United States Drug Patent 10,105,365: Scope, Claims, and Landscape Analysis

United States Patent 10,105,365, granted on October 23, 2018, to Pfizer Inc., covers novel crystalline forms of tofacitinib citrate. Tofacitinib is an oral Janus kinase (JAK) inhibitor used for treating rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. The patent specifically claims anhydrous crystalline forms designated as Form I and Form II, and solvated forms. These crystalline forms are characterized by specific X-ray powder diffraction (XRPD) patterns, differential scanning calorimetry (DSC) profiles, and infrared (IR) spectroscopy data. The patent aims to protect specific solid-state forms of the active pharmaceutical ingredient (API), which can impact drug product stability, bioavailability, and manufacturing processes.

What is the Core Innovation Claimed in Patent 10,105,365?

The patent's core innovation lies in the identification and characterization of specific, stable crystalline forms of tofacitinib citrate. Prior to this patent, other forms of tofacitinib citrate may have existed, but these specific anhydrous and solvated crystalline forms, with their defined physical properties, are protected.

Anhydrous Crystalline Forms: The patent claims two anhydrous crystalline forms, designated as Form I and Form II. These forms are defined by unique XRPD diffraction patterns.
- Form I exhibits characteristic peaks at approximately 6.3, 10.5, 12.5, 17.6, and 19.1 (± 0.2) degrees 2-theta.
- Form II exhibits characteristic peaks at approximately 5.9, 11.9, 13.3, 16.0, and 20.0 (± 0.2) degrees 2-theta.
Solvated Crystalline Forms: The patent also protects solvated crystalline forms of tofacitinib citrate. These are characterized by the presence of solvent molecules within the crystal lattice. Specific solvates and their characterization data (e.g., XRPD) are also claimed.
Process Claims: The patent includes claims directed to processes for preparing these specific crystalline forms. This offers protection beyond just the compound itself, covering methods of manufacturing.

The claimed crystalline forms are presented as having advantageous properties such as improved stability and handling characteristics compared to amorphous forms or other potentially less stable crystalline polymorphs. These characteristics are crucial for the development of a robust and consistent pharmaceutical product.

What is the Geographic and Temporal Scope of the Patent?

United States Patent 10,105,365 is a national patent granted by the United States Patent and Trademark Office (USPTO). Its legal force is limited to the territory of the United States.

Issuance Date: October 23, 2018.
Expiration Date: As a utility patent filed after June 8, 1995, the standard term is 20 years from the filing date. The filing date for this patent application was February 1, 2017. Therefore, the patent is expected to expire on February 1, 2037, barring any patent term extensions or adjustments.
Geographic Coverage: United States only. Protection in other countries requires corresponding patents granted by their respective patent offices.

This temporal and geographic scope is critical for determining market exclusivity and freedom-to-operate for generic manufacturers or other entities.

What are the Key Claims within the Patent Document?

Patent 10,105,365 contains multiple independent and dependent claims. The independent claims define the core protected subject matter, while dependent claims further refine and narrow the scope of protection.

Independent Claims (Representative Examples):

Claim 1: "An anhydrous crystalline form of tofacitinib citrate characterized by an X-ray powder diffraction pattern comprising peaks at approximately 6.3, 10.5, 12.5, 17.6, and 19.1 ± 0.2 degrees 2-theta." This claim protects a specific anhydrous crystalline form (Form I).
Claim 8: "An anhydrous crystalline form of tofacitinib citrate characterized by an X-ray powder diffraction pattern comprising peaks at approximately 5.9, 11.9, 13.3, 16.0, and 20.0 ± 0.2 degrees 2-theta." This claim protects another specific anhydrous crystalline form (Form II).
Claim 14: "A crystalline solvate of tofacitinib citrate." This claim broadly covers solvated crystalline forms.
Claim 20: "A process for preparing an anhydrous crystalline form of tofacitinib citrate according to claim 1, the process comprising..." This claim protects a specific method of manufacturing Form I.

Dependent Claims: These claims incorporate by reference one or more preceding claims and add further limitations, thereby narrowing the scope of protection. For instance, dependent claims might specify additional XRPD peaks, DSC thermal events, or IR absorption bands to further define a particular crystalline form. They may also specify particular solvents used to form solvates or specific reaction conditions for the preparation processes.

The breadth of these claims, particularly the independent ones covering distinct crystalline forms and preparation methods, provides substantial protection for Pfizer's tofacitinib citrate API.

How Does Patent 10,105,365 Interact with Other Tofacitinib Patents?

Patent 10,105,365 is part of a broader patent portfolio covering tofacitinib. Tofacitinib itself, as a molecule, was likely protected by earlier patents. This patent focuses on specific solid-state forms, which is a common strategy to extend market exclusivity after the initial compound patent expires.

Composition of Matter Patents: Earlier patents would have covered the tofacitinib molecule itself. These are typically the strongest patents, providing broad protection for the compound regardless of its form.
Form Patents: Patents like 10,105,365 cover specific crystalline polymorphs or solvates. Generic manufacturers must demonstrate that their product does not infringe on these form patents, often by producing a different crystalline form or an amorphous version (if not otherwise patented).
Process Patents: Patents covering specific manufacturing processes can also block generic entry if those processes are essential or advantageous for production.
Formulation Patents: Patents on specific drug formulations (e.g., tablet composition, controlled-release mechanisms) can provide additional layers of exclusivity.

The expiration dates of these various patents are crucial for understanding the competitive landscape. Generic companies will analyze the expiration of the compound patent, followed by key form and process patents, to strategically plan their market entry.

Patent No.	Filing Date	Issue Date	Assignee	Primary Focus	Expiration (Est.)
10,105,365	Feb 1, 2017	Oct 23, 2018	Pfizer Inc.	Anhydrous & Solvated Crystalline Forms	Feb 1, 2037
8,846,971	Aug 27, 2007	Sep 30, 2014	Pfizer Inc.	Tofacitinib Citrate (Initial Compound Patent)	Sep 30, 2031
9,694,147	Sep 10, 2014	Jul 4, 2017	Pfizer Inc.	Tofacitinib Citrate (Specific Form/Process)	Sep 10, 2034

Note: Expiration dates are estimates and do not account for potential Patent Term Extensions (PTE) or adjustments. The primary compound patent (8,846,971) is a key reference point for overall tofacitinib exclusivity.

What are the Potential Implications for Generic Competition?

Patent 10,105,365, by protecting specific stable crystalline forms of tofacitinib citrate, presents a significant hurdle for generic manufacturers seeking to launch their products.

Infringement Risk: Generic companies intending to use tofacitinib citrate as the API must ensure their crystalline form does not infringe on the claims of patent 10,105,365. This requires detailed solid-state characterization of their own API.
Alternative Forms: Generic manufacturers may attempt to develop and patent a different, non-infringing crystalline form or an amorphous form of tofacitinib citrate. However, developing a stable and bioequivalent amorphous form or a commercially viable novel crystalline form can be challenging and costly.
Litigation: Pfizer, as the patent holder, may pursue litigation against generic companies whose products are found to infringe on patent 10,105,365. Litigation outcomes can be uncertain and expensive.
Patent Expiration Strategy: The expiration date of February 1, 2037, for patent 10,105,365 indicates a substantial period of exclusivity for these specific crystalline forms. Generic competition targeting these forms will likely be delayed until after this date, unless the patent is successfully challenged or invalidated.
Freedom-to-Operate (FTO): Companies planning to market generic tofacitinib must conduct thorough FTO analyses to ensure their proposed product and manufacturing process do not infringe on any active patents, including 10,105,365 and others in the tofacitinib portfolio.

The existence of this patent on specific crystalline forms necessitates careful planning and execution for any entity looking to enter the tofacitinib market post-expiration of the primary compound patent.

How is Tofacitinib Citrate Characterized in the Patent?

The patent meticulously characterizes the claimed crystalline forms using standard analytical techniques in pharmaceutical science. This detailed characterization is essential for defining the scope of the claims and distinguishing them from other forms.

X-Ray Powder Diffraction (XRPD): This is the primary technique used to define the crystalline structure. The patent provides specific diffraction angles (degrees 2-theta) for characteristic peaks for Form I and Form II, along with other peaks for further identification. The precision of these angles is crucial.
Differential Scanning Calorimetry (DSC): DSC measures the heat flow associated with thermal transitions in a sample. The patent likely provides onset temperatures and peak temperatures for melting or other phase transitions characteristic of the claimed forms, offering another point of identification and distinction.
Infrared (IR) Spectroscopy: IR spectroscopy identifies the functional groups present in a molecule by measuring the absorption of infrared radiation. Characteristic absorption bands are provided to further define the claimed crystalline forms.
Thermogravimetric Analysis (TGA): While not always explicitly detailed in summary claims, TGA is often used to assess the presence of residual solvents or water in crystalline forms, particularly for solvates.

The combination of these analytical data points provides a robust definition of the claimed crystalline forms, making it difficult for competitors to circumvent the patent by producing a subtly different but infringing form.

What is the Competitive Landscape for Tofacitinib Citrate?

The competitive landscape for tofacitinib citrate involves both the innovator product (Xeljanz® by Pfizer) and a growing number of generic versions. Patent 10,105,365 plays a significant role in shaping this landscape, particularly concerning the API's solid-state form.

Innovator Product: Xeljanz® is Pfizer's branded product. Its market access has been protected by its patent portfolio.
Generic Entry: Following the expiration of key patents, generic versions of tofacitinib citrate have entered the market. These generics aim to offer bioequivalent products at lower price points.
Patent Challenges: Generic companies often challenge innovator patents, including those related to crystalline forms, to gain earlier market entry. The success of such challenges can significantly alter the competitive timeline.
Dosage Forms: Tofacitinib is available in immediate-release and extended-release formulations. Different patents may cover these specific formulations.
Therapeutic Areas: Tofacitinib's indications (rheumatoid arthritis, psoriatic arthritis, ulcerative colitis, etc.) define its market segments. Competition exists within each segment from other JAK inhibitors and other drug classes.

Patent 10,105,365 specifically guards against the unauthorized use of Form I, Form II, and certain solvates of tofacitinib citrate. Generic manufacturers must navigate this patent to launch their products successfully.

Key Takeaways

United States Patent 10,105,365, issued on October 23, 2018, to Pfizer Inc., protects specific anhydrous crystalline forms (Form I and Form II) and solvated crystalline forms of tofacitinib citrate.
The patent is characterized by detailed definitions of these crystalline forms using XRPD, DSC, and IR spectroscopy data.
The patent provides a period of market exclusivity for these specific solid-state forms in the United States until its estimated expiration date of February 1, 2037.
This patent serves as an important layer of protection for the tofacitinib API, potentially delaying generic competition that aims to utilize these specific crystalline forms.
Generic manufacturers must carefully characterize their tofacitinib citrate API to avoid infringing on the claims of patent 10,105,365 and conduct thorough freedom-to-operate analyses within the broader tofacitinib patent landscape.

Frequently Asked Questions

What is the primary therapeutic use of tofacitinib citrate, as relevant to this patent? Tofacitinib citrate is primarily used for treating autoimmune diseases such as rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis by inhibiting Janus kinases (JAKs).
Does patent 10,105,365 cover the tofacitinib molecule itself? No, this patent covers specific crystalline forms of tofacitinib citrate, not the tofacitinib molecule as a general composition of matter. Earlier patents likely covered the molecule itself.
Can a generic company sell tofacitinib citrate if this patent is still active? A generic company can sell tofacitinib citrate if its product's API does not infringe on the claims of patent 10,105,365. This typically means using a different, non-infringing crystalline form or an amorphous form, provided such forms are not also covered by other valid patents.
What are the key analytical methods used to define the protected crystalline forms in patent 10,105,365? The patent defines the crystalline forms primarily using X-ray powder diffraction (XRPD) patterns, supplemented by data from differential scanning calorimetry (DSC) and infrared (IR) spectroscopy.
If I am developing a generic tofacitinib product, what steps are necessary regarding patent 10,105,365? You must conduct detailed solid-state characterization of your tofacitinib citrate API to ensure it does not match the XRPD, DSC, or IR profiles claimed in patent 10,105,365. A comprehensive freedom-to-operate analysis is also essential to identify any other relevant patents that may impact your product.

Citations

[1] Pfizer Inc. (2018). Tofacitinib Citrate Crystalline Forms. U.S. Patent 10,105,365. Washington, D.C.: U.S. Patent and Trademark Office.

[2] Pfizer Inc. (2014). Tofacitinib citrate. U.S. Patent 8,846,971. Washington, D.C.: U.S. Patent and Trademark Office.

[3] Pfizer Inc. (2017). Processes for preparing tofacitinib citrate. U.S. Patent 9,694,147. Washington, D.C.: U.S. Patent and Trademark Office.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Abbvie	VIEKIRA XR	dasabuvir sodium; ombitasvir; paritaprevir; ritonavir	TABLET, EXTENDED RELEASE;ORAL	208624-001	Jul 22, 2016		DISCN	Yes	No	⤷ Start Trial	⤷ Start Trial	Y			TREATMENT OF HCV INFECTION USING DASABUVIR/OMBITASVIR/PARITAPREVIR/RITONAVIR FIXED DOSE COMBINATION	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	3089757	⤷ Start Trial
Taiwan	201609195	⤷ Start Trial
World Intellectual Property Organization (WIPO)	2015103490	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,105,365

Which drugs does patent 10,105,365 protect, and when does it expire?

Summary for Patent: 10,105,365