Unicycive gets FDA rejection letter for kidney drug NDA

Unicycive Therapeutics said the FDA issued a Complete Response Letter for its resubmitted NDA for oxylanthanum carbonate, a kidney-disease treatment for dialysis patients. The agency did not cite efficacy or safety problems, but the review still hinges on unresolved third-party manufacturing issues.

Why it matters: - The FDA action delays Unicycive Therapeutics’ lead program, oxylanthanum carbonate, in a market where hyperphosphatemia affects nearly all patients with end-stage renal disease. - The agency did not ask for new clinical efficacy or safety data, which keeps the focus on manufacturing readiness rather than the drug’s core medical profile. - Approval would matter because OLC is designed to reduce pill burden for dialysis patients who must take phosphate binders with meals every day.

What happened: - Unicycive Therapeutics said the FDA issued a Complete Response Letter for the resubmitted NDA for oxylanthanum carbonate, or OLC. - The application seeks approval for treatment of hyperphosphatemia in patients with chronic kidney disease on dialysis. - The company said the FDA raised no concerns about clinical efficacy or safety data and requested no additional data. - Unicycive said the CRL is based on the same third-party manufacturing deficiencies cited in the prior CRL from June 2025. - The company said the FDA has not yet inspected that third-party manufacturing vendor as part of the resubmitted NDA review.

The details: - Unicycive said the resubmission reflected its belief that the original third-party manufacturing vendor had made continued progress toward fixing FDA-cited deficiencies and showing inspection readiness. - The company said it discussed those milestones with the FDA in a Type A meeting in September 2025. - Unicycive said the FDA did not raise additional issues at that meeting and did not express concerns about the vendor’s progress. - The OLC NDA is supported by a Phase 1 study in healthy volunteers, a bioequivalence study in healthy volunteers, a tolerability study in CKD patients on dialysis, multiple preclinical studies and chemistry, manufacturing and controls data. - OLC is an investigational oral phosphate binder that uses proprietary nanoparticle technology to deliver high phosphate-binding potency and reduce the number and size of pills patients must take. - The company is seeking approval through the FDA’s 505(b)(2) pathway. - Unicycive said OLC has issued composition-of-matter patents with exclusivity until 2031 and potential patent-term extension to 2035. - The company said hyperphosphatemia is a serious condition that occurs in nearly all patients with end-stage renal disease. - Unicycive cited more than 450,000 people in the U.S. who need medication each year to control phosphate levels. - The company said uncontrolled hyperphosphatemia is strongly associated with higher death and hospitalization rates in CKD patients on dialysis.

Between the lines: - The FDA’s response suggests the regulatory path is still open on the science, but not on the manufacturing package backing the application. - That distinction matters because manufacturing deficiencies can block approval even when the clinical data package is intact. - Unicycive’s emphasis on label and packaging discussions signals the company is trying to clear remaining administrative and production hurdles quickly. - CEO Shalabh Gupta said the company remains confident in OLC’s efficacy and safety and is optimistic about a successful inspection and rapid resubmission.

What’s next: - Unicycive said it is in active and ongoing discussions with the FDA about label and packaging. - The company is waiting for a successful inspection of the third-party manufacturing vendor. - Unicycive plans to resubmit the NDA after the manufacturing issues are resolved. - The company’s other investigational program, UNI-494, is in development for conditions related to acute kidney injury and has FDA orphan drug designation for prevention of delayed graft function in kidney transplant patients.

The bottom line: - Unicycive did not lose the drug on clinical grounds, but the FDA again stopped the application over manufacturing compliance, putting the timeline for OLC approval back in the hands of a third-party vendor inspection.