Unicycive Therapeutics Receives Complete Response Letter from FDA Regarding Resubmitted Oxylanthanum Carbonate (OLC) New Drug Application (NDA)

-- Complete Response Letter relates to deficiencies previously identified at third-party manufacturing vendor --

-- FDA inspection of third-party facility did not occur during the NDA resubmission review --

-- Labeling discussions currently underway; latest communication received by the Company from FDA on June 29 regarding carton and container label --

-- FDA did not raise concerns regarding the clinical efficacy or safety data of OLC, and no additional data was requested --

MOUNTAIN VIEW, Calif., June 30, 2026 — Unicycive Therapeutics, Inc. (Nasdaq: UNCY), a clinical-stage biotechnology company developing therapies for patients with kidney disease, today announced that it has received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) regarding the resubmitted New Drug Application (NDA) for oxylanthanum carbonate (OLC) for the treatment of hyperphosphatemia in patients with chronic kidney disease (CKD) on dialysis. The FDA has not raised any concerns regarding clinical efficacy or safety data, and no additional data was requested from Unicycive.

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. The NDA for OLC had been resubmitted based on Unicycive’s belief of continued progress by the original third-party manufacturing vendor in resolving FDA-cited deficiencies and demonstrating inspection readiness. Unicycive previously discussed these milestones during a Type A meeting with the FDA in September 2025, which was held to obtain feedback and alignment on resolving the deficiencies identified in the Company’s CRL related to the compliance status of the vendor. The FDA did not express any concerns about the third-party manufacturer’s progress and no additional issues were raised by the FDA at the Type A meeting.

“We remain confident in the efficacy and safety of OLC,” said Shalabh Gupta, M.D., Chief Executive Officer of Unicycive. “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.”

The OLC NDA is supported by data from three clinical studies: a Phase 1 study in healthy volunteers, a bioequivalence study in healthy volunteers, and a tolerability study of OLC in chronic kidney disease (CKD) patients on dialysis, multiple preclinical studies, as well as chemistry, manufacturing and controls (CMC) data.

About Oxylanthanum Carbonate

OLC is an investigational oral phosphate binder that leverages proprietary nanoparticle technology to deliver high phosphate binding potency, reducing the number and size of pills that patients must take to treat hyperphosphatemia in patients with chronic kidney disease (CKD) on dialysis. Its potential best-in-class profile may have meaningful patient adherence benefits over currently available treatment options as it requires a lower pill burden. Unicycive is seeking FDA approval of OLC via the 505(b)(2) regulatory pathway. OLC is protected by a strong global patent portfolio including issued patents on composition of matter with exclusivity until 2031, and with the potential for patent term extension until 2035.

About Hyperphosphatemia

Hyperphosphatemia is a serious medical condition that occurs in nearly all patients with End Stage Renal Disease (ESRD). Annually there are over 450,000 individuals in the U.S. that require medication to control their phosphate levels.1 Uncontrolled hyperphosphatemia is strongly associated with increased death and hospitalization for CKD patients on dialysis. Treatment of hyperphosphatemia is aimed at lowering serum phosphate levels via two means: (1) restricting dietary phosphorus intake; and (2) using, on a daily basis, and with each meal, oral phosphate binding drugs that facilitate fecal elimination of dietary phosphate rather than its absorption from the gastrointestinal tract into the bloodstream.

1Flythe JE. Dialysis-Past, Present, and Future: A Kidney360 Perspectives Series. Kidney360. 2023 May 1;4(5):567-568. doi: 10.34067/KID.0000000000000145.

About Unicycive Therapeutics

Unicycive Therapeutics is a biotechnology company developing novel treatments for kidney diseases. Unicycive’s lead investigational treatment is oxylanthanum carbonate, a novel phosphate binding agent for the treatment of hyperphosphatemia in patients with chronic kidney disease who are on dialysis. Unicycive’s second investigational treatment UNI-494 is intended for the treatment of conditions related to acute kidney injury. It has been granted orphan drug designation (ODD) by the FDA for the prevention of Delayed Graft Function (DGF) in kidney transplant patients and has completed a Phase 1 dose-ranging safety study in healthy volunteers. For more information, please visit Unicycive.com and follow us on LinkedIn and X.

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