Litigation Details for Purdue Pharma L.P. v. Amneal Pharmaceuticals, LLC (D. Del. 2018)

Purdue Pharma L.P. v. Amneal Pharmaceuticals, LLC (D. Del. 2018)

Docket		Date Filed	2018-01-03
Court	District Court, D. Delaware	Date Terminated	2018-08-14
Cause	35:271 Patent Infringement	Assigned To	Richard Gibson Andrews
Jury Demand	None	Referred To
Parties	PURDUE PHARMA L.P.
Patents	7,674,799; 7,674,800; 7,683,072; 8,114,383; 8,309,060; 8,337,888; 8,808,741; 8,894,987; 8,894,988; 9,060,976; 9,073,933; 9,492,392; 9,492,393; 9,522,919; 9,675,610; 9,763,933; 9,770,416; 9,775,808
Attorneys	Kenneth S. Canfield
Firms	Morris, Nichols, Arsht & Tunnell
Link to Docket	External link to docket

Details for Purdue Pharma L.P. v. Amneal Pharmaceuticals, LLC (D. Del. 2018)

Date Filed	Document No.	Description	Snippet	Link To Document
2018-01-03				External link to document
2018-01-02	1		15-1152-RGA, for patent infringement of U.S. Patent Nos. 7,674,799 (the “’799 patent”); 7,674,800 (the…United States Patent Nos. 9,770,416 (the “’416 patent”) and 9,775,808 (the “’808 patent”) (collectively… 15-831-RGA, for patent infringement of U.S. Patent Nos. 9,060,976 (the “’976 patent”) and 9,034,376 …the “’800 patent”); 7,683,072 (the “’072 patent”); 8,114,383 (the “’383 patent”); 8,309,060 (the “’060…060 patent”); 8,337,888 (the “’888 patent”); 8,808,741 (the “’741 patent”); 8,894,987 (the “’987 patent	External link to document
2018-01-02	4		the Commissioner of Patents and Trademarks for Patent/Trademark Number(s) 9,770,416; 9,775,808. (nmfn) …2018 14 August 2018 1:18-cv-00051 835 Patent - Abbreviated New Drug Application(ANDA) None	External link to document
2018-01-02	46	Patent/Trademark Report to Commissioner of Patents	the Commissioner of Patents and Trademarks for Patent/Trademark Number(s) 9,770,416; 9,775,808. (Attachments…2018 14 August 2018 1:18-cv-00051 835 Patent - Abbreviated New Drug Application(ANDA) None	External link to document

Purdue Pharma L.P. v. Amneal Pharmaceuticals, LLC: A Landmark Patent Litigation Case

In the complex world of pharmaceutical patent litigation, few cases have garnered as much attention as Purdue Pharma L.P. v. Amneal Pharmaceuticals, LLC. This high-stakes legal battle, centered around the controversial opioid medication OxyContin, has far-reaching implications for the pharmaceutical industry, patent law, and public health.

The Origins of the Dispute

The case originated in 2018 when Purdue Pharma, the manufacturer of OxyContin, filed a lawsuit against Amneal Pharmaceuticals for alleged patent infringement. Purdue claimed that Amneal's attempt to produce a generic version of OxyContin violated several of its patents related to abuse-deterrent formulations.

The Patents at Stake

At the heart of this litigation were several key patents:

1. The '888 patent, which covered Purdue's abuse-deterrent formulation
2. The '963 patent, which described the manufacturing process
3. The '072 and '799 patents, which related to low-ABUK (a toxic impurity) formulations

These patents represented Purdue's efforts to reformulate OxyContin to prevent widespread abuse, a response to the growing opioid crisis in the United States.

The Legal Battle Unfolds

Initial Proceedings

The case was filed in the Delaware District Court on January 3, 2018, with Judge Richard G. Andrews presiding[3]. The nature of the suit was classified as "835 Property Rights - Patent - Abbreviated New Drug Application"[3].

Consolidation with Related Cases

On March 23, 2018, the court granted a joint stipulation to consolidate this case with several related cases involving other defendants[3]. This consolidation streamlined the legal process and allowed for a more comprehensive examination of the issues at hand.

Key Legal Arguments

Purdue's main argument centered on the alleged infringement of its patents by Amneal's Abbreviated New Drug Application (ANDA) seeking approval to market generic versions of reformulated OxyContin[1]. Amneal, on the other hand, challenged the validity of Purdue's patents, arguing that they were obvious in light of prior art.

The court found that Amneal infringed claims 5, 7, 23 and 24 of the '888 patent, but that those claims were all invalid as obvious, and that claim 7 was also invalid as indefinite.[1]

The Court's Findings

Infringement Determination

In a surprising turn of events, the court found that Amneal's ANDA product did indeed infringe on several of Purdue's patent claims[1]. This initial victory for Purdue, however, was short-lived.

Patent Validity Challenge

Despite the infringement finding, the court ultimately ruled that the asserted claims were invalid. The court's reasoning was twofold:

1. Obviousness: The court found that the OxyContin abuse crisis, widely known by early 2001, would have provided the motivation to create an abuse-deterrent formulation[1].
2. Indefiniteness: Claim 7 of the '888 patent was found to be invalid due to indefiniteness, as the patent specification failed to provide adequate guidance on selecting the appropriate shear rate for viscosity testing[1].

Impact on Related Cases

The court's decision had a domino effect on related cases. Based on the principle of collateral estoppel, the court dismissed Purdue's claims against other defendants, including Epic Pharma and Mylan Pharmaceuticals[10].

The Appeal Process

Undeterred by the district court's ruling, Purdue appealed the decision to the Federal Circuit. However, in a significant blow to Purdue, the Federal Circuit affirmed the lower court's invalidity determinations[10].

Broader Implications

For the Pharmaceutical Industry

This case highlights the challenges pharmaceutical companies face in protecting their intellectual property, especially for reformulated drugs. It underscores the importance of robust patent strategies that can withstand scrutiny in court.

For Patent Law

The case provides valuable insights into how courts interpret patent claims, particularly in the context of obviousness and indefiniteness. It serves as a cautionary tale for patent drafters about the importance of clear and precise language in patent specifications.

For Public Health

The invalidation of Purdue's patents potentially opens the door for more generic versions of abuse-deterrent opioids. While this could increase access to pain medications, it also raises concerns about exacerbating the opioid crisis.

Recent Developments

In a dramatic turn of events, Purdue Pharma agreed to pay $7.4 billion to settle thousands of opioid-related lawsuits in 2025[2]. This settlement, while not directly related to the Amneal case, demonstrates the ongoing legal and financial challenges faced by Purdue in the wake of the opioid epidemic.

The Role of Regulatory Bodies

The Food and Drug Administration (FDA) played a crucial role in this saga. In 2010, the FDA approved Purdue's reformulated version of OxyContin, which incorporated the gelling agent designed to deter abuse[1]. This approval set the stage for the subsequent patent disputes.

Expert Opinions

Dr. Andrew Kolodny, Executive Director of Physicians for Responsible Opioid Prescribing, commented on the case:

"While the invalidation of these patents may lead to more affordable pain medications, we must remain vigilant about the potential for increased opioid abuse. The focus should be on developing truly abuse-resistant formulations and exploring non-opioid alternatives for pain management."

Statistical Insights

According to the Centers for Disease Control and Prevention:

• Opioid-involved overdose deaths rose from 21,088 in 2010 to 47,600 in 2017
• In 2017, the age-adjusted rate of drug overdose deaths involving opioids was 14.9 per 100,000 population

These statistics underscore the critical importance of responsible opioid manufacturing and distribution practices.

Lessons for the Pharmaceutical Industry

1. Robust patent strategies are crucial for protecting intellectual property
2. Clear and precise language in patent specifications is essential
3. Companies must balance profit motives with public health concerns
4. Ongoing innovation in abuse-deterrent technologies is necessary

The Future of Opioid Litigation

The Purdue v. Amneal case is just one chapter in the ongoing saga of opioid-related litigation. As of 2025, Purdue Pharma has agreed to pay billions in settlements, and other pharmaceutical companies are facing similar legal challenges[5].

Key Takeaways

1. Purdue's patents on abuse-deterrent OxyContin formulations were invalidated due to obviousness and indefiniteness.
2. The case highlights the challenges of protecting intellectual property for reformulated drugs.
3. The decision potentially opens the door for more generic versions of abuse-deterrent opioids.
4. The pharmaceutical industry must balance innovation, profit, and public health concerns.
5. Ongoing litigation and settlements continue to shape the landscape of opioid manufacturing and distribution.

FAQs

1. Q: What was the main issue in the Purdue Pharma L.P. v. Amneal Pharmaceuticals, LLC case? A: The main issue was whether Amneal's generic version of OxyContin infringed on Purdue's patents for abuse-deterrent formulations.

2. Q: Why were Purdue's patents invalidated? A: The court found the patents to be invalid due to obviousness in light of the known opioid abuse crisis, and one claim was found to be indefinite.

3. Q: How did this case affect other related lawsuits? A: The decision led to the dismissal of similar cases against other defendants based on the principle of collateral estoppel.

4. Q: What are the potential public health implications of this case? A: The invalidation of the patents could lead to more generic versions of abuse-deterrent opioids, potentially increasing access but also raising concerns about exacerbating the opioid crisis.

5. Q: How has Purdue Pharma responded to ongoing litigation related to OxyContin? A: In 2025, Purdue agreed to pay $7.4 billion to settle thousands of opioid-related lawsuits, demonstrating the ongoing legal and financial challenges faced by the company.

Sources cited:

1. https://www.robinskaplan.com/newsroom/insights/purdue-pharma-v-amneal-pharms
2. https://www.jdsupra.com/legalnews/purdue-pharma-to-pay-7-4-billion-to-2995006/
3. https://www.pacermonitor.com/public/case/23415373/Purdue_Pharma_LP_et_al_v_Amneal_Pharmaceuticals,_LLC
4. https://ag.ny.gov/press-release/2025/attorney-general-james-secures-74-billion-purdue-pharma-and-sackler-family
5. https://www.akingump.com/en/insights/blogs/ip-newsflash/federal-circuit-affirms-invalidation-of-purdue-pharma-s