Unicycive Therapeutics Receives Second FDA Complete Response Letter for Oxylanthanum Carbonate Due to Unresolved Manufacturer Deficiencies

Unicycive Therapeutics Receives Second FDA Complete Response Letter for Oxylanthanum Carbonate Due to Unresolved Manufacturer Deficiencies

On June 30, 2026, Unicycive Therapeutics received a second Complete Response Letter (CRL) from the FDA regarding its resubmitted New Drug Application (NDA) for oxylanthanum carbonate (OLC). OLC is an investigational oral phosphate binder designed to treat hyperphosphatemia in chronic kidney disease (CKD) patients on dialysis.

Crucially, the FDA did not raise any concerns regarding the clinical safety or efficacy data of OLC, nor did it request any new clinical trials. Instead, the rejection stems entirely from unresolved deficiencies at a third-party manufacturing vendor—the exact same issues that triggered Unicycive's first CRL in June 2025.¹

The NDA was resubmitted under the assumption that the third-party manufacturer was making adequate progress toward resolving the FDA's concerns. However, the FDA has not yet conducted its follow-up inspection of the facility. Unicycive remains in active labeling and packaging discussions with the FDA and plans to expeditiously resubmit the NDA once a successful inspection of the manufacturing vendor occurs.

"The CRL is based on the same third-party manufacturing deficiencies that were identified in the previous CRL issued in June 2025. Unicycive understands that the FDA has not yet conducted its inspection of that third-party manufacturing vendor as part of the review process of the resubmitted NDA."

"We remain confident in the efficacy and safety of OLC... We are in active and ongoing discussion with the FDA regarding label and packaging, and we are optimistic that there will be a successful inspection of the third-party manufacturing vendor and that we will be able to expeditiously resubmit the NDA."