Analysis of the Judgment on the Revocation Petition of Malladi Drugs & Pharmaceuticals' Patent [(T)OP(PT) No.45 of 2023]

The judgement involves a petition filed by Embio Limited (Petitioner) to revoke a patent granted to Malladi Drugs & Pharmaceuticals Ltd. (Respondent) under section 64 of The Patents Act, 1970 (hereinafter referred to as ‘the Act’). The patent IN 249376 (IN’376) in question titled "A method for the preparation of new chiral beta-amino alcohols from R(-)-phenyl acetyl carbinol" was granted to Malladi Drugs on 18.10.2011. Embio Limited challenged the validity of the said patent, alleging lack of novelty and inventive step, among other assertions.

Background 

The respondent’s patent filed on 25.06.2007, concerns the preparation of optically pure 1-phenyl-2-(N-alkyl/arylamino) propanol hydrochlorides. The method uses R(-)-phenyl acetyl carbinol as the starting material and involves a sequence of steps, including the use of noble metal catalysts, organic solvents, and hydrogenation under specific temperature and pressure conditions. The patent claims a high optical purity of 100% for the products, which are intermediates in the synthesis of various Active Pharmaceutical Ingredients (APIs).

Contentions of Petitioner

The petitioner, a pharmaceutical company known for manufacturing ephedrine and pseudoephedrine salts, challenged the patent on the grounds that the respondent’s invention was not novel u/s 64(1)(e) of the Act and did not include any inventive step u/s 64(1)(f). They claimed that the steps, reactants, and process parameters used in the patented method were well-known and had been documented in prior patents and literature, particularly in European patent no. EP 1 142 864 A1 and two U.S. patents (US2,509,309 and US2004/0249212 A1). The petitioner further contended that patent IN’376 did not meet the legal requirement of non-obviousness, as the method could have been easily derived by a person skilled in the art. Additionally, they claimed that the respondent did not provide sufficient experimental data or comparative examples to support their claims of technical advancement and optical purity. The petitioner further asserted to be a person interested since both the petitioner and the respondent are in the same industry, dealing with similar kind of medicines.

Contentions of Respondent

The respondent asserted that the claimed method represented a significant technical advancement in the synthesis of API intermediates having high optical purity (close to 100%) and high yield (60%-70%) which were far superior to those disclosed in the prior arts. Furthermore, the respondent has shown inventive step in as much as adopting a process for compounds which is different from ephedrine and its salts. The respondent contented that the petitioner can no longer rely on the originally filed claims as the claims were amended twice and the grant of patent was thereafter. 

The respondent also questioned whether the petitioner could be considered an “interested person” under Section 2(t) of the Act, as the petitioner had not shown any direct interest or actual harm resulting from the respondent’s patent. The patent had been published for several years without any opposition, which indicated, in the respondent’s view, that the patent was sound and justifiable.

Judgement

After considering the arguments from both sides, the Hon’ble Justice P.B. Balaji first addressed the issue of whether the petitioner qualified as an “interested person.” According to Section 2(t) of the Act, an interested person is someone engaged in the same field or promoting research related to the patent.  Further, in Aloys Wobben v. Yogesh Mehra [(2014) 15 SCC 360], the Hon’ble Supreme Court clarified the definition of "person interested" under the Act, stating that it includes anyone with a direct and tangible interest in the patented invention. In M/s. La Renon (CDJ 2019 MHC 868), this Hon'ble Court held that “person interested’ is an inclusive definition and merely because the Petitioner is not a manufacturer, he cannot be shut out from filing an application for revocation under Section 64(1)”. Pursuant to the cited judgements the court ruled out that the petitioner did indeed qualify as an interested party as both companies operated in the pharmaceutical industry and produced similar compounds. As such, the petition was considered maintainable. 

On the issue of novelty and inventive step, the court carefully examined the respondent’s patented process in comparison with the prior arts cited by the petitioner. It found that the claimed process did represent a technical advance, particularly in terms of achieving significantly higher optical purity (close to 100% compared to 82% achieved by the prior EP patent) and better yields (60-70% compared to 42.5% in US patent). Furthermore, the court found that the claimed process was simpler and more efficient than the methods outlined in the prior U.S. patents. The court also noted that the cited documents were significantly old (1950 and 1999), and that a minor development meeting a long-felt want may be non-obvious because, although prior art has been available, the development was not hit upon by others as observed by Delhi High Court in Societe Des Products Nestle SA [2023(95) PTC445(Del)].

The court ruled that the respondent’s patent demonstrated both novelty and an inventive step, as it provided a technical advancement over the prior arts. The inventive step was not obvious to a person skilled in the field, which justified the granting of the patent. As a result, the court concluded that the patent was valid and did not require revocation.

In dismissing Embio’s petition, the court emphasized the importance of demonstrating non-obviousness and technical advancement when challenging a patent. It highlighted the principle that even minor improvements can be patentable if they result in significant practical benefits, such as improved yield or purity. The case also reinforced the idea that the burden of proof rests on the party seeking to invalidate a granted patent. In post-grant challenges, the petitioner must provide compelling evidence of lack of novelty or inventive step, which the petitioner was unable to do in this case.

Ultimately, the court upheld the validity of Malladi’s patent, finding that the petitioner had failed to provide sufficient grounds for revocation. The ruling underscored the significance of non-obviousness in patent law and highlighted the importance of demonstrating a clear technical advancement in the face of prior arts.