Litigation Details for LEO Pharma A/S v. Perrigo UK FINCO Limited Partnership (D. Del. 2018)

LEO Pharma A/S v. Perrigo UK FINCO Limited Partnership (D. Del. 2018)

Docket		Date Filed	2018-11-27
Court	District Court, D. Delaware	Date Terminated	2019-04-02
Cause	35:271 Patent Infringement	Assigned To	Colm Felix Connolly
Jury Demand	None	Referred To
Patents	10,117,812
Link to Docket	External link to docket

Details for LEO Pharma A/S v. Perrigo UK FINCO Limited Partnership (D. Del. 2018)

Date Filed	Document No.	Description	Snippet	Link To Document
2018-11-27				External link to document
2018-11-26	4		the Commissioner of Patents and Trademarks for Patent/Trademark Number(s) 10,117,812 B2. (ceg) (Entered…2018 2 April 2019 1:18-cv-01874 835 Patent - Abbreviated New Drug Application(ANDA) None	External link to document

LEO Pharma A/S v. Perrigo UK FINCO: Enstilar Patent Litigation Summary

Last updated: August 3, 2026

LEO Pharma A/S sued Perrigo UK FINCO Limited Partnership in the U.S. District Court for the District of Delaware after Perrigo filed an abbreviated new drug application for a generic version of Enstilar foam. The case concerned calcipotriene and betamethasone dipropionate topical foam, a prescription psoriasis treatment marketed by LEO Pharma.

The litigation, Case No. 1:18-cv-01874, was an ANDA patent case under 35 U.S.C. § 271(e)(2). LEO asserted patents covering the drug’s composition and foam formulation. The public docket does not show a merits judgment invalidating or upholding the asserted patents. The case concluded without a reported trial decision, and publicly available docket materials do not disclose the commercial terms of any resolution. [1]

What drug and formulation were at issue in LEO Pharma v. Perrigo?

The dispute involved Enstilar, a topical aerosol foam containing two active ingredients:

Product	Active ingredients	Dosage form	Sponsor
Enstilar	Calcipotriene and betamethasone dipropionate	Topical aerosol foam	LEO Pharma A/S
Perrigo ANDA product	Calcipotriene and betamethasone dipropionate	Proposed generic topical foam	Perrigo

Enstilar is approved for the topical treatment of plaque psoriasis in patients 18 years of age and older. The product combines calcipotriene, a vitamin D analog, with betamethasone dipropionate, a corticosteroid. The formulation is delivered as an aerosol foam rather than as an ointment, cream or conventional suspension. [2]

The commercial and technical value of Enstilar lies in the combination of the active ingredients and the formulation system. The foam is designed to spread on the skin and deliver both active agents in a substantially anhydrous vehicle. Those formulation characteristics were central to LEO’s patent strategy.

Which patents did LEO Pharma assert against Perrigo?

The litigation is associated with two LEO Pharma patents covering the calcipotriene-betamethasone foam technology:

Patent	General subject matter	Relevance to litigation
U.S. Patent No. 9,730,865	Pharmaceutical composition containing calcipotriene and betamethasone dipropionate	Composition and active-ingredient combination claims
U.S. Patent No. 9,744,179	Foamable pharmaceutical composition	Foam vehicle and formulation claims

The patents were directed to different technical aspects of the product. The ’865 patent addressed the pharmaceutical composition, while the ’179 patent addressed foamable formulations and related composition characteristics. [3][4]

LEO’s complaint followed Perrigo’s ANDA filing. An ANDA filing with a Paragraph IV certification creates an artificial act of infringement under the Hatch-Waxman Act when the applicant asserts that a listed patent is invalid, unenforceable or will not be infringed. The filing permits the patent holder to sue before generic commercial launch. [5]

What was the legal basis for the LEO Pharma lawsuit?

LEO brought the case under the Hatch-Waxman patent litigation framework. The lawsuit sought to prevent FDA approval or commercial marketing of Perrigo’s proposed generic product before expiration of the relevant Orange Book-listed patents.

The core issues in a case of this type generally include:

1. Whether Perrigo’s proposed formulation falls within the asserted patent claims.
2. Whether the asserted claims are invalid for obviousness, anticipation or lack of written description.
3. Whether the patents are enforceable.
4. The length of any FDA regulatory stay triggered by LEO’s patent suit.
5. The date on which Perrigo could launch if the parties settled.

The public case record identifies the action as a pharmaceutical patent dispute involving Perrigo’s ANDA product. The publicly reported record does not provide a final infringement or validity ruling in this specific action. [1]

What is the litigation status of LEO Pharma v. Perrigo?

The case did not produce a reported trial judgment addressing the validity or infringement of the asserted patents. The docket reflects a resolution and termination of the action rather than a published merits opinion.

Litigation element	Status
Court	U.S. District Court for the District of Delaware
Case number	1:18-cv-01874
Plaintiff	LEO Pharma A/S
Defendant	Perrigo UK FINCO Limited Partnership
Technology	Calcipotriene/betamethasone dipropionate topical foam
Case type	Hatch-Waxman ANDA patent litigation
Asserted patents	U.S. Patent Nos. 9,730,865 and 9,744,179
Trial judgment	No reported merits judgment
Publicly disclosed settlement terms	Not identified in the public docket record
Current litigation posture	Terminated

The absence of a merits decision means the case does not establish a binding ruling on the validity of the Enstilar patents against all generic manufacturers. Any claim-construction or validity arguments made in the case must be distinguished from a final adjudication.

Did Perrigo file a Paragraph IV challenge to Enstilar?

The case was initiated in response to Perrigo’s ANDA filing and associated patent certifications. The litigation therefore reflects a Paragraph IV-style challenge or another ANDA certification dispute involving LEO’s listed patents.

A Paragraph IV certification alleges that a listed patent is invalid, unenforceable or will not be infringed by the proposed generic product. The patent owner’s lawsuit can trigger a 30-month stay of FDA approval under 21 U.S.C. § 355(j)(5)(B)(iii), subject to statutory exceptions and court developments. [5]

The filing of the case did not itself authorize Perrigo to launch. FDA approval, patent settlement terms, any court-ordered launch restriction and applicable exclusivity rights would determine the actual entry date.

What was the effect of the litigation on FDA approval?

The litigation could delay final FDA approval of Perrigo’s ANDA through the statutory stay mechanism. The effect depended on the timing of LEO’s lawsuit, the status of the ANDA, the nature of Perrigo’s patent certification and the ultimate disposition of the case.

Enstilar was approved under NDA No. 207589. FDA’s labeling identifies calcipotriene and betamethasone dipropionate foam as the approved dosage form and provides the product’s psoriasis indication. [2]

The litigation did not create new regulatory exclusivity for LEO. Patent protection and FDA regulatory exclusivity are separate. An ANDA applicant can face a patent barrier after regulatory exclusivity has expired, and a product can remain commercially protected by patents after ordinary New Chemical Entity or other FDA exclusivity periods have ended.

What formulation patents protect Enstilar?

The Enstilar patent estate is commercially important because formulation patents can limit generic substitution even when the active ingredients are old.

Foam delivery system

The asserted formulation claims relate to a foamable pharmaceutical composition containing calcipotriene and betamethasone dipropionate. The claims are directed to the physical and chemical characteristics of the vehicle, including the composition’s ability to form a stable topical foam.

Combination composition

The composition patent addresses the combination of a vitamin D analog and a corticosteroid in a topical pharmaceutical formulation. This type of claim can create a barrier where a generic applicant uses the same active ingredients but modifies inactive ingredients or manufacturing parameters only within the scope of the claims.

Manufacturing and vehicle design

Foam products can create technical design-around problems. A generic applicant must match the reference product’s active ingredients, dosage form, strength and performance characteristics while avoiding the asserted claims. Changes to propellant, solvent, emulsifier, vehicle composition or manufacturing process can affect:

• Foam stability.
• Drug solubility.
• Dose uniformity.
• Skin deposition.
• Container performance.
• Product equivalence.
• Patent infringement risk.

A formulation patent does not necessarily block every alternative calcipotriene-betamethasone product. Its commercial impact depends on claim breadth and whether the generic’s proposed formulation practices each claim limitation.

What are the patent expiration dates for the Enstilar patents?

The relevant patent terms must be determined from the individual patent records, PTA calculations, PTE or pediatric extensions, continuation relationships and FDA Orange Book listings. The public litigation record alone is not a reliable substitute for the current Orange Book entry.

The central protection period extended beyond the initial Enstilar approval because the asserted patents were filed after the underlying active ingredients had long been known. The patents therefore represented formulation and combination protection rather than basic molecule protection.

For launch analysis, the controlling data points are:

Launch variable	Commercial significance
Orange Book patent expiration	Establishes the listed patent’s ordinary term
Patent-term adjustment	Can extend the expiration date
Pediatric exclusivity	Can add six months to qualifying exclusivity or patent protection
Paragraph IV certification	May permit earlier litigation-driven entry
Settlement date	Can create a negotiated launch date
Authorized generic agreement	Can alter expected price erosion
ANDA approval status	Determines whether a launch is legally and commercially possible

Because the Perrigo case ended without a public merits ruling, the litigation record does not establish that either asserted patent was invalid or unenforceable.

Did LEO Pharma and Perrigo enter a settlement agreement?

The case ended without a reported judicial determination on the asserted patents. Publicly available docket materials do not disclose the detailed economic or launch provisions of the parties’ resolution.

A Hatch-Waxman settlement can contain several commercially important terms:

• A date on which Perrigo may launch.
• A license to the asserted patents.
• A contingent launch date tied to patent litigation involving another generic.
• An authorized generic arrangement.
• Supply or distribution rights.
• Restrictions on challenging other patents.
• Acceleration provisions if LEO loses related litigation.

The absence of publicly disclosed terms prevents a reliable calculation of Perrigo’s agreed launch date, royalty obligation or expected market-share position. The case termination alone does not show whether Perrigo obtained an early launch license or whether its product remained blocked until patent expiry.

How does this case compare with LEO Pharma’s other Enstilar litigation?

LEO litigated the Enstilar patent estate against multiple generic applicants. The most significant reported parallel litigation included LEO Pharma A/S v. Teva Pharmaceuticals USA, Inc., involving the same general Enstilar formulation technology.

That separate litigation produced substantive Federal Circuit analysis concerning obviousness and the patentability of the foam formulation. The Federal Circuit’s decision in LEO Pharma A/S v. Teva Pharmaceuticals USA, Inc. addressed the nonobviousness of claims directed to the pharmaceutical foam composition and recognized the relevance of the formulation’s technical properties and objective indicia. [6]

The Teva decision should not be treated as a final merits ruling in the Perrigo case. It may, however, affect the negotiating environment for related generic applicants and the perceived strength of the LEO patent estate.

Issue	Perrigo case	Reported LEO v. Teva litigation
Product technology	Calcipotriene/betamethasone foam	Calcipotriene/betamethasone foam
Procedural posture	Terminated without reported merits judgment	Substantive appellate decision
Validity ruling	No reported final ruling in this case	Federal Circuit addressed obviousness
Commercial effect	Depended on undisclosed resolution terms	Strengthened LEO’s position in related litigation
Precedential effect	No reported merits precedent	Relevant to related Enstilar patent disputes

How strong was LEO’s patent estate?

LEO’s patent position was stronger than a simple active-ingredient patent strategy because it combined composition and formulation protection. The relevant strengths were:

• Protection for a commercial combination of two established actives.
• Claims directed to a differentiated foam dosage form.
• Potential Orange Book listing and Hatch-Waxman enforcement.
• Technical barriers associated with foam stability and drug delivery.
• Favorable analysis in related litigation concerning obviousness.

The principal weaknesses were also clear:

• Calcipotriene and betamethasone dipropionate were known pharmaceutical agents.
• Generic applicants could challenge whether the claimed formulation was obvious.
• A competitor could attempt a noninfringing formulation design-around.
• Composition and formulation claims may not cover every alternative vehicle.
• Patent expiration remained a fixed limit on exclusivity.

On balance, the Enstilar estate was commercially meaningful but depended heavily on the scope and validity of the formulation claims. The absence of a Perrigo merits decision leaves the specific infringement dispute unresolved as a matter of precedent.

What generic entry risks existed for Enstilar?

The principal generic-entry scenarios were:

Delayed entry after patent expiry

Perrigo could wait until the relevant patent and regulatory barriers expired. This would reduce litigation risk but allow other generic applicants to reach the market first.

Settlement-based entry

Perrigo could launch on a negotiated date before the latest patent expiration. This is the most common commercial outcome in ANDA disputes that terminate without trial, although the public record does not disclose the terms here.

Launch after invalidity or noninfringement

A generic applicant could launch after defeating the asserted patents or obtaining a ruling that its product did not infringe. That scenario did not occur through a reported merits judgment in this case.

Authorized generic or licensed entry

LEO could permit Perrigo to commercialize under a license, potentially with supply, royalty or distribution conditions. No public record cited here confirms such an arrangement.

What was the revenue exposure for LEO Pharma?

Enstilar is a branded specialty topical product used in psoriasis. Generic entry would expose LEO to:

• Direct unit-price erosion.
• Pharmacy substitution.
• Payer formulary changes.
• Reduced branded prescription volume.
• Loss of premium pricing for the foam dosage form.
• Competitive pressure from other topical psoriasis products.

The financial impact would depend on the timing of Perrigo’s launch, the number of additional ANDA applicants, the availability of authorized generic supply and the extent to which prescribers and payers treated the generic as therapeutically interchangeable.

The Perrigo case alone did not determine the full exclusivity period for Enstilar. Other patents, settlements and generic applications could independently affect the product’s market protection.

Key Takeaways

• LEO Pharma sued Perrigo in Delaware over an ANDA for generic calcipotriene and betamethasone dipropionate foam.
• The dispute concerned Enstilar, approved under NDA No. 207589.
• The asserted patents were U.S. Patent Nos. 9,730,865 and 9,744,179.
• The patents covered the active-ingredient composition and foamable formulation technology.
• The case ended without a reported trial or final merits ruling.
• Public docket materials do not disclose the economic terms or agreed launch date of the resolution.
• Related LEO litigation against Teva produced substantive appellate analysis supporting the nonobviousness of the Enstilar foam technology.
• The main generic-entry risk was a negotiated launch by Perrigo before the latest patent expiration, but the public record does not establish whether that occurred or on what terms.
• Enstilar’s commercial protection depended on formulation patents, Orange Book status, ANDA certifications and settlement provisions rather than molecule exclusivity.

FAQs About LEO Pharma v. Perrigo UK FINCO

Was LEO Pharma v. Perrigo a biologic or biosimilar case?

No. The case involved a small-molecule topical drug and an ANDA. Biosimilar litigation under the Biologics Price Competition and Innovation Act was not involved.

What is the Enstilar active ingredient combination?

Enstilar contains calcipotriene and betamethasone dipropionate in a topical aerosol foam formulation.

Did Perrigo win the Enstilar patent case?

The public record does not show a merits judgment awarding Perrigo a victory on invalidity or noninfringement. The case terminated without a reported final trial decision.

Did the case establish that the Enstilar patents were valid?

No. The Perrigo docket did not produce a reported final validity ruling. Related litigation may have addressed similar patent claims, but those decisions must be analyzed separately.

Can a generic manufacturer avoid the Enstilar patents by changing the foam vehicle?

Potentially, but only if the alternative product does not practice the asserted claims. A vehicle change could affect infringement, equivalence, stability, bioavailability and FDA approval requirements.

References

1. U.S. District Court for the District of Delaware. (2018). LEO Pharma A/S v. Perrigo UK FINCO Limited Partnership, No. 1:18-cv-01874. Public docket record.

2. U.S. Food and Drug Administration. (2015). Enstilar (calcipotriene and betamethasone dipropionate) foam prescribing information, NDA No. 207589.

3. United States Patent and Trademark Office. (2017). U.S. Patent No. 9,730,865, pharmaceutical composition comprising calcipotriol and betamethasone.

4. United States Patent and Trademark Office. (2017). U.S. Patent No. 9,744,179, foamable pharmaceutical composition.

5. Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 355(j); 35 U.S.C. § 271(e)(2).

6. United States Court of Appeals for the Federal Circuit. (2021). LEO Pharma A/S v. Teva Pharmaceuticals USA, Inc., 976 F.3d 1295.