Specialist Chapter: Why a Robust Specification is Crucial for Satisfying Disclosure Requirements for Chemical and Non-chemical Inventions

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In summary

This article discusses key considerations while preparing a patent application that meets the standards of the Indian Patents Act. It also emphasises the significance of writing patent specifications that satisfy both sufficiency and best method criteria, and it gives recent judgments relating to the assessment of these factors for both chemical and non-chemical inventions. It further underlines the need to draft a specification that covers multiple embodiments, in order to give adequate support for possible divisional applications in the future.

Discussion points

  • Importance of quid pro quo agreement in India
  • Implications of article 29 of the TRIPS Agreement concerning sufficiency of disclosure and best method of performing an invention in India
  • Enhanced efficiency and synergism according to the Indian Patents Act and the significance of supporting data
  • ‘Best method’ consideration for non-chemical subject matters
  • Interpretation of section 16 of the Indian Patents Act

Referenced in this article

Introduction: an art and a science

Drafting patent specifications is an art because it tells a story. A good story includes, among other aspects, a plot, development of each character, interaction between characters to resolve one or more conflicts in an unexpected yet tactful way, and a common theme (or a ‘big idea’) that runs through the entire story. Attention to detail is the hallmark of a story worth telling. Similarly, a patent specification tells the story of an invention. A good specification includes the rudiments of a good story.

Drafting a patent specification is also a science because it follows a set of scientific rules. The specification identifies a problem in the state of the art or a possible improvement over the existing technology, suggests a solution hypothesis (or multiple), explains the purpose and scope of the hypothesis, describes the testing of the hypothesis using drawings, charts, equations, examples, etc, and substantiates the hypothesis with data and evidence. Simply put, a patent specification sufficiently answers the why, how and what questions. The technical problem of the existing technology and the solution offered by the inventors typically answer the why question. The how question can be answered by providing at least one exemplary embodiment that explains the best method to perform the invention. Clear and succinctly worded ‘claims’ answer the what question by including the lowest number of interdependent elements needed to distinguish the invention from the closest prior art.

Quid pro quo

The function of the patent system has evolved over the centuries and has shifted its character from an exclusive privilege to a social contract.[1] The patent system now serves to promote the dissemination of knowledge pertaining to innovations in exchange for exclusive rights. Since a patent is now a quid pro quo agreement, the significance of drafting a robust patent specification cannot be emphasised enough.

Sufficiency of disclosure and best method requirements

The sufficiency of disclosure and the best method of performing the invention are desideratum when constructing a robust specification. The need for stringent sufficiency of disclosure and best method requirements in India can be attributed to India’s substantial import market. According to data released by the Indian government,[2] imports of commodities into India during 2021 and 2022 (April to January) increased by 62.68 per cent when compared with 2020 and 2021 (April to January).

As astutely observed by Bingbin,[3] developing countries (including India) have a growing need to import technologies. Therefore, the sufficiency and best method disclosure requirements will ensure that developing countries get access to those technologies with ‘sufficient and valuable information’. Further, Bingbin envisages that the best method disclosure requirement may be beneficial to domestic companies to build newer technologies based on ‘sufficient and pivotal information’ in the patent specification.[4]

Also, article 29 of the https://www.wto.org/english/docs_e/legal_e/27-trips.pdfAgreement on Trade-Related Aspects of Intellectual Property Rights (the TRIPS Agreement) stipulates that:

… an applicant for a patent shall disclose the invention in a manner sufficiently clear and complete for the invention to be carried out by a person skilled in the art and may require the applicant to indicate the best mode for carrying out the invention ….

The TRIPS Agreement specifies that the ‘sufficiency of disclosure’ is a compulsory obligation and the ‘best method/mode’ requirement is optional. Within this broad requirement specified in the TRIPS Agreement, each jurisdiction may differ regarding interpretation as to what constitutes sufficiency and best mode.

Sufficiency of disclosure (equivalent to the enablement requirement in some countries) assesses whether a patent application describes an invention such that one skilled in the art can make and use the claimed invention without undue experimentation. Sections 25(1)(g), 25 (2)(g) and 64(1)(h) of the Indian Patents Act 1970 state that failure to sufficiently and fairly describe the invention in the complete specification is a ground for opposition and invalidation of the patent.

The best method (best mode in some countries) for performing an invention requires that the invention, after the end of its patent term, ‘can be exploited in equality of condition between the former holder and a third [interested] party’.[5] In the US, for example, although the United States Patent and Trademark Office may raise objections to the effect that the best mode of performing an invention has not been disclosed in the specification, the Leahy–Smith America Invents Act 35 USC 282 states that the failure to disclose the best mode shall no longer be a basis in patent validity or infringement proceedings.

The best method requirement in India is laid out in section 10(4)(b) of the Indian Patents Act, which states that every complete specification shall disclose the best method of performing the invention that is known to the applicant and for which they are entitled to claim protection. Further, section 64(1)(h) states that failure to disclose the best method of performing an invention that was known to the applicant is a ground for invalidation of a patent claim.

Therefore, according to the Indian Patents Act, a complete specification accompanying an application must meet both the sufficiency of disclosure (enablement) and best method (best mode) requirements, and failure to do so can be used as a ground to invalidate the patent.

Assessing sufficiency and best method

The guidelines issued by the Indian Patent Office (IPO) for examining pharmaceutical patent applications state the following:

While assessing the sufficiency of disclosure … the best method for performing the invention known to the applicant is described so that the whole subject-matter that is claimed in the claims, and not only a part of it, must be capable of being carried out by a skilled person in the relevant art without the burden of an undue amount of experimentation or application of inventive ingenuity.[6]

Further, the guidelines state that:

The description in the specification should contain at least one example or more than one example, covering the full breadth of the invention as claimed, which enable(s) the person skilled in the art to carry out the invention.

The guidelines also state:

If the invention is related to product per se, description shall be supported with examples for all the compounds claimed or at least all the genus of the compounds claimed.[7]

Noting that the role of complete specifications is to ‘teach’ what the invention is, how the invention is to be made and how the invention is to be used, the Delhi High Court, in the matter of Communication Components Antenna Inc v Mobi Antenna Technologies also observed that:

The criteria determinative of the sufficiency of disclosure … has to be construed impartially, when any of the grounds enumerated under Section 64 of the Act are invoked. The Court would be generally slow to construe patent specifications against the patentee.[8]

Enhanced efficiency and synergism

The enigma surrounding https://ipindia.gov.in/writereaddata/Portal/ev/sections/ps3.htmlsection 3(d) and https://ipindia.gov.in/writereaddata/Portal/ev/sections/ps3.htmlsection 3(e) of the Indian Patents Act is well known worldwide. To put it succinctly, a claimed substance’s ‘enhanced efficacy’ in relation to a known substance’s efficacy is evaluated under section 3(d), while a claimed composition’s synergistic effects are evaluated under section 3(e). To establish technical advancement, enhanced efficacy or synergism, data and evidence should be included in the specification. The question before the courts has been on the timing of presenting such evidence. Should it be part of the original specification? Can it be provided during the prosecution of the application by way of affidavit?

The courts have previously ruled that post-priority date evidence disclosed subsequent to filing the application can be admissible only if the evidence confirms the existence of technical effect ‘plausibly demonstrated’ and ‘found embedded’ in the original specification (Astrazeneca v Intas Pharma[9]).

In the matter of Janssen Pharmaceuticals v by the Network of Maharashtra people living with HIV (NMP+) and Anr, the IPO found that the claims lacked inventive step and were not patentable under sections 3(d) and 3(e) of the Indian Patents Act. The invention pertained to a pharmaceutical composition including fumarate salt of bedaquiline for the treatment of a mycobacterial infection, particularly tuberculosis. During oral proceedings, the applicant had provided an affidavit to show a 159 per cent increase in bioavailability of the drug in its fumarate salt form over the base compound, and an intrinsic dissolution rate of the claimed salt double the rate of the non-salt form of the compound. The IPO observed that:

[n]o data has been shown in the complete specification to substantiate that a combination of fumarate salt of Bedaquiline along with Tween 20 (wetting agent) would show surprising effect over the known composition of Bedaquiline on the treatment of a patient,” and that “the applicant failed to disclose any evidence to support the statement made out regarding increase in bio-availability as well as rate of increase in dissolution profile of the composition.

The purported surprising effect of increased bioavailability as a consequence of increased solubility was not found convincing by the IPO. The IPO opined that the increased bioavailability as claimed by the applicant was an afterthought because there had been no discussion on this point in the original specification. The IPO stated that:

[h]ad it been the only problem to be solved, all such findings could have been well documented and incorporated before the priority date of the application.[10]

The IPO further observed that the inventor’s affidavit, which the applicant filed only after the objections surfaced, did not provide adequate data for the claimed 159 per cent increased bioavailability. Although the IPO appears to have erred in rejecting the composition claims under section 3(d), refusal of the application on the ground of inventive step and section 3(e) for lack of specific data in the disclosure seems to be consistent with Indian law.

In the matter of Societe Des Produits Nestle SA v The Controller of Patents and Design and Ors, the Delhi High Court set aside the objection of the Controller under section 3(e) as it was proved to be not sustainable. The invention related to a composition comprising dihomo-γ-linolenic acid (DGLA), which is known to exhibit anti-inflammatory properties. The synergistic effect of the claimed composition is the reduction of interleukin 4 (IL-4), known to be an anti-inflammatory cytokine, since excess production of IL-4 may cause tumours.

A detailed comparison between the IL-4 values of the control group, the DGLA 60 group, the NIF 2.14 group and the composition of the impugned application was provided in the specification. Other parameters, including IgE values, mast cells and IL-10 secretion in brachial lymph nodes, were also disclosed in the specification. The Delhi High Court correctly observed that:

the appellant has provided extensive experimental data in the specification supported by examples as well as drawings showing the synergistic effect.[11]

Supporting data and its significance

A clear pattern emerges when analysing the judgments issued by the courts and the IPO in the cases of chemical- and pharmaceutical-related inventions. Indicative data in support of technical advancement, efficacy and synergism in the form of comparative examples, experimental data, charts and tabulation, etc, must be disclosed in the specification, preferably at the time of filing the application. Providing data post-filing, for instance to overcome an objection raised by the examiner, may be allowed entirely at the discretion of the examiner and only if the original description plausibly demonstrates, or reasonably points to, a hitherto unknown technical effect or advancement.

If the post-filing data significantly deviates from the original specification, the patent office will most likely decline to take the post-filing data into consideration when determining inventive step or sufficiency of disclosure. However, if the post-filing data corroborates the disclosure made in the original specification, the patent office can be persuaded to admit the data.

The approach of the IPO is not very different from that of other major patent offices. The Australian Patent Office, for instance, in the matter of BASF Corporation [2019] APO 34, following the guidance of a UK Supreme Court ruling, agreed that subsequent data cannot be a substitute for sufficient disclosure in the specification.[12] Japan and Korea are also disinclined to accept post-filing data for determining sufficiency of disclosure, although they can be persuaded to consider the same for establishing inventive step. On the other hand, countries like the USA, Europe and China are more liberal in accepting post-filing data for the purposes of establishing inventive step and for enablement (sufficiency) considerations.

In India, especially in cases where patents are sought for incremental innovations or derivatives of a known pharmaceutical composition, the requirement of data demonstrating therapeutic efficacy is sine qua non. Although incremental inventions may have ‘huge potential for the development of drugs with superior health benefits’,[13] in the absence of evidence to the contrary, they can potentially become an attempt at evergreening existing patents for the same base compound. One of the continuing challenges facing drug manufacturers is that the amount of qualitative and quantitative data required to demonstrate enhanced efficacy of an incremental invention over the prior art remains subjective.[14] Also, the ambiguity of the language ‘enhancement of the known efficacy’ in section 3(d) could be addressed by way of further explanation or amendment ‘which in turn would enable the protection of truly inventive innovations without exacerbating the chances of evergreening’.[15]

Applicants may find themselves in a quandary while deciding on when to file a patent application. Waiting for sufficient test data and examples before filing the application may run the risk of having a later priority date, thereby exposing the application to newer prior arts. Filing without sufficient supportive data and examples may invite objections on insufficiency of disclosure or lack of best method of working the claimed invention. Although there is no one-size-fits-all solution to this predicament, it would be prudent to provide sufficient information in the specification that can form a basis for any post-filing data filed during the prosecution of the application.

Assessing best method for non-chemical applications

While evaluating whether a patent application pertaining to a non-chemical subject matter includes the best method of performing the invention as known to the applicant (section 10(4)), the courts seem to employ a different yardstick. For instance, in the matter of Titan Umreifungstechnik Gmbh and Co KG v Assistant Controller of Patents and Designs and Ors, the Delhi High Court ruled that:

there is no mandatory requirement to provide examples for non-chemical related inventions … furnishing of working examples [is] as an essential condition only in case of chemical related inventions. Thus, although working examples can be beneficial in assessing the patentability of an application, they are not strictly necessary ... Mere absence of working examples does not render the subject application liable for rejection.[16]

The Delhi High Court also mentioned that the controller, in order to satisfy themself, can ask the appellant to prove that their claims are supported with workings. In the case of non-chemical inventions, it is advisable to disclose the best method of performing the invention in the complete specification as an exemplary embodiment of the invention.

Support for prospective divisional applications

The description and claims of a patent application should be drafted taking into consideration the unique requirements in India. As per certain recent judgments:

  • the claims of the first application should define a plurality of inventions (Esco Corporation v The Controller of Patents & Designs)[17]; and
  • the claims of the divisional application should have been present in the claims of the first application. A divisional application is not maintainable solely on the basis of disclosure made in the specification (Boehringer Ingelheim v The Controller Of Patents & Anr)[18].

However, a more recent judgment (Syngenta v Controller of Patents)[19] has revisited and challenged the Boehringer decision and has referred the matter to a Division Bench. The Division Bench will decide on the matter of maintainability of a divisional application based solely on the original disclosure.

Given the above developments governing divisional applications in India, it is important that the first application includes all possible embodiments – both significant and optional – to support a divisional application preferred in the future.


In any contentious proceeding, the patent specification comes under intense scrutiny. Applicants who disclose adequate information to meet the sufficiency and best method requirements are ensured full protection under the law and can successfully enforce their patents against infringers. Also, since the description and claims form the basis for deciding on the maintainability of a divisional application, it is prudent to draft the application with sufficient scope for pursuing divisional applications in the future.


[1] https://eprints.lse.ac.uk/48995/1/WPS2013-06_Thambisetty.pdfThambisetty, Sivaramjani (2013) ‘The Evolution of Sufficiency in Common Law’, LSE Law, Society and Economy Working Papers 6/2013.

[2] Ministry of Commerce and Industry ‘https://commerce.gov.in/press-releases/indias-merchandise-trade-preliminary-data-january-2022/India’s Merchandise Trade: Preliminary Data January 2022’.

[3] Lu, Bingbin (2011) ‘Best Mode Disclosure for Patent Applications: An International and Comparative Perspective’, Journal of Intellectual Property Rights, volume 16.

[4] ibid.

[5] Braga, Edimilson Junqueira et al ‘The Role of Specification in Patent Applications: A Comparative Study on Sufficiency of Disclosure’, World Patent Information 53 (2018) 58–65, web.

[6] Intellectual Property India ‘https://ipindia.gov.in/writereaddata/Portal/IPOGuidelinesManuals/1_37_1_3-guidelines-for-examination-of-patent-applications-pharmaceutical.pdfGuidelines for Examination of Patent Applications in the Field of Pharmaceuticals’, paragraph 11.5.

[7] Intellectual Property India ‘https://ipindia.gov.in/writereaddata/Portal/IPOGuidelinesManuals/1_37_1_3-guidelines-for-examination-of-patent-applications-pharmaceutical.pdfGuidelines for Examination of Patent Applications in the Field of Pharmaceuticals’, paragraph 11.6.

[8] https://indiankanoon.org/doc/56633834/Communication Components vs Mobi Antella (2022/DHC/000855).

[9] http://d4.manupatra.in/ShowPDF.asp?flname=Astrazeneca_AB_and_Ors_vs_Intas_Pharmaceuticals_LiDE202019112016222325COM968311.pdfAstrazeneca AB and Ors v Intas Pharmaceuticals Limited and Ors (2 November 2020, Delhi High Court) MANU/DE/1939/2020.

[10] ibid.

[11] http://d4.manupatra.in/ShowPDF.asp?flname=Societe_Des_Produits_Nestle_SA_vs_The_Controller_oDE202314022317473553COM578470.pdfSociete Des Produits Nestle SA v The Controller of Patents and Design and Ors (3 February 2023) MANU/DE/0642/2023.

[12] https://jade.io/article/655456BASF Corporation [2019] APO 34 (19 July 2019).

[13] Banerjee, Meghna and Roy, Yajnaseni (2009) ‘Patentability of Incremental Innovation vis-à-vis § 3(d) of the Indian Patents Act: Striking a Balance’, NUJS Law Review, volume 2, issue 4.

[14] Mueller, Janice M (2007) ‘https://lawreview.law.pitt.edu/ojs/lawreview/article/view/79The Tiger Awakens: The Tumultuous Transformation of India’s Patent System and the Rise of Indian Pharmaceutical Innovation’, University of Pittsburgh Law Review, volume 68, No. 3.

[15] Banerjee, Meghna and Roy, Yajnaseni (2009) ‘Patentability of Incremental Innovation vis-à-vis § 3(d) of the Indian Patents Act: Striking a Balance’, NUJS Law Review, volume 2, issue 4, page 636.

[16] http://d4.manupatra.in/ShowPDF.asp?flname=Titan_Umreifungstechnik_Gmbh_and_Co_KG_vs_AssistanDE2023310523164547140COM223229.pdfTitan Umreifungstechnik Gmbh and Co KG v Assistant Controller of Patents and Designs and Ors (2 May 2023 - DELHC) MANU/DE/3614/2023.

[18] https://indiankanoon.org/doc/164938320/Boehringer Ingelheim ... v The Controller Of Patents & Anr (12 July 2022).

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