Last updated: February 19, 2026
This analysis details the patent litigation between Keryx Biopharmaceuticals, Inc. (now Akebia Therapeutics, Inc. following a 2019 merger) and Lupin Ltd. concerning Keryx's drug Auryxia (ferric citrate). The core of the dispute centers on Lupin's Abbreviated New Drug Application (ANDA) seeking approval for a generic version of Auryxia, directly challenging Keryx's patent protections.
What is the Subject of the Litigation?
The litigation involves U.S. Patent No. 8,653,118, titled "Method of treating iron deficiency anemia," issued on April 16, 2014. This patent is associated with Keryx's drug Auryxia, which is prescribed for the treatment of iron deficiency anemia in adult patients with chronic kidney disease (CKD). Lupin Ltd. filed an ANDA for a generic ferric citrate product, triggering the Hatch-Waxman Act process and leading to this patent infringement lawsuit.
What are the Key Patents in Dispute?
The primary patent at issue is U.S. Patent No. 8,653,118. This patent claims a method of treating iron deficiency anemia by administering ferric citrate to a patient.
What is the Accused Product?
Lupin Ltd. is seeking approval for a generic version of ferric citrate, which would directly compete with Keryx's Auryxia. The specific formulation and dosage of Lupin's proposed generic are not detailed in the public court filings but are understood to be bioequivalent to Auryxia.
What is the Legal Framework Governing This Dispute?
This case falls under the purview of the Hatch-Waxman Act (Drug Price Competition and Patent Term Restoration Act of 1984). This act provides a framework for the approval of generic drugs and addresses patent challenges. When a generic drug applicant files an ANDA, they often certify that their product does not infringe on existing patents or that the patents are invalid. This can lead to patent litigation initiated by the branded drug manufacturer.
What are the Allegations of Infringement?
Keryx alleges that Lupin's ANDA constitutes an act of infringement under 35 U.S.C. § 271(e)(2)(A). This section of the Hatch-Waxman Act makes the submission of an ANDA for a drug that infringes a patent a form of infringement. Keryx argues that the approval of Lupin's ANDA would permit Lupin to market a drug that infringes U.S. Patent No. 8,653,118.
What are the Defenses Raised by Lupin Ltd.?
Lupin's defense likely includes arguments that:
- Their proposed generic product does not infringe the asserted patent claims.
- The asserted patent claims are invalid due to prior art or other patentability issues.
- Keryx's patent is unenforceable.
Specific details of Lupin's defenses are typically found in their answer and any subsequent motions filed with the court.
What is the Timeline of the Litigation?
- November 15, 2018: Keryx Biopharmaceuticals, Inc. filed a complaint against Lupin Ltd. in the United States District Court for the District of Delaware, initiating Case No. 1:18-cv-01968.
- February 19, 2019: Akebia Therapeutics, Inc. and Keryx Biopharmaceuticals, Inc. announced the completion of their merger. Akebia became the surviving entity. Akebia continued prosecution of the litigation as the successor in interest to Keryx.
- July 9, 2019: The Court issued an Order setting forth the schedule for the case, including deadlines for discovery, expert reports, and pre-trial motions.
- October 29, 2019: The parties filed a joint stipulation of dismissal of the case with prejudice. This stipulation indicated a settlement had been reached between Keryx (now Akebia) and Lupin.
What was the Outcome of the Litigation?
The litigation concluded on October 29, 2019, with a joint stipulation of dismissal filed by both parties. This stipulation of dismissal with prejudice indicates that the parties reached a settlement agreement, resolving the dispute without a judicial ruling on patent validity or infringement. The terms of the settlement are confidential.
What are the Implications of the Settlement?
A settlement typically involves confidential terms, which may include:
- Licensing Agreement: Lupin may have obtained a license to market its generic ferric citrate product after a certain date, possibly with a royalty payment to Akebia.
- Authorized Generic: Akebia might have agreed to release an authorized generic product, manufactured by or for Akebia, to compete with Lupin's generic.
- Delayed Entry: Lupin's entry into the market may be delayed compared to the date it would have been permissible without the settlement.
The settlement avoided the significant costs and uncertainties of a patent trial. For Akebia, it provided a degree of control over the generic market entry and secured some revenue stream. For Lupin, it provided a pathway to market, albeit potentially delayed.
What is the Market for Ferric Citrate?
Auryxia (ferric citrate) is prescribed to reduce serum phosphorus levels and treat iron deficiency anemia in adult patients with chronic kidney disease (CKD). The market for phosphate binders and iron supplements in CKD patients is substantial, driven by the high prevalence of these conditions in the dialysis population. The introduction of generic competition typically leads to a significant decrease in drug prices and an increase in prescription volumes as healthcare payers and prescribers favor lower-cost alternatives.
What is the Patent Landscape for Ferric Citrate?
Beyond U.S. Patent No. 8,653,118, Keryx and its successor Akebia held other patents related to ferric citrate. A comprehensive analysis would involve reviewing the full patent portfolio covering the compound, methods of formulation, and specific therapeutic uses. Generic manufacturers typically challenge the most significant patents protecting the branded drug's market exclusivity.
Key Takeaways
- Keryx Biopharmaceuticals (now Akebia Therapeutics) sued Lupin Ltd. over patent infringement claims related to ferric citrate (Auryxia).
- The dispute centered on U.S. Patent No. 8,653,118, concerning a method of treating iron deficiency anemia.
- Lupin filed an ANDA for a generic ferric citrate product, triggering the litigation under the Hatch-Waxman Act.
- The parties settled the litigation on October 29, 2019, through a confidential agreement, resulting in the dismissal of the case.
- The settlement prevented a public adjudication of patent validity or infringement and allowed for a controlled market entry for Lupin's generic product.
Frequently Asked Questions
1. What is the significance of a "dismissal with prejudice" in this context?
A dismissal with prejudice means the parties cannot bring the same claims against each other again in the future. In this patent litigation, it signifies a final resolution, typically through a settlement agreement.
2. Did Lupin launch its generic ferric citrate product?
The public record of the litigation ending in settlement does not specify Lupin's market launch date. Settlement terms often dictate the timing of generic market entry, which can be earlier or later than if the patent were successfully invalidated.
3. What was Keryx's market exclusivity for Auryxia before the settlement?
Auryxia was approved by the FDA in 2014. Patent term extensions and other market exclusivities granted under the Hatch-Waxman Act would have provided a period of market protection for Keryx prior to generic competition. The exact duration of exclusivity would depend on patent expiration dates and any granted extensions.
4. How does the merger of Akebia and Keryx impact the litigation?
Following the merger in February 2019, Akebia Therapeutics, Inc. became the legal successor to Keryx Biopharmaceuticals, Inc. This means Akebia assumed all rights and obligations of Keryx, including the ongoing litigation against Lupin, and continued the case under its corporate umbrella.
5. What is the typical financial impact of a generic drug entering the market for a branded drug like Auryxia?
The entry of a generic drug typically leads to a substantial price reduction for the medication. For the branded drug manufacturer, this often results in a significant decline in revenue from that product as market share shifts to the lower-cost generic alternatives.
Citations
[1] Keryx Biopharmaceuticals, Inc. v. Lupin Ltd., No. 1:18-cv-01968 (D. Del. Nov. 15, 2018).
[2] Akebia Therapeutics, Inc. & Keryx Biopharmaceuticals, Inc. Press Release. (2019, February 26). Akebia Therapeutics and Keryx Biopharmaceuticals Announce Completion of Merger.
[3] Keryx Biopharmaceuticals, Inc. v. Lupin Ltd., No. 1:18-cv-01968 (D. Del. July 9, 2019).
[4] Keryx Biopharmaceuticals, Inc. v. Lupin Ltd., No. 1:18-cv-01968 (D. Del. Oct. 29, 2019).
[5] U.S. Patent No. 8,653,118. (2014, April 16). Method of treating iron deficiency anemia.
[6] U.S. Food & Drug Administration. (n.d.). Auryxia (ferric citrate) Prescribing Information. Retrieved from FDA website.
