Section 3(d) of the Indian Patents Act – Part II

This is part II of a two part posting examining Section 3(d) of the Indian Patents Act.  Part I examined the genesis of Section 3(d).  This post provides patent drafting strategies to reduce the risk of receiving a Section 3(d) objection as well as overcoming such a ground of objection if received during prosecution and/or an opposition.

Section 3(d) provides that inventions that constitute the “mere discovery of a new form of a known substance which do not result in enhancement of the known efficacy of that substance” do not constitute patent eligible subject matter.  According to the explanatory note, inventions directed to salts, esters, polymorphs, metabolites, pure forms, new forms having a certain particle size, isomers, mixtures of isomers and derivatives of known substance are patent ineligible unless these new forms “differ significantly in properties with regard to efficacy”.

The term “efficacy” is defined in Webster’s dictionary as “the capacity to produce an effect”.  In the Glivec decision, the Indian Supreme Court took a much narrower view of the term “efficacy”, saying that for drugs administered to treat diseases, “efficacy” meant “therapeutic efficacy”.  Additionally, the Supreme Court stated that evidence demonstrating a link between an increase in bioavailability for a new form and an increase in therapeutic efficacy could be used to avoid or overcome a Section 3(d) objection.  In fact, in an order dated November 29, 2012, the Controller for Patents found that a patent application claiming a beta form of Rifaximin (106/DELNP/2008) was new and did not constitute patent ineligible subject matter under Section 3(d).  In this case, the Applicant (Alda Wassermann, S.P.A), in order to overcome an objection raised under Section 3(d), submitted an affidavit that provided data proving that the beta form of Rifaximin B had an in vivo absorption level that was about 100 times less than Rifaximin (which was disclosed in U.S. Patent No. 4,341,785 and was the closest prior art), thereby resulting in a reduction of the toxicity 100 times due to absorption (this fact had been disclosed on page 5 of the specification as originally filed).  Therefore, although the beta form of Rifaximin had a similar effect as Rifaximin, it was 100 times less toxic and showed enhanced efficacy over the prior art.

Given the importance of the Indian market for pharmaceuticals, it is important for patent drafters to keep Section 3(d) in mind when drafting patent applications for new forms of known substances, particularly if there is a desire to ultimately file and prosecute such applications in India.

When drafting a patent application for a new form of a known substance, it is important to include in the specification as much detail regarding the novel properties, which establish the enhanced therapeutic efficacy of the new form.  It would also be helpful to include a comparison of the properties of the new form with those of the closest prior art.  Most importantly, it is recommended to include in the specification data that establishes a link between the properties of the new form and enhanced therapeutic efficacy of that form.  Also, the improvement in therapeutic efficacy should be significant and should not merely be an incremental improvement when compared to the closest prior art.  What constitutes a “significant” improvement will need to be determined on a case-by-case basis and will depend also on the prior art.

In many instances, however, data demonstrating an improvement in therapeutic efficacy will simply not be available at the time of filing.  If the drafter finds him or herself in this situation, it is recommended, as mentioned above, to include in the specification as much detail as possible regarding the new properties of the new form along with a comparison to the closest prior art.  Once the application is filed at the appropriate Patent Office, it would be advisable to begin generating data to demonstrate the enhanced therapeutic efficacy of the new form compared to the closest prior art.  Such data could be submitted in an affidavit during prosecution, if the Examiner raises a Section 3(d) objection.

Strategies for responding to a Section 3(d) objection raised during  prosecution and/or an opposition will depend on the data contained in the application as well as the prior art.  If the application as filed contains data demonstrating improved therapeutic efficacy for the new form and this improvement is significant over the prior art, the Applicant should respond to the Examiner by specifically pointing to the parts of the specification that disclose such data.  Additionally, consider filing an affidavit by an expert in the field attesting that in his/her opinion that the data in the specification clearly demonstrates improved therapeutic efficacy of the new form over the prior art.  Further, consider filing a request to schedule a hearing (namely, an interview) with the Controller in order to discuss the data in the specification so as to facilitate his or her understanding as to why the new form does not constitute patent ineligible subject matter under Section 3(d) and thereby overcome the objection raised. 

If the specification does not contain any data demonstrating improved therapeutic efficacy of the new form over the prior art, the applicant will need to file an affidavit with this data.  However, it is important to note that any post-filing data demonstrating improved therapeutic efficacy must find some basis for support in the specification of the application as originally filed.  Although, not explicitly worded in the Indian Patents Act, it is preferable to provide as much data demonstrating the enablement of the invention at the time of filing as possible. Without such data, the likelihood of overcoming a Section 3(d) objection during prosecution and/or an opposition is reduced.  With respect to such an affidavit, the affidavit should contain a detailed description of the experiments or clinical trials conducted and the results clearly establishing enhanced therapeutic efficacy of the new form over the prior art form.  The affidavit should include a comparison of the results with the new form and the closest prior art.

As shown in the case involving Indian Patent Application 106/DELNP/2008, it is possible to overcome a Section 3(d) objection.  The key is presenting the appropriate data to the Indian Patent Office to demonstrate the enhanced therapeutic efficacy of the new form over the closest prior art.  Applicants should have a strategy for providing and presenting this data prior to the start of prosecution in the Indian Patent Office in order to maximize their chances for allowance.

This post was written by Anthony Wenn, Lisa Mueller and the attorneys at Chadha & Chadha.

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