Supplemental examination affords that information believed to be relevant to an existing patent be considered, reconsidered, or corrected by the US Patent and Trademark Office (USPTO). Supplemental examination is available exclusively to patent owners, which may submit a supplemental examination request to the USPTO at any time before a patent expires. During supplemental examination, the USPTO may consider, among other things, factual information, patents, and printed publications.
Supplemental examination has two stages—a request stage and an examination stage. In the request stage, the requesting patent owner may submit up to 12 items of information for consideration. If the patent owner wants the USPTO to consider additional items of information, multiple requests may be submitted. Although the items of information are not limited to printed publications and patents, they must be submitted in writing.
Upon review of the submitted items and within three months, the USPTO decides whether such information raises a substantial new question of patentability. If it does not, the USPTO denies the supplemental examination, closes the case, and issues a Supplemental Examination Certificate (published as an attachment to the patent) indicating that no substantial new question of patentability has been raised . If the USPTO decides that the information does raise a substantial new question of patentability, the supplemental examination enters into the examination stage, during which the patent is fully reexamined. The reexamination can take several years to complete and can result in claims being canceled, narrowed, or confirmed as patentable.
A significant advantage of supplemental examination is its estoppel effect against potential allegations of inequitable conduct relating to withholding information material to patentability. Simply by submitting a supplemental examination request, a patent owner can foreclose any such allegations, thus avoiding any challenges to the validity of the patent for inequitable conduct relating to that information.