AstraZeneca v. Lupin: LOKELMA® Patent Infringement Settled by Consent Judgment
ZS Pharma and AstraZeneca filed suit against Lupin in Delaware over 14 patents protecting LOKELMA® (sodium zirconium cyclosilicate), a potassium-lowering therapy. The case resolved in 222 days via a negotiated consent judgment that enjoins Lupin from commercialising its ANDA product unless specifically authorised under the settlement terms.
ANDA infringement suit over potassium binder LOKELMA® ends in injunction
On 20 October 2023, ZS Pharma, Inc. and AstraZeneca Pharmaceuticals LP filed a Hatch-Waxman infringement action in the District of Delaware against Lupin Limited and Lupin Pharmaceuticals, Inc., asserting fourteen patents — including US11738044B2 — that collectively protect LOKELMA® (sodium zirconium cyclosilicate) oral suspension. Lupin had filed ANDA No. 217549 seeking FDA approval to market a generic version of the 5 g and 10 g per-packet product.
The case closed on 29 May 2024, just 222 days after filing, via a consent judgment entered by Judge Jennifer L. Hall. Under the judgment, Lupin and its affiliates are enjoined from making, using, selling, offering to sell, importing, or distributing the Lupin ANDA product unless specifically authorised by the underlying Settlement Agreement. All claims and counterclaims were dismissed with prejudice, and neither party was awarded costs or attorneys’ fees.
Resolution within 222 days — well inside the typical 30-month Hatch-Waxman stay period — suggests the parties reached commercial alignment before full Markman or trial proceedings were required. The public record does not disclose the licensed entry date, royalty terms, or any market-exclusivity provisions negotiated in the confidential Settlement Agreement, leaving the precise commercial upside for Lupin unknown.
Filing to Consent Judgment in 222 days
222 days — resolved well within the 30-month Hatch-Waxman stay window
Consent judgment with injunction: what the settlement means for both sides
Consent judgment is more than a dismissal — it is a court order
Unlike a voluntary dismissal, a consent judgment is a binding court decree. Lupin is formally enjoined by Judge Hall’s order, not merely by private contract. This means AstraZeneca can seek contempt proceedings in Delaware if Lupin commercialises its ANDA product outside the Settlement Agreement’s authorised terms — a materially stronger enforcement position than contract litigation alone.
Enforceable injunctionAstraZeneca secures injunction across all 14 Licensed Patents
The consent judgment names all fourteen Licensed Patents and enjoins Lupin and its affiliates from any commercialisation activity not explicitly permitted under the Settlement Agreement. AstraZeneca retains LOKELMA® market exclusivity under court order. The ‘with prejudice’ dismissal forecloses Lupin from re-litigating the same infringement claims, and the court retains jurisdiction to supervise compliance — giving AstraZeneca a durable enforcement hook.
Market exclusivity protectedLupin gains a structured path — but only on AstraZeneca’s terms
Lupin is currently enjoined from launching its ANDA product. However, the Settlement Agreement likely contains a confidential authorised-entry date — standard practice in Hatch-Waxman consent judgments. Lupin’s future LOKELMA® generic launch, if any, is therefore contractually gated. The ‘with prejudice’ dismissal also closes Lupin’s counterclaims, meaning it cannot separately challenge patent validity in this forum.
Entry date likely negotiatedFourteen-patent fortress signals strong LOKELMA® lifecycle management
AstraZeneca’s assertion of fourteen patents — spanning formulations, methods of use, and potentially dosage forms — reflects a classic lifecycle-management strategy around a branded oral suspension. Any competitor filing an ANDA for sodium zirconium cyclosilicate must navigate this portfolio. The consent judgment with injunction raises the practical barrier for subsequent ANDA filers, who now face both Orange Book-listed patents and a judicial precedent of AstraZeneca’s willingness to litigate promptly.
High barrier for follow-on ANDAsFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | ZS Pharma, Inc. | Company | Pharmaceutical innovator — co-holder of 14 LOKELMA® sodium zirconium cyclosilicate patentsSearch in Eureka ↗ |
| Co-Plaintiff | Astrazeneca Pharmaceuticals, LP | Company | Search in Eureka ↗ |
| Defendant | Lupin Limited | Individual | Lupin Limited and Lupin Pharmaceuticals, Inc. — generic pharmaceutical manufacturer, ANDA filerSearch in Eureka ↗ |
| Co-Defendant | Lupin Pharmaceuticals, Inc. | Company | Search 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 | 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 | David A. Bilson | Attorney | Counsel for Lupin LimitedSearch in Eureka ↗ |
| Defendant counsel | John C. Phillips , Jr. | Attorney | Counsel for Lupin LimitedSearch in Eureka ↗ |
| Defendant counsel | Kurt A. Mathas | Attorney | Counsel for Lupin LimitedSearch in Eureka ↗ |
| Defendant law firm | Phillips, Goldman, McLaughlin & Hall PA | Law Firm | Representing Lupin LimitedSearch in Eureka ↗ |
| Presiding judge | Judge Jennifer L. Hall | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The consent judgment is unusually detailed for a settlement instrument: it defines ‘Lupin Product’, ‘Licensed Patents’, and ‘Affiliate’ with precision, and the injunction tracks the language of 35 U.S.C. § 271 verbatim — making, using, selling, offering to sell, importing, and distributing. The ‘with prejudice’ dismissal of all claims and counterclaims is significant: Lupin cannot revive invalidity or non-infringement arguments in this court. The court’s retention of jurisdiction to supervise compliance transforms this from a private contract into an enforceable judicial order.
US11738044B2 — sodium zirconium cyclosilicate oral suspension formulation
US11738044B2 (application no. US16/415,550) is one of fourteen Licensed Patents protecting LOKELMA® (sodium zirconium cyclosilicate), an inorganic cation exchanger indicated for hyperkalaemia (high potassium). The patent sits in a portfolio spanning at least US8,802,152 through US11,738,044, suggesting layered protection across formulation composition, particle engineering, dosage forms, and methods of treatment. The 5 g and 10 g per-packet oral suspension format is the specific ANDA-challenged product.
LOKELMA® competes in the potassium binder category alongside patiromer (Veltassa®). AstraZeneca’s fourteen-patent portfolio creates significant lifecycle protection, with later-filed patents such as US11738044B2 potentially extending exclusivity well beyond the original composition claims. For generic manufacturers, this stacked portfolio represents a multi-front validity and infringement challenge — and the consent judgment demonstrates that AstraZeneca is prepared to litigate all fourteen patents simultaneously against a single ANDA filer.
Should you run an FTO against LOKELMA®’s sodium zirconium cyclosilicate patents?
Any pharmaceutical company developing or filing an ANDA for sodium zirconium cyclosilicate oral suspension must assess freedom-to-operate across all fourteen Licensed Patents, not only US11738044B2. R&D and regulatory teams evaluating hyperkalaemia treatments — or novel potassium-binding formulations — should determine whether their process, formulation, or dosage form falls within claims across this portfolio. A single unanalysed patent can result in a consent-judgment-level injunction, as this case illustrates.
PatSnap Eureka’s FTO Search Agent allows you to map your compound or formulation against the full AstraZeneca/ZS Pharma LOKELMA® portfolio in minutes. Run claim-by-claim comparison across all 14 Licensed Patents, identify design-around opportunities, and flag expiry timelines — giving your IP and product teams a defensible clearance record before ANDA filing or product launch.
Run a freedom-to-operate analysis on US11738044B2 to assess your product’s exposure
Run FTO in Eureka →Similar Hatch-Waxman ANDA infringement cases in Delaware District Court
Cases involving branded oral suspension patents, multi-patent ANDA challenges, and consent judgment resolutions in Delaware District Court — the primary venue for Hatch-Waxman litigation.
Related patent case — similar technology
Comparable case in the same technology domain. Patent holder and defendant reached resolution after proceedings.
SettledRelated infringement action — same court
Comparable LOKELMA® (sodium zirconium cyclosilicate) for oral suspension 5 g per packet and 10 g per packet-adjacent infringement action. Patent enforcement dynamics analysed in depth.
Active · District CourtRelated invalidity challenge — appellate outcome
Combined invalidity and infringement action in the same technology space. Decided after substantive proceedings.
DecidedZS Pharma, Inc.’s broader IP enforcement history
ZS Pharma, Inc.’s full litigation history covering prior enforcement, licensing activity, and inter partes review proceedings.
Portfolio viewWhat this case signals for the potassium binder and ANDA IP landscape
AstraZeneca’s rapid settlement-with-injunction sets a clear enforcement benchmark for LOKELMA® and similar branded oral suspension portfolios.
Swift resolution inside the 30-month stay is a deliberate Hatch-Waxman strategy
By resolving in 222 days, AstraZeneca avoided expensive Markman and trial proceedings while still securing a court-ordered injunction. For branded pharmaceutical companies, early settlement with a consent judgment — rather than dismissal — preserves enforcement optionality at lower litigation cost. Generic filers should expect this playbook when a branded portfolio covers fourteen or more patents.
Fourteen-patent assertion means any LOKELMA® ANDA faces a wide-net challenge
The Licensed Patents span multiple US patent numbers, likely covering formulation, particle size, dosage, and method-of-use claims for sodium zirconium cyclosilicate. A competitor cannot design around a single patent and expect clearance. IP teams evaluating entry into the potassium binder space should conduct FTO analysis across the full portfolio — not just the lead patent listed on the ANDA.
The confidential entry date in the Settlement Agreement is the real commercial lever
Hatch-Waxman consent judgments almost invariably include a licensed entry date. The gap between that date and the last patent expiry determines AstraZeneca’s effective exclusivity runway. Tracking patent expiries across all 14 Licensed Patents — including US11738044B2’s priority date — allows competitors to estimate when the market opens regardless of the settlement’s confidentiality.
Lupin’s ANDA No. 217549 could trigger 180-day exclusivity for subsequent filers
If Lupin was a Paragraph IV first filer, any settlement-based delay in its launch may toll or complicate 180-day exclusivity entitlement under Hatch-Waxman. Later ANDA filers for sodium zirconium cyclosilicate should analyse whether Lupin’s consent-judgment entry triggers, forfeits, or preserves first-filer exclusivity — a scenario with significant commercial value for the second entrant.
ZS v Lupin — key questions answered
The consent judgment lists fourteen Licensed Patents: US8,802,152; US8,808,750; US8,877,255; US9,592,253; US9,844,567; US9,861,658; US9,913,860; US10,300,087; US10,335,432; US10,398,730; US10,413,569; US10,695,365; US11,406,662; and US11,738,044. All protect LOKELMA® (sodium zirconium cyclosilicate) oral suspension and are asserted against Lupin’s ANDA No. 217549.
Under the consent judgment, Lupin and its affiliates are enjoined from making, using, selling, offering to sell, importing, or distributing the ANDA product unless specifically authorised by the confidential Settlement Agreement. The public record does not disclose a licensed entry date, but Hatch-Waxman consent judgments typically include one. Until that date arrives — or unless AstraZeneca grants authorisation — Lupin cannot launch.
The case closed in 222 days, well within the 30-month Hatch-Waxman automatic stay period. This timeline suggests the parties reached commercial agreement before substantive proceedings — such as Markman hearings or summary judgment — were required. Early settlement is common in ANDA cases where the branded company holds a large patent portfolio and the generic filer’s litigation risk is high.
Dismissal with prejudice means all claims, counterclaims, and affirmative defenses — including any invalidity or non-infringement arguments raised by Lupin — are permanently extinguished in this court. Lupin cannot re-file the same claims. This is more restrictive than a voluntary dismissal without prejudice and, combined with the injunction, gives AstraZeneca a strong enforcement position.
LOKELMA® (sodium zirconium cyclosilicate) is an inorganic cation exchanger approved for treating hyperkalaemia (elevated blood potassium). It is marketed by AstraZeneca following its acquisition of ZS Pharma. The product is protected by at least fourteen US patents covering formulation composition, dosage, and methods of use — creating a dense patent thicket that any generic entrant must navigate through ANDA Paragraph IV certification and associated litigation.
Track LOKELMA® patent expiries and ANDA activity before your next filing
PatSnap Eureka lets you monitor all fourteen LOKELMA® Licensed Patents, track Lupin and competitor ANDA activity, and run automated FTO searches across the sodium zirconium cyclosilicate portfolio. Stay ahead of the next consent judgment.
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