PTAB challenges

Proceedings overview

There is one active AIA trial proceeding on US Patent 10865400. This is an Inter Partes Review (IPR) that is currently pending, meaning the patent claims have not yet been challenged through a final written decision. The defensive posture for a defendant is that the patent is currently being challenged, and the outcome of this IPR could significantly impact the scope of the asserted claims.

IPR2026-00312 — Merck Sharp & Dohme LLC v. Halozyme Inc.

• Type: Inter Partes Review
• Filed: 2026-03-23
• Status: Pending. The proceeding is ongoing and has not yet reached a final decision.
• Judge panel: Information not yet publicly available in the initial stages.
• Petition grounds: Specific claims challenged, prior art cited, and statutory bases (e.g., obviousness under § 103, anticipation under § 102) are not yet publicly detailed in the provided data.
• Institution decision: Not yet issued. The deadline for the institution decision is generally six months from the filing date, which would be around September 23, 2026.
• Final Written Decision: Not issued, as the proceeding is pending.
• Settlement / termination: Not applicable at this stage.
• Appeal: Not applicable at this stage.
• Defensive value: This active IPR indicates that the validity of US10865400 is currently under scrutiny. If institution is granted, it means the petitioner has shown a reasonable likelihood of prevailing on at least one challenged claim. If claims are subsequently invalidated, any infringement theories relying on those claims would be significantly weakened or eliminated. Conversely, if institution is denied or the patent owner prevails, it could strengthen the patent's validity against similar prior art challenges.

Strategic summary

Currently, no claims of US10865400 have been CANCELED or SUSTAINED through an AIA trial proceeding. All claims remain UNTESTED by a final PTAB decision. The patent is facing a challenge, but its full impact on the claim scope is yet to be determined.

Regarding the estoppel landscape, since IPR2026-00312 is pending, no estoppel has yet attached under § 315(e)(2). If the PTAB institutes the IPR and issues a final written decision, the petitioner (Merck Sharp & Dohme LLC) and its privies would be estopped from asserting invalidity grounds that were raised or reasonably could have been raised during the IPR against the claims that reached a final decision. For other potential defendants, prior-art grounds not addressed in IPR2026-00312 would still be available for challenges, assuming they are not in privity with the petitioner.

There are no clear pattern signals from the provided data. This is the first IPR filed against the patent, and it's being brought by Merck Sharp & Dohme LLC, which is a pharmaceutical company, suggesting a potential interest in the subject matter of the patent (PH20 polypeptide variants). It is too early to determine if the patent owner will pursue PTAB appeals aggressively as no FWD has been issued.

Recommended next steps

For a defendant facing assertion of US10865400:

• Monitor IPR2026-00312: Closely track the progress of IPR2026-00312. The most immediate milestone is the institution decision, expected around 2026-09-23. The institution decision will reveal which claims, if any, the PTAB has agreed to review and on what grounds. This decision is crucial as it indicates the initial strength of the invalidity challenge.
• Review Petition: Obtain and review the full petition filed by Merck Sharp & Dohme LLC to understand the specific claims being challenged and the prior art relied upon. This will provide insights into potential weaknesses of the patent.
• Assess Impact: Depending on the outcome of the institution decision and any subsequent Final Written Decision, evaluate the impact on your potential infringement liability. If claims critical to an assertion against you are challenged or invalidated, it could significantly alter the negotiation landscape.

The USPTO Open Data Portal shows the proceeding status at: https://portal.unifiedpatents.com/ptab/case/IPR2026-00312.