You got a notice of issuance, paid the fees, and received the patent, so you’re home free, right? Wrong. Even before the new patent law, an issued patent was not necessarily a done deal. At any time during its term, and up to six years after it expired, an issued patent could be challenged.

U.S. patent laws and regulations allow for what’s called “reexamination.” Anyone can request a patent be reexamined. In fact, one can do so anonymously. Reexaminations, however, are not done capriciously. A request for a reexamination requires the requestor to furnish the grounds, and must be accompanied by the documentary references the requestor believes establish a substantial new question (called “a SNQ”) of patentability.

During the normal course of patent prosecution, a United States Patent and Trademark Office (USPTO) examiner will search for any documents or patents, U.S. or foreign, that could preclude issuing that patent. For example, it could be a patent issued more than a year before the current application’s filing date that discloses and claims an invention that is indistinguishable from that application’s invention. Also, if the examiner finds that an invention has been publicly described or offered for sale more than a year before application filing date; that, too, would preclude that invention receiving a patent.

However, a reexamination cannot be requested based on evidence that something was offered for sale more than a year before the issue date. A SNQ requires proof, for example, that a patent or document describes that issued-patent’s invention and is more than a year older than its filing date. Or, it can involve a set of patents and/or documents that pre-date the application filing date by more than a year, none of which describes the issued-patent’s invention, but the combination of which would make the invention obvious to those who read them.

The reexamination process begins with a request that is then followed by notification of such to the patent holder. If the examiner does not agree that a SNQ is raised, the request is denied. On the other hand, if the examiner believes that a SNQ has been raised, it triggers the initiation of a reexamination proceeding.

Cutting to the chase, a reexamination proceeding can find that none of the claims in the issued patent are invalidated by the reexamination evidence. Or, it could find some or all of them are invalidated. Reexamination is the USPTO’s way of rectifying prosecution shortcomings. The new law now allows for a post-grant review which has a deadline for filing that is no later than nine months after the grant date. In addition to the same SNQ qualifications of a request for reexamination, a post-grant review can also be instituted if the petition “raises a novel or unsettled legal question that is important to other patents or patent applications.”