# 2025-11029: FDA Sets Patent-Extension Clock for Drug With Unusual Name XOLREMDI

2025-11029, Determination of Regulatory Review Period for Purposes of Patent Extension; XOLREMDI, is a Federal Register notice from Health and Human Services Department, Food and Drug Administration published 2025-06-16, effective Anyone may submit comments asking for a redetermination by August 15, 2025. Any interested person may petition FDA regarding whether the applicant acted with due diligence during the regulatory review period by December 15, 2025.; PRIA reads it as touching household money (as of 2026-11-02).

- Canonical: https://policyrisk.com/federal-register/2025-11029
- As of: 2026-11-02
- Plain-text twin of the page above; the HTML and this file carry the same facts.

## Facts
- Document number: 2025-11029
- Title: Determination of Regulatory Review Period for Purposes of Patent Extension; XOLREMDI
- Type: Notice
- Agencies: Health and Human Services Department; Food and Drug Administration
- Citation: 90 FR 25311
- Published: 2025-06-16
- Effective: Anyone may submit comments asking for a redetermination by August 15, 2025. Any interested person may petition FDA regarding whether the applicant acted with due diligence during the regulatory review period by December 15, 2025.
- Comments close: not stated
- Significant: no
- Touches household money: yes
- Regulation identifier numbers: none
- Last updated: 2026-11-02

## In one line

FDA Sets Patent-Extension Clock for Drug With Unusual Name XOLREMDI

## Summary

The FDA has officially set the review period for the drug XOLREMDI, which helps the company extend its patent protection. This means the drug maker might get extra time to keep their invention exclusive, potentially affecting when generic versions can appear. If anyone thinks the dates are wrong or wants to challenge the company’s review speed, they have until late 2025 to speak up.

## Abstract

The Food and Drug Administration (FDA or the Agency) has determined the regulatory review period for XOLREMDI and is publishing this notice of that determination as required by law. FDA has made the determination because of the submission of applications to the Director of the U.S. Patent and Trademark Office (USPTO), Department of Commerce, for the extension of a patent which claims that human drug product.

## Effects PRIA read

- FDA sets XOLREMDI review period: benefit, high. FDA determined the regulatory review period for XOLREMDI is 6,923 days total: 6,683 days in the testing phase and 240 days in the approval phase. Key dates are: investigational new drug (IND) effective May 15, 2015; new drug application (NDA) initially submitted August 31, 2023; NDA approved April…
- Company seeks ~490 days patent extension: benefit, high. X4 Pharmaceuticals has applied to the USPTO for patent term restoration and, in its applications, seeks either 490 days or 498 days of patent term extension for U.S. Patent Nos. 10,610,527; 10,953,003; and 11,219,621. FDA notes that its regulatory-review-period determination establishes the maximum…
- Deadlines to challenge dates or due diligence: benefit, low. Anyone who believes the published dates are incorrect can submit comments and request a redetermination by August 15, 2025. Any interested person may petition FDA about whether the applicant acted with due diligence during the regulatory review period by December 15, 2025, with filing instructions…

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## Sources
- [2025-11029 on federalregister.gov](https://www.federalregister.gov/documents/2025/06/16/2025-11029/determination-of-regulatory-review-period-for-purposes-of-patent-extension-xolremdi)
- [2025-11029 as published (PDF)](https://www.govinfo.gov/content/pkg/FR-2025-06-16/pdf/2025-11029.pdf)

## Related
- [Previous: 2025-11028, Determination of Regulatory Review Period for Purposes of Patent Extension; AV…](https://policyrisk.com/federal-register/2025-11028)
- [Next: 2025-11030, Determination of Regulatory Review Period for Purposes of Patent Extension; VOY…](https://policyrisk.com/federal-register/2025-11030)
- [All Federal Register documents](https://policyrisk.com/federal-register)

Source: PRIA, https://policyrisk.com/federal-register/2025-11029 (as of 2026-11-02).