New matter

No amendment shall introduce new matter into the disclosure of the invention (35 U.S.C. 132(a))¹. The rule says the same: no amendment may introduce new matter into the disclosure of an application (37 CFR 1.121(f))⁴.

The MPEP says that information in any one of the specification, claims or drawings as filed may be added to any other part of the application without introducing new matter, and that mere rephrasing of a passage, where the same meaning remains intact, is not new matter³. An applicant may rely on the specification and drawings as filed and also on the claims present on the filing date, if their content justifies it⁵. Matter not present in the specification, claims or drawings on the filing date that is added later is usually new matter⁵.

• New matter in the specification, abstract or drawings. The examiner objects under 35 U.S.C. 132 and requires the applicant to cancel it³.
• New matter in the claims. The examiner rejects the claims under 35 U.S.C. 112(a) for lack of written description^3,5. See Written description requirement.
• Review. If the new matter is confined to amendments to the specification, review of the requirement to cancel it is by petition. If it is introduced into the claims or affects them, the question is appealable⁵.
• Provisional applications. No amendment is permitted in a provisional application after it receives a filing date⁵.
• Best mode. If the best mode contemplated by the inventor at filing was not disclosed, an amendment adding a mode not described in the application as filed cannot cure the defect and is treated as new matter⁶. See Best mode.

Article 123(2) EPC says the European patent application or patent may not be amended in such a way that it contains subject-matter which extends beyond the content of the application as filed². The EPO Guidelines state that if an amendment introduces such subject-matter, the application as so amended cannot be allowed⁷.

The Guidelines regard an amendment as introducing such subject-matter if the overall change in the content of the application, by addition, alteration or excision, leaves the skilled person with information that is not directly and unambiguously derivable from what the application previously presented, even taking account of matter implicit to the skilled person (referring to decision G 2/10)⁷. The Enlarged Board of Appeal has called this test the "gold standard" (G 2/10). As summarized in the Case Law of the Boards of Appeal, it asks what a skilled person would derive directly and unambiguously, using common general knowledge, from the whole of the documents as filed⁸.

The Guidelines give the purpose: applicants may not improve their position by adding subject-matter not disclosed in the application as filed, which would give them an unwarranted advantage and could damage the legal security of third parties who rely on the original content⁷.

After grant, subject-matter extending beyond the content of the application as filed is a ground of opposition (Article 100(c)). For a patent granted on a divisional application or on a new application under Article 61, the comparison is with the earlier application as filed⁹. Article 123(3) separately bars amendments that extend the protection conferred². See Written description requirement for how Article 123(2) differs from the sufficiency requirement.

In China, an amendment to the application documents for an invention or utility model may not go beyond the scope of disclosure contained in the original description and claims (Article 33 of the Patent Law)¹⁰.

A continuation-in-part is an application filed during the lifetime of a prior-filed application, repeating some substantial portion or all of it and adding matter not disclosed in the prior-filed application. It must claim the benefit of the prior-filed application under 35 U.S.C. 120, 121, 365(c) or 386(c)¹¹. See Continuation-in-part application.

Section 120 gives a later application the effect of the earlier filing date for an invention disclosed in the earlier application in the manner provided by section 112(a), other than the best mode requirement¹². The MPEP says the later application must claim an invention that is also disclosed in the prior application to get that date, and that a continuation or divisional application cannot include anything that would be new matter if inserted in the prior-filed application¹³. See Continuation application.