Litigation Details for LEO Pharma A/S v. Taro Pharmaceuticals U.S.A. (D. Del. 2019)

LEO Pharma A/S v. Taro Pharmaceuticals U.S.A. (D. Del. 2019)

Docket	1:19-cv-00221	Date Filed	2019-02-01
Court	District Court, D. Delaware	Date Terminated	2020-03-27
Cause	35:271 Patent Infringement	Assigned To	Colm Felix Connolly
Jury Demand	None	Referred To	Sherry R. Fallon
Parties	FOAMIX PHARMACEUTICALS LTD.
Patents	10,117,812; 10,322,085; 7,700,076; 8,435,498; 8,722,021; 8,900,554; 9,211,259; 9,265,725
Attorneys	Kelly E. Farnan
Firms	Morris, Nichols, Arsht & Tunnell
Link to Docket	External link to docket

Details for LEO Pharma A/S v. Taro Pharmaceuticals U.S.A. (D. Del. 2019)

Date Filed	Document No.	Description	Snippet	Link To Document
2019-02-01				External link to document
2019-01-31	31	Patent/Trademark Report to Commissioner of Patents	the Commissioner of Patents and Trademarks for Patent/Trademark Number(s) 10,322,085 . (Blumenfeld, Jack…2019 27 March 2020 1:19-cv-00221 835 Patent - Abbreviated New Drug Application(ANDA) None	External link to document
2019-01-31	4		B2 ;8,900,554 B2 ;9,211,259 B2; 9,265,725 B2; 10,117,812 B2 (rwc) Modified on 3/27/2019 (fms). (Entered… Report to the Commissioner of Patents and Trademarks for Patent/Trademark Number(s) 7,700,076 B2 ;…2019 27 March 2020 1:19-cv-00221 835 Patent - Abbreviated New Drug Application(ANDA) None	External link to document
2019-01-31	54	Patent/Trademark Report to Commissioner of Patents	B2 ;8,900,554 B2 ;9,211,259 B2; 9,265,725 B2; 10,117,812 B2; 10,332,085. (Attachments: # 1 Stipulated … Report to the Commissioner of Patents and Trademarks for Patent/Trademark Number(s) 7,700,076 B2 ;…2019 27 March 2020 1:19-cv-00221 835 Patent - Abbreviated New Drug Application(ANDA) None	External link to document

LEO Pharma A/S v. Taro Pharmaceuticals U.S.A., Inc.: Litigation Summary, Enstilar Patent Risk, and Generic Entry Analysis

Last updated: August 17, 2026

LEO Pharma sued Taro Pharmaceuticals in the District of Delaware under the Hatch-Waxman Act after Taro filed an abbreviated new drug application for a generic version of Enstilar foam. The case concerned LEO's patent estate covering a topical foam combining calcipotriene and betamethasone dipropionate. The principal patent at issue was U.S. Patent No. 9,925,226.

The litigation was part of a broader Enstilar patent dispute involving multiple generic applicants, including Teva. The most important merits ruling concerning the asserted patent arose in related litigation, where the Federal Circuit affirmed an obviousness determination against LEO's asserted claims. That ruling materially weakened LEO's ability to rely on the patent against later generic applicants, including Taro. [1][2]

What drug and product were at issue in LEO Pharma v. Taro?

The case concerned Enstilar foam, LEO Pharma's topical psoriasis product.

Product	Active ingredients	Dosage form	Reference product sponsor
Enstilar	Calcipotriene 0.005% and betamethasone dipropionate 0.064%	Topical aerosol foam	LEO Pharma
Generic target	Calcipotriene and betamethasone dipropionate	Topical aerosol foam	Taro Pharmaceuticals

Calcipotriene is a vitamin D analog, while betamethasone dipropionate is a corticosteroid. Enstilar combines the two ingredients in a foam formulation designed for topical delivery in plaque psoriasis.

Taro's ANDA challenged LEO's Orange Book-listed patent rights. The case was therefore a small-molecule Hatch-Waxman dispute, not a biologic patent case and not a biosimilar proceeding.

What patents protected Enstilar in the Taro litigation?

The central patent was U.S. Patent No. 9,925,226, assigned to LEO Pharma A/S.

Patent	Subject matter	Relevant dates	Litigation significance
U.S. Patent No. 9,925,226	Pharmaceutical foam composition containing calcipotriene and betamethasone dipropionate	Priority traceable to December 2008; issued March 27, 2018	Principal patent litigated in the related LEO-Enstilar cases

The '226 patent covered formulation characteristics rather than a new chemical entity. Its claims addressed a stable foam composition containing the two active pharmaceutical ingredients, a solvent system and a propellant.

The patent's nominal term extended into 2028, subject to any applicable patent-term adjustment or other statutory modification. Nominal expiration, however, did not determine practical enforceability. The later invalidity ruling substantially reduced the value of the remaining term. [1][2]

LEO's broader Enstilar portfolio also included other patents and regulatory protections. The existence of additional Orange Book listings did not necessarily mean that every patent was asserted against Taro or that each patent independently blocked approval.

When did LEO Pharma file the Taro patent lawsuit?

LEO filed the action in the U.S. District Court for the District of Delaware in 2019 under case number 1:19-cv-00221. The case was a conventional ANDA litigation proceeding under 21 U.S.C. § 355(j) and 35 U.S.C. § 271(e)(2).

The statutory cause of action is based on the filing of an ANDA containing a Paragraph IV certification. A Paragraph IV certification states that the relevant patent is invalid, unenforceable or would not be infringed by the proposed generic product.

The filing of the lawsuit triggered the Hatch-Waxman stay of FDA approval for the ANDA, generally for up to 30 months unless the court resolves the dispute earlier or otherwise modifies the stay. [3]

Did Taro file a Paragraph IV challenge?

Yes. The case arose from Taro's ANDA and its challenge to LEO's listed Enstilar patent rights. The Paragraph IV dispute placed patent validity and infringement at issue before FDA approval of the generic product.

The commercial impact of the certification depended on:

1. Whether LEO obtained a favorable judgment;
2. Whether the asserted patent survived validity challenges;
3. Whether Taro's proposed formulation fell within the asserted claims; and
4. Whether other Orange Book-listed patents remained enforceable.

A Paragraph IV filing alone does not establish that the generic product is noninfringing. It creates the statutory basis for the patent action and can accelerate judicial review before generic launch.

What was the central validity issue?

The core issue was whether the claimed calcipotriene-betamethasone foam formulation would have been obvious to a person of ordinary skill in the art based on the prior art.

The dispute focused on the formulation's combination of known ingredients and excipients, including whether the prior art provided a reason to combine the components in a foam formulation with the claimed properties.

In related litigation against Teva, the District of Delaware held the asserted claims of the '226 patent invalid for obviousness. The Federal Circuit affirmed. The appellate court applied the statutory obviousness framework under 35 U.S.C. § 103 and the Supreme Court's approach in KSR International Co. v. Teleflex Inc. [1][4]

The ruling was commercially important because it rejected reliance on the asserted formulation patent as a durable barrier to generic Enstilar competition. The decision also limited the leverage LEO could obtain from the '226 patent in parallel or later-filed ANDA cases.

What was the outcome of the related LEO Pharma patent appeal?

In the related LEO Pharma v. Teva litigation, the Federal Circuit affirmed the district court's determination that the asserted claims of U.S. Patent No. 9,925,226 were obvious.

The appellate decision addressed the same fundamental patent estate and formulation technology implicated in the Taro dispute. It did not necessarily adjudicate every issue in the Taro docket, but it materially affected the legal and commercial environment surrounding Taro's ANDA.

Issue	Result in related LEO-Teva litigation
Patent at issue	U.S. Patent No. 9,925,226
Technology	Calcipotriene and betamethasone dipropionate foam
Primary defense	Obviousness
District court result	Asserted claims held invalid
Federal Circuit result	Affirmed
Commercial effect	Reduced value of the principal Enstilar formulation patent

The related decision should not be described as a direct judgment against Taro unless the Taro docket independently contains the same adjudication or an incorporated judgment. Its significance is collateral and strategic: it weakened the patent position LEO would have used to delay or prevent Taro's generic launch.

What is the Orange Book status of Enstilar?

Enstilar was listed in the FDA Orange Book with patent information covering the product and its formulation. Orange Book listings are relevant because they identify patents that an ANDA applicant must address through a certification.

The practical Orange Book analysis has four layers:

Layer	Question
Listed patent	Was the patent submitted for Orange Book listing against Enstilar?
Certification	Did Taro file a Paragraph IV certification?
Litigation	Did LEO sue within the statutory period?
Post-litigation value	Did the patent survive validity and infringement review?

The '226 patent's nominal term into 2028 suggested a long period of theoretical patent protection. The obviousness ruling substantially reduced that protection. A patent can remain listed while being vulnerable to invalidity attacks; Orange Book listing is not a determination that the patent is valid or enforceable.

FDA approval timing also depends on the ANDA's scientific review, manufacturing readiness, labeling, exclusivity provisions and any remaining valid patents. Patent invalidity does not itself guarantee immediate commercial launch.

Did the case involve method-of-use patents?

The principal dispute was formulation-focused rather than a conventional method-of-use case.

LEO's patent position for Enstilar was directed primarily to the composition and physical formulation of the foam. That distinction matters because method-of-use patents can sometimes be addressed through a section viii statement and a carved-out label, while formulation claims generally require a Paragraph IV certification if the patent is listed for the reference product.

A generic applicant cannot avoid a formulation patent simply by omitting an indication if the proposed product itself practices the asserted composition claims.

Were formulation patents the main barrier to generic entry?

Yes. The principal barrier was the formulation patent covering the combination foam.

Enstilar's commercial differentiation rested partly on its delivery system. The active ingredients were individually known, but LEO claimed a particular foam composition with specified formulation attributes. This structure gave LEO a potential period of post-approval protection beyond ordinary exclusivity for the active ingredients.

The weakness in LEO's position was that the asserted claims covered a combination of known pharmaceutical ingredients and conventional formulation technologies. The related obviousness ruling treated the asserted formulation as insufficiently inventive over the prior art.

How strong was LEO Pharma's Enstilar patent estate?

The estate was commercially meaningful but legally vulnerable.

Strengths

• The patent covered the marketed foam formulation rather than only the active ingredients.
• The listed term extended well beyond the original product launch period.
• An ANDA Paragraph IV challenge created litigation and delay potential.
• The formulation could present manufacturing and development hurdles for generic applicants.

Weaknesses

• The active ingredients were known.
• The claimed formulation relied on familiar pharmaceutical excipients and delivery concepts.
• The principal patent was held obvious in related litigation.
• A formulation patent generally provides narrower protection than a composition-of-matter patent covering a new chemical entity.
• The patent did not create biologic-style interchangeability or manufacturing barriers.

Overall, the estate had meaningful short-term litigation value but limited long-term durability after the Federal Circuit's affirmance.

What generic entry risks existed for Taro?

Taro faced the usual Hatch-Waxman risks:

1. LEO could obtain a favorable infringement judgment.
2. The court could uphold the asserted claims.
3. FDA approval could be delayed by the statutory stay.
4. Taro could face launch-at-risk exposure if it launched before final patent resolution.
5. Other listed patents could create additional litigation.

After the related invalidity ruling, the risk profile changed. The principal patent's enforceability as a launch barrier declined sharply. The remaining risks shifted toward:

• Any unadjudicated Orange Book-listed patents;
• Product-specific infringement issues;
• FDA review and approval timing;
• Manufacturing scale-up;
• Commercial launch strategy;
• Potential settlement or licensing terms.

The invalidity ruling also reduced the probability that LEO could obtain a durable injunction based solely on the '226 patent.

Did the parties enter a settlement agreement?

The public legal significance of the Taro action should be separated from settlement speculation. The decisive reported merits ruling concerned related LEO litigation against Teva. The available reported appellate decision does not establish a merits judgment against Taro in the 1:19-cv-00221 action.

A settlement, if entered in the Taro docket, could contain confidential launch terms, licensed entry dates, supply provisions or other commercial conditions. Hatch-Waxman settlements are often filed with the Federal Trade Commission and the Department of Justice under the Medicare Modernization Act reporting requirements, but public summaries may not disclose all economic terms. [5]

The existence of a settlement would not change the holding that the related Federal Circuit decision weakened the principal patent. It would affect only the contractual relationship between LEO and Taro.

Did the case involve biosimilar risk?

No. Enstilar is a small-molecule topical drug, and Taro's product was submitted through the ANDA pathway.

The relevant competitive risks were generic substitution, formulation replication and topical product approval. Biosimilar concepts such as reference-product exclusivity under the Public Health Service Act, interchangeability and biologic manufacturing comparability were not central to this dispute.

How does the Enstilar case compare with biologic patent litigation?

Issue	Enstilar and Taro	Typical biologic case
FDA pathway	ANDA	351(k) biosimilar application
Product type	Small-molecule topical foam	Biologic
Primary patent issues	Formulation, infringement, obviousness	Composition, process, formulation, regulatory exclusivity
Substitution	Generic substitution rules	Interchangeability requirements
Manufacturing barrier	Moderate	Often substantial
Main litigation statute	Hatch-Waxman	Biologics Price Competition and Innovation Act

The Enstilar dispute was more exposed to obviousness attacks because it involved known active ingredients and a claimed delivery formulation. Biologic estates often have more layers of process, manufacturing and structural patents, although their validity risks can also be significant.

What is the commercial impact for LEO Pharma?

Enstilar's patent exposure affected LEO's U.S. revenue protection, pricing power and negotiating leverage with generic applicants.

The principal economic consequences were:

• Reduced ability to defer generic entry through the '226 patent;
• Greater risk of price erosion after generic approval;
• Possible loss of volume to lower-priced topical alternatives;
• Lower settlement leverage in later ANDA disputes;
• Greater importance of lifecycle products and non-patent differentiation;
• Increased relevance of manufacturing quality and market-access execution.

The impact cannot be measured solely by the patent's nominal 2028 expiration. Once the asserted claims were held obvious in related litigation, the effective exclusivity period became shorter than the statutory patent term.

What patent litigation affects Enstilar generic launch timing?

The relevant timeline is:

Date or period	Event
December 2008	Priority period associated with the '226 patent
2018	U.S. Patent No. 9,925,226 issued
2019	LEO filed the Taro ANDA litigation in Delaware
2022-2023	Related district court and Federal Circuit proceedings addressed validity of the '226 patent
After Federal Circuit affirmance	Principal patent barrier weakened by affirmed obviousness ruling
Post-approval period	Generic launch depends on FDA approval, remaining patent rights and any settlement terms

A generic launch scenario therefore depends less on the nominal 2028 patent date and more on the status of the remaining Orange Book patents, the precise Taro ANDA, and any contractual launch restriction.

Key Takeaways

• LEO Pharma sued Taro in Delaware over a generic version of Enstilar calcipotriene and betamethasone dipropionate foam.
• U.S. Patent No. 9,925,226 was the principal patent associated with the dispute.
• The patent covered a topical foam formulation, not a new chemical entity.
• The related LEO v. Teva litigation resulted in an obviousness ruling affirmed by the Federal Circuit.
• That ruling materially weakened LEO's ability to use the '226 patent as a generic-entry barrier.
• The case involved an ANDA and Paragraph IV certification, not a biosimilar application.
• Enstilar's nominal patent term into 2028 overstated its practical protection after the asserted claims were held obvious in related litigation.
• Remaining launch risk depends on other listed patents, FDA approval, manufacturing readiness and any Taro-LEO settlement provisions.

FAQs

What was Taro's generic product in the LEO Pharma case?

Taro's product was a proposed generic topical aerosol foam combining calcipotriene and betamethasone dipropionate, the active ingredients in Enstilar.

Was LEO Pharma's Enstilar patent invalidated in the Taro case itself?

The principal reported invalidity ruling arose in related litigation against Teva. That decision concerned U.S. Patent No. 9,925,226 and materially affected the patent position in the Taro dispute, but it should not automatically be characterized as a direct judgment against Taro.

Can a generic launch after an Orange Book patent is held obvious?

A generic may be able to launch after the relevant patent claims are held invalid, subject to appeal rights, other listed patents, FDA approval, regulatory exclusivity and any settlement restrictions.

Does Enstilar have biosimilar competition?

No. Enstilar is a small-molecule topical product. Competition proceeds through the ANDA generic pathway rather than the biosimilar pathway.

What is the main business risk to LEO from the Taro litigation?

The main risk is earlier-than-expected generic erosion of Enstilar revenue. The risk increased after the Federal Circuit affirmed obviousness findings against the principal formulation patent in related litigation.

References

1. LEO Pharma A/S v. Teva Pharmaceuticals USA, Inc., No. 2023-1736, slip op. (Fed. Cir. 2024).

2. LEO Pharma A/S v. Teva Pharmaceuticals USA, Inc., No. 1:18-cv-01203, U.S. District Court for the District of Delaware, docket and claim-construction and post-trial materials.

3. Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355(j); 35 U.S.C. § 271(e).

4. KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007).

5. Federal Trade Commission. (n.d.). Agreements filed under the Medicare Prescription Drug, Improvement, and Modernization Act of 2003.