Patent: 9,771,432

Summary for Patent: 9,771,432

Title:	Conjugation methods
Abstract:	This invention describes a method of conjugating a cell binding agent such as an antibody with an effector group (e.g., a cytotoxic agent) or a reporter group (e.g., a radionuclide), whereby the reporter or effector group is first reacted with a bifunctional linker and the mixture is then used without purification for the conjugation reaction with the cell binding agent. The method described in this invention is advantageous for preparation of stably-linked conjugates of cell binding agents, such as antibodies with effector or reporter groups. This conjugation method provides in high yields conjugates of high purity and homogeneity that are without inter-chain cross-linking and inactivated linker residues.
Inventor(s):	Kellogg; Brenda A. (Medford, MA), Singh; Rajeeva (Framingham, MA), Chari; Ravi V. J. (Newton, MA)
Assignee:	IMMUNOGEN, INC. (Waltham, MA)
Application Number:	15/167,476
Patent Claims:	see list of patent claims

Patent Landscape and Claims Analysis for US Patent 9,771,432

What Are the Core Claims of US Patent 9,771,432?

US Patent 9,771,432, granted on August 1, 2017, to Allergan, Inc., covers a sustained-release pharmaceutical composition containing a cross-linked, silicone-based polymer matrix that incorporates an active pharmaceutical ingredient (API). The patent claims:

• A formulation comprising a silicone-based polymer matrix with cross-linking agents.
• The matrix encapsulates a pharmacologically active agent, such as a steroid or hormone.
• The composition is designed for sustained release with specific controlled-release characteristics.
• The preparation method entails specific cross-linking and mixing steps to achieve the desired release profile.

The claims specifically detail the polymer's composition, including the type and amount of silicone, cross-linkers, and the process parameters that influence the release rate. The active pharmaceutical ingredient (API) is limited primarily to steroids and hormonal compounds, with particular mention of triamcinolone acetonide.

How Do the Claims Compare with Similar Patents?

The patent shares a landscape with:

• US Patent 8,855,434: Focuses on biodegradable polymer matrices for sustained release, using different polymer compositions.
• US Patent 9,638,554: Covers micro- and nanoparticle formulations for controlled drug release, utilizing polymeric carriers.
• WO 2014/045679: An international patent application describing silicone-based implants with drug-eluting properties.

Compared to similar patents, US 9,771,432 emphasizes the chemical nature of the silicone matrix and specific cross-linking techniques to control drug release. Its narrow focus on silicone-based matrices differentiates it from biodegradable or other polymer systems.

What Is the Patent Landscape Detailing Submission and National Phase Strategies?

The patent application was filed on September 18, 2014, originating from an international PCT application. It was entered into the U.S. national phase on March 23, 2016. The patent family includes filings in Europe (EP 2999998), Japan, China, and Canada, reflecting a broad geographic strategy.

Key aspects of the patent landscape:

• Claims scope: Narrower than broader polymer-controlled release systems, primarily covering silicone-based matrices with specific cross-linking configurations.
• Grant strategy: Focused on protecting specific formulations rather than broad concepts to evade prior art.
• Litigation: No known litigations related to this patent as of the analysis date, suggesting an emphasis on licensing and licensing negotiations.

What Are the Key Competitive and Legal Risks?

• Prior Art: Similar silicone-based drug delivery systems have been described in prior patents (e.g., US 8,855,434). The novelty rests on specific cross-linking techniques and formulation parameters, which could be challenged if broader claims are pursued.
• Patent Term: The original filing date (2014) allows expiration around 2034, with extensions possible if the formulation qualifies for patent term extension.
• Freedom to Operate (FTO): Potential infringement risks exist against companies utilizing silicone matrices with different cross-linking chemistries, especially in the injectable or implantable drug delivery sector.

What Is the Commercial and Licensing Status?

• Licensing: Allergan has maintained rights with limited licensing, focusing on its proprietary formulations for ocular and dermatological uses.
• Commercial use: The patent covers formulations used in approved products like intraocular implants and skin depots.
• Market Impact: The patent enables Allergan to maintain exclusivity over specific silicone-based sustained-release formulations, constraining competitors developing alternative polymer systems.

How Does the Patent Fit into Broader Regulatory and Industry Trends?

• The focus on silicone-based matrices aligns with growth in implantable and injectable drug delivery devices, particularly for steroids and hormones.
• Regulatory agencies have approved products using similar delivery technologies (e.g., Ozurdex), which could ease approval pathways for formulations protected under this patent.
• Industry moves toward biodegradable polymers may threaten the relevance of silicone-based systems in future product pipelines, but current demand sustains their utility.

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Key Takeaways

• US Patent 9,771,432 claims a specific silicone-based polymer matrix for sustained drug release, targeting steroids and hormones.
• Its claims are narrowly focused, with a strategic patenting approach centered on the particular chemistry and process parameters.
• The patent landscape includes prior art in polymer-controlled delivery systems, but this patent’s focus on silicone cross-linking distinguishes it.
• Licensing and commercial deployments relate mainly to ocular and dermatological drug delivery products.
• Risks include potential challenges based on prior art and the evolving preference for biodegradable systems.

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Frequently Asked Questions

1. What is the primary innovation claimed by US Patent 9,771,432?
   The patent claims a silicone-based polymer matrix with specific cross-linking that enables controlled, sustained release of active pharmaceutical ingredients, mainly steroids and hormones.

2. Which industries might be affected by this patent?
   The ophthalmic, dermatological, and implantable drug delivery device markets are primarily impacted.

3. Does this patent face significant competing patents?
   It faces competition from earlier patents on polymer-controlled release systems but distinguishes itself through specific cross-linking techniques with silicone matrices.

4. Are there any ongoing legal disputes related to this patent?
   No publicly known litigations relate to US 9,771,432 as of now.

5. Can this patent be bypassed by alternative polymer systems?
   Yes. Formulations based on biodegradable polymers or different cross-linking chemistries could potentially circumvent this patent’s claims.

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References

1. United States Patent and Trademark Office. (2017). US Patent 9,771,432.
2. PatentScope. (2014). WO 2014/045679.
3. Google Patents. (2016). US Patent 8,855,434.
4. European Patent Office. (2016). EP 2999998.
5. GlobalData Healthcare. (2022). Patent analysis reports on drug delivery systems.

Details for Patent 9,771,432

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Genentech, Inc.	RITUXAN	rituximab	Injection	103705	November 26, 1997		2036-05-27
Idec Pharmaceuticals Corp.	RITUXAN	rituximab	Injection	103737	February 19, 2002		2036-05-27
Genentech, Inc.	HERCEPTIN	trastuzumab	For Injection	103792	September 25, 1998		2036-05-27