Exeltis USA v. Lupin: SLYND® Drospirenone Patent Dispute Dismissed With Prejudice
Exeltis USA and its Chemo Group affiliates filed suit against Lupin Limited and Lupin Pharmaceuticals in Delaware District Court, asserting US11951213B2 covering SLYND® drospirenone 4mg tablets. After 435 days of litigation, all parties stipulated to a full dismissal with prejudice and no costs awarded to either side — a resolution consistent with a negotiated settlement.
SLYND® Patent Fight Ends by Mutual Stipulation After 14 Months
On 20 June 2024, Exeltis USA, Inc., together with co-plaintiffs Laboratorios Leon Farma S.A., Chemo Iberica S.A., and Chemo Research S.L., filed a patent infringement action in the District of Delaware against Lupin Limited and its U.S. subsidiary Lupin Pharmaceuticals, Inc. The suit centred on US11951213B2, a patent protecting SLYND® drospirenone 4mg tablets — a progestin-only oral contraceptive marketed in the United States by Exeltis USA. The filing is consistent with a standard Hatch-Waxman ANDA litigation triggered by Lupin’s attempt to enter the drospirenone 4mg market.
The case closed on 29 August 2025 — 435 days after filing — when all parties jointly filed a Rule 41(a)(1)(A)(ii) stipulation of dismissal with prejudice and without costs to any party. Dismissal with prejudice is a final adjudication on the merits under federal procedural rules, meaning Exeltis and its co-plaintiffs are permanently barred from re-asserting the same claims against Lupin on this patent. The mutual no-costs provision further signals a consensual resolution rather than a contested judicial determination.
A resolution at 435 days — before any trial or substantive claim construction ruling appears in the public record — is broadly consistent with the timeline of negotiated licensing or market-entry agreements in Hatch-Waxman litigation. The with-prejudice designation and absence of any cost award are hallmarks of a confidential settlement, though the specific commercial terms, any agreed generic entry date, or licensing arrangement are not disclosed in the public docket. What remains unknown is whether Lupin secured a launch date, a royalty-bearing licence, or agreed to withdraw its ANDA.
Filing to Dismissed with Prejudice in 435 days
435 days litigated — resolved before trial, typical for ANDA pharma disputes in Delaware
Dismissed with prejudice: what the stipulated exit means for both sides
Rule 41(a)(1)(A)(ii) dismissal with prejudice explained
A stipulated dismissal under Rule 41(a)(1)(A)(ii) requires agreement of all parties and, when filed with prejudice, operates as a final adjudication on the merits. No court order or judicial findings are entered — the case simply terminates. The with-prejudice designation means the plaintiffs are permanently foreclosed from re-filing the same claims against Lupin on US11951213B2. This mechanism is the standard procedural vehicle used to close Hatch-Waxman cases following private settlement.
Procedural finalityUS11951213B2 survives — no invalidity finding on the record
Because the case was dismissed by stipulation rather than a contested merits ruling, the patent’s validity was never adjudicated. US11951213B2 remains enforceable and can be asserted against other ANDA filers or infringers. Exeltis and the Chemo Group retain full enforcement rights. The dismissal with prejudice protects Lupin specifically but does not impair claims against third parties — a commercially important distinction for Exeltis’s broader SLYND® IP strategy.
Patent remains enforceableLupin permanently shielded from these specific claims
Lupin obtains absolute protection from any future suit by Exeltis and the co-plaintiffs on the same claims under US11951213B2. However, the with-prejudice dismissal yields no public invalidity finding that Lupin or other generic filers could use offensively in subsequent proceedings. Lupin’s ANDA status and any agreed commercial terms — including any authorised generic arrangement or negotiated launch date — are not disclosed in the public record.
No re-suit risk on these claimsSettlement signals negotiated market access for drospirenone 4mg
Private resolution in Hatch-Waxman cases commonly reflects a negotiated generic entry date or licensing arrangement. For the drospirenone 4mg market, this outcome suggests Lupin likely secured some form of agreed pathway — whether a future launch date, authorised generic rights, or a royalty licence — without forcing a trial. Competitors watching this space should note that US11951213B2 remains unchallenged and that Exeltis retains full enforcement options against any other ANDA filer in the progestin-only contraceptive segment.
Likely negotiated generic entryFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Exeltis USA, Inc. | Company | Specialty pharma group — holder of US11951213B2 covering SLYND® drospirenone 4mgSearch in Eureka ↗ |
| Co-Plaintiff | Chemo Iberica, SA | Company | Search in Eureka ↗ |
| Co-Plaintiff | Laboratorios Leon Farma, SA | Company | Search in Eureka ↗ |
| Co-Plaintiff | Chemo Research, SL | Individual | Search in Eureka ↗ |
| Defendant | Lupin Limited | Individual | Lupin Limited & Lupin Pharmaceuticals — generic pharmaceutical manufacturer seeking ANDA approvalSearch in Eureka ↗ |
| Co-Defendant | Lupin Pharmaceuticals, Inc. | Company | Search in Eureka ↗ |
| Plaintiff counsel | AnnaMartina Tyreus Hufnal | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Bernard C. Cryan | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Brian D. Coggio | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Douglas Edward McCann | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Excylyn Hardin-Smith | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Gregory Robert Booker | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Jon Bell | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Madelyn McCormick | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Nitika Gupta Fiorella | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Philip K. Chen | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Yun Dong | Attorney | Counsel for Exeltis USA, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Fish & Richardson LLP | Law Firm | Representing Exeltis USA, 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 law firm | Phillips, McLaughlin & Hall PA | Law Firm | Representing Lupin LimitedSearch in Eureka ↗ |
| Presiding judge | Judge Richard G. Andrews | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulation invokes Rule 41(a)(1)(A)(ii), requiring mutual consent of all named parties — four plaintiffs and two defendants — and explicitly covers all claims, counterclaims, and defenses. The with-prejudice designation is legally significant: it constitutes a final adjudication, permanently barring the Exeltis group from re-asserting these claims against Lupin entities. The no-costs clause reflects a balanced negotiated exit rather than a party prevailing on the merits. No judicial findings on validity or infringement of US11951213B2 appear in the record.
US11951213B2 — SLYND® Drospirenone 4mg Oral Contraceptive Formulation
US11951213B2 (application number US18/365877) covers the formulation underlying SLYND® — a progestin-only oral contraceptive containing drospirenone 4mg per tablet. Drospirenone, a synthetic progestin with anti-androgenic and anti-mineralocorticoid properties, distinguishes SLYND® from earlier progestin-only pills in its pharmacological profile. The patent protects the specific composition and dosage form, providing a critical barrier to generic entry in a product segment that has attracted significant commercial interest since SLYND® received FDA approval.
For the specialty women’s health pharmaceutical sector, US11951213B2 represents a strategically important asset: it is the primary IP barrier cited against Lupin, one of the world’s largest generic pharmaceutical groups. With no invalidity finding on the record following this litigation, the patent’s commercial blocking power remains fully intact. Any generic manufacturer targeting the drospirenone 4mg market must navigate this patent — either by challenging validity, designing around the claims, or, as Lupin’s resolution suggests, negotiating a commercial arrangement with the Exeltis–Chemo Group.
Should your team run an FTO analysis against US11951213B2?
Any pharmaceutical company with a current or planned ANDA, 505(b)(2) application, or product development programme targeting drospirenone 4mg oral contraceptives should treat US11951213B2 as a live blocking patent. The Lupin dismissal provides no invalidity precedent. R&D and regulatory teams exploring progestin-only contraceptive formulations — including alternative drospirenone dosage forms or delivery mechanisms — should assess whether their product falls within the patent’s claim scope before committing to clinical or manufacturing investment.
PatSnap Eureka’s FTO Search Agent can map US11951213B2’s claim boundaries against your specific formulation parameters, identify relevant prior art, and flag forward citations that may affect enforceability. Eureka also surfaces co-pending applications in the Chemo Group’s broader portfolio, helping you identify continuations or divisionals that could extend protection beyond the cited patent. Run a targeted freedom-to-operate analysis before your next regulatory filing milestone.
Run a freedom-to-operate analysis on US11951213B2 to assess your product’s exposure
Run FTO in Eureka →Similar Hatch-Waxman drospirenone and progestin patent cases in Delaware
Delaware District Court is the dominant forum for Hatch-Waxman progestin-only contraceptive patent cases — these comparable drospirenone and oral contraceptive IP disputes provide critical precedent context.
What this case signals for the drospirenone and progestin-only contraceptive IP landscape
This dismissal illustrates the standard Hatch-Waxman playbook — but leaves key commercial questions unanswered for generic competitors and brand holders alike.
US11951213B2 remains valid and enforceable against all other ANDA filers
The dismissal with prejudice resolves only the Exeltis–Lupin dispute. No invalidity, non-infringement, or claim construction ruling was issued. Any other generic manufacturer with a pending or planned ANDA for drospirenone 4mg faces the same patent barrier and cannot rely on this case’s outcome as a shield.
The no-costs, with-prejudice structure is the fingerprint of a private settlement
Hatch-Waxman settlements routinely include a negotiated generic entry date or authorised generic deal in exchange for dismissal. The mutual no-costs provision and 14-month timeline — well before any scheduled trial — are strongly consistent with this pattern, though the specific terms remain confidential and unconfirmed from the public docket.
Exeltis v Lupin — key questions answered
The dismissal with prejudice means the case was terminated with finality — Exeltis and its co-plaintiffs cannot re-sue Lupin on the same claims under US11951213B2. However, no court ruled on the patent’s validity or infringement. The patent remains fully enforceable against other parties, and Exeltis retains all enforcement rights against other ANDA filers for SLYND® drospirenone 4mg.
The stipulated dismissal under Rule 41(a)(1)(A)(ii) — with prejudice and no costs to either party — is the standard procedural mechanism used to close Hatch-Waxman patent cases following a private settlement. The mutual no-costs provision and 14-month resolution timeline, well before any scheduled trial, are consistent with a negotiated commercial agreement, though specific terms are not disclosed on the public docket.
No. Because the case ended by stipulated dismissal without any invalidity or non-infringement finding, there is no public ruling that other ANDA filers could rely on as a defence. US11951213B2 remains an active blocking patent. Any other generic manufacturer targeting drospirenone 4mg must independently address the patent through litigation, design-around, or licensing.
US11951213B2 (application US18/365877) is a U.S. patent held by the Exeltis/Chemo Group covering the formulation of SLYND® drospirenone 4mg tablets — a progestin-only oral contraceptive. Drospirenone is a synthetic progestin with anti-androgenic and anti-mineralocorticoid properties. The patent protects the specific composition and dosage form that underpins SLYND®’s commercial differentiation in the progestin-only contraceptive market.
Plaintiffs were Exeltis USA, Inc., Laboratorios Leon Farma S.A., Chemo Iberica S.A., and Chemo Research S.L. — collectively the Exeltis/Chemo pharmaceutical group. Defendants were Lupin Limited (the Indian parent) and Lupin Pharmaceuticals, Inc. (its U.S. subsidiary). The case was litigated before Judge Richard G. Andrews in the District of Delaware, with Fish & Richardson LLP representing the plaintiffs and Phillips, McLaughlin & Hall PA representing Lupin.
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