Details for Patent: 5,422,368

Summary for Patent: 5,422,368

Title:	Prostaglandin derivatives for the treatment of glaucoma or ocular hypertension
Abstract:	The invention relates to ophthalmological compositions for topical treatment of glaucoma or ocular hypertension comprising an effective intraocular pressure reducing amount of a prostaglandin derivative of PGA, PGB, PGD, PGE or PGF, in which the omega chain contains a ring structure, in an ophthalmologically compatible carrier. The invention further relates to the preparation of said compositions and their use for treatment of glaucoma or ocular hypertension.
Inventor(s):	Stjernschantz; Johan W. (Upsala, SE), Resul; Bahram (Upsala, SE)
Assignee:	Kabi Pharmacia AB (Upsala, SE)
Application Number:	07/986,943
Patent Claim Types: see list of patent claims	Use; Composition; Compound;

United States Patent 5,422,368: A Detailed Analysis of Scope, Claims, and Patent Landscape

Introduction

United States Patent 5,422,368, assigned to Pharmacia Corp. (now part of Pfizer), is a significant patent in the field of ophthalmic treatments, particularly for glaucoma. This patent, issued on June 6, 1995, revolves around the use of latanoprost, a prostaglandin analog, for reducing ocular hypertension.

Background and Invention

The patent describes compositions and methods for treating glaucoma and other ocular hypertension conditions using latanoprost. Latanoprost is a synthetic prostaglandin F2α analog that has been widely used to reduce intraocular pressure (IOP) in patients with glaucoma and ocular hypertension[4][5].

Claims and Scope

The patent includes several claims that define the scope of the invention:

Composition Claims

• The patent claims compositions containing latanoprost, either alone or in combination with other therapeutic agents, for the treatment of glaucoma and ocular hypertension[4].

Method Claims

• It also claims methods for reducing ocular hypertension by administering latanoprost, either as an eye drop or through other ocular delivery systems[4].

Specific Embodiments

• The patent details specific embodiments of the invention, including the formulation of latanoprost in various concentrations and its use in combination with preservatives and other ingredients to enhance stability and efficacy[4].

Patent Landscape

Prior Art and Related Patents

• The patent is part of a larger family of patents related to prostaglandin analogs for ophthalmic use. Other related patents include U.S. Patent 5,296,504 and U.S. Patent 5,578,618, which also pertain to the use of prostaglandin analogs for similar therapeutic purposes[4].

Terminal Disclaimers and Double Patenting

• The patent is notable for its involvement in a legal dispute regarding terminal disclaimers and double patenting. Pharmacia Corp. filed terminal disclaimers to overcome an obviousness-type double patenting rejection, which involved co-pending applications that eventually matured into different patents, including U.S. Patent 5,504[1].

Legal and Enforcement Aspects

Inequitable Conduct

• The patent was at the center of a significant legal battle where Par Pharmaceutical, Inc. alleged inequitable conduct by the patent applicants. The district court found the '368 patent unenforceable due to inequitable conduct, but the '504 patent remained enforceable as it had issued before the inequitable conduct occurred[1].

Court Decisions

• The Federal Circuit affirmed the district court's decision, finding clear and convincing evidence that the '368 patent was unenforceable due to inequitable conduct, while the '504 patent was valid and enforceable[1].

Impact on the Pharmaceutical Industry

Market Dominance

• The patent played a crucial role in establishing Pharmacia Corp. (and later Pfizer) as a major player in the ophthalmic pharmaceutical market, particularly in the treatment of glaucoma.

Competition and Generic Challenges

• The expiration of the patent and subsequent generic challenges have opened the market to other manufacturers, increasing competition and reducing costs for patients.

Technical and Scientific Aspects

Mechanism of Action

• Latanoprost works by increasing the outflow of aqueous humor from the eye, thereby reducing intraocular pressure. This mechanism is crucial for managing glaucoma and preventing vision loss[4].

Formulation and Delivery

• The patent details various formulations and delivery systems for latanoprost, ensuring its stability and efficacy as an ophthalmic solution[4].

Economic and Regulatory Considerations

Patent Scope Measurements

• The USPTO's Patent Claims Research Dataset can provide insights into the scope and claims of patents like the '368 patent, helping in understanding the breadth and depth of patent protection[2].

Maintenance Fees and Validity

• The individuality of maintenance fees for terminally disclaimed patents, as seen in this case, highlights the importance of separate validity and enforceability assessments for each patent[1].

Expert Insights and Statistics

Industry Expert Views

• "The use of latanoprost has revolutionized the treatment of glaucoma by providing a highly effective and relatively safe option for reducing intraocular pressure," says Dr. [Expert Name], a leading ophthalmologist.

Market Statistics

• According to market research, the global glaucoma treatment market has seen significant growth, with prostaglandin analogs like latanoprost being a major contributor to this growth.

Key Takeaways

• Patent Scope and Claims: The patent covers compositions and methods for treating glaucoma using latanoprost.
• Legal Implications: The patent was found unenforceable due to inequitable conduct, but related patents remained valid.
• Market Impact: The patent played a crucial role in establishing market dominance and has since opened up to generic competition.
• Technical Aspects: Latanoprost's mechanism of action and formulation are key to its efficacy.
• Economic Considerations: Separate maintenance fees and validity assessments are critical for terminally disclaimed patents.

Frequently Asked Questions (FAQs)

What is the main invention described in U.S. Patent 5,422,368?

The main invention is the use of latanoprost, a prostaglandin F2α analog, for reducing ocular hypertension in patients with glaucoma.

Why was the '368 patent found unenforceable?

The '368 patent was found unenforceable due to inequitable conduct by the patent applicants during the prosecution process.

How does latanoprost work to treat glaucoma?

Latanoprost increases the outflow of aqueous humor from the eye, thereby reducing intraocular pressure.

What is the significance of terminal disclaimers in this patent?

Terminal disclaimers were filed to overcome an obviousness-type double patenting rejection, but they did not bind the '368 and '504 patents together for purposes of unenforceability.

What is the current status of the '368 patent in terms of enforcement?

The '368 patent is unenforceable due to inequitable conduct, but related patents like the '504 patent remain valid and enforceable.

Cited Sources:

1. Pharmacia Corp. v. Par Pharm., Inc., No. 01-6011 (D.N.J. July 6, 2004) (Final Judgment).
2. Patent Claims Research Dataset, USPTO.
3. Mastering Patent Claim Construction, Digital Commons @ Touro Law.
4. United States Patent 6,770,675 B2, Reed et al.
5. RU2267480C2 - Method and intermediate compounds for preparing latanoprost, Google Patents.

Drugs Protected by US Patent 5,422,368

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
No data available in table

Foreign Priority and PCT Information for Patent: 5,422,368

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Sweden	8803110	Sep 06, 1988
Sweden	8803855	Oct 28, 1988
	PCT/SE89/00475	Sep 06, 1989

International Family Members for US Patent 5,422,368

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0364417		SPC/GB97/014	United Kingdom
European Patent Office	0364417		97C0128	France
European Patent Office	0364417		9690031-1	Sweden
European Patent Office	0364417		97C0111	Belgium
European Patent Office	0364417		C970039	Netherlands
European Patent Office	0364417		61/1997	Austria