The Patent Trial and Appeal Board’s docket entry in Entegris, Inc., PGR2026-00037, marks the start of a post-grant review proceeding that practitioners should watch closely. Although a newly filed PTAB matter does not yet provide a final merits ruling, the case is significant because post-grant review remains one of the most powerful mechanisms for attacking recently issued patents on a wide range of grounds, including patent eligibility, written description, enablement, indefiniteness, and novelty or obviousness.

Based on the filing posture, the key issue is not yet who ultimately wins, but what the PTAB will permit the challenger to litigate and how aggressively it will examine the patent under the broader PGR framework.