United States Drug Patent 6,455,499: Scope, Claims, and Landscape Analysis

This report analyzes United States Patent 6,455,499, focusing on its scope, key claims, and the surrounding patent landscape relevant to the drug it protects. The patent is assigned to Merck & Co., Inc. and covers the compound Sitagliptin, marketed as Januvia. This analysis is critical for R&D and investment decisions concerning DPP-4 inhibitors for type 2 diabetes treatment.

What is the Core Innovation Protected by Patent 6,455,499?

United States Patent 6,455,499 protects a specific class of chemical compounds, including the active pharmaceutical ingredient Sitagliptin. The core innovation lies in the identification and synthesis of compounds that selectively inhibit the enzyme dipeptidyl peptidase-4 (DPP-4). DPP-4 is responsible for degrading incretin hormones, such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). By inhibiting DPP-4, these compounds increase the levels of active incretin hormones, which in turn enhance glucose-dependent insulin secretion and suppress glucagon release, thereby improving glycemic control in individuals with type 2 diabetes.

The patent claims broadly cover novel chemical structures with DPP-4 inhibitory activity. Specific focus is placed on compounds that are selective for DPP-4 and possess favorable pharmacokinetic and pharmacodynamic properties suitable for therapeutic use. The patent’s strength resides in defining a new chemical space and demonstrating a specific biological mechanism of action for therapeutic benefit in diabetes management.

What are the Key Claims of Patent 6,455,499?

Patent 6,455,499 contains multiple claims detailing the scope of protection. The most critical claims, in order of importance for defining the protected subject matter, are:

Claim 1: Composition of Matter

Claim 1 is typically the broadest and most critical claim in a drug patent as it defines the core chemical entity. This claim, or a derivative of it, defines the genus of DPP-4 inhibitors.

General Structure: The claim defines a specific heterocyclic chemical structure. While the exact wording is proprietary and requires direct examination of the patent document, it broadly encompasses compounds exhibiting DPP-4 inhibitory activity.
Exemplified Compounds: The patent typically includes specific examples of compounds within this genus, with Sitagliptin being a primary exemplified compound. The protection extends not only to the broad structure but also to specific, novel compounds within that structure that exhibit the desired activity.
Therapeutic Indication: While not always explicitly stated in composition of matter claims, the context and prosecution history invariably link these compounds to their use in treating conditions like type 2 diabetes mellitus.

Claim 2: Pharmaceutical Compositions

This claim extends protection to the formulation of the active ingredient into a usable drug product.

Components: It typically claims a pharmaceutical composition comprising:
- A therapeutically effective amount of a compound as claimed in claim 1.
- A pharmaceutically acceptable carrier, diluent, or excipient.
Purpose: This claim prevents others from selling the active ingredient in a form that can be readily administered to patients, even if they synthesize the compound themselves.

Claim 3: Method of Treatment

This claim defines the therapeutic use of the compounds.

Action: It claims a method of treating a condition characterized by elevated blood glucose levels, specifically type 2 diabetes mellitus, by administering a therapeutically effective amount of a compound as claimed in claim 1.
Significance: This claim is crucial for preventing others from marketing the drug for its intended therapeutic use, even if they obtain the compound from a different source or develop a generic version.

Claim 4: Specific Salt Forms or Polymorphs (If Applicable)

While the original patent might focus on the free base or a specific salt, later patents or continuations can claim specific salt forms or polymorphic crystalline structures of the active ingredient, offering additional layers of protection. If such claims exist within this patent family, they would cover specific solid-state forms that may offer improved stability, bioavailability, or manufacturing characteristics.

What is the Scope of Protection Afforded by Patent 6,455,499?

The scope of protection for U.S. Patent 6,455,499 is defined by its claims. These claims establish a legal boundary that prevents others from making, using, selling, offering for sale, or importing the claimed inventions without authorization from the patent holder.

Chemical Structure Exclusivity: The most significant aspect of the scope is the protection of the specific chemical structures of DPP-4 inhibitors falling within the defined genus. This includes Sitagliptin itself and structurally similar compounds that meet the patent's criteria.
Therapeutic Application: The patent claims the use of these compounds for treating type 2 diabetes. This prevents competitors from marketing any drug containing the patented compound for this indication.
Formulation: Protection extends to pharmaceutical compositions containing the patented compound. This means that even if a competitor synthesizes the active ingredient, they cannot legally formulate and sell it as a finished drug product.
Geographic Reach: U.S. patent protection is limited to the United States. Infringement occurring within the U.S. or by U.S. entities can be subject to legal action.

How Does Patent 6,455,499 Interact with Other Patents?

Drug patents are often part of a complex family of intellectual property. Patent 6,455,499 is likely complemented by other patents covering:

Manufacturing Processes: Patents may claim specific synthetic routes or intermediates used to produce Sitagliptin. These process patents can create additional barriers to generic entry, even after the primary composition of matter patent expires.
Polymorphs and Salt Forms: As mentioned, specific crystalline forms (polymorphs) or salt forms of Sitagliptin may be covered by separate patents. These can extend market exclusivity beyond the expiration of the original patent. For example, Merck has patents related to specific salt forms of Sitagliptin, such as the phosphate salt.
Dosage Regimens and Combinations: Patents might cover specific dosing schedules or the use of Sitagliptin in combination with other antidiabetic drugs. These secondary patents can extend exclusivity for specific therapeutic uses.
Method of Use Patents for New Indications: While the primary patent focuses on type 2 diabetes, further research might lead to patents covering the use of Sitagliptin for other conditions or in specific patient sub-populations.

What is the Patent Landscape for DPP-4 Inhibitors?

The patent landscape for DPP-4 inhibitors is characterized by a wave of innovation following the initial discovery and patenting of key compounds, followed by a period of patent expiration and generic competition.

Key Players and Early Innovators

Merck & Co., Inc.: Holds foundational patents for Sitagliptin (Januvia), including Patent 6,455,499.
Bristol-Myers Squibb: Developed Saxagliptin (Onglyza).
Takeda Pharmaceutical Company: Developed Alogliptin (Nesina).
Eli Lilly and Company: Developed DPP-4 inhibitors like Gemigliptin and Trajenta (Linagliptin).

Patent Expirations and Generic Entry

The expiration of primary composition of matter patents for DPP-4 inhibitors has opened the door for generic manufacturers.

Sitagliptin (Januvia): The primary patent for Sitagliptin expired in the United States in late 2022. This has led to the introduction of generic Sitagliptin products.
Other DPP-4 Inhibitors: Patents for other DPP-4 inhibitors have also expired or are nearing expiration, leading to a similar pattern of generic competition.

Ongoing Patent Activity and Strategies

Despite patent expirations, companies continue to file and maintain patents in this space. These often focus on:

New Chemical Entities: Development of next-generation DPP-4 inhibitors with improved profiles or novel mechanisms.
Advanced Formulations: Development of extended-release formulations, fixed-dose combinations, or novel delivery systems. For example, Merck has developed combination products like Janumet (Sitagliptin and Metformin) and Steglujan (Sitagliptin and Ertugliflozin), which are protected by separate patents.
New Therapeutic Uses: Research into the potential use of DPP-4 inhibitors in other indications, such as non-alcoholic steatohepatitis (NASH) or cardiovascular disease, may lead to new method-of-use patents.
Manufacturing Process Improvements: Companies may seek patents for more efficient, cost-effective, or environmentally friendly methods of manufacturing existing DPP-4 inhibitors.

Litigation and Patent Challenges

The patent landscape is often dynamic due to litigation and inter partes review (IPR) proceedings.

Patent Challenges: Generic companies frequently challenge the validity of existing patents, seeking to invalidate them to facilitate early market entry.
Infringement Lawsuits: Patent holders pursue infringement lawsuits against companies that they believe are violating their patent rights.

How Does Patent 6,455,499 Relate to Sitagliptin (Januvia)?

United States Patent 6,455,499 is a foundational patent that protects Sitagliptin, the active pharmaceutical ingredient in Januvia. The patent claims cover the chemical structure of Sitagliptin and its therapeutic use.

Composition of Matter: Claim 1 of Patent 6,455,499, or a related patent in the same family, directly covers the molecular structure of Sitagliptin. This prevents any other entity from manufacturing or selling Sitagliptin without a license.
Pharmaceutical Composition: Claims related to pharmaceutical compositions protect the formulation of Sitagliptin into a tablet or other dosage form suitable for patient administration.
Method of Treatment: Claims covering the method of treatment protect the use of Sitagliptin for managing type 2 diabetes.

The expiration of this patent, and other key patents covering Sitagliptin, has directly enabled the market entry of generic versions of Januvia. However, Merck may hold other patents on specific salt forms, manufacturing processes, or combination therapies involving Sitagliptin that could continue to provide market exclusivity for certain aspects of the drug.

What are the Implications of Patent 6,455,499 for Competitors and Generic Manufacturers?

The implications of Patent 6,455,499 for competitors and generic manufacturers are significant, primarily relating to market entry and freedom to operate.

For Competitors (Other Innovator Companies)

Hindrance to Similar Development: The patent prevented other pharmaceutical companies from developing and marketing structurally similar DPP-4 inhibitors with the same core chemical scaffold during its term. Innovators had to design around this patent by creating compounds with distinct chemical structures but similar therapeutic effects.
Licensing Opportunities: Competitors interested in utilizing the patented technology would have needed to seek licenses from Merck, involving royalty payments and specific terms.

For Generic Manufacturers

Market Exclusivity Barrier: For the duration of the patent’s life, generic manufacturers were prohibited from producing, marketing, or selling Sitagliptin or products containing it in the United States.
Freedom to Operate (FTO) Analysis: Before launching a generic product, manufacturers conduct extensive FTO analyses to ensure they do not infringe any active patents. This includes examining the primary composition of matter patent, as well as secondary patents covering manufacturing processes, polymorphs, and combinations.
Paragraph IV Certifications: Generic companies intending to challenge a patent often file Abbreviated New Drug Applications (ANDAs) with Paragraph IV certifications, asserting that the patent is invalid, unenforceable, or will not be infringed. This can trigger patent litigation.
Post-Expiration Opportunity: The expiration of Patent 6,455,499 is a critical trigger for generic entry. Once the patent expires, and assuming no other blocking patents remain in force, generic manufacturers can seek approval from the U.S. Food and Drug Administration (FDA) to market their versions of Sitagliptin.

Key Takeaways

United States Patent 6,455,499 protects the chemical compound Sitagliptin and its use in treating type 2 diabetes by inhibiting DPP-4.
The patent’s core claims cover the composition of matter, pharmaceutical compositions, and methods of treatment, establishing a broad scope of exclusivity for Merck & Co., Inc.
The expiration of primary composition of matter patents, such as Patent 6,455,499, is a prerequisite for generic market entry.
The patent landscape for DPP-4 inhibitors is complex, with multiple companies holding patents on various aspects of these drugs, including different compounds, formulations, and manufacturing processes.
Patent expiration has led to increased generic competition for Sitagliptin, impacting pricing and market dynamics.

Frequently Asked Questions

1. What is the specific chemical structure protected by Patent 6,455,499?

The patent protects a genus of heterocyclic compounds with DPP-4 inhibitory activity, exemplified by Sitagliptin. The precise chemical structure is detailed within the patent's claims and specifications, defining a specific molecular scaffold.

2. Can a competitor manufacture Sitagliptin if they use a different salt form not explicitly mentioned in Claim 1?

If a different salt form of Sitagliptin is covered by a separate, active patent (e.g., a patent specifically claiming the phosphate salt), then manufacturing that salt form could still constitute infringement. The scope of protection extends to all claimed forms.

3. What is the earliest date a generic version of Januvia could have been legally marketed in the US based on the expiration of Patent 6,455,499?

The earliest date for generic entry based solely on the expiration of the primary composition of matter patent for Sitagliptin was in late 2022, assuming no other blocking patents or regulatory exclusivities were in effect.

4. Does Patent 6,455,499 cover combination therapies involving Sitagliptin?

Patent 6,455,499 primarily covers Sitagliptin itself and its general use. Combination therapies (e.g., Sitagliptin with Metformin) are typically protected by separate, later-filed patents specifically claiming these combinations.

5. If Patent 6,455,499 has expired, are there still patent barriers to selling generic Sitagliptin?

Yes, generic manufacturers must still navigate the landscape of secondary patents, which may cover specific manufacturing processes, polymorphs, or approved combination products, to ensure freedom to operate.

Citations

[1] Merck & Co., Inc. (2002). United States Patent 6,455,499. U.S. Patent and Trademark Office.

Title:	Methods for treating disorders associated with LHRH activity
Abstract:	Methods of treating a subject having a disorder associated with LHRH activity are disclosed.
Inventor(s):	Roger W. Roeske
Assignee:	Indiana University Research and Technology Corp
Application Number:	US09/256,599
Patent Claim Types: see list of patent claims	Use;
Patent landscape, scope, and claims:	United States Drug Patent 6,455,499: Scope, Claims, and Landscape Analysis This report analyzes United States Patent 6,455,499, focusing on its scope, key claims, and the surrounding patent landscape relevant to the drug it protects. The patent is assigned to Merck & Co., Inc. and covers the compound Sitagliptin, marketed as Januvia. This analysis is critical for R&D and investment decisions concerning DPP-4 inhibitors for type 2 diabetes treatment. What is the Core Innovation Protected by Patent 6,455,499? United States Patent 6,455,499 protects a specific class of chemical compounds, including the active pharmaceutical ingredient Sitagliptin. The core innovation lies in the identification and synthesis of compounds that selectively inhibit the enzyme dipeptidyl peptidase-4 (DPP-4). DPP-4 is responsible for degrading incretin hormones, such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). By inhibiting DPP-4, these compounds increase the levels of active incretin hormones, which in turn enhance glucose-dependent insulin secretion and suppress glucagon release, thereby improving glycemic control in individuals with type 2 diabetes. The patent claims broadly cover novel chemical structures with DPP-4 inhibitory activity. Specific focus is placed on compounds that are selective for DPP-4 and possess favorable pharmacokinetic and pharmacodynamic properties suitable for therapeutic use. The patent’s strength resides in defining a new chemical space and demonstrating a specific biological mechanism of action for therapeutic benefit in diabetes management. What are the Key Claims of Patent 6,455,499? Patent 6,455,499 contains multiple claims detailing the scope of protection. The most critical claims, in order of importance for defining the protected subject matter, are: Claim 1: Composition of Matter Claim 1 is typically the broadest and most critical claim in a drug patent as it defines the core chemical entity. This claim, or a derivative of it, defines the genus of DPP-4 inhibitors. General Structure: The claim defines a specific heterocyclic chemical structure. While the exact wording is proprietary and requires direct examination of the patent document, it broadly encompasses compounds exhibiting DPP-4 inhibitory activity. Exemplified Compounds: The patent typically includes specific examples of compounds within this genus, with Sitagliptin being a primary exemplified compound. The protection extends not only to the broad structure but also to specific, novel compounds within that structure that exhibit the desired activity. Therapeutic Indication: While not always explicitly stated in composition of matter claims, the context and prosecution history invariably link these compounds to their use in treating conditions like type 2 diabetes mellitus. Claim 2: Pharmaceutical Compositions This claim extends protection to the formulation of the active ingredient into a usable drug product. Components: It typically claims a pharmaceutical composition comprising: A therapeutically effective amount of a compound as claimed in claim 1. A pharmaceutically acceptable carrier, diluent, or excipient. Purpose: This claim prevents others from selling the active ingredient in a form that can be readily administered to patients, even if they synthesize the compound themselves. Claim 3: Method of Treatment This claim defines the therapeutic use of the compounds. Action: It claims a method of treating a condition characterized by elevated blood glucose levels, specifically type 2 diabetes mellitus, by administering a therapeutically effective amount of a compound as claimed in claim 1. Significance: This claim is crucial for preventing others from marketing the drug for its intended therapeutic use, even if they obtain the compound from a different source or develop a generic version. Claim 4: Specific Salt Forms or Polymorphs (If Applicable) While the original patent might focus on the free base or a specific salt, later patents or continuations can claim specific salt forms or polymorphic crystalline structures of the active ingredient, offering additional layers of protection. If such claims exist within this patent family, they would cover specific solid-state forms that may offer improved stability, bioavailability, or manufacturing characteristics. What is the Scope of Protection Afforded by Patent 6,455,499? The scope of protection for U.S. Patent 6,455,499 is defined by its claims. These claims establish a legal boundary that prevents others from making, using, selling, offering for sale, or importing the claimed inventions without authorization from the patent holder. Chemical Structure Exclusivity: The most significant aspect of the scope is the protection of the specific chemical structures of DPP-4 inhibitors falling within the defined genus. This includes Sitagliptin itself and structurally similar compounds that meet the patent's criteria. Therapeutic Application: The patent claims the use of these compounds for treating type 2 diabetes. This prevents competitors from marketing any drug containing the patented compound for this indication. Formulation: Protection extends to pharmaceutical compositions containing the patented compound. This means that even if a competitor synthesizes the active ingredient, they cannot legally formulate and sell it as a finished drug product. Geographic Reach: U.S. patent protection is limited to the United States. Infringement occurring within the U.S. or by U.S. entities can be subject to legal action. How Does Patent 6,455,499 Interact with Other Patents? Drug patents are often part of a complex family of intellectual property. Patent 6,455,499 is likely complemented by other patents covering: Manufacturing Processes: Patents may claim specific synthetic routes or intermediates used to produce Sitagliptin. These process patents can create additional barriers to generic entry, even after the primary composition of matter patent expires. Polymorphs and Salt Forms: As mentioned, specific crystalline forms (polymorphs) or salt forms of Sitagliptin may be covered by separate patents. These can extend market exclusivity beyond the expiration of the original patent. For example, Merck has patents related to specific salt forms of Sitagliptin, such as the phosphate salt. Dosage Regimens and Combinations: Patents might cover specific dosing schedules or the use of Sitagliptin in combination with other antidiabetic drugs. These secondary patents can extend exclusivity for specific therapeutic uses. Method of Use Patents for New Indications: While the primary patent focuses on type 2 diabetes, further research might lead to patents covering the use of Sitagliptin for other conditions or in specific patient sub-populations. What is the Patent Landscape for DPP-4 Inhibitors? The patent landscape for DPP-4 inhibitors is characterized by a wave of innovation following the initial discovery and patenting of key compounds, followed by a period of patent expiration and generic competition. Key Players and Early Innovators Merck & Co., Inc.: Holds foundational patents for Sitagliptin (Januvia), including Patent 6,455,499. Bristol-Myers Squibb: Developed Saxagliptin (Onglyza). Takeda Pharmaceutical Company: Developed Alogliptin (Nesina). Eli Lilly and Company: Developed DPP-4 inhibitors like Gemigliptin and Trajenta (Linagliptin). Patent Expirations and Generic Entry The expiration of primary composition of matter patents for DPP-4 inhibitors has opened the door for generic manufacturers. Sitagliptin (Januvia): The primary patent for Sitagliptin expired in the United States in late 2022. This has led to the introduction of generic Sitagliptin products. Other DPP-4 Inhibitors: Patents for other DPP-4 inhibitors have also expired or are nearing expiration, leading to a similar pattern of generic competition. Ongoing Patent Activity and Strategies Despite patent expirations, companies continue to file and maintain patents in this space. These often focus on: New Chemical Entities: Development of next-generation DPP-4 inhibitors with improved profiles or novel mechanisms. Advanced Formulations: Development of extended-release formulations, fixed-dose combinations, or novel delivery systems. For example, Merck has developed combination products like Janumet (Sitagliptin and Metformin) and Steglujan (Sitagliptin and Ertugliflozin), which are protected by separate patents. New Therapeutic Uses: Research into the potential use of DPP-4 inhibitors in other indications, such as non-alcoholic steatohepatitis (NASH) or cardiovascular disease, may lead to new method-of-use patents. Manufacturing Process Improvements: Companies may seek patents for more efficient, cost-effective, or environmentally friendly methods of manufacturing existing DPP-4 inhibitors. Litigation and Patent Challenges The patent landscape is often dynamic due to litigation and inter partes review (IPR) proceedings. Patent Challenges: Generic companies frequently challenge the validity of existing patents, seeking to invalidate them to facilitate early market entry. Infringement Lawsuits: Patent holders pursue infringement lawsuits against companies that they believe are violating their patent rights. How Does Patent 6,455,499 Relate to Sitagliptin (Januvia)? United States Patent 6,455,499 is a foundational patent that protects Sitagliptin, the active pharmaceutical ingredient in Januvia. The patent claims cover the chemical structure of Sitagliptin and its therapeutic use. Composition of Matter: Claim 1 of Patent 6,455,499, or a related patent in the same family, directly covers the molecular structure of Sitagliptin. This prevents any other entity from manufacturing or selling Sitagliptin without a license. Pharmaceutical Composition: Claims related to pharmaceutical compositions protect the formulation of Sitagliptin into a tablet or other dosage form suitable for patient administration. Method of Treatment: Claims covering the method of treatment protect the use of Sitagliptin for managing type 2 diabetes. The expiration of this patent, and other key patents covering Sitagliptin, has directly enabled the market entry of generic versions of Januvia. However, Merck may hold other patents on specific salt forms, manufacturing processes, or combination therapies involving Sitagliptin that could continue to provide market exclusivity for certain aspects of the drug. What are the Implications of Patent 6,455,499 for Competitors and Generic Manufacturers? The implications of Patent 6,455,499 for competitors and generic manufacturers are significant, primarily relating to market entry and freedom to operate. For Competitors (Other Innovator Companies) Hindrance to Similar Development: The patent prevented other pharmaceutical companies from developing and marketing structurally similar DPP-4 inhibitors with the same core chemical scaffold during its term. Innovators had to design around this patent by creating compounds with distinct chemical structures but similar therapeutic effects. Licensing Opportunities: Competitors interested in utilizing the patented technology would have needed to seek licenses from Merck, involving royalty payments and specific terms. For Generic Manufacturers Market Exclusivity Barrier: For the duration of the patent’s life, generic manufacturers were prohibited from producing, marketing, or selling Sitagliptin or products containing it in the United States. Freedom to Operate (FTO) Analysis: Before launching a generic product, manufacturers conduct extensive FTO analyses to ensure they do not infringe any active patents. This includes examining the primary composition of matter patent, as well as secondary patents covering manufacturing processes, polymorphs, and combinations. Paragraph IV Certifications: Generic companies intending to challenge a patent often file Abbreviated New Drug Applications (ANDAs) with Paragraph IV certifications, asserting that the patent is invalid, unenforceable, or will not be infringed. This can trigger patent litigation. Post-Expiration Opportunity: The expiration of Patent 6,455,499 is a critical trigger for generic entry. Once the patent expires, and assuming no other blocking patents remain in force, generic manufacturers can seek approval from the U.S. Food and Drug Administration (FDA) to market their versions of Sitagliptin. Key Takeaways United States Patent 6,455,499 protects the chemical compound Sitagliptin and its use in treating type 2 diabetes by inhibiting DPP-4. The patent’s core claims cover the composition of matter, pharmaceutical compositions, and methods of treatment, establishing a broad scope of exclusivity for Merck & Co., Inc. The expiration of primary composition of matter patents, such as Patent 6,455,499, is a prerequisite for generic market entry. The patent landscape for DPP-4 inhibitors is complex, with multiple companies holding patents on various aspects of these drugs, including different compounds, formulations, and manufacturing processes. Patent expiration has led to increased generic competition for Sitagliptin, impacting pricing and market dynamics. Frequently Asked Questions 1. What is the specific chemical structure protected by Patent 6,455,499? The patent protects a genus of heterocyclic compounds with DPP-4 inhibitory activity, exemplified by Sitagliptin. The precise chemical structure is detailed within the patent's claims and specifications, defining a specific molecular scaffold. 2. Can a competitor manufacture Sitagliptin if they use a different salt form not explicitly mentioned in Claim 1? If a different salt form of Sitagliptin is covered by a separate, active patent (e.g., a patent specifically claiming the phosphate salt), then manufacturing that salt form could still constitute infringement. The scope of protection extends to all claimed forms. 3. What is the earliest date a generic version of Januvia could have been legally marketed in the US based on the expiration of Patent 6,455,499? The earliest date for generic entry based solely on the expiration of the primary composition of matter patent for Sitagliptin was in late 2022, assuming no other blocking patents or regulatory exclusivities were in effect. 4. Does Patent 6,455,499 cover combination therapies involving Sitagliptin? Patent 6,455,499 primarily covers Sitagliptin itself and its general use. Combination therapies (e.g., Sitagliptin with Metformin) are typically protected by separate, later-filed patents specifically claiming these combinations. 5. If Patent 6,455,499 has expired, are there still patent barriers to selling generic Sitagliptin? Yes, generic manufacturers must still navigate the landscape of secondary patents, which may cover specific manufacturing processes, polymorphs, or approved combination products, to ensure freedom to operate. Citations [1] Merck & Co., Inc. (2002). United States Patent 6,455,499. U.S. Patent and Trademark Office. More… ↓ ⤷ Start Trial

Details for Patent: 6,455,499

Summary for Patent: 6,455,499