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Singapore: Patent can be amended when its validity is being challenged

29th January, 2013

In the case of Novartis AG and another v Ranbaxy (Malaysia) Sdn. Bhd., the High Court of Singapore allowed Novartis AG the leave to amend the claims of its patent although the validity of the patent is being challenged by Ranbaxy (Malaysia) Sdn. Bhd.

Novartis AG (hereinafter referred to as ‘the Plaintiff’) is the registered proprietor of the Singapore Patent No SG 120119 (hereinafter referred to as ‘the Patent’). Ranbaxy (Malaysia) Sdn. Bhd. (hereinafter referred to as ‘the Defendant’) is a subsidiary of Ranbaxy Laboratories Limited, India. The Defendant has a huge production facility in Malaysia which is used as the production hub for drugs for the South East Asian market. The Defendant sought to export pharmaceutical tablets into Singapore, the composition of which relate to the Patent.

Under Section 12A(3)(a) of the Medicines Act of Singapore, a party who is applying to market a drug that is patented in Singapore has an obligation to inform the patent owner that they are applying for a drug marketing license from the Health Sciences Authority (HSA) of Singapore which could potentially infringe a Singapore Patent and that the patent owner ought to commence the necessary action before the High Court within 45 days to assert its rights under the Patent and to obtain necessary relief from the court, failing which the relevant drug marketing license would be granted to the party applying for the license.

In this case, after the receipt of the notice from the Defendant, the Plaintiff asserted that if the licenses sought were granted and the Defendant’s products were imported and marketed in Singapore, the Patent would be infringed. However, the Defendant asserted that the Patent was invalid because the invention disclosed in the Patent had been anticipated in the prior art, uncovered during the prosecution of a corresponding patent application at the European Patent Office (EPO). In response, the Plaintiff sought to amend the Patent claims to further distinguish the claims from the matter disclosed in the prior art.

The High Court first set out to decide whether the amendments to the patent claims add new subject matter to the application as filed. As a threshold issue, both the parties argued that the other’s expert witness was not sufficiently qualified. The Plaintiff argued that the Defendant’s expert was a patent agent with a degree in chemistry but no practical experience in the formulation of tablets. The High Court stated that although the Defendant’s expert lack practical experience in tablet formulation, it did not per se mean that the Defendant’s expert was unable to assist the court, since he could and did comment on matters which relate to his expertise as a patent attorney who often act for companies relating to pharmaceutical patents in the matters before the EPO. However, the High Court conceded that the Defendant’s expert’s opinion was at best of limited utility.

The Defendant had also alleged that the Plaintiff’s expert evidence should be disregarded as he had no practical experience in relation to whether an amendment to the Patent would add matter, and had never given expert evidence on a related issue before. The Court rejected this objection stating that the Plaintiff’s expert had more than 35 years experience in research and development in tablet formulation, and therefore was clearly a person skilled in the art and in a position to assist the court in assessing whether the amendment to the Patent claims would add matter to the application as filed.

On the issue of the Patent claims, the Defendant argued that the Patent claims taught use of the compound Valsartan in the form of a salt and not in free form. However, the High Court stated that the presence of Valsartan in free form had been clearly and without doubt disclosed in the application as filed. The Plaintiff argued that the proposed amendments to disclose that Valsartan in free form is to be the only active agent in claims 1 and 5 have been clearly and unambiguously disclosed in the original specification which disclosed the invention of tablets comprising Valsartan as the active agent. However, the Defendant submitted that the specification does not expressly disclose the teaching that Valsartan is to be included in free form as the only active agent. The High Court rejected the Defendant’s submission stating that the examples listed in the application as filed of preferred compositions consisted of Valsartan in free form as the only active agent.

The Defendant further argued that limiting the disclosed proportion of Crospovidone from 2-13% to 2-10% amounted to addition of matter. The Plaintiff argued that the composition of the invention comprising 2-10% Crospovidone had been disclosed in the patent specification. The High Court rejected the Defendant’s argument stating that the Defendant, at no point, informed the court as to what exactly was the nature of the added matter which would be added to the disclosure and that this amendment by the Plaintiff would, in fact, lead to narrowing and not expansion of the scope of the Patent.

The Defendant then proceeded to allege that the combination of various teachings i.e. the teaching of the combination of 20-65% Valsartan with 31-65% Microcrystalline Cellulose and 2-10% Crospovidone, while disclosed in examples 7, 8, 9 and 11 of the specification, were not disclosed clearly and unambiguously in the specification of the application as filed, and thus, if the amendments were allowed, matter would be added. The High Court refuted this claim stating that the principle of intermediate generalization seeks to answer whether a person skilled in the art would learn something new which had not been disclosed in the application as filed. The High Court further rejected the Defendant’s claim that a person skilled in the art would need to mix and match to generate a hybrid which is not apparent from the patent specification and therefore does not clearly and unambiguously disclose the invention. Hence, the High Court acknowledged that the proposed amendments to the claims would not amount to adding matter which has not been disclosed in the application as filed.

Next, the Defendant argued that there was an undue delay on the behalf of the Plaintiff in applying for the amendments. The Defendant contented that the Plaintiff could have applied for the amendments upon seeing the prior art in 2009 which would have necessitated an amendment; yet the Plaintiff waited until after the Defendant served its notice to the Plaintiff in 2011. Therefore, such delay amounted to taking unfair advantage of the Patent and as such the Court should refuse the leave to amend. The Plaintiff counter-argued that after 2009, they had proposed the inclusion of disclaimers to overcome the objections of the third parties, and that the process of resolving the matter had been ongoing, even up to the point when the Defendant served its notices on the Plaintiff. The Plaintiff also submitted that it would not be reasonable to expect the Plaintiff to amend their specifications for patents filed worldwide the moment prior art has been raised in one jurisdiction. The High Court sided with the Plaintiff stating that as the Plaintiff believed and successfully prevailed in the opposition proceedings at the EPO, it was unfair to state that the Plaintiff made undue delay in relation to the Singapore Patent.

The Defendant further argued that the Plaintiff had taken advantage of the wider claims of the Patent, as the Plaintiff had commenced infringement proceedings on wider claims than the amended claims. However the High Court stated that the Plaintiff cannot be expected to wait until after the leave amend is granted to commence an action of for declaration of infringement.

Consequently, the High Court of Singapore granted the Plaintiff the leave to amend the claims in the Patent.