Novartis vs Silom Medical: Summarising the Valsartan case in Thailand

by | Jun 22, 2018

Valsartan is known in the pharmaceutical industry as the drug for treatment of high blood pressure.

In the infringement action filed by Novartis against Silom Medical in relation to Valsartan and the patent of “solid oral dosage form”, the main issues before the Central Intellectual Property and International Trade Court (Thailand) to be considered are:

  1. Whether the first plaintiff has capacity to bring this action to court;
  2. Whether the Thai patent number 18749 is not valid and shall be revoked;
  3. Whether the first plaintiff does not have legitimate right to file this patent application in Thailand as at the time of filing in Thailand, the right to the patent application has not been assigned to the first plaintiff yet;
  4. Whether all the defendants had infringed the Thai patent (number : 18749) claims 1,2,4-7 and 38-41 on the pharmaceutical product and claims 18-35 on the manufacturing process;
  5. If the answer to no. 4 is yes, what are the damages that occurred the first plaintiff and whether all the six defendants shall be held liable for those damages and how much should they be liable for.

The Central IPIT court ruled that the patent is valid but there was no infringement of patented product.(Red case no. 81-82/2555). Both plaintiff and defendant appealed to the Supreme Court – IP division (acting as appeal instance) (Supreme Court case no.9832-9833/2560). This article will focus on the Supreme Court’s discussion in relation to right of priority, novelty and inventive step assessment.

Right of priority

The first plaintiff filed the patent application in Thailand on June 16th 1997, claiming priority from the patent application GB9613470.5 which was filed on June 17th 1996 in the United Kingdom.

The question relating to priority claim arose as, on the filing date in Thailand, the first plaintiff’s representative could not provide the power of attorney at the time of filing (allowed with 90 days extension of time). The issue was related to the inventor’s assignment of right to the applicant since not all the inventors had assigned the right before the date of filing in Thailand.

The Supreme Court deemed that an assignment by 2 out of 5 inventors is enough and constitutes a legitimate right to the assignee to file patent application. If all the inventors have to agree and authorise the assignment, it will be very cumbersome as some inventors might not be reachable and can prevent the assignment. This shall not be the underlying purpose of section 10 paragraph 2 and section 15 paragraph 1 and 3 of Thai patent act.


The court has defined the scope of protection limiting to the products resulting from dry granulation which are agreed by both parties.

The main assessment of novelty is to make the assessment of prior art disclosure. The defendants did not provide enough proof to show that the patent US6,071,931 can be considered as prior art. Hence, there is only one closest prior art to be considered:  US5,399,578.

The court laid down the assessment of novelty. One shall find differences between the patent in suit and the prior art if there is any technical feature that is different from the prior art, the invention shall be deemed as novel.

The court accepted the fact presented by the parties that the Thai patent in dispute is concerned with

Thai patent US patent ‘578
Product invention of tablet drug containing the active ingredient “Valsartan” or pharmaceutically acceptable salt thereof with more than 35% active ingredient by weight of the gross weight and at least one pharmaceutically acceptable additive. Product invention of Acryl compounds with description and claims in relation to chemical and physical properties of Acyl compounds and derivatives thereof
The process of forming the aforementioned the dosage comprises of the steps of
1) grinding the active agent and additives,
2) compressing mixture of the ground active agent and additives to form a comprimate
3) converting the comprimate into a granulate and
4) compressing the granulate to form tablet by dry granulation with roller compactor or slugging
Synthesis and synthetic method, molecule model composition


Bearing in mind that Valsartan is a substance in Acryl compound group and the patent ‘578 discloses probability of including Acryl compound in different drug forms, the court considered the invention is novel as the US patent does not disclose the product and method of manufacturing tablet with Valsartan in the same way as can be seen from the description and claims of the Thai patent.

Additionally, the disclosed range and the patented range of the quality of the active ingredient are different.  

Thai patent US patent’ 578
the use of active ingredient more than 35% by weight with preferred quality of more than 50% by weight of the tablet. When comparing the whole weight of the tablet, the active ingredient could be adopted between 45% to 65% e.g. between 57% to 62%. between 10-80% with further preferred quality of 20-60% by weight and the calculation of active ingredient by weight have results at 34.5 and 35.3%.


As such, the description and claim of the Thai patent are more specific and different from the information disclosed in the US patent.

In relation to the manufacturing method, considering column 26 and 27 of the patent ‘ 578 they provide examples of different form of drugs in combination with example 92th and 93th, those informations do not suggest specifically which form of medicine should people produce using Acryl compounds and what are the reasons behind those suggestions. The main difference is that example 92th and 93th referred to wet granulation while the process claimed in Thai patent is dry granulation and the process detail in the Thai patent is clearer and more specific than the information in the US patent. The information shows the functions or effects that is more advantageous from existing invention.

Therefore the patent in suit for both product and process claim has main claims that are different from disclosed information by the patent ‘578 which is the prior art. Claim 1,2,4-7,38-41 for product claims and claim 18-25 for process claims are considered to be novel.  

Inventive step

The court underlined the assessment of obviousness that it is a technical question which shall be considered based on testimonials of knowledgeable witnesses that are not relating to any parties of the case.

The testimonials of some of the expert witnesses of the plaintiff and the defendant were not admissible due to past experiences and relation with the parties. For example, one of the witness is considered :

  • to be a patent expert rather than an ordinary skill person in pharmaceutical industry ;
  • to have direct relationship with one of the party.

Additionally, there was no evidence from the plaintiff showing that the formulas disclosed in the patent ‘578 are not workable as well as there is no proof that there are failed attempts by using the teaching from the prior art.

The defendant has provided court with more convincing witnesses and evidences and the invention in dispute shall be considered obvious. Therefore, based on Thai Patent Act B.E. 2522 section 54 para. 1, section 5(2) and section 7,the Thai patent 18749 is not valid as it does not involve inventive step and The Supreme Court shall reverse the decision of the Central IP court in relation to inventive step.


In this case, there is a small discussion in relation to skilled person and one of the expert witness that the defendant has included, the court had denied to accept him as the skilled person in relation to pharmaceutical industry and emphasized that the person has more experience in patent litigation rather than pharmacy.

In recent case from Central IP court (Red case 195/2560 (2017)) that decided on pharmaceutical-related patent, the court has actually laid down the definition of skilled person in the art.  The court moved on in the discussion with the principle of “hypothetical person” which is so called “reasonable man”. The court considered that the principle of skilled person should be compared to reasonable man’s interpretation by Thai courts.

Inventive step should be linked to the obviousness as regard to the ordinary skilled person in that specific art wherever the R&D institute is situated. Usually R&D personnels in scientific and technology institute hold PH.D. in that specific field and continue to do R&D but they might lack imagination or creativity. (The court referred to Windsurfing International Inc. v Tabur Marine (GB) Ltd. [1985] RPC 59). These people are skilled person in the art until they can create or invent non-obvious invention in their field.*

Hence, the reasonable person standard in relation to skilled person in the art for pharmaceutical industry which work in R&D department should have studied and done research in the work of PH.D. level, persevere with the disputed work but lack imagination and has no obstacle in accessing pharmaceutical English, has access to all academic information disclosed before first filing date.

*Author’s Note:

The court at the end rejected the standard of skilled person qualification by the plaintiff that the skilled person in organic chemistry and pharmaceutical industry should hold a bachelor degree in pharmacy and have approximately 2-3 years experience in pharmaceutical industry as well as the standard that was presented by the defendant that the skilled person should have 4-5 year of experience more so that they can create formulations.


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