We are currently developing a new site to host the Patent Manual of Practice and Procedure. The BETA version of this site is now available for you to review. The information and content displayed in the BETA site is only available for testing purposes. Do not use or reference the information in the BETA site when making any decisions or actions regarding IP rights.

2.19.6 Differentiation From the Parent

Date Published

The claims of a patent of addition must be for matter which was not disclosed in the specification of the parent.  However, under sec 25 and reg 2.4, such matter need not involve an inventive step with respect to the parent (P. and S.'s Application (1952) 69 RPC 249) (see also ‘Section 25’ below).  The claims of the patent of addition must, however, meet the requirements for inventive step with respect to matter other than that disclosed in the parent.

Note: Section 25 does not preclude an objection of lack of novelty in the light of the parent specification.

In the case of a series of additional applications, sec 25 does not protect the second application from an objection based on the publication of the invention in the parent of the parent (or earlier, where applicable) specification.

If part of the subject matter described in the complete specification of the parent application or patent is excised after the parent case becomes open to public inspection, sec 25 will not protect the additional application from an objection based on the excised matter if that matter was published before the priority date of the additional application (see P. and S.'s Application supra).


Section 25

Section 25 and reg 2.4 preclude objections on the ground of lack of inventive step having regard to publication during the period extending from the priority date of the claims of the main invention (or the earliest priority date of the claims of the main invention in the case of multiple priorities) to the priority date of the relevant claim of the additional application.

Section 25 does not apply where there was publication or use of the main invention before the priority date (or earliest priority date) of the claims of the parent specification.

The publication and use of the main invention referred to in sec 25 means publication or use either by the applicant or by other persons. Thus, "publication" is not restricted to publication in the specification in which the main invention was described (see Monsanto Co.'s (Salyer's) Application (1969) RPC 75).


Note: Where the application for the patent of addition contains one or more claims that repeat claims of the parent application or patent, an objection under sec 64(2) may apply (see 2.18.8 Additionals/Divisionals).

Back to top