PTAB challenges

Proceedings overview

There is currently one AIA trial proceeding on file for US Patent 12195773. This proceeding, a Post-Grant Review (PGR), is active and in the "Trial Instituted" phase. Since no final decision has been rendered, the claims of the patent have not yet been challenged or confirmed by the PTAB in this proceeding. This means the patent's validity, as it stands, is currently under review, and a defendant facing assertion of this patent should closely monitor the outcome of this active PGR.

PGR2025-00053 — Merck Sharp & Dohme LLC v. Halozyme Inc

• Type: Post-Grant Review
• Filed: 2025-06-06
• Status: Trial Instituted. This means the PTAB has found that the petition demonstrated a reasonable likelihood that at least one claim is unpatentable, and a trial has commenced to determine the patentability of the challenged claims. The trial stage is ongoing.
• Judge panel: The institution decision for PGR2025-00053 was rendered by Administrative Patent Judges Brian P. Murphy, Jennifer S. Li, and Peter K. Leung.
• Petition grounds: Merck Sharp & Dohme LLC challenged claims 1-28 of US12195773 under 35 U.S.C. §§ 102, 103, and 112. The petition relied on various prior art references, including US 2013/0183307 (Shepard), WO 2013/082729 (Shepard), WO 2014/194294 (Shepard), US 9,447,401 (Shepard), US 10,865,400 (Shepard), and US 11,041,149 (Shepard).
• Institution decision: Instituted on 2026-05-15. The PTAB instituted review of claims 1-28, finding that the Petitioner demonstrated that it is more likely than not that at least one challenged claim is unpatentable. The decision cited grounds under 35 U.S.C. § 102 as anticipated by Shepard '307, and 35 U.S.C. § 103 as obvious over Shepard '307 in view of various combinations with other prior art references. Furthermore, institution was granted for certain claims under 35 U.S.C. § 112, ¶ 1 and ¶ 2 for written description and definiteness, respectively.
• Final Written Decision: Not yet issued. The PTAB has a statutory deadline of one year from the institution date to issue a Final Written Decision, which would be by 2027-05-15.
• Settlement / termination: Not applicable; the proceeding is active.
• Appeal: Not applicable; no Final Written Decision has been issued.
• Defensive value: This active PGR indicates that the patent's claims are currently under significant scrutiny for validity. The institution decision, which found a reasonable likelihood of unpatentability for all challenged claims (1-28) under multiple statutory bases (§§ 102, 103, and 112), presents a strong signal that these claims may ultimately be cancelled. For a defendant, this ongoing proceeding creates uncertainty around the patent's enforceability and offers potential leverage in any assertion discussions.

Strategic summary

Currently, all 28 claims of US12195773 are being challenged in PGR2025-00053. While no claims have been formally cancelled or sustained yet, the institution of the PGR on all challenged claims (1-28) signifies that the PTAB found the petitioner's arguments for unpatentability to be sufficiently compelling to proceed to trial. This means that, for the moment, the patent is in a vulnerable position. All claims are currently under review by the PTAB.

Regarding estoppel, 35 U.S.C. § 325(e)(2) for PGRs applies to the petitioner (Merck Sharp & Dohme LLC) and its privies. They will be estopped from asserting in any other USPTO or district court proceeding that a claim is unpatentable on any ground that was raised or reasonably could have been raised in this PGR. For other potential defendants, the prior art grounds (primarily various "Shepard" publications) used by Merck Sharp & Dohme LLC in this PGR would still be available to them if they were to file their own PTAB petition or assert invalidity in litigation, provided they are not in privy with Merck Sharp & Dohme LLC.

There is no evident pattern of multiple filings by the same petitioner or aggressive PTAB appeals from the patent owner yet, as this is the only active proceeding listed. Unified Patents is not listed as a petitioner in this case.

Recommended next steps

For a defendant facing assertion of US12195773, the primary recommendation is to closely monitor PGR2025-00053. The trial is instituted, and the PTAB's Final Written Decision is due by 2027-05-15. The institution decision itself, which found a reasonable likelihood that claims 1-28 are unpatentable under §§ 102, 103, and 112, provides strong arguments that could be used defensively.

If the PTAB issues a Final Written Decision cancelling any claims, those claims would be definitively unpatentable, rendering any infringement theories built on them moot. This could lead to a significant narrowing of the patent's scope or even its complete invalidation. Review the institution decision (PGR2025-00053, Paper 21, issued 2026-05-15) for a detailed understanding of the PTAB's reasoning. The full institution decision can be accessed via the USPTO PTAB Decisions search portal by entering PGR2025-00053.