The Scope of Permissible Amendment

1Section 59 stipulates the scope of amendment of an application or a specification. An amendment will not be allowed if the amended specification fails to describe or claim an invention for which a valid patent can be granted. (See Pharmacia Corpn v Merck & Co Inc [2001] EWCA Civ 1610, (2002) RPC 41, para 146 (CA). See also Unifloc Reagents Ltd v Newstead Collieries Ltd (1943) 60 RPC 165, p 168.) Where the claim is found to be invalid, the question arises whether such invalidity can be rectified by giving the patentee an opportunity to amend the specification. (See Van der Lely NV v Bramfords Ltd (1964) RPC 54, p 76.)

2Chapter X of the Patents Act provides for the amendment of the following documents:

(a) Application for the patent; (b) Complete specification; and (c) Any document relating to the application or the complete specification.

Any document relating to an application or a complete specification can be amended under the Patents Act. The documents will include amendment to drawings and appended additional drawings which did not form a part of the original application if such drawings are required to define the disclaimer which the applicant/patentee intends to make. It will also include an abstract. (Patents Act 1970, s 10(4).) Though s 59 restricts its scope to the above three sets of documents, the Controller has the power to amend any other document for which no specific provision has been made in the Patents Act and any irregularity in procedure may be obviated by the Controller, without detriment to the interests of any person. (Patents Rules 2003, r 137.)

3The fact that amendments under ss 57 and 58 are subject to the provisions of s 59, clearly illustrates that the requirements with regard to the scope of amendment contained in s 59 apply to both amendments before and after the grant.

4The scope of amendment under s 57 is wider than that under s 58. Section 58 allows amendment as an alternative to revocation of the patent. Both sections are subject to the stipulations on amendment laid down in s 59 which clarifies the nature of amendment that is permissible under the Patents Act. Section 59 allows for the following types of amendments:

(a) Amendments by way of disclaimer, correction or explanation; (b) An amendment for the incorporation of an actual fact.

5Section 59 specifically excludes two kinds of amendments. First, no amendment of a complete specification shall be allowed if such amendment would claim or describe matter not in substance disclosed or shown in the specification before the amendment. Secondly, no amendment of the specification shall be allowed if any claim of the specification as amended would not fall wholly within the scope of a claim of the specification before the amendment. The most significant issue in allowing an amendment is to determine whether the amendment is consistent with the complete specification as originally accepted. (Patents Act 1970, s 59(3).) In OpenTV v Controller of Patents and Designs (2023), the Court held that “amendments are permissible in the Claims so long as the said amendments are within the scope of the originally filed Claims as filed and do not expand the said Claims. Thus, reduction or narrowing down a Claim is permissible, but broadening, widening or expansion of Claims is not permissible.” (para 50).

6In Allergan v Controller of Patents (2023) the Delhi High Court refused to follow an interpretation of Section 59(1) that would create “an artificial distinction between the claims in a patent and the complete specifications that accompany it” (para 29).

Amendments before and after the grant

7In Nippon A&L v Controller of Patents (2022) the Delhi High Court held that “Section 59 has two aspects. Sub-section (1) deals with amendment of a pending application, its specification, claims or any document related thereto. Sub-section (2) deals with amendment after the grant of the patent.” (para 39) On the scope of the amendments, the Court held:

an amendment of an application, specification or any document related thereto would be permissible only if the following conditions are satisfied:
(i) The amendment has to be by way of disclaimer, correction or explanation;
(ii) The amendment has to be for the purpose of incorporation of actual facts;
(iii)(a) The effect of the amendment ought not be to amend the specification to claim or describe any matter which was not disclosed in substance or shown in the originally filed specification.
(iii)(b) The amended claims have to fall within the scope of claims as originally filed. (para 40)

The Court held that only amendments that satisfy all of the above conditions will be allowed. (para 41)

8In Nippon the Court also held that “A reading of the unamended provision and the provision post the amendment shows that the power to amend has not been abridged or curtailed or narrowed but has been expanded.” (para 43) The Court held that “amendments to a patent specification or claims prior to grant ought to be construed more liberally rather than narrowly.” The Court further held that “So long as the invention is disclosed in the specification and the claims are being restricted to the disclosures already made in the specification, the amendment ought not be rejected, especially, at the stage of examination prior to grant.” (para 55)

9In Kroll Information Assurance v Controller General of Patents, Designs and Trademarks (2025) the Delhi High Court held that “while amending the Claims, the scope of the original Claims should not be broadened and the proposed amendments should be in line with the original Complete Specification.” (para 13) On the proposed amendments the Court held that “These additional features narrow down the scope of the Claims. Further, the additional features are in the nature of explanation, which explains how the locating of a specific file and person is done, and do not include anything which was not disclosed in the Complete Specification.” (para 14)

10In Syngenta Crop Protection v Assistant Controller of Patents (2024) the Delhi High Court held that “any amendment made under Section 58(1) is subject to Section 59 of the Patents Act. These provisions act as a ‘check and balance mechanism’ to ensure that no new subject matter is introduced and that the scope of the claims is not broadened.” (para 11)

11In EMD Millipore v Assistant Controller of Patents and Designs (2025) the Delhi High Court held that “Any amendment that introduces new matter or results in a broadening of the scope of the claims beyond what was originally disclosed in the Complete Specification is expressly prohibited.” (para 75) The Court reproduced from OpenTV that “irrespective of whether the amendment is directed by the Court or is at the instance of Patent Applicant, so long as the requirements as laid down under Section 59 of the Act are fulfilled such that the amended claims are within the scope of original claims, is not breached, the amendment is permissible.” (para 76)