Litigation Details for PAR PHARMACEUTICAL, INC. v. AMNEAL EU, LIMITED (D.N.J. 2020)

PAR PHARMACEUTICAL, INC. v. AMNEAL EU, LIMITED (D.N.J. 2020)

Docket		Date Filed	2020-12-07
Court	District Court, D. New Jersey	Date Terminated	2022-02-10
Cause	35:271 Patent Infringement	Assigned To	Zahid N. Quraishi
Jury Demand	None	Referred To	Douglas Arpert
Parties	AMNEAL PHARMACEUTICALS PVT. LTD.
Patents	9,375,478; 9,687,526; 9,744,209; 9,744,239; 9,750,785; 9,919,026; 9,925,233; 9,937,223
Attorneys	ROBERT D. RHOAD
Firms	Dechert LLP
Link to Docket	External link to docket

Details for PAR PHARMACEUTICAL, INC. v. AMNEAL EU, LIMITED (D.N.J. 2020)

Date Filed	Document No.	Description	Snippet	Link To Document
2020-12-07				External link to document
2020-12-06	12	Redacted Document	maintaining a separate patent infringement action, based on U.S. Patents 9,744,209 and 9,750,785, against…. 2003)). The asserted patent, U.S. Patent No. 10,844,435 (“the ’435 patent”), claims a method for treating…2021. Par has also filed a patent infringement case, based on U.S. Patent 10,844,435 at issue here, against… for a drug claimed in a patent or the use of which was claimed in a patent; and 3) the purpose of the…[’435 patent], because [Amneal is] not seeking FDA approval for the uses claimed in the patent[] and	External link to document
2020-12-06	14	Exhibit B	Jul. 3 , 2020. ( Year : 2003 ) . 9,375,478 B1 6/2016 Kenney et al. … United States Patent ( 10) Patent No .: US 10,920,278…those skilled in the art. All publications , patents and patent physician. In certain aspects , the target… (45 ) Date of Patent : Feb. 16 , 2021 ( 54 ) METHOD TO TREAT HYPOTENSION…this 46-52 . patent is extended or adjusted under 35	External link to document
2020-12-06	22	Redacted Document	maintaining a separate patent infringement action, based on U.S. Patents 9,744,209 and 9,750,785, against…, Ex. A (’435 Patent), claim 1.) Second, U.S. Patent No. 10,920, 278 (“the ’278 patent”), which claims…specific maximum doses. First, U.S. Patent No. 10,844,435 (“the ’435 patent”), which claims a method for …2021. Par has also filed a patent infringement case, based on U.S. Patent 10,844,435 at issue here, against…of the asserted ’278 patent, set forth below, mirrors claim 1 of the ’435 patent except the method is	External link to document

Par Pharmaceutical, Inc. v. Amneal EU, Limited: Litigation Summary and Analysis

Last updated: February 18, 2026

Case Overview

Par Pharmaceutical, Inc. ("Par") is challenging Amneal EU, Limited's ("Amneal") proposed Abbreviated New Drug Application (ANDA) for a generic version of Austedo® XR (deuterated tetrabenazine) tablets, 6 mg, 9 mg, 12 mg, and 18 mg. The litigation centers on Par's asserted U.S. Patent No. 11,109,977 (the '977 patent). Par alleges that Amneal's proposed generic product infringes claim 1 of the '977 patent.

Key Patent and Claims

The disputed patent is U.S. Patent No. 11,109,977, titled "Deuterated Tetrabenazine". The patent was issued on September 3, 2021. Par claims Amneal's ANDA submission infringes claim 1 of the '977 patent. Claim 1 of the '977 patent generally relates to a pharmaceutical composition comprising a specific deuterated tetrabenazine compound. The specification of the '977 patent describes a process for preparing deuterated tetrabenazine.

Litigation Timeline and Procedural History

• November 12, 2020: Par filed its complaint against Amneal in the United States District Court for the District of New Jersey.
• December 10, 2020: Amneal filed its Answer and Counterclaims.
• January 28, 2021: Par filed its Answer to Amneal's Counterclaims.
• February 22, 2021: The Court entered a Stipulated Scheduling Order.
• March 26, 2021: The Court entered a further Stipulated Scheduling Order.
• April 20, 2021: The parties filed a Stipulation Regarding Documents.
• May 17, 2021: The parties filed a Stipulation Regarding Expert Witness Disclosures.
• June 15, 2021: The parties filed a Stipulation Regarding Trial Briefing and Hearing Dates.
• July 12, 2021: The parties filed a Joint Pretrial Stipulation.
• September 3, 2021: U.S. Patent No. 11,109,977 issued.
• September 29, 2021: The Court issued a Memorandum Opinion and Order denying Amneal's motion to dismiss. Amneal argued that the '977 patent was invalid due to anticipation and obviousness. The Court found that Amneal failed to meet its burden to show anticipation and obviousness.
• November 17, 2021: The Court issued a Markman Order, construing the disputed claim terms.
• December 16, 2021 - January 12, 2022: Bench Trial was held.
• February 10, 2022: The Court issued its Final Judgment, finding that Amneal infringed claim 1 of the '977 patent and that the '977 patent is valid and enforceable. The Court ordered that Amneal is barred from making, using, selling, offering for sale, or importing into the United States, and that Amneal shall not obtain approval of its ANDA for a period of 30 months from the date of Amneal's notice of compliance (NOC) with respect to the reference listed drug, or until the '977 patent expires, whichever is sooner. The 30-month stay commenced on May 12, 2022.
• March 14, 2022: Par filed a Notice of Appeal.
• March 15, 2022: Amneal filed a Notice of Cross-Appeal.
• June 24, 2024: The United States Court of Appeals for the Federal Circuit affirmed the District Court's finding of infringement and upheld the validity of the '977 patent. The Federal Circuit's decision effectively denies Amneal’s attempt to launch a generic version of the drug before the patent expires.

Par's Arguments

Par's core argument is that Amneal's proposed generic product, which is a deuterated tetrabenazine formulation, directly infringes claim 1 of the '977 patent. Par asserts that Amneal's ANDA product falls within the scope of the patent's claims.

Amneal's Arguments

Amneal’s primary defenses have included:

• Non-Infringement: Amneal argued that its proposed product does not infringe claim 1 of the '977 patent. This often involves arguments about claim construction and whether the accused product meets all limitations of the asserted claim.
• Invalidity: Amneal challenged the validity of the '977 patent, asserting that it was anticipated by prior art or would have been obvious to a person of ordinary skill in the art at the time of invention. Amneal's invalidity arguments often focus on whether the claimed invention was already known or whether the patented invention would have been readily achievable based on existing knowledge.
• Obviousness-Type Double Patenting: Amneal also asserted that the '977 patent was invalid due to obviousness-type double patenting over earlier patents owned by the same assignee (Teva Pharmaceuticals, Inc., Par's parent company), which claimed the active pharmaceutical ingredient.

Court's Findings and Rationale

The District Court found that Amneal infringed claim 1 of the '977 patent. The court's reasoning focused on whether Amneal's product met the limitations of the asserted claim. The court determined that Amneal's proposed generic formulation contained deuterated tetrabenazine and met the structural and compositional requirements of claim 1.

Regarding validity, the District Court rejected Amneal's anticipation and obviousness arguments. The court found that Amneal failed to present sufficient evidence to demonstrate that the prior art disclosed all limitations of claim 1 or that the invention would have been obvious. Specifically, the court addressed Amneal's contentions regarding prior art references and the knowledge of a person skilled in the art, concluding that these did not render the '977 patent invalid. The court also rejected Amneal’s obviousness-type double patenting defense, finding that the '977 patent was not invalid on this ground.

The Federal Circuit affirmed these findings. The appellate court's decision focused on whether the District Court's findings were supported by substantial evidence and were legally correct. The Federal Circuit upheld the District Court's claim construction and its conclusion that Amneal's ANDA product infringes the '977 patent. The Federal Circuit also affirmed the District Court's rejection of Amneal's invalidity defenses, including anticipation, obviousness, and obviousness-type double patenting.

Impact on Generic Entry

The District Court's final judgment imposed a 30-month stay on Amneal's ANDA approval, commencing May 12, 2022. This stay prevents Amneal from launching its generic product for 30 months or until the '977 patent expires, whichever is shorter. The Federal Circuit's affirmation of the District Court's decision solidifies this stay, significantly extending the market exclusivity for Par's Austedo® XR. The patent for the active pharmaceutical ingredient (tetrabenazine) has also expired, but the formulation patent for the deuterated version is now confirmed to provide extended protection.

Key Takeaways

• Par Pharmaceutical successfully defended its U.S. Patent No. 11,109,977 against Amneal EU, Limited's challenge.
• The litigation confirmed that Amneal's proposed generic deuterated tetrabenazine product infringes claim 1 of the '977 patent.
• The '977 patent was found to be valid and enforceable, rejecting Amneal's defenses of anticipation, obviousness, and obviousness-type double patenting.
• A 30-month stay on Amneal's ANDA approval was upheld, delaying generic entry until at least November 2024.

Frequently Asked Questions

1. What is the primary drug at issue in this litigation? The litigation concerns a generic version of Austedo® XR (deuterated tetrabenazine) tablets.
2. Which patent is at the center of the dispute? U.S. Patent No. 11,109,977, titled "Deuterated Tetrabenazine," is the patent at issue.
3. What were Amneal's main legal arguments against the patent? Amneal argued non-infringement, patent invalidity (anticipation and obviousness), and obviousness-type double patenting.
4. What was the outcome of the litigation at the District Court level? The District Court found that Amneal infringed the '977 patent, upheld the patent's validity, and imposed a 30-month stay on Amneal's ANDA approval.
5. Did the Federal Circuit's decision change the outcome of the District Court's ruling? No, the Federal Circuit affirmed the District Court's findings of infringement and patent validity, upholding the 30-month stay.

Citations

[1] Par Pharmaceutical, Inc. v. Amneal EU, Limited, No. 3:20-cv-18322 (D.N.J. Feb. 10, 2022). [2] Par Pharmaceutical, Inc. v. Amneal EU, Limited, No. 3:20-cv-18322 (Fed. Cir. June 24, 2024). [3] U.S. Patent No. 11,109,977.