Intas Pharmaceuticals Ltd. v. Atossa Therapeutics, Inc. et al.

This case, Intas Pharmaceuticals Ltd. v. Atossa Therapeutics, Inc. et al., IPR2025-00799, was an Inter Partes Review (IPR) proceeding before the U.S. Patent and Trademark Office's Patent Trial and Appeal Board (PTAB), not a district court patent infringement litigation. Intas Pharmaceuticals Ltd., a multinational Indian pharmaceutical company known for developing and manufacturing generic therapeutic drugs, filed the IPR as the Petitioner. The Patent Owners were Atossa Therapeutics, Inc., a clinical-stage biopharmaceutical company focusing on oncology, particularly breast cancer treatments, and Jina Pharmaceuticals, Inc., a company engaged in the research and development of therapeutic products for various diseases. Jina Pharmaceuticals has also partnered with Intas in the development of endoxifen.

The IPR specifically challenged U.S. Patent No. 11,261,151, titled "Methods for making and using endoxifen." This patent broadly claims industrially scalable methods for synthesizing (Z)-endoxifen or its salts, various crystalline forms of endoxifen, and compositions containing them. Furthermore, the patent covers methods for using these compositions to treat hormone-dependent breast and reproductive tract disorders. While no specific accused product was formally identified within the IPR itself, such proceedings are often initiated by generic pharmaceutical companies like Intas in anticipation of, or in response to, potential patent infringement allegations, particularly given Atossa's development of oral (Z)-endoxifen as its lead product candidate.

The procedural posture involved Intas challenging the validity of Atossa and Jina's patent claims at the PTAB. This administrative venue is significant because it offers a potentially faster and less costly alternative to district court litigation for challenging patentability, employing different standards for claim construction and a lower burden of proof for invalidity. The case is notable for its direct linkage to a broader pharmaceutical patent dispute concerning Endoxifen-related intellectual property, which also included a related Post-Grant Review (PGR2025-00043) on another patent (US 12071391). The proceedings ultimately terminated on April 16, 2026, after the parties reached a settlement agreement on April 13, 2026, which Atossa expects will allow its patents to remain issued and enforceable against other third parties.

Intas Pharmaceuticals Ltd. initiated an Inter Partes Review (IPR) against Atossa Therapeutics, Inc. and Jina Pharmaceuticals, Inc., challenging U.S. Patent No. 11,261,151. This IPR proceeding, designated IPR2025-00799, concluded with a settlement among the parties on April 16, 2026.

Here are the key legal developments and outcomes:

Filing of IPR Petition (2025-04-03)

• On April 3, 2025, Intas Pharmaceuticals Ltd. filed a petition for Inter Partes Review, IPR2025-00799, against U.S. Patent No. 11,261,151, owned by Atossa Therapeutics, Inc.. The petition alleged that all 21 claims of the patent were unpatentable based on anticipation and obviousness, specifically referencing the "Liu prior art".
• Jina Pharmaceuticals, Inc. was identified by Intas as a party with an interest in the proceeding, having partnered with Intas in developing Zonalta and bringing Endoxifen to the U.S. market.

Pre-Trial Motions and Institution Decision (2025-11-03)

• During the pre-institution phase, Atossa sought discovery regarding Jina Pharmaceuticals, Inc.'s status as a real party-in-interest. Intas argued against this discovery, stating that Jina was not time-barred or subject to estoppel.
• On November 3, 2025, the Patent Trial and Appeal Board (PTAB) instituted trial for IPR2025-00799, indicating that Intas had demonstrated a reasonable likelihood that at least one challenged claim of U.S. Patent No. 11,261,151 was unpatentable.

Settlement and Termination (2026-04-16)

• On April 13, 2026, Intas Pharmaceuticals Ltd., Atossa Therapeutics, Inc., and Jina Pharmaceuticals, Inc. reached a comprehensive settlement agreement to resolve ongoing patent disputes related to Endoxifen intellectual property.
• Atossa Therapeutics, Inc. publicly announced the settlement on April 16, 2026, stating that the agreement was intended to resolve pending proceedings before the U.S. Patent and Trademark Office Patent Trial and Appeal Board (PTAB).
• As part of the settlement, all parties agreed to seek termination of the PTAB proceedings. The IPR2025-00799 proceeding was subsequently terminated due to this settlement.
• The settlement stipulated that Atossa's patents, including U.S. Patent No. 11,261,151 and U.S. Patent No. 12,071,391, were anticipated to remain issued and enforceable against third parties. The agreement also included mutual commitments not to challenge certain Endoxifen-related patents and patent applications owned or controlled by the other parties, with limited exceptions.

Parallel PTAB Proceedings

• The settlement agreement also encompassed another PTAB proceeding, PGR2025-00043, which challenged Atossa's U.S. Patent No. 12,071,391 B2. Intas Pharmaceuticals Ltd. was also the petitioner in this related Post-Grant Review.
• For PGR2025-00043, the Board authorized a joint motion to terminate on April 22, 2026, and a termination order due to settlement was subsequently entered on May 11, 2026.
• Separately, Atossa Therapeutics, Inc. had previously faced a PGR (PGR2023-00043) concerning U.S. Patent No. 11,572,334, where the PTAB issued a final written decision on January 30, 2025, finding all challenged claims unpatentable. Atossa decided not to appeal that decision.

Intas Pharmaceuticals Ltd. was represented by the following counsel in IPR2025-00799:

• Alejandro Menchaca (Shareholder/Attorney at Law)

  • Firm: McAndrews, Held & Malloy, Ltd., Chicago, Illinois
  • Note: Mr. Menchaca is a shareholder at McAndrews, Held & Malloy, Ltd. and was actively involved in communications related to the IPR, including discussions about adding Jina Pharmaceuticals as a Real Party-in-Interest.

• Ben J. Mahon (Attorney)

  • Firm: McAndrews, Held & Malloy, Ltd., Chicago, Illinois
  • Note: Mr. Mahon is an attorney at McAndrews, Held & Malloy, Ltd. and was involved in communications regarding the IPR proceedings.

Atossa Therapeutics, Inc. and Jina Pharmaceuticals, Inc. were represented by the following counsel in IPR2025-00799:

• Jacob M. Berman (Litigation Attorney)

  • Firm: (Firm and office location not explicitly stated in the provided search results, but his declaration was executed in Hoboken, NJ. Further search would be needed to identify his firm.)
  • Note: Mr. Berman is an experienced litigation attorney with over five years of practice, having litigated numerous patent infringement cases at various stages in different District Courts across the country. He has participated in multiple trials, Markman hearings, and other patent-related hearings concerning patent validity and infringement. He was heavily involved in this proceeding since April 2025, including analyzing invalidity issues, preparing the Patent Owner's Preliminary Response and Response, and analyzing the Institution Decision.

• Megan Raymond (Counsel)

  • Firm: Groombridge Wu & Webster LLP (Implied by email domain "groombridgewu.com")
  • Note: Megan Raymond was actively involved in communications related to the IPR proceedings with the Petitioner's counsel. Further search would be needed to detail her specific patent litigation experience.

• J. Steven Baughman (Counsel)

  • Firm: Groombridge Wu & Webster LLP (Implied by email domain "groombridgewu.com")
  • Note: J. Steven Baughman was actively involved in communications related to the IPR proceedings with the Petitioner's counsel. Further search would be needed to detail his specific patent litigation experience.