United States Patent 7,427,638: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
The United States Patent 7,427,638, held by Amgen, is a crucial patent related to the pharmaceutical compositions of apremilast, a drug used to treat psoriasis. This patent has been at the center of several legal battles involving generic drug manufacturers like Sandoz and Zydus. Here, we delve into the scope, claims, and the patent landscape surrounding this patent.
Background of the Patent
The patent in question, U.S. Patent 7,427,638 (the “’638 patent”), was granted to Amgen and relates to the use of stereomerically pure apremilast and its crystal forms for treating psoriasis. Apremilast, marketed under the name Otezla®, is a phosphodiesterase 4 (PDE4) inhibitor that has shown significant efficacy in treating moderate to severe plaque psoriasis[2][4].
Scope of the Patent
The ’638 patent encompasses pharmaceutical compositions of apremilast, specifically focusing on the stereomerically pure form of the drug. This includes oral formulations and dosing forms that contain greater than about 97% by weight of the (+) isomer of apremilast. The patent highlights the importance of the stereomerically pure form, which has been shown to have superior therapeutic effects compared to racemic mixtures[1][4].
Key Claims
The patent includes several key claims that have been central to the legal disputes:
- Claim 3: This claim pertains to the pharmaceutical composition containing the stereomerically pure (+) isomer of apremilast.
- Claim 6: This claim specifies the method of using the stereomerically pure compound, where the compound comprises greater than about 97% by weight of the (+) isomer based on the total weight percent of the compound[1][4].
Validity and Nonobviousness
The validity of the ’638 patent has been challenged by Sandoz and Zydus, who argued that the claims were obvious over prior art. However, both the district court and the Court of Appeals for the Federal Circuit (CAFC) have upheld the nonobviousness of the patent.
- Expert Testimony: The CAFC found Dr. Schafer’s testimony, one of the inventors of the ’638 patent, persuasive in establishing the presence of unexpected results. This included a 20-fold difference in efficacy between the stereomerically pure apremilast and a racemic mixture, which was not expected by skilled artisans[2][4].
- Objective Indicia: The court also considered objective indicia of nonobviousness, such as the commercial success of Otezla since its FDA approval, with approximately 1.7 million prescriptions between its launch in 2014 and April 2020[4].
Legal Battles and Appeals
The ’638 patent has been a focal point in a series of legal battles:
- District Court Ruling: The district court found that the defendants had stipulated to infringement and that the ’638 patent was not shown to be invalid. This led to a judgment in favor of Amgen[1].
- CAFC Appeal: Sandoz appealed the district court’s ruling, arguing that the court erred in not finding a reasonable expectation that a mixture could be separated. However, the CAFC affirmed the district court’s decision, upholding the validity of the ’638 patent[2][4].
Patent Term and Extensions
The patent term of the ’638 patent has been extended due to statutorily authorized time extensions. The CAFC ruled that the difference in expiration dates between the ’638 patent and another related patent (the ’283 patent) was due to patent-term adjustments and extensions under 35 U.S.C. § 154(b) and § 156, and not due to prosecution gamesmanship or improper conduct[1].
Impact on Generic Competition
The validity of the ’638 patent has significant implications for generic competition. Sandoz and Zydus have been barred from producing generic versions of Otezla until February 2028, following the CAFC’s affirmation of the district court’s ruling. This decision protects Amgen’s exclusive rights to Otezla, a drug that generated nearly $2.3 billion in sales in 2022[2].
Conclusion on the Patent Landscape
The ’638 patent is a cornerstone in Amgen’s intellectual property portfolio for Otezla. The legal victories in upholding its validity have ensured Amgen’s continued market dominance for this drug. The patent landscape around apremilast is complex, with multiple patents covering different aspects of the drug, including pharmaceutical compositions, crystal forms, and dosing schedules. The ongoing legal battles highlight the importance of robust patent protection in the pharmaceutical industry.
Key Takeaways
- Validity of Claims: The ’638 patent’s claims related to stereomerically pure apremilast have been upheld as nonobvious.
- Legal Protections: The patent has been protected through successful legal battles, preventing generic competition until 2028.
- Commercial Impact: The patent’s validity ensures Amgen’s continued market exclusivity and significant revenue from Otezla sales.
- Patent Term Extensions: Statutorily authorized time extensions have prolonged the patent term, further securing Amgen’s rights.
FAQs
What is the main subject of U.S. Patent 7,427,638?
The main subject of U.S. Patent 7,427,638 is the pharmaceutical composition of apremilast, specifically the stereomerically pure form used to treat psoriasis.
Why is the stereomerically pure form of apremilast important?
The stereomerically pure form of apremilast is important because it has been shown to have superior therapeutic effects compared to racemic mixtures, with a significant difference in efficacy.
What were the key claims upheld by the CAFC?
The CAFC upheld claims 3 and 6 of the ’638 patent, which pertain to the pharmaceutical composition and method of using the stereomerically pure (+) isomer of apremilast.
How has the validity of the ’638 patent impacted generic competition?
The validity of the ’638 patent has barred Sandoz and Zydus from producing generic versions of Otezla until February 2028, protecting Amgen’s exclusive rights to the drug.
What were the statutorily authorized time extensions that affected the patent term?
The patent term was extended due to patent-term adjustments under 35 U.S.C. § 154(b) and patent-term extensions under 35 U.S.C. § 156.
Sources
- Finnegan: “Show More of You”: Amgen v. Sandoz, Battling it Out on Amgen’s Otezla Drug.
- IPWatchdog: CAFC Affirms Ruling that Blocks Generic Version of Amgen's Psoriasis Drug.
- Seyfarth Shaw LLP: The BioLoquitur Bulletin.
- Court of Appeals for the Federal Circuit: AMGEN INC. v. SANDOZ INC.
- PR Newswire: AMGEN WINS PATENT APPEAL ON OTEZLA® (APREMILAST).
