The importance of following due process when reviewing patent applications was reinforced in the recent Intellectual Property Appellate Board’ (IPAB) decision which has directed the patent office to consider the patent application of US-based Schering Corporation for a crystalline form of a compound for treatment of heart related disease afresh. Schering’s patent (2491/CHENP/2006) claims a crystalline polymorph of a bisulfate salt of a thrombin receptor antagonist, vorapaxar. Vorapaxar is used for the treatment of acute coronary syndrome chest pain caused by coronary artery disease.The parent invention of the crystalline form of vorapaxar itself is yet to be fully developed as a drug.

In 2009, the Assistant Controller of Patents & Designs rejected the application based on lack of therapeutic efficacy of the crystalline form as required by Section 3(d) of the Indian Patents Act, 1970 and lack of inventive step under Section2 (i) (j)(a) of the Patents (Amendment act) 2005.However, the counsel appeared for Schering submitted that there is no data available to be provided for the therapeutic efficacy.The Counsel for the applicant added that the invention is still in the development stage and argued that the claims and contents by the appellants produced were not properly considered by the Controller thereby the order failed to substantiate the reason for refusal of the patent. The counsel for the Controller replied that the reasons for refusals were included in the order and mentioned the Section 3(d) of the Patents Act, in connection to the case.


In an order issued by IPAB, the board stated that the Controller had passed a cryptic and wrong speaking order. IPAB also stated that the applicant was not given an opportunity to substantiate and discuss his claims and thereby rendering finding on each and every aspect. Pertinent to the present case, IPAB quoted Section 15 of the Patents Act, which reads hereunder:

“Where the Controller is satisfied that the application or any specification or any other document filed in pursuance thereof does not comply with the requirements of this Act or of any rules made there under, the Controller may refuse the application or may require the application, specification or the other documents, as the case may be, to be amended to his satisfaction before he proceeds with the application and refuse the application on failure to do so.”1

The aforesaid provision clearly indicate that the Assistant Controller resorted to passing judgment superficially rather than exercising his discretion in giving an opportunity to the applicant in making amendments in the application.

“The reading of the above said provisions makes it abundantly clear that the learned Controller ought not to have mechanically refused the application and on the other hand he could have exercised discretion to give opportunity to the applicant/appellant by making amendments in the application. As submitted by the learned counsel for the appellant to the effect that there is no data to be provided, the appellant could have given opportunity to make his submission by clearly stating that there is no question of providing any data and on the other hand, he could have given the opportunity to substantiate his claim on the basis of the documents produced by the applicant”. 2

Further, in substantiating the lack of inventive step ground, the board criticized the Controller for stating bald and vague reasons without getting into the details of the entire document.


A careful reading of the description of the corresponding PCT application (as the Indian application is not accessible in IPAIRS website) reveals that the bisulfate salt  of  vorapaxar  is  more  stable, exhibit  improved thermodynamic properties and consistent physical properties than its parent compound. It is worthy to note that the patentability of a crystalline polymorph form of a compound was a matter of dispute in relation with the Section 3(d) of the Indian Patent Act, in the matter of Novartis' Glivec patent application.

Keeping in mind, the lack of therapeutic efficacy as one of the reason for refusal of Schering’s patent it is pertinent to discuss in brief on Section 3(d) and interpretation of the term therapeutic efficacy. It is a well known fact that the concept of ‘efficacy’ is very vague under any patent regime in the world. Such an in-determinate status of ‘efficacy’ leaves discretion in application in the hands of the patent authorities which results in misconception, legal uncertainty, corruption thus leading to welfare loss. The Supreme Court’s decision on Novartis’s Glivac case made it crystal clear that efficacy in the context of Section 3(d) should be construed as therapeutic efficacy. . The interpretation of the word ‘efficacy’ is a pivotal factor with regards to Section 3(d). The main section requires ‘enhancement of known efficacy’ and the explanation section requires the derivatives ‘to differ significantly in properties with regards to efficacy’. The standard of proof regarding efficacy is an insurmountable requirement as there is an uncertainty regarding what quantum of ‘enhanced efficacy’ would be ‘significant’ as well as the properties regarding efficacy.

Though the section 3(d) requirements are territorial, the introduction of product patents in India since 2005 requires the foreign applicants via PCT to provide proof for efficacy along with their application. The current standard of proof required by the system is very unclear. Submission of pre-clinical trials or lab tests are easier as standards of proof rather than conducting full fledged clinical trials and generate results by that way (normal method to obtain drug regulatory approval)3. Comparing the efficacy of the substance with an earlier known substance is undependable and unethical.

Information pertaining to the therapeutic efficacy are gathered from clinical trials much later in the developmental process of a drug. Hence to provide information on clinical trails at the stage of filing of patent application is a tedious procedure. Also, carrying out full fledged clinical trials to establish efficacy during the discovery process before the filing of patent application would jeopardize the novelty aspect of the invention. The public disclosure of the clinical trails restricts the filing of results within a year of its disclosure. One year time is quite impossible to complete many clinical trials and hence makes the process burdensome.


With regards to Section 15, IPAB has implemented ‘Principle of Natural Justice’ by setting aside the order of the Assistant Controller and directed the Patent office to consider the matter afresh by affording sufficient opportunity to the applicant to substantiate or amend their claims.The second ground of contention in Schering’s case is the crucial therapeutic efficacy which is a serious matter of concern. Efficacy directly determines patentability and other related regimes such as Drugs (Control) Act, etc,. Though it is a cumbersome requirement of Section 3(d) of Indian Patents Act, proof of efficacy for the crystalline form of drugs is required for the applicants to surmount section 3(d) without the trepidation of their patents getting rejected/refused/invalidated in the hands of patent authorities.