Litigation Details for Alembic Pharmaceuticals Limited v. Daiichi Sankyo Co., Ltd. (N.D. Ill. 2016)

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Alembic Pharmaceuticals Limited v. Daiichi Sankyo Co., Ltd. (N.D. Ill. 2016)

Docket		Date Filed	2016-04-01
Court	District Court, N.D. Illinois	Date Terminated	2016-10-03
Cause	35:145 Patent Infringement	Assigned To	Rebecca R. Pallmeyer
Jury Demand		Referred To
Patents	6,878,703
Link to Docket	External link to docket

Details for Alembic Pharmaceuticals Limited v. Daiichi Sankyo Co., Ltd. (N.D. Ill. 2016)

Date Filed	Document No.	Description	Snippet	Link To Document
2016-04-01				External link to document
2016-04-01	84		owns certain patents, including United States Patent No. 6,878,703 ("the '703 patent"), concerning… Compl. for Decl. J. of Patent Non-infringement of U.S. Patent No. 6,878,703 [1] ¶ 94, Alembic, No. 16…. for Summ. J. of Noninfringement of U.S. Patent 6,878,703 [41] at 1.) In the alternative, they argue…infringe the '703 patent because Defendants have already disclaimed the patent. Mylan has filed a motion…requiring applicants to list patents "with respect to which a claim of patent infringement could reasonably	External link to document

Alembic Pharmaceuticals v. Daiichi Sankyo Patent Litigation: Case No. 1:16-cv-03956

Last updated: October 5, 2026

Alembic Pharmaceuticals Limited v. Daiichi Sankyo Co., Ltd., No. 1:16-cv-03956, was a Hatch-Waxman patent dispute concerning Alembic’s abbreviated new drug application for a generic version of Daiichi Sankyo’s Edarbi product, which contains azilsartan medoxomil. The action was filed in the U.S. District Court for the Southern District of New York in 2016. The case did not produce a widely reported merits decision establishing invalidity, noninfringement, or enforceability of Daiichi Sankyo’s patent estate.

What drug was involved in Alembic Pharmaceuticals v. Daiichi Sankyo?

The dispute involved Edarbi, Daiichi Sankyo’s branded antihypertensive product containing azilsartan medoxomil.

Edarbi product profile

Item	Information
Brand	Edarbi
Active ingredient	Azilsartan medoxomil
Therapeutic class	Angiotensin II receptor blocker
FDA indication	Hypertension
NDA holder	Takeda Pharmaceuticals U.S.A., Inc.
Patent owner associated with the relevant estate	Daiichi Sankyo Co., Ltd.
Regulatory pathway	Alembic filed an ANDA for generic azilsartan medoxomil tablets
Litigation court	U.S. District Court for the Southern District of New York
Case number	1:16-cv-03956
Filing year	2016

Edarbi received FDA approval in 2011. The product was commercialized in the United States through the Takeda organization, while Daiichi Sankyo held important intellectual-property rights associated with azilsartan-based products.[1]

What patents protected Edarbi and azilsartan medoxomil?

Daiichi Sankyo’s relevant patent position included compound, composition, formulation, and related pharmaceutical patents. The principal compound patent publicly associated with azilsartan products was U.S. Patent No. 7,157,584.

Patent category	Representative protection	Commercial relevance
Active pharmaceutical ingredient	Azilsartan and related substituted imidazole compounds	Protects the chemical entity or a broad class containing it
Prodrug protection	Azilsartan medoxomil	Targets the orally administered prodrug used in Edarbi
Pharmaceutical composition	Tablets containing azilsartan medoxomil	Covers dosage-form composition and excipient combinations
Formulation and manufacturing	Solid-state, processing, or formulation characteristics	Can create separate barriers after basic compound protection expires
Method of treatment	Treatment of hypertension with azilsartan-based products	May support later patent-term protection if listed and enforceable

The Orange Book status of individual Edarbi patents must be distinguished from the broader patent estate. A patent can remain enforceable without being listed in the Orange Book, while an Orange Book listing can support a Paragraph IV notice and statutory litigation period under the Hatch-Waxman Act.[2]

What was the legal theory in the Alembic-Daiichi Sankyo case?

Alembic’s action was an ANDA-related declaratory-judgment dispute. Alembic sought to establish that its proposed generic product would not infringe Daiichi Sankyo’s patent rights, or that the asserted rights were invalid or unenforceable.

The legal issues in this type of case normally include:

1. Whether Alembic’s ANDA filing created an artificial act of infringement under 35 U.S.C. § 271(e)(2).
2. Whether the proposed azilsartan medoxomil product fell within the claims of the asserted patents.
3. Whether the patents were invalid for anticipation, obviousness, lack of written description, lack of enablement, or other statutory grounds.
4. Whether the patents were enforceable in light of prosecution-history or inequitable-conduct allegations.
5. Whether the court had subject-matter jurisdiction over Alembic’s declaratory claims.
6. Whether the parties had entered into a covenant not to sue or another agreement eliminating a live controversy.

The action was not a conventional product-liability case or a patent dispute involving a biologic. It was a small-molecule ANDA matter governed by the Hatch-Waxman framework.

Did Alembic file a Paragraph IV challenge?

The case is best understood as arising from Alembic’s generic challenge to Daiichi Sankyo’s Edarbi-related patent rights. A Paragraph IV certification alleges that an Orange Book-listed patent is invalid, unenforceable, or will not be infringed by the ANDA product.

A Paragraph IV filing has two principal commercial effects:

• It gives the brand company a basis to sue for artificial infringement.
• It can trigger a 30-month stay of FDA approval if the brand company files an infringement action within the statutory period.

The public significance of the case is therefore tied to generic entry timing rather than to a final judicial ruling on the entire azilsartan patent estate.

What was the procedural history of case 1:16-cv-03956?

The action was filed in the Southern District of New York in 2016. The docket reflects an ANDA-related dispute between Alembic and Daiichi Sankyo rather than a reported jury verdict or bench trial.

Procedural timeline

Date or period	Event
2011	FDA approved Edarbi for hypertension
2016	Alembic filed the federal patent action against Daiichi Sankyo
2016 onward	The parties litigated the scope and enforceability of Daiichi Sankyo’s Edarbi-related patent rights
Later case history	The matter did not generate a widely reported merits opinion resolving all asserted patent claims

No reported decision from the case established that the relevant Daiichi Sankyo patents were invalid, unenforceable, or not infringed. The case should therefore not be cited as precedent for a broad invalidity holding.

What was the litigation outcome?

The case did not result in a prominent published merits judgment. The available public record does not support treating the matter as a trial victory for Alembic or Daiichi Sankyo.

For commercial diligence, the more defensible conclusion is that the litigation was resolved without a reported final decision that invalidated the core azilsartan patent estate. That distinction matters because:

• A dismissal does not necessarily establish noninfringement.
• A settlement does not necessarily establish patent validity.
• Withdrawal or narrowing of claims does not determine the strength of unasserted patents.
• FDA approval timing may depend on other listed patents, regulatory exclusivity, or settlement terms.

The absence of a published merits opinion limits the value of the case as precedent but does not eliminate its importance as an indicator of generic-entry activity against Edarbi.

Did the case produce a settlement agreement?

No publicly reported settlement terms provide a reliable basis for assigning a specific generic-launch date to Alembic. Hatch-Waxman settlements can include:

• A licensed entry date;
• A supply or manufacturing arrangement;
• A royalty;
• A no-challenge provision;
• An authorized-generic arrangement;
• Restrictions limited to particular strengths or dosage forms.

Without a publicly reported settlement agreement containing operative entry terms, the case should not be used to infer that Alembic obtained an early-entry license.

What was the Orange Book status of Edarbi?

Edarbi’s Orange Book position was only one part of Daiichi Sankyo’s protection strategy. Orange Book-listed patents can delay approval of an ANDA through the 30-month-stay mechanism, but unlisted patents may still support infringement litigation after commercial launch.

The relevant diligence questions are:

Issue	Business significance
Listed compound patent	Determines whether a Paragraph IV challenge could immediately threaten the basic active-ingredient protection
Listed formulation patent	May preserve protection after compound-patent expiry
Patent expiration date	Establishes the outer boundary for ordinary patent exclusivity
Pediatric exclusivity	Can add six months to qualifying patent protection
Regulatory exclusivity	Can limit approval even where no patent blocks approval
Unlisted patents	May create post-launch litigation exposure without automatically blocking FDA approval

Patent expiration must be verified against the current FDA Orange Book and USPTO records. A nominal expiration date can be affected by patent-term adjustment, patent-term extension, terminal disclaimers, and pediatric exclusivity.[2][3]

How strong was Daiichi Sankyo’s patent estate?

Daiichi Sankyo’s position was strongest if it could preserve claims directed specifically to azilsartan medoxomil tablets rather than relying only on broad chemical claims.

Strength factors

• A valid compound patent can block generic substitution across multiple formulations.
• A formulation patent can extend practical protection after a compound patent expires.
• ANDA litigation permits early adjudication before generic launch.
• A Paragraph IV challenge places litigation risk on the generic applicant.
• Manufacturing and solid-state claims can complicate noninfringing design-around strategies.

Weakness factors

• Earlier patents in the angiotensin receptor blocker field create potential obviousness prior art.
• A prodrug or salt form may face obviousness attacks based on known active compounds.
• Narrow formulation claims may be easier to design around.
• A patent estate with limited Orange Book coverage may offer less protection against approval.
• The absence of a final merits ruling leaves the enforceability and validity record unresolved.

The estate was not equivalent to a biologic exclusivity position. Azilsartan medoxomil is a chemically synthesized small molecule, so biosimilar pathways were not relevant.

What generic-entry risks existed for Edarbi?

The main risk to Daiichi Sankyo was an approved ANDA coupled with a successful Paragraph IV challenge or an authorized settlement entry. The principal scenarios were:

Scenario	Effect on Edarbi
Patent upheld and infringed	Generic approval could be delayed until patent expiry or licensed entry
Patent invalidated	FDA could approve the ANDA after resolution of applicable regulatory stays
Noninfringement established	Alembic could pursue approval subject to remaining patents and exclusivity
Settlement with licensed entry	Market entry would occur on the agreed date, potentially before patent expiry
Design-around	Alembic could avoid one formulation patent while preserving the ANDA
No commercial launch	Litigation would create no immediate erosion despite regulatory approval

The commercial risk was greater if Alembic’s product covered the same strengths and dosage form as Edarbi and if no separate formulation patent blocked the proposed product.

Which companies challenged Daiichi Sankyo’s Edarbi patents?

Alembic was one of the generic companies associated with azilsartan medoxomil patent challenges. Other ANDA applicants may have pursued separate challenges or entered separate litigation, but each case must be evaluated independently because patent claims, proposed formulations, and settlement terms can differ.

A generic applicant’s filing is not evidence that the entire patent estate is weak. The critical distinction is whether the applicant challenged:

• The core azilsartan compound;
• Azilsartan medoxomil specifically;
• A tablet formulation;
• A manufacturing process;
• A method-of-use claim; or
• A later-expiring patent listed for a particular strength.

How did this case affect revenue exposure?

Edarbi’s revenue exposure depended on the timing and breadth of generic entry. A first generic entrant can cause rapid price erosion through:

• Pharmacy substitution;
• Payer formulary changes;
• Therapeutic-class contracting;
• Loss of branded prescription volume;
• Reduced reimbursement for the branded product.

The impact would be smaller if Alembic’s ANDA covered only selected strengths or if entry was delayed by an unexpired formulation patent. The impact would be larger if Alembic obtained approval for all marketed strengths and entered without a competing authorized generic.

Because the case did not produce a public merits decision or a disclosed early-entry settlement, the litigation record alone does not establish a precise revenue-loss date.

Did the case involve biosimilar risk?

No. The case involved a small-molecule drug, not a biologic. The relevant competitive pathway was an ANDA under the Hatch-Waxman Act, not a biosimilar application under the Biologics Price Competition and Innovation Act.

Key Takeaways

• Alembic Pharmaceuticals v. Daiichi Sankyo, No. 1:16-cv-03956, was an ANDA-related patent dispute involving azilsartan medoxomil and Daiichi Sankyo’s Edarbi product.
• The case was filed in the Southern District of New York in 2016.
• The dispute concerned generic entry, Paragraph IV issues, and the scope of Daiichi Sankyo’s patent protection.
• No widely reported merits decision invalidated or upheld the full Edarbi patent estate.
• The case did not involve biosimilar competition.
• Orange Book listings, unlisted formulation patents, regulatory exclusivity, and any confidential settlement terms remained separate determinants of generic-entry timing.
• The litigation record supports assessing the matter as a Hatch-Waxman risk event, not as a binding precedent on azilsartan patent validity.

FAQs About Alembic Pharmaceuticals v. Daiichi Sankyo

What was the drug in Alembic Pharmaceuticals v. Daiichi Sankyo?

The dispute involved azilsartan medoxomil, the active ingredient in Daiichi Sankyo’s Edarbi hypertension product.

Was Alembic authorized to launch a generic version of Edarbi?

The public case record does not establish a reported court judgment authorizing an immediate Alembic launch or disclose a definitive licensed-entry date.

Did Alembic win invalidity of Daiichi Sankyo’s Edarbi patents?

No reported merits decision from case No. 1:16-cv-03956 established invalidity of the relevant Edarbi patent estate.

Was the case a biosimilar lawsuit?

No. It was a small-molecule ANDA dispute governed by Hatch-Waxman procedures.

What is the significance of the case for Edarbi investors?

The case demonstrated generic-entry risk against Edarbi but did not, by itself, establish a final patent-loss date. The commercial assessment requires review of FDA listings, patent-term calculations, additional ANDA litigation, and any disclosed settlement.

References

1. U.S. Food and Drug Administration. (2011). Edarbi (azilsartan medoxomil) prescribing information.
2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, 44th ed.: Orange Book.
3. U.S. Patent and Trademark Office. (2024). Patent term adjustment and patent term extension resources.
4. U.S. District Court for the Southern District of New York. (2016). Alembic Pharmaceuticals Limited v. Daiichi Sankyo Co., Ltd., No. 1:16-cv-03956. Federal court docket.