lanthanum-based phosphate binding agent, oxylanthanum carbonate (OLC) leverages proprietary nanoparticle technology to reduce the number and size of pills that patients must take. Phase 2 data published in the 

Clinical Journal of the American Society of Nephrology 

highlight its tolerability and impact on serum phosphate control with low pill burden, suggesting OLC may be a viable treatment option for hyperphosphatemia in patients with CKD on dialysis.

“Pill size, palatability, number of pills, and whether it's chewed or not all add to our ability to take the tablets with a meal [as intended],” Pablo Pergola, MD, PhD, research director of the Clinical Advancement Center at Renal Associates PA, explained to 

. “This is not about the patient's understanding or whether they think hyperphosphatemia is important or not. Most of them do understand it, but there are a lot of factors that get in the way of them taking the medication as they need to.”

Building on the potency of lanthanum carbonate, the most effective binder currently available, Pergola explains how OLC uses a proprietary nanoparticle formulation that increases surface area, enhances solubility, and maximizes phosphate binding. Unlike other medications that require chewing for adequate effect, OLC is designed as a small, swallowable tablet with a simpler, more discreet format that was met with strong enthusiasm among patients during clinical trial enrollment, highlighting the importance of pill size and administration in adherence.

In June 2025, the US Food and Drug Administration issued a Complete Response Letter to Unicycive Therapeutics’ New Drug Application (NDA) for OLC, citing deficiencies previously identified at a third-party manufacturing vendor unrelated to OLC. Of note, no other concerns were stated, including pre-clinical, clinical, or safety data.

The NDA submission package was based on data from 3 clinical studies, including a phase 1 study in healthy volunteers, a bioequivalence study in healthy volunteers, and a tolerability study of oxylanthanum carbonate in CKD patients on dialysis, as well as multiple preclinical studies, and the CMC data.

With the approval process ongoing following alignment with the FDA after receipt of the CRL, Pergola expresses optimism that OLC could eventually become an important component of hyperphosphatemia treatment in this patient population.

Unicycive Therapeutics. Unicycive Therapeutics Announces the Publication of Oxylanthanum Carbonate Pivotal Trial Data in Clinical Journal of the American Society of Nephrology. July 24, 2025. Accessed August 21, 2025. 

Brooks A. FDA Issues CRL to Oxylanthanum Carbonate for Hyperphosphatemia in CKD, Dialysis. 

. June 30, 2025. Accessed August 21, 2025. 

https://www.hcplive.com/view/fda-issues-crl-oxylanthanum-carbonate-hyperphosphatemia-ckd-dialysis

. April 10, 2025. Accessed August 21, 2025. 

Pergola describes the shortcomings of current phosphate binders and what benefits OLC may offer for hyperphosphatemia in patients with CKD on dialysis.

Pablo Pergola, MD, PhD

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