“Known Substance” Must be Disclosed Before the Date of Priority for Section 3(d) of Patents Act: Madras High Court

“Known Substance” Must be Disclosed Before the Date of Priority for Section 3(d) of Patents Act: Madras High CourtNon-patentable inventions are always a bone of contention between the applicant and the patent office. The patent office tends to interpret the provision with maximum coverage; on the other hand, the applicant always insists on taking a more liberal approach so that their invention may not fall under the provision related to non-patentability. The interpretation of section 3(d) is of utmost importance as it aims to prevent the “evergreening of patents” in India. The Madras High Court recently gave the interpretation in this context in the matter of Mr. Tony Mon George, constituted attorney of ABBVIE Inc., Vs. Deputy Controller of Patents & Designs. In this matter, ABBVIE Inc. (the applicant) filed a patent application no. 7096/CHENP/2015, which relates to two polymorphic forms of RTA-408. The compound RTA-408 was granted a patent under Indian Patent No. IN345058, which is based on Indian Patent Application No. 8486/DELNP/2014, filed by Reata Pharmaceuticals Inc. The Controller has refused to grant the application vide order dated 18 September 2020. Aggrieved by this order, the applicant then approached the Madras High Court to set aside said order of the Controller of Patents & Designs.

The counsel for the applicant argued that the patent application relates to two polymorphic forms, Form A and Form B, of compound RTA-408. As per the applicant, these two polymorphic forms exhibit technical advancement over the existing knowledge as they possess greater stability and are solvent-free; these properties are in addition to the superior anti-inflammatory, anti-oxidative and anti-proliferative properties. The counsel for the applicant argued that the publication date of the patent for compound RTA-408 was 31 October 2013, whereas the priority date of the patent application 7096/CHENP/2015 is 24 April 2013. It was argued that RTA-408 does not qualify as a “known substance”, and the patent document related to RTA-408 does not qualify as a valid prior art, as it was published after the date of priority of the patent application in question.

The counsel also argued for the applicant that the Controller has erred in comparing the compounds of the present application with the compounds 402-38 and TX-63682. Further, it was argued that the corresponding patent applications in jurisdictions like the USA, Japan, Europe and China, in view of the same prior art documents D2 and D3. The counsel points out that the Controller has differed from the written opinion provided by the International Search Authority (ISA) without giving any cogent reason. The ISA has classified both the prior art documents D2 and D3 under the “A” category. With respect to inventive step objection, in view of the disclosure of D3, the counsel referred that if the intention of the person skilled in the art is to identify the compound with low IC50 values with regard to IFNy-induced nitric oxide (NO) production, the person will then select compounds such as TX-63522, TX-63558, TX-63811, TX-63914, TX-63925, TX-63928 and TX-63929, as these compounds exhibit lower IC50 values and the person skilled in the art will not select TX-63682. The reliance was placed on the Honorable Delhi High Court judgement in Roche V. Cipla, 2015, SCC Online Del 13619.

The counsel representing the Controller of Patents & Designs argued that document D2 disclosed compound 402-38, and the difference between the claimed compound and document 402-38 is the addition of fluorine atoms in claimed compounds. Also, it was stated that the enhanced stability and the solvent-free nature of forms are inherent characteristics and thus cannot be claimed as technical advancement. It was also argued that the compound TX-63682 is a known substance for the claimed compounds as the only difference between the compounds is di-methyl substitution, which is present in claimed compounds. It was pointed out that the applicant failed to demonstrate significant improvement in efficacy or technical advancement over the known substance. With respect to the inventive step, it was argued that the IC50 values of the claimed invention are higher than TX-63682, which indicates that the claimed compound possesses lower effectiveness in inhibiting inflammation.

For composition claims, it was argued that the applicant failed to show any synergy between the ingredients of the composition. The composition is thus the result of the sum of its parts. Therefore, the composition claimed by claim 7 is not a patentable subject matter as per section 3(e) of the Patents Act.

The Court held that section 3(d) has three limbs separated by the disjunctive “or’. The three limbs are as follows:

(i) the mere discovery of a new form of a known substance which does not result in the enhancement of the known efficacy of that substance.

(ii) the mere discovery of any new property or use of a known substance.

(iii) the mere use of a known process, machine or apparatus unless such known process results in a new product or employs at least one new reactant.

The Court mentioned that the first two limbs of the provision are related to known substances. While discussing the applicability of the first limb in the present matter, the Court agreed with the contention of the applicant that the compound RTA-408 does not qualify as a known substance for the purposes of section 3(d), as the compound was known to the public after the priority date of the claimed compounds.

The next question considered by the Court was whether the polymorphic forms qualify as new forms of either 402-38, as disclosed by prior art D2 or TX 63682, as disclosed by prior art D3. In this regard, the Court held that polymorphic form is a substance where two or more crystalline forms have “identical chemical composition”. Thus, the Court stated that the claimed compounds are not a new form of 402-38 or TX 63682, as the claimed compounds have specific structural differences from these compounds 402-38 and TX 63682. The Court further explained that the explanation to section 3(d) also refers to other derivatives such as salts, ether, metabolites, etc. However, the Controller has not placed the claimed compound under these categories. Thus, the Court concluded that the claimed invention is not a new form of a known substance, and therefore, it is not required by the applicant to overcome the section 3(d) requirement. However, the requirement of an invention, as per the Act, must be satisfied.

While discussing the inventive step, the Court held that the polymorphic forms show enhanced anti-inflammation activity, enhanced anti-oxidation, increased expression of nuclear factor, increased glutathione levels, greater stability and solvent-free nature without toxic chemicals. All these features are defined under the “pharmacodynamics” heading of the complete specification. Compound RT 408 is available on the market as Omaveloxone, and the US FDA has approved the same for the treatment of Friedriech’s Ataxia. Compound RT 408 possesses all the above-referred advantages except greater stability and a solvent-free nature without toxic chemicals. The Controller was of the opinion that these properties are inherent characteristics of the crystalline form of any compound. Also, the Controller believed that the IC50 value of TX 63682 is lower; thus, the compound has greater potency regarding the suppression of IFNy-induced NO production.

The Court also considered the argument presented by the applicant that many compounds disclosed in D3 have a lower IC50. The Court held that there is no reason why a person skilled in the art picked the compound TX-63682 out of 100+ compounds and arrived at RT 408 by adding a methyl substituent in position 4a. While acknowledging the inventive step of the claims, the Court held that without the benefit of hindsight and the resultant recognition of TX-63682 as a structural analogue, it does not appear to lack an inventive step.

While allowing claims 1 – 6 of the patent application, the Court reaffirmed that section 3(d) is not applicable as RT 408 is not a known substance for the polymorphic form. The Controller addresses the issue of evergreening and states that in the present case if granted, the term of the patent exceeds by only one year. Also, the Court held that D3 does not detract from the technical advancement of the claimed invention or render it obvious. The Court refused composition claim 7 on the grounds that there is no demonstration of any synergy between the ingredients.

This judgment has further defined the scope of section 3(d), and a very interesting fact has been added that to qualify as a “known substance”, the substance should be in the public domain before the priority date of the application. Also, the judgement provides that for the assessment of the inventive step, no hindsight analysis has to be done, and proper reasoning has to be provided for selecting any prior art compound for sighting the lack of the inventive step. This judgement will have a significant impact on the pharmaceutical patents. It would be interesting to watch how this judgement will help pharma companies design their strategy to get a patent on polymorphs, which is otherwise barred under section 3(d).

Authors: Manisha Singh and Avi Garg

First Published by: AsiaLaw Here