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

Hyperphosphatemia is a persistent and clinically significant complication in patients with chronic kidney disease (CKD) 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 HCPLive. “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.

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

References

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

2. Brooks A. FDA Issues CRL to Oxylanthanum Carbonate for Hyperphosphatemia in CKD, Dialysis. HCPLive. June 30, 2025. Accessed August 21, 2025. https://www.hcplive.com/view/fda-issues-crl-oxylanthanum-carbonate-hyperphosphatemia-ckd-dialysis

3. Brooks A. Oxylanthanum Carbonate May Offer Desirable Alternative to Current Phosphate Binders. HCPLive. April 10, 2025. Accessed August 21, 2025. https://www.hcplive.com/view/oxylanthanum-carbonate-may-offer-desirable-alternative-current-phosphate-binders