A recent patent infringement case involving Roche’s Risdiplam[1], a critical drug for the treatment for Spinal Muscular Atrophy (SMA), has yet again sparked the debate about balance between patent rights and public health needs, highlighting the complex intersection of patent law and affordable health care. The Single Judge of the Delhi High Court rejected Roche’s plea for an interim injunction, and allowed Natco to manufacture the drug; with Natco liable to pay damages if the final verdict goes in Roche’s favour. Accordingly, directions were given to Natco to maintain complete accounts of the manufacture, sale, and supply of the products. While the judgment appears to prioritize public interest, it also adjudicates on other issues of pharmaceutical patents, particularly those involving genus and species patents. The present article provides a review of the Court’s ruling, examining both the legal challenges faced by the plaintiff and the broader implications for patent enforcement in the pharmaceutical sector.
Facts of the case
An infringement suit was filed by Roche (Plaintiff) against Natco (Defendant) alleging infringement of the Suit Patent IN334397 (IN’397) entitled “Compounds for treating Spinal Muscular Atrophy” that claims the Active Pharmaceutical Ingredient (API) Risdiplam. The Defendant was preparing for the commercial production of said API and had also filed an Indian patent application related to an improved process for the preparation of Risdiplam and its intermediates. During the proceedings of the case, the Court also allowed two interveners (patients suffering from SMA) to make their submissions, in view of the public interest involved.
The suit patent, IN’397 is a species patent of the genus covered by WO 2013/119916 (WO’916). The issues that were contested in this matter were: novelty, patentability i.e., subject eligibility, and relevance of statements made in foreign proceedings. The Plaintiffs argued that Risdiplam, the subject matter of IN’397, was not specifically disclosed in WO’916 and had been recognized as a new chemical entity with patent protection in over 60 countries, without facing any challenge. Roche also tried to impress upon the Court that foreign prosecution statements were irrelevant and highlighted their (plaintiff’s) efforts to ensure access through price reductions. The Defendant, however, alleged evergreening and unlawful patent term extension (by only filing the species and not the genus patent in India), asserting that IN’397 lacked enhanced efficacy over WO’916 and that statements made in foreign jurisdictions were relevant for assessing patentability. They also raised concerns over non-working of the patent in India. Interveners stressed upon the unaffordability of the drug (~₹1.48 crore/year), the inadequacy of government support, and urged the Court to prioritize public interest and the constitutional right to health by allowing local manufacturing to enhance access.
Analysis
A. Genus vs species and coverage vs disclosure conundrum: The Defendant challenged the validity of IN’397 on various grounds including anticipation and cited WO’916 and its corresponding US patent (US’955). The suit patent IN’397 relates to a compound of Formula (I), Risdiplam, and the anticipatory reference cited by the Defendant was of the genus patent related to said species patent. Therefore, the question was to analyse whether Risdiplam was explicitly or implicitly disclosed in WO’916. As per the Defendant’s submissions, the core structure of the compound of Formula (I) of the Suit Patent was disclosed in WO’916. Further, the teachings contained in said genus patent also disclosed Risdiplam. On the contrary, the stand of the Plaintiffs was that WO’916 did not specifically disclose Risdiplam, while it claimed a genus of compounds to which the Risdiplam belonged. Accordingly, the Court opined that it was an admitted position that the genus patent WO’916 and the species patent IN’397 related to the same product Risdiplam.
In this regard, the Court also observed that the Plaintiffs had filed an infringement suit in the US, enforcing the US genus patent (corresponding to WO’916) against a Defendant who was planning to launch Risdiplam. Accordingly, it was opined that the Plaintiffs could not assert non-disclosure of Risdiplam in WO’916 when it came to the suit ‘species’ patent. Reference was made to the Division Bench judgement in Astrazeneca vs Intas[2], wherein it was held that, “when a party has pleaded infringement of its genus patent, while claiming a species patent, at the stage of consideration of interim application, the same has to be treated as an admission that the invention in question was known while obtaining the genus patent.”
The next issue was with respect to the gap between ‘coverage’ and ‘disclosure’. While the Plaintiffs asserted that coverage and disclosure are different; the Defendant argued that there was no distinction between coverage or claim in the species patent and disclosure in the genus patent. Further, Defendant also submitted that in case of Markush claims, only fair disclosure is required and not express or specific disclosure. While contemplating on the same, the Court cited various judicial precedents to assert that coverage in a patent could not go beyond the disclosure and that a vast gap between coverage and the disclosure under a patent was never desired[3]. Further, based on settled judicial precedents, it was reiterated that disclosure could be either explicit or implicit/inherent in nature. To further elaborate on the concepts of ‘implicit disclosure’ and ‘inherent anticipation’ and clarify the position in law that “inherency operates to anticipate entire inventions as well as single limitations within an invention”[4]; reference was made to the judgements in Bayer Healthcare LLC Versus NATCO Pharma Limited[5] and Schering Corporation Versus Geneva Pharmaceuticals, INC. & Others[6]. Accordingly, an inherent disclosure was held to be a valid ground for challenging validity of a patent.
B. Plaintiffs’ admissions in foreign jurisdictions: For securing a PTE (patent term extension) for the US genus patent (US’955), the Plaintiffs had submitted to the USPTO that discovery of Risdiplam could be traced to said genus patent. Said admissions made by the Plaintiffs in the foreign jurisdictions were relied upon by the Defendant to argue that IN’397 was invalid. The Court observed that on one hand, the Plaintiffs were asserting their rights over the species patent by stating that WO’916 did not specifically disclose Risdiplam whereas on the other hand for securing PTEs, it was submitted that Risdiplam was covered and claimed in US’955, which is the counterpart of WO’916. Similar stance was taken before the Australian Patent Office also wherein it was admitted by the Plaintiffs that Risdiplam was in ‘substance generically disclosed’ in the Genus patent AU’870. Further, it was also observed that on the date of filing of the request for PTE for the US genus patent citing Risdiplam, the US species patent already stood granted. Additionally, in the US FDA (Food and Drug Administration) Orange Book Listing for Risdiplam, the product is claimed for the US Genus patent, which is equivalent to WO’916. Said fact was also found to be evident from the letter written on behalf of the USPTO to the Food and Drug Administration. Similar statements were also made in connection with the Canadian genus patent regarding patent rights over Risdiplam. Accordingly, the Plaintiffs were deemed to be taking inconsistent stances.
The Court, relying on the Supreme Court’s judgement in Novartis AG Versus Union of India and Others[7] as well as Astrazeneca AB and Others Versus P. Kumar and Another[8], held that while determining if a credible challenge has been raised by the Defendant during the application for interim injunction, the statements/conduct in foreign jurisdictions are material and relevant.
C. Test for obviousness: While determining obviousness of IN’397 in view of WO’916, it was observed that four of the inventors of WO’916 and IN’397 were common. Accordingly, placing reliance on the judgement in Astrazeneca AB and Another Versus Intas Pharmaceutical Limited (DB)[9], it was held that the test of obviousness here would be seen in the context of a ‘person in the know’ and not in the context of ‘person ordinarily skilled in the art.’
Further, the Court noted that the Defendant had relied upon ‘Compound 809’ of WO’916. On comparison, the primary distinction between Risdiplam and Compound 809, was observed to be the presence of Nitrogen in Risdiplam and a CH group in Compound 809, at same position. It was observed that the compounds disclosed in WO’916 have both pyrimidine and pyridine as constituents, indicating that Nitrogen is a critical component. The Court held that since Nitrogen and CH groups are often considered bio isosteres, a person skilled in the art/a person in the know could be easily motivated to replace Carbon atom with Nitrogen. Accordingly, IN’397 was found to be obvious and the Court held that a credible challenge to the validity of the suit patent was laid down by the Defendant.
Further, the Court observed that Plaintiffs are not manufacturing Risdiplam in India and are importing the same, the drug is not available at affordable prices and only a miniscule number of patients are being helped by the Patient Assistance Programs, hence the balance of convenience was held to be in favour of the Defendant. The Court concluded that the Plaintiffs can be compensated by damages, if they succeed in trial, and accordingly, the injunction was not granted.
Conclusion
As evident from the discussion above, pharmaceutical patents suffer from various challenges in view of the nature of the invention, necessitating consideration of several factors such as:
a. Drafting of specification: Dealing with claims having Markush structures can be tricky, especially when multiple patent applications are filed relating to the same or similar subject matter. Accordingly, drafting of specifications is crucial. When drafting an application for a ‘species’ patent, it must be ensured that scope of protection of a ‘species’ patent be justified and that the claimed subject matter has technical advancement over the genus patent, as evidenced from the supporting data. In the present matter, it was argued by the Defendant that since the species patent did not disclose any technical advantage/enhanced therapeutic efficacy over the genus patent, it cannot be patented. Accordingly, due care must be taken to satisfy said requirement. Mindful disclosure is perhaps the key. Additionally, it must be noted that if the genus and the species patent applications have common inventors, the test of obviousness would be in the context of ‘a person in the know’ and not ‘a person skilled in the art.’ The bar is higher and the inventive merit of a species patent must thus, be accordingly justified.
b. IP filing strategies: The filing strategies must be suitably devised taking into consideration major markets. In the present case, while the genus patent was filed in major jurisdictions like the US, Canada and Australia, somehow, no corresponding genus patent was filed in India, where only the species patent was filed.
c. IP enforcement strategies: Coverage and disclosure conundrum is very common in pharmaceutical patents where a genus patent is filed covering a broader class of compounds and a species patent pertains to specific compounds or embodiments. It is an established position of law that coverage and disclosure are not same[10] and that filing an infringement suit for enforcing both the genus and species patent indicates that the species is covered in the genus patent. In the present case, while no genus patent was filed in India, infringement suit was filed for enforcing the genus patent in the US while in India, species patent is being enforced. Such situations must be pre-empted and strategies must be accordingly devised.
d. Admission in foreign jurisdictions: This turned out to be problematic in the present case. The doctrine of prosecution history estoppel is well known, and when dealing with a large patent portfolio, taking contradictory stances in various jurisdictions must be avoided.
While consideration of the factors stated above, it also needs to be noted that corresponding patent applications of IN’397 have been granted in several jurisdictions and that both genus and species patents co-exist in various jurisdictions. While there is no presumption of validity of a patent in India, it is not so in many other jurisdictions. The fact that the suit patent has been duly examined and granted by so many Patent Offices, certainly goes in its favour.
An appeal was filed in the matter by the Plaintiff, wherein the Divisional Bench ordered a status quo to be maintained regarding launching of the product by the Defendant. The matter is currently being heard and is pending final adjudication.