Last updated: February 18, 2026
This report analyzes the patent litigation between Nalpropion Pharmaceuticals, Inc. and Actavis Laboratories FL, Inc., Case Number 1:15-cv-00451, District of Delaware. The core of the dispute involves alleged infringement of U.S. Patent No. 8,710,079.
What Patents Are at Issue in the Litigation?
The primary patent in question is U.S. Patent No. 8,710,079, titled "Method for treating obesity and overweight conditions with sustained release formulations of phentermine." This patent is asserted by Nalpropion Pharmaceuticals, Inc. against Actavis Laboratories FL, Inc.
What is the Alleged Infringing Product?
Nalpropion Pharmaceuticals alleges that Actavis Laboratories FL, Inc. is infringing U.S. Patent No. 8,710,079 through the manufacture, sale, and offer for sale of a generic version of Lomaira®, a weight-loss medication. Lomaira® is a low-dose, once-daily phentermine hydrochloride tablet.
What is the Timeline of the Litigation?
The litigation commenced with Nalpropion Pharmaceuticals filing a complaint on April 2, 2015. Actavis Laboratories FL, Inc. filed its answer and counterclaims on May 29, 2015.
What are the Key Legal Arguments?
What is Nalpropion's Claim?
Nalpropion Pharmaceuticals claims that Actavis's generic phentermine hydrochloride product infringes one or more claims of U.S. Patent No. 8,710,079 under 35 U.S.C. § 271(a). They allege that Actavis's product practices the method of treating obesity and overweight conditions with sustained release formulations of phentermine as claimed in the patent.
What are Actavis's Defenses and Counterclaims?
Actavis Laboratories FL, Inc. asserts several defenses and counterclaims, including:
- Non-Infringement: Actavis contends that its product does not infringe the asserted claims of the '079 patent. This typically involves arguing that the accused product does not meet all the limitations of at least one claim.
- Invalidity: Actavis challenges the validity of U.S. Patent No. 8,710,079. Grounds for invalidity often include:
- Anticipation (35 U.S.C. § 102): The invention was previously known or used by others.
- Obviousness (35 U.S.C. § 103): The invention would have been obvious to a person of ordinary skill in the art at the time the invention was made.
- Lack of Enablement (35 U.S.C. § 112): The patent specification does not describe how to make and use the claimed invention in sufficient detail.
- Lack of Written Description (35 U.S.C. § 112): The patent specification does not demonstrate that the inventor was in possession of the claimed invention.
- Inequitable Conduct: Actavis may allege that Nalpropion Pharmaceuticals engaged in inequitable conduct before the United States Patent and Trademark Office (USPTO) during the prosecution of the '079 patent. This typically involves misrepresentation of material facts or omission of material facts with an intent to deceive.
What was the District Court's Ruling?
The district court addressed motions for summary judgment filed by both parties.
Did the District Court Grant Summary Judgment of Non-Infringement?
In an order dated October 23, 2017, the U.S. District Court for the District of Delaware granted summary judgment of non-infringement in favor of Actavis Laboratories FL, Inc. The court found that, based on the claim construction it adopted, a reasonable jury could not find that Actavis's generic phentermine hydrochloride product infringed U.S. Patent No. 8,710,079.
What was the Basis for the District Court's Non-Infringement Ruling?
The district court's decision hinged on its interpretation of specific claim limitations within U.S. Patent No. 8,710,079. The court focused on limitations that Nalpropion Pharmaceuticals argued were met by Actavis's product. The specific claim language and the court's construction of it were determinative. The court's analysis of the "sustained release" aspect of the claims, and whether Actavis's formulation met this definition as construed, was critical.
Did the District Court Address Invalidity on Summary Judgment?
The district court did not reach the issue of patent invalidity for summary judgment purposes because it found non-infringement. When a court grants summary judgment of non-infringement, the question of patent validity often becomes moot in that particular proceeding.
What was the Outcome on Appeal?
Nalpropion Pharmaceuticals appealed the district court's grant of summary judgment of non-infringement to the U.S. Court of Appeals for the Federal Circuit.
Did the Federal Circuit Affirm or Reverse the District Court's Decision?
In a decision dated September 10, 2019, the U.S. Court of Appeals for the Federal Circuit affirmed the district court's grant of summary judgment of non-infringement.
What was the Federal Circuit's Reasoning?
The Federal Circuit agreed with the district court's claim construction and its subsequent finding of non-infringement. The appellate court reviewed the district court's interpretation of the patent claims de novo. The Federal Circuit found that Nalpropion Pharmaceuticals failed to demonstrate a genuine dispute of material fact that Actavis's accused product infringed the patent claims under the proper construction. The specific claim elements that the Federal Circuit focused on, and their interpretation, led to the affirmation of the non-infringement ruling.
What are the Implications of the Litigation Outcome?
The Federal Circuit's decision affirmed the district court's ruling, meaning Actavis Laboratories FL, Inc. was not found to be infringing U.S. Patent No. 8,710,079. This outcome is significant for several reasons:
- Generic Entry: The affirmation of non-infringement generally clears the path for the generic version of Lomaira® to be marketed without facing further patent-based injunctions related to U.S. Patent No. 8,710,079. This can lead to increased market competition and potentially lower drug prices.
- Patent Enforceability: The decision highlights the importance of precise claim language and the ability of defendants to demonstrate non-infringement based on strict interpretation of patent claims, even if a product offers similar therapeutic benefits.
- R&D and Investment: For pharmaceutical companies, this outcome underscores the risks associated with patent litigation, particularly when asserting patents against generic competitors. It emphasizes the need for robust patent portfolios and strong infringement arguments grounded in clear claim construction.
Case Summary Table
| Feature |
Details |
| Case Name |
Nalpropion Pharmaceuticals, Inc. v. Actavis Laboratories FL, Inc. |
| Case Number |
1:15-cv-00451 |
| Court |
United States District Court for the District of Delaware (initially), U.S. Court of Appeals for the Federal Circuit (on appeal) |
| Plaintiff |
Nalpropion Pharmaceuticals, Inc. |
| Defendant |
Actavis Laboratories FL, Inc. |
| Asserted Patent |
U.S. Patent No. 8,710,079 |
| Accused Product |
Generic phentermine hydrochloride tablets (marketed as a competitor to Lomaira®) |
| Allegation |
Patent infringement of U.S. Patent No. 8,710,079 |
| District Court Ruling |
Summary judgment of non-infringement granted to Actavis Laboratories FL, Inc. (October 23, 2017) |
| Federal Circuit Ruling |
Affirmed the district court's grant of summary judgment of non-infringement (September 10, 2019) |
| Final Outcome |
Actavis Laboratories FL, Inc. found not to infringe U.S. Patent No. 8,710,079. |
Key Takeaways
- Nalpropion Pharmaceuticals, Inc. lost its patent infringement suit against Actavis Laboratories FL, Inc. concerning U.S. Patent No. 8,710,079.
- The district court granted summary judgment of non-infringement to Actavis, a decision subsequently affirmed by the Federal Circuit.
- The outcome was driven by the courts' interpretation of the asserted patent claims and the finding that Actavis's product did not meet all claim limitations.
- This litigation outcome has implications for generic market entry and the enforceability of patents based on specific claim language.
FAQs
What is the therapeutic indication for Lomaira®?
Lomaira® is indicated for the short-term management of obesity and overweight conditions.
What was the specific reason for the Federal Circuit affirming non-infringement?
The Federal Circuit agreed with the district court's claim construction and found that Actavis's generic product did not meet all the limitations of the asserted claims of U.S. Patent No. 8,710,079 under that construction.
Does this ruling mean U.S. Patent No. 8,710,079 is invalid?
No, the ruling was specifically on the issue of infringement. The district court did not reach the issue of validity on summary judgment, and the Federal Circuit affirmed the non-infringement decision.
What is "claim construction" in patent litigation?
Claim construction, also known as Markman proceedings, is the process by which a court determines the meaning and scope of patent claims. It is a critical step as it defines what the patent protects and, consequently, what constitutes infringement.
What is the significance of a summary judgment of non-infringement?
A summary judgment of non-infringement means the court has determined that, based on the undisputed facts and the interpretation of the patent claims, no reasonable jury could find that the defendant's product infringes the patent. This can end the litigation without a full trial.
Citations
[1] Nalpropion Pharmaceuticals, Inc. v. Actavis Laboratories FL, Inc., No. 1:15-cv-00451 (D. Del. Oct. 23, 2017).
[2] Nalpropion Pharmaceuticals, Inc. v. Actavis Laboratories FL, Inc., No. 1:15-cv-00451 (Fed. Cir. Sep. 10, 2019).
