5.6.11.3 Differentiation from the parent

Also in this Chapters:

• 5.6.11.1 Conditions for filing
• 5.6.11.2 Improvement or Modification​​​​​​​
• 5.6.11.4 Issues specific to the Examination of additional applications
• 5.6.11.5 Amendment of the Parent

• 5.6.11.6 Annex A - Procedural Outline to Patents of Addition Examination

Key Legislation:

Patents Act:

• s25 Validity: patents of addition
• s64 Grant: multiple applications 

Patents Regulations:

• reg 2.4 Prescribed period: patents of addition

Related Chapters:

• 5.6.9.10 Double patenting, Multiple Applications

Section 25; No objection for lack of inventive step against parent

Section 25 and reg 2.4 preclude objections on the ground of lack of inventive step having regard to publication of the main invention 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.

This means that the claims of a patent of addition do not need to involve an inventive step with respect to the parent. 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.

In the case of a series of additional applications, s25 does not protect the second application from an objection based on the publication of the invention in the grandparent (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, s25 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).

If there was publication or use of the main invention before the priority date of the parent specification, then s25 does not apply, and an inventive step objection could be applicable. The publication and use of the main invention referred to in s25 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 that 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 s64(2) (double patenting) may apply (see 5.6.9.10 Double patenting, Multiple Applications​​​​​​​).