PTAB challenges

Proceedings overview

There is one AIA trial proceeding on file for US patent 12297278, which is currently pending. The patent is facing a Post-Grant Review (PGR) challenging claims 1-5. This active challenge indicates that the patent's validity is currently under scrutiny, and its defensive posture is still being determined by the outcome of this proceeding.

PGR2026-00027 — Merck Sharp & Dohme LLC v. Surrozen Operating Inc

• Type: Post-Grant Review
• Filed: 2026-02-12
• Status: Pending - The case is ongoing and has not yet reached a final decision.
• Judge panel: Pending Judge Assignment
• Petition grounds: Merck Sharp & Dohme LLC challenges claims 1-5 of US Patent 12297278, arguing that they lack written description, enablement, and are anticipated by the Garcia reference over an undisclosed genus. The challenges are based on statutory grounds which can include 35 U.S.C. § 102 (anticipation), 35 U.S.C. § 103 (obviousness), and 35 U.S.C. § 112 (written description and enablement).
• Institution decision: Not yet issued. The institution decision typically occurs within six months of the petition filing. The PTAB's institution rate for PGRs in fiscal year 2026 (through November 2025) was 37%. Recent changes in PTAB policy indicate a preference for PGRs when eligibility requirements are met, and that petitions for PGRs are favored due to their early filing window (no later than nine months from patent grant).
• Final Written Decision (if issued): Not yet issued.
• Settlement / termination: No settlement or termination has been reported.
• Appeal: Not applicable as no Final Written Decision has been issued.
• Defensive value: This active PGR indicates that claims 1-5 are currently under challenge. If these claims are found unpatentable, it would significantly narrow the scope of the patent. A defendant facing assertion of these claims should closely monitor the outcome of this proceeding.

Strategic summary

Currently, claims 1-5 of US patent 12297278 are being challenged in a pending Post-Grant Review, PGR2026-00027. The outcome of this single proceeding will determine whether these foundational claims are canceled or sustained. All other claims of the patent (beyond claims 1-5) are currently untested in an AIA trial.

The estoppel landscape will be shaped by the institution decision and, if instituted, the final written decision of PGR2026-00027. If the PTAB institutes trial, Merck Sharp & Dohme LLC (and its privies) will be estopped from later asserting invalidity grounds in district court or the ITC that they raised or reasonably could have raised in the PGR against claims that result in a Final Written Decision. As PGRs allow challenges under all invalidity grounds (§§ 101, 102, 103, and 112), a robust institution could significantly limit future challenges by the petitioner. Currently, it is too early to determine the full estoppel implications. There is no indication of repeated filings by the same petitioner or aggressive PTAB appeals by the patent owner at this stage.

Recommended next steps

The institution decision for PGR2026-00027 is pending. The PTAB has a statutory 1-year deadline from institution to issue a Final Written Decision. Given the filing date of 2026-02-12, the institution decision is expected in Q3/Q4 2026. A defendant should closely monitor the USPTO Patent Trial and Appeal Board (PTAB) Decisions portal for updates on this proceeding, particularly the institution decision. The outcome of this decision will dictate the immediate defensive value of this patent.