DCT
1:25-cv-00424
Pfizer Inc v. Annora Pharma Pvt Ltd
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Pfizer Inc. (Delaware) and its affiliates C.P. Pharmaceuticals International C.V., PF Prism CV., PBG Puerto Rico LLC, and PF Prism Imb BV.
- Defendant: Annora Pharma Private Limited (India)
- Plaintiff’s Counsel: Morris, Nichols, Arsht & Tunnell LLP
- Case Identification: 1:25-cv-00424, D. Del., 04/04/2025
- Venue Allegations: Venue is alleged to be proper because the defendant is a foreign corporation, which may be sued in any judicial district.
- Core Dispute: Plaintiff alleges that Defendant’s filing of an Abbreviated New Drug Application (ANDA) for a generic version of the drug Xeljanz® (tofacitinib) constitutes an act of infringement of a patent covering the tofacitinib compound.
- Technical Context: The technology relates to pyrrolo[2,3-d]pyrimidine compounds, which function as Janus Kinase (JAK) inhibitors for treating autoimmune diseases such as rheumatoid arthritis.
- Key Procedural History: The patent-in-suit is a reissue of U.S. Patent No. 6,627,754. The USPTO granted a patent term extension, setting the expiration date as December 8, 2025. The litigation was triggered by Defendant's filing of an ANDA with a Paragraph IV certification, asserting the patent is invalid, unenforceable, or will not be infringed.
Case Timeline
| Date | Event |
|---|---|
| 1999-12-10 | Priority Date for RE41,783 Patent |
| 2003-09-30 | Issue Date of Original U.S. Patent No. 6,627,754 |
| 2010-09-28 | Issue Date of Reissue Patent No. RE41,783 |
| 2016-12-14 | USPTO Determination Extending Patent Expiration Date |
| 2025-02-19 | Date of Defendant's ANDA Notice Letter to Plaintiff |
| 2025-04-04 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Reissue Patent No. 41,783 - Pyrrolo[2,3-d]pyrimidine Compounds
- Patent Identification: U.S. Reissue Patent No. 41,783, Pyrrolo[2,3-d]pyrimidine Compounds, issued September 28, 2010.
The Invention Explained
- Problem Addressed: The patent addresses the need for effective immunosuppressive agents to treat a range of conditions, including organ transplant rejection and autoimmune diseases like rheumatoid arthritis and psoriasis (RE’783 Patent, col. 1:12-24). The patent identifies the Janus Kinase 3 (JAK3) enzyme, whose expression is limited to hematopoietic cells, as a key target for modulating the immune system, particularly T cell function (RE’783 Patent, col. 1:28-42).
- The Patented Solution: The invention provides a class of chemical compounds based on a pyrrolo[2,3-d]pyrimidine structure that act as inhibitors of protein kinases, specifically JAK3 (RE’783 Patent, Abstract; col. 1:12-16). By inhibiting JAK3, these compounds are designed to block signaling pathways critical for immune cell maturation and function, thereby achieving an immunosuppressive effect (RE’783 Patent, col. 1:36-42).
- Technical Importance: The invention provided a targeted mechanism for immunosuppression by focusing on the JAK3 pathway, suggesting a novel therapeutic approach for managing T cell proliferative disorders and other immune-mediated conditions (RE’783 Patent, col. 1:39-42).
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 4 (Compl. ¶35).
- Claim 4 recites a specific chemical compound:
- "3-{4-Methyl-3-[methyl-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)-amino]-piperidin-1-yl}-3-oxo-propionitrile", or a pharmaceutically acceptable salt thereof.
- The complaint does not explicitly reserve the right to assert other claims.
III. The Accused Instrumentality
Product Identification
- Annora Generic Tofacitinib Tablets, which are the subject of Abbreviated New Drug Application (ANDA) No. 218437 (Compl. ¶2).
Functionality and Market Context
- The accused products are proposed generic versions of Pfizer’s Xeljanz® tablets, containing tofacitinib citrate as the active pharmaceutical ingredient in 5 mg and 10 mg dosages (Compl. ¶2, ¶15, ¶28). Tofacitinib is an inhibitor of Janus kinases (JAKs) indicated for the treatment of several autoimmune conditions (Compl. ¶17). The complaint alleges that Annora seeks FDA approval to market its generic tablets prior to the expiration of the RE'783 patent (Compl. ¶2).
IV. Analysis of Infringement Allegations
No probative visual evidence provided in complaint.
The complaint does not include a claim chart. The infringement theory is based on the allegation that the active ingredient in Annora's proposed generic product is the specific chemical compound recited in claim 4 of the RE'783 patent.
RE41,783 Infringement Allegations
| Claim Element (from Independent Claim 4) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| The compound "3-{4-Methyl-3-[methyl-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)-amino]-piperidin-1-yl}-3-oxo-propionitrile"... | The active ingredient in Annora's proposed product is tofacitinib, which the complaint identifies by the chemical name "(3R,4R)-4-methyl-3-(methyl-7H-pyrrolo [2,3-d] pyrimidin-4-ylamino)-ẞ-oxo-1-piperidinepropanenitrile". This chemical structure corresponds to the compound claimed in claim 4. | ¶16, ¶28, ¶35 | col. 24:26-30 |
| ...or a pharmaceutically acceptable salt thereof. | Annora's proposed product is formulated as "Tofacitinib Citrate Tablets," which contains the citrate salt of the tofacitinib compound. | ¶15, ¶16, ¶28 | col. 24:26-30 |
- Identified Points of Contention:
- Technical Questions: The complaint alleges that Annora’s detailed statement, provided with its Paragraph IV notice, "does not contain a noninfringement argument with respect to the RE'783 patent" (Compl. ¶32). This suggests that the chemical identity of Annora's active pharmaceutical ingredient is not in dispute.
- Legal Questions: With infringement seemingly uncontested, the central dispute may focus on Annora's asserted defenses that the RE'783 patent is invalid or unenforceable (Compl. ¶30). The key question for the court will be whether Annora can meet its burden to prove these invalidity or unenforceability contentions by clear and convincing evidence.
V. Key Claim Terms for Construction
The complaint does not provide sufficient detail for analysis of potential claim construction disputes. As claim 4 recites a specific chemical compound, disputes over claim term meaning are less common than in other technology areas. The term "pharmaceutically acceptable salt thereof" is a standard term in the art, and its construction is not identified as a point of dispute in the complaint.
VI. Other Allegations
- Indirect Infringement: The prayer for relief seeks to enjoin Annora from inducing or contributing to infringement (Compl., Prayer for Relief ¶C). The factual basis for this appears to be Annora's intent to market and sell its generic product for the same FDA-approved indications as Pfizer's Xeljanz, which would cause physicians and patients to use the drug in an infringing manner (Compl. ¶11, ¶37).
- Willful Infringement: The complaint does not contain an explicit allegation of willful infringement. However, it alleges that "Annora had knowledge of the RE’783 patent when it submitted ANDA No. 218437" (Compl. ¶36) and requests a finding that the case is "exceptional" under 35 U.S.C. § 285, which could entitle Pfizer to an award of attorneys' fees (Compl., Prayer for Relief ¶D).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of patent validity. The complaint alleges that Annora's Paragraph IV certification "did not contain a non-infringement argument" (Compl. ¶32), which would focus the litigation on whether Annora can prove by clear and convincing evidence that claim 4, which covers the specific tofacitinib molecule, is invalid or unenforceable.
- A key procedural question will be one of statutory remedy. The case is an action under the Hatch-Waxman Act, where the primary legal question is whether Pfizer is entitled to an order preventing the FDA from approving Annora’s ANDA until after the expiration of the RE’783 patent in December 2025 (Compl. ¶35).