AstraZeneca & ZS Pharma v. Sandoz: LOKELMA Patent Consent Judgment
ZS Pharma and AstraZeneca sued Sandoz in Delaware over 14 patents protecting LOKELMA (sodium zirconium cyclosilicate), a potassium-lowering drug for hyperkalemia. After 758 days of litigation, the parties reached a confidential settlement resulting in a consent judgment that enjoins Sandoz from commercializing its ANDA product without authorization.
14-patent LOKELMA portfolio defended in Delaware ANDA consent judgment
ZS Pharma, Inc. and AstraZeneca Pharmaceuticals LP filed suit on 22 August 2022 in the District of Delaware against Sandoz, Inc., asserting infringement of 14 US patents directed to sodium zirconium cyclosilicate (SZC) compositions and methods — the active ingredient in LOKELMA, AstraZeneca’s FDA-approved treatment for hyperkalemia available as 5 g and 10 g oral suspension packets. The trigger was Sandoz’s filing of Abbreviated New Drug Application No. 217405, a standard Paragraph IV ANDA challenge.
The action closed on 18 September 2024 via a consent judgment and confidential settlement agreement. Under the consent judgment, Sandoz and its affiliates are permanently enjoined from making, using, selling, offering to sell, or importing the Sandoz ANDA product unless specifically authorized under the confidential settlement terms. All claims and counterclaims were dismissed with prejudice, with no costs or fees awarded to any party, suggesting a negotiated licensing arrangement or delayed entry date is embedded in the confidential terms.
At 758 days, the case ran longer than many ANDA settlements, suggesting substantive negotiation over entry date and licensing scope rather than an early capitulation by either side. The confidential nature of the settlement agreement means the precise authorized-launch timeline for Sandoz — if any — remains unknown from the public record. What is clear is that AstraZeneca secured an injunction preserving LOKELMA’s market position through at least the settlement’s effective date.
Filing to Consent Judgment in 758 days
758 days — above the median for ANDA patent cases in Delaware District Court
Consent judgment and injunction: what the settlement means for both parties
Consent judgment locks in injunction by court order
A consent judgment differs from a pure settlement: the court formally enters an order, making the injunction enforceable as a court decree rather than merely a contractual promise. Sandoz and its affiliates are now bound by a court-ordered injunction prohibiting commercialisation of ANDA No. 217405 products except as permitted under the confidential settlement. AstraZeneca retains standing to enforce directly through contempt proceedings.
Court-ordered injunction in forceAstraZeneca secures injunctive protection across all 14 patents
By obtaining a consent judgment rather than litigating to verdict, AstraZeneca avoids the risk of any patent being invalidated or found non-infringed. All 14 licensed patents emerge from the litigation without a single adverse merits ruling. The dismissal with prejudice bars Sandoz from re-filing the same infringement claims, and the court retains jurisdiction to supervise compliance — a meaningful enforcement lever for AstraZeneca going forward.
All 14 patents uncontested on meritsSandoz avoids invalidity risk but accepts launch constraints
Sandoz did not obtain a court ruling invalidating or narrowing any of the 14 asserted patents, which would have benefited the broader generic industry. The confidential settlement likely contains a licensed entry date that determines when Sandoz may commercially launch — a common resolution in ANDA litigation. The dismissal with prejudice means Sandoz cannot reopen this specific challenge, though IPR or other post-grant proceedings would remain theoretically available.
Launch timing governed by confidential termsLOKELMA exclusivity reinforced; sector watches for entry date signals
With 14 patents spanning compositions, formulations, and methods of use, AstraZeneca’s SZC portfolio presents a layered exclusivity stack that proved resilient under challenge. Other ANDA filers seeking to launch competing SZC products face the same 14-patent barrier without the benefit of any invalidity ruling from this case. The hyperkalemia treatment market, which LOKELMA leads, remains protected pending any authorised generic entry under the confidential agreement.
14-patent barrier remains intactFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | ZS Pharma, Inc. | Company | Pharmaceutical innovator — co-holder of 14 SZC patents covering LOKELMASearch in Eureka ↗ |
| Co-Plaintiff | Astrazeneca Pharmaceuticals, LP | Company | Search in Eureka ↗ |
| Defendant | Sandoz, Inc. | Company | Generic pharmaceutical company pursuing ANDA No. 217405 for sodium zirconium cyclosilicateSearch in Eureka ↗ |
| Plaintiff counsel | Alexandra M. Joyce | Attorney | Counsel for ZS Pharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Daniel M. Silver | Attorney | Counsel for ZS Pharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Daniel O’boyle | Attorney | Counsel for ZS Pharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Gyuhyun (joanne) Bae | Attorney | Counsel for ZS Pharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Hassen Sayeed | Attorney | Counsel for ZS Pharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | James Yi Li | Attorney | Counsel for ZS Pharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Mark A. Hayden | Attorney | Counsel for ZS Pharma, Inc.Search in Eureka ↗ |
| Plaintiff law firm | McCarter & English LLP | Law Firm | Representing ZS Pharma, Inc.Search in Eureka ↗ |
| Defendant counsel | Alison M. King | Attorney | Counsel for Sandoz, Inc.Search in Eureka ↗ |
| Defendant counsel | Ashley Graham | Attorney | Counsel for Sandoz, Inc.Search in Eureka ↗ |
| Defendant counsel | Chang Hahn | Attorney | Counsel for Sandoz, Inc.Search in Eureka ↗ |
| Defendant counsel | Charles B. Klein | Attorney | Counsel for Sandoz, Inc.Search in Eureka ↗ |
| Defendant counsel | Claire A. Fundakowski | Attorney | Counsel for Sandoz, Inc.Search in Eureka ↗ |
| Defendant counsel | David A. Bilson | Attorney | Counsel for Sandoz, Inc.Search in Eureka ↗ |
| Defendant counsel | John C. Phillips , Jr. | Attorney | Counsel for Sandoz, Inc.Search in Eureka ↗ |
| Defendant law firm | Phillips, McLaughlin & Hall PA | Law Firm | Representing Sandoz, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Jennifer L. Hall | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The consent judgment is notable for its dual function: it simultaneously records the parties’ negotiated resolution and constitutes a binding court order. The injunction’s scope covers Sandoz, all affiliates, successors, and assigns — unusually broad language that forecloses indirect commercialisation routes. Critically, paragraph 6 dismisses all claims and counterclaims with prejudice, meaning Sandoz’s invalidity and non-infringement defences are extinguished. No merits adjudication occurred, so the 14 licensed patents carry no litigation-tested validity status from this proceeding.
US8802152B2 and 13 further patents — sodium zirconium cyclosilicate (LOKELMA)
The 14 asserted patents collectively protect the composition, formulation, manufacturing, and therapeutic use of sodium zirconium cyclosilicate (SZC), an inorganic ion-exchange compound that selectively captures potassium ions in the gastrointestinal tract. The portfolio spans application dates across the early-to-mid 2010s, consistent with ZS Pharma’s foundational R&D programme that preceded AstraZeneca’s acquisition of ZS Pharma in 2015. The earliest priority patent (US8802152) traces to application US13/371080, establishing a priority anchor for the broader portfolio.
For the hyperkalemia treatment market — where LOKELMA competes with Vifor’s patiromer (Veltassa) — this 14-patent portfolio represents a formidable exclusivity stack. Each patent addresses a different aspect of the SZC technology, meaning a generic challenger must overcome all of them to achieve a clear path to market. The absence of any invalidity ruling from this case means the portfolio’s untested strength may deter or delay future ANDA filers, maintaining AstraZeneca’s pricing power in a chronic-disease indication with high patient persistence.
Should your SZC product run an FTO against LOKELMA’s 14-patent portfolio?
Any pharmaceutical company developing a sodium zirconium cyclosilicate-based product, a competing potassium binder, or an SZC formulation for hyperkalemia should treat all 14 licensed patents as live risks. Because the Sandoz consent judgment made no merits findings, none of these patents has been judicially weakened. R&D teams working on alternative polymorphs, dosing regimens, or combination products for hyperkalemia are particularly exposed if their compositions fall within the broad SZC composition claims.
PatSnap Eureka’s FTO Search Agent can map your compound’s structural and functional characteristics against all 14 LOKELMA patents simultaneously, flagging claim overlap and identifying prosecution history that may define patent boundaries. Eureka’s portfolio visualisation also shows how the 14 patents interlock chronologically, helping you identify any temporal gaps or claim scope limitations that could inform a design-around strategy or a targeted IPR petition on the most vulnerable claims.
Run a freedom-to-operate analysis on US10398730B2 to assess your product’s exposure
Run FTO in Eureka →Similar ANDA patent cases: sodium zirconium cyclosilicate and hyperkalemia IP
These cases involve comparable ANDA patent disputes over potassium binders and specialty oral suspension formulations litigated in Delaware District Court.
What the LOKELMA settlement signals for pharma ANDA patent strategy
A 14-patent consent judgment with injunction is a strong defensive outcome — here is what it means for stakeholders across the SZC and hyperkalemia treatment space.
Portfolio depth is the most durable ANDA defence
AstraZeneca’s ability to assert 14 patents — spanning compositions, dosage forms, and methods of use — created a litigation risk profile that made patent-by-patent invalidation an unattractive path for Sandoz. Innovators building ANDA-defence strategies should consider stacking patents across multiple claim types rather than relying on a single foundational patent.
Consent judgments preserve portfolio integrity where verdicts cannot
A litigated verdict always risks narrowing or invalidating at least one patent claim. By settling to a consent judgment, AstraZeneca exits with all 14 patents unscathed on the merits — a materially stronger position for deterring the next ANDA filer. This pattern is consistent with a calculated decision to avoid appellate uncertainty on any individual patent.
ZS v Sandoz — key questions answered
14 US patents were asserted: US8802152, US8808750, US8877255, US9592253, US9844567, US9861658, US9913860, US10300087, US10335432, US10398730, US10413569, US10695365, US11406662, and US11738044 — all covering sodium zirconium cyclosilicate compositions and methods underlying LOKELMA.
The case resolved on 18 September 2024 via a consent judgment entered by Judge Jennifer L. Hall in Delaware District Court. The parties reached a confidential settlement; Sandoz is permanently enjoined from commercialising ANDA No. 217405 except as authorised under the confidential agreement. All claims were dismissed with prejudice, with no costs awarded.
No. The consent judgment contains no merits findings. None of the 14 patents was adjudicated invalid, not infringed, or unenforceable. All patents exit the litigation with their presumption of validity fully intact, providing no invalidity shield for future ANDA challengers.
The injunction prohibits Sandoz and all its affiliates, successors, and assigns from making, using, selling, offering to sell, or importing the ANDA No. 217405 product unless specifically authorised under the confidential Settlement Agreement. The court retains jurisdiction to enforce the injunction.
No. Because the case settled without any patent being found invalid or not infringed, subsequent ANDA filers receive no legal benefit from this proceeding. Any new challenger must independently assert invalidity or non-infringement against all 14 licensed patents, significantly increasing the cost and risk of a future challenge.
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