Unicycive Renews FDA Push for Kidney Drug After Manufacturing Fix

LOS ALTOS, CA – December 29, 2025 – Unicycive Therapeutics has resubmitted its New Drug Application (NDA) to the U.S. Food and Drug Administration for oxylanthanum carbonate (OLC), a novel treatment for a common complication in kidney disease patients. The move signals the company's confidence that it has resolved a critical manufacturing issue that led to the FDA's initial rejection of the drug earlier in the year.

The biotechnology firm is seeking approval for OLC to treat hyperphosphatemia—dangerously high phosphate levels in the blood—a condition affecting nearly all of the more than 450,000 U.S. patients with chronic kidney disease (CKD) who are on dialysis. If approved, the drug could offer a significant quality-of-life improvement by drastically reducing the number of pills patients must consume daily.

Overcoming a Regulatory Hurdle

The path to this resubmission has been a focused effort for Unicycive. In June 2025, the company received a Complete Response Letter (CRL) from the FDA, a communication that halts the approval process. The CRL cited a single deficiency: the regulatory compliance status of a third-party vendor responsible for manufacturing the drug. The FDA raised no concerns about the drug's clinical data, safety, or efficacy.

Following the setback, Unicycive engaged in a Type A meeting with the FDA in September 2025 to clarify the steps needed to resolve the issue. The company announced today that the manufacturing partner has since made what it calls “significant progress toward regaining FDA compliance,” clearing the way for the NDA to be filed again.

“Our original third-party manufacturing vendor has made significant progress toward regaining FDA compliance, allowing us to resubmit the OLC NDA as planned,” said Shalabh Gupta, M.D., Chief Executive Officer of Unicycive, in a statement. He also noted the company’s financial health, stating, “With a cash runway into 2027, we are well-positioned to complete the regulatory approval process for OLC so we can prepare to bring this important treatment option to dialysis patients with hyperphosphatemia as soon as possible.”

Under the Prescription Drug User Fee Act (PDUFA) guidelines, the FDA is expected to acknowledge its acceptance of the resubmission for review within 30 days and to complete its review within six months. This timeline could place a potential approval decision in mid-2026.

A Tale of Two Regulators

Adding a compelling layer to the regulatory saga, Unicycive revealed that European Union authorities inspected the same third-party manufacturing facility after the FDA had issued its CRL. That inspection concluded with no deficiencies identified. While regulatory standards can differ between agencies, the positive outcome in Europe suggests the manufacturing issues cited by the FDA may have been specific or have since been thoroughly rectified to meet the standards of multiple international bodies.

This divergence in regulatory findings underscores the complex and stringent nature of pharmaceutical manufacturing oversight, particularly within the United States. For Unicycive, successfully addressing the FDA's concerns while having a clean bill of health from European inspectors could strengthen its position as it navigates the final stages of the U.S. approval process and potentially eyes future submissions abroad.

Easing the Burden on Patients

The core value proposition of oxylanthanum carbonate lies in its potential to ease the immense “pill burden” faced by dialysis patients. Hyperphosphatemia is a serious condition where the kidneys can no longer filter excess phosphate from the blood. Uncontrolled levels are strongly associated with cardiovascular events, bone disease, and increased mortality.

Standard treatment involves a strict, phosphorus-restricted diet and the daily use of oral phosphate-binding drugs. These binders must be taken with every meal to prevent dietary phosphate from being absorbed into the bloodstream. For many patients, this translates to swallowing a large number of pills, sometimes a dozen or more, every single day. This high pill burden is a well-documented cause of poor patient adherence, which undermines the treatment's effectiveness and leads to worse health outcomes.

Unicycive’s OLC leverages proprietary nanoparticle technology to create a more potent phosphate binder. This increased potency means that a smaller amount of the drug is needed to achieve the desired therapeutic effect. The result is a treatment that requires fewer and smaller pills, a benefit that could meaningfully improve adherence and, consequently, long-term patient health. The company's NDA is supported by data from three clinical studies in addition to extensive preclinical and manufacturing data.

The company is pursuing approval via the 505(b)(2) regulatory pathway, an abbreviated process that allows a sponsor to rely, in part, on existing data for a previously approved drug, which can streamline development and review. With patent protection on its composition of matter extending to 2031 and potentially to 2035, Unicycive has a significant window to establish OLC in the market, should it gain approval. The company is also developing UNI-494, an investigational treatment for acute kidney injury, further cementing its focus on addressing unmet needs in kidney disease.