PTAB challenges

The USPTO ODP API previously indicated no AIA trial proceedings for US patent 12161628. My web searches for "US12161628 PTAB IPR", "US12161628 PTAB PGR", "US12161628 PTAB CBM", and related terms also did not directly yield any specific PTAB proceeding numbers (IPR, PGR, CBM) for US Patent 12,161,628.

The search results primarily discuss the patent's content, its litigation in district court (e.g., Astellas Pharma Inc. et al v. Hikma Pharmaceuticals USA Inc., 3:25-cv-00578), and general information about IPR and PGR proceedings. One search result from DrugPatentWatch briefly mentions "WO2017027665 · ⤷ Start Trial", which refers to an international application and not directly to the US patent 12,161,628, nor does it provide an actual PTAB trial number. It seems to be a feature of their platform rather than an active PTAB case.

Given the patent was issued on December 10, 2024, the nine-month window for filing a Post-Grant Review (PGR) (which allows challenges on any ground, including novelty, obviousness, and written description, within nine months of issuance) would still be open until around September 10, 2025. Inter Partes Review (IPR) (which can only be based on prior art under §§ 102 or 103) can typically be filed after the later of nine months after the patent grant or the termination of any PGR.

Therefore, as of today's date (2026-05-30), it is plausible that no PGR was filed within the initial 9-month window, and the earliest an IPR could typically be filed would be after September 2025 (or after any PGR concluded). However, my search did not identify any such filings.

The absence of PTAB proceedings for a relatively newly granted patent, especially one involved in active district court litigation, is notable. This could indicate that potential challengers are still evaluating their options, or that the patent owners have strategically engaged in settlement discussions that preclude PTAB challenges, or that the claims are perceived as robust enough to discourage PTAB challenges at this time.

Proceedings overview

There are no AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method review) on file for U.S. Patent 12,161,628 as of the most recent data from the USPTO Open Data Portal and supplementary web searches. This indicates that all claims (1-6) of the patent remain untested at the PTAB.

Strategic summary

As of May 30, 2026, U.S. Patent 12,161,628 has no PTAB trial proceedings on record. This means that all six claims of the patent, including the independent Claim 1 and its dependent claims 2-6, have not been challenged or adjudicated before the Patent Trial and Appeal Board. Consequently, all claims are currently sustained as granted by the USPTO and remain untested in an administrative trial setting.

The absence of PTAB activity is particularly noteworthy given that the patent is involved in multiple district court litigations against generic drug manufacturers (e.g., Astellas Pharma Inc. et al v. Hikma Pharmaceuticals USA Inc., 3:25-cv-00578). In such Hatch-Waxman disputes, defendants often simultaneously pursue PTAB challenges to the asserted patents. The patent was issued on December 10, 2024, making it eligible for Post-Grant Review (PGR) for nine months following its issuance, which concluded around September 10, 2025. Inter Partes Review (IPR) could typically be filed after that period or later. No such filings were found.

The current estoppel landscape is entirely open. Since no PTAB proceedings have occurred, there are no prior art grounds that have been "raised or reasonably could have been raised" and subsequently barred from future challenges under 35 U.S.C. § 315(e)(2). Therefore, any potential defendant still has the full range of prior art grounds (under §§ 102 and 103 for IPR, or broader grounds including § 101 and § 112 for PGR if applicable) available for a future PTAB challenge, should they choose to initiate one.

Recommended next steps

• No PTAB activity exists. The absence of any Inter Partes Review, Post-Grant Review, or Covered Business Method proceedings for U.S. Patent 12,161,628 means that the patent's validity has not been challenged or decided by the PTAB. This is an important signal, as patents involved in active litigation often face such challenges.
• Monitor for future filings. Any party interested in challenging this patent's validity should continue to monitor the USPTO's Patent Trial and Appeal Case Tracking System (P-TACTS) for new IPR or PGR petitions. Given the ongoing district court litigation, future PTAB challenges remain a possibility.
• Evaluate prior art for IPR. For a defendant currently facing assertion of this patent, an IPR petition could still be a viable strategy, as all claims remain untested. The grounds for IPR are limited to novelty (§ 102) and obviousness (§ 103) based on patents and printed publications. The prior art analyzed in the "Obviousness" section (WO2017027660A1, for example) could be a basis for such a challenge.
• Consider a PGR if within the 9-month window. While the 9-month window for PGR has likely passed (patent issued December 10, 2024), if a reissue patent were to issue, a new PGR window might open. PGR allows for a broader range of invalidity grounds beyond just prior art.