In an important decision, Justice Senthilkumar Ramamoorthy, discussed Section 3(d) of the Patents Act, 1970.[1] The case involved a patent application no. 7096/CHENP/2015, which claimed priority from the US application number 61/815,502 dated 24 April 2013. The patent application claimed two polymorphic forms—A and B—of a compound RTA-408. Compound RTA-048 was claimed and granted in the Indian Patent Application No. 8486/DELNP/2014.[2] The patent application 7096/CHENP/2015 was refused essentially on the grounds of being not patentable under Section 3(d) of the Indian Patents Act.
The primary issue the court discussed was whether Section 3(d) would apply in this case. Section 3(d) of the Patents Act, 1970, considers as non-patentable “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.” For the purposes of this clause, salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations, and other derivatives of known substance are regarded as the same, unless the efficacy in properties is significantly different.
In the present case, the appellant contended that the claimed invention relates to the polymorphic forms of a parent compound known as RTA-40. The appellant elaborated that the claimed forms exhibited technical advancement over existing knowledge and showed greater stability and superior anti-inflammatory, anti-oxidative and anti-proliferative properties. This parent compound, however, was made public (publication date—31 October 2013) after the priority date (24 April 2013) of the claimed invention. In this factual context, RTA-408, thus did not qualify as a “known substance” for the purposes of Section 3(d) and the patent/patent application disclosing RTA-408 did not qualify as prior art. Further, with regard to the controller referencing in the refusal to the compounds 402-38 and TX-63682 as a “known substance”, the appellant submitted that the claimed invention was not in respect of the polymorphic forms of 402-38 and TX-63682; therefore, any reference to 402-38 and TX-63682 for Section 3(d) was incorrect
The appellant further submitted that even de hors Section 3(d), the claimed invention exhibited technical advancement and that its IC50 value was higher than that of TX-63682.
The court highlighted the three limbs of Section 3(d):
- 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.
- the mere discovery of any new property or use of a known substance.
- 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 held that of the first two limbs of Section 3(d) related to “known substance,” the first was relevant to the case. It agreed with the appellant’s contention that the compound RTA-408 did not qualify as a “known substance” for the purposes of Section 3(d), as the said compound was known/available to the public only after the priority date of the patent application 7096/CHENP/2015. The court also held that the claimed polymorphic forms would also not qualify as a new form of compounds 402-38 or TX 63682 disclosed by cited art. RT-408, whose polymorphic forms are claimed in the patent application 7096/CHENP/2015 have specific structural differences from the compounds 402-38 and TX 63682. The court held that while the claimed invention contains additional fluorine atoms compared with the compound 402-38, it is also structurally different from the compound TX-63682 in that it contains a di-methyl substitution. The court, therefore, concluded that since the claimed invention is not “a new form of a known substance,” the applicant does not need to overcome the Section 3(d) requirement.
The court acknowledged the inventive step of the claim by observing that the polymorphic forms show enhanced anti-inflammation activity and anti-oxidation, increased expression of nuclear factor, increased glutathione levels, greater stability, and have a solvent-free nature without toxic chemicals. The court found no reason why a person skilled in the art could not pick the compound TX-63682 out of 100+ compounds disclosed in the cited documents to arrive at RT 408 by adding a methyl substituent in position 4a and eventually compose its claimed polymorphic form. The court held that without the benefit of hindsight, the appellant could not have arrived at the present compound without any inventive step.
For further information, please contact:
Swati Sharma, Partner, Cyril Amarchand Mangaldas
swati.sharma@cyrilshroff.com
[1] 2023:MHC:5451
[2] IN 345058
