Case Details
- Citation: [2023] SGHC 360
- Court: High Court (General Division)
- Suit No: 817 of 2019
- Date of Decision: 29 December 2023
- Judgment Reserved: Judgment reserved (date not specified in extract)
- Judges: Dedar Singh Gill J
- Hearing Dates: 19–20, 22, 26–27 October 2021; 27 February 2023; 5 May 2023
- Title: Millennium Pharmaceuticals, Inc. & Anor v Zyfas Medical Co (Sued as a firm)
- Plaintiffs/Applicants: (1) Millennium Pharmaceuticals, Inc; (2) Johnson & Johnson Pte Ltd
- Defendant/Respondent: Zyfas Medical Co (sued as a firm)
- Legal Area(s): Intellectual Property — Patents and inventions (Validity, Infringement, Licences)
- Statutes Referenced: Not specified in the provided extract
- Cases Cited: Not specified in the provided extract
- Judgment Length: 200 pages; 51,956 words
- Patents in Issue: Singapore Publication No. SG 151322 (“SG 322”); Singapore Application No. SG 10201600029P (“SG 29P”)
- Key Context: Process patents for the manufacture of bortezomib (a cancer drug). Bortezomib itself is not protected by a product patent in Singapore.
- Procedural History (high-level): Related applications included (i) HC/OS 1034/2019 (declaration re false/misleading statements under reg 23(2) of the Health Products (Therapeutic Products) Regulations 2016); (ii) HC/OS 264/2021 (judicial review of HSA decision to maintain registration of the alleged infringing product); (iii) HC/SUM 2368/2020 (striking out proceedings).
Summary
In Millennium Pharmaceuticals, Inc v Zyfas Medical Co [2023] SGHC 360, the High Court considered a dispute between patent proprietors and a Singapore distributor of a generic bortezomib product. The plaintiffs relied on two Singapore process patents covering methods for manufacturing bortezomib. The defendant denied infringement and countered that the patents were invalid, principally for lack of novelty, lack of inventive step, and insufficiency.
The court found that one of the patents (SG 322) was valid but not infringed. By contrast, the other patent (SG 29P) was invalid for lack of inventive step. The decision is significant because it illustrates how Singapore courts approach claim construction, novelty and inventive step analysis in chemical process patents, and the evidential burdens that arise in process infringement cases where the defendant’s manufacturing process is not fully disclosed.
What Were the Facts of This Case?
The plaintiffs were Millennium Pharmaceuticals, Inc (a Delaware company and registered proprietor of the patents) and Johnson & Johnson Pte Ltd (alleged exclusive licensee and distributor of the brand-name bortezomib drug, Velcade, in Singapore). The defendant, Zyfas Medical Co, is a Singapore-registered partnership engaged in wholesale and distribution of pharmaceutical products. The defendant distributed pharmaceutical products manufactured by various global manufacturers, including Dr Reddy’s Laboratories Limited (“DRL”).
In February 2018, the defendant applied to the Health Sciences Authority (“HSA”) for approval to import, market and distribute a generic version of bortezomib, described as “MYBORTE POWDER FOR SOLUTION FOR INJECTION 3.5MG/VIAL”, manufactured by DRL. On 5 July 2019, HSA approved registration under Registration No. SIN15736P. The plaintiffs’ case was that, although bortezomib itself was not protected by a product patent in Singapore, the defendant’s supply of the generic product infringed the plaintiffs’ process patents for manufacturing bortezomib.
Technically, the patents concerned chemical processes for producing bortezomib, an international non-proprietary name for a cancer drug used for multiple myeloma and mantle cell lymphoma. Bortezomib is a boronic acid derivative (a boronic acid where one hydroxyl group is replaced by an alkyl or aryl group). The general synthetic approach involves producing intermediates and then converting them into bortezomib through chemical reactions. Because there are multiple known routes to bortezomib and its intermediates, the plaintiffs’ patents focused on specific process features rather than the compound itself.
SG 322 (Singapore Publication No. SG 151322) purported to teach an improved asymmetric Matteson homologation protocol. In simplified terms, the Matteson homologation process synthesises a boronic ester compound using zinc chloride as a catalyst. The reaction sequence includes (i) formation of a boron “ate” complex (an intermediate) and (ii) contacting that complex with a Lewis acid to generate the boronic ester. SG 322’s claimed improvement related to performing the first step in a coordinating ether solvent of low miscibility with water. SG 322 contained 56 claims, with 39 asserted in the litigation, including multiple independent claims.
SG 29P (Singapore Application No. SG 10201600029P) contained 10 claims, with five asserted. The central concept was “convergent synthesis” for large-scale manufacture of bortezomib. The parties did not seriously dispute that the sole independent claim in SG 29P was claim 1, making the validity and infringement analysis largely claim-centric.
What Were the Key Legal Issues?
The court had to determine, first, whether Johnson & Johnson Pte Ltd (the second plaintiff) had standing to commence and maintain the suit for patent infringement. Standing in patent litigation can be critical where the plaintiff is not the registered proprietor but relies on licensing or other rights derived from the proprietor.
Second, the court addressed validity of the two patents. For SG 322, the issues included novelty (whether the claimed subject matter was anticipated by prior art) and inventive step (whether the claimed invention would have been obvious to the person skilled in the art). The court also considered sufficiency, ie whether the patent specification sufficiently disclosed the invention so that a skilled person could perform it.
Third, for SG 29P, the court focused on novelty and inventive step, with the ultimate finding being that SG 29P lacked inventive step. In chemical process cases, inventive step often turns on whether the prior art would have led the skilled person to the claimed solution with a reasonable expectation of success, and whether there was any “technical prejudice” against adopting the claimed approach.
Finally, for SG 322, the court had to decide infringement. Because the case concerned process patents, the infringement analysis required determining whether the defendant’s manufacturing process for the alleged infringing product was made by the process taught in the patents. The court also considered whether the burden of proof shifted to the defendant in process infringement circumstances and whether the plaintiffs could show that the defendant’s product was made using the patented process.
How Did the Court Analyse the Issues?
Standing was addressed as a threshold matter. The court examined the second plaintiff’s asserted status as an exclusive licensee and distributor in Singapore. While the extract does not set out the full reasoning, the court’s structure indicates that it treated standing as a distinct issue before moving to validity and infringement. This approach reflects the general principle that a plaintiff must demonstrate a sufficient legal interest in the patent rights being enforced.
Claim construction and the person skilled in the art formed the foundation for the validity analysis. The court identified the “person skilled in the art” and the relevant common general knowledge. It then construed the relevant claims, including claim 1 in SG 322 and the independent claim in SG 29P. In patent disputes involving complex chemical processes, claim construction is often determinative because small differences in process parameters (such as solvent choice, miscibility, moisture control, or reaction conditions) can separate non-infringing alternatives from infringing embodiments.
For SG 322 validity, the court assessed novelty by comparing the claimed features against the state of the art. The extract indicates that the court considered specific prior art documents, including WO 266 and US 454, and US 309, in relation to claim 1. The novelty inquiry asked whether each essential feature of the claim was disclosed in a single prior art reference (anticipation), or whether the claim’s combination of features was not directly and unambiguously disclosed.
On inventive step, the court evaluated whether the state of the art rendered claim 1 obvious. The analysis appears to have been structured around whether the prior art would have motivated the skilled person to adopt the claimed solvent-related improvement in the Matteson homologation process. The extract also shows the court considered whether there was “technical prejudice” in the context of SG 29P; while that phrase is explicitly mentioned for SG 29P, similar reasoning often informs inventive step analysis in chemical process patents generally.
For sufficiency, the court considered whether claim 12 (as referenced in the extract) sufficiently disclosed the invention. Sufficiency in process patents is particularly important because the patent must enable the skilled person to carry out the claimed method without undue experimentation. In chemical synthesis, enablement can depend on whether the specification provides adequate guidance on reaction conditions, reagents, and practical steps that affect outcomes such as stereochemical integrity and yield.
For SG 29P validity, the court found it invalid for lack of inventive step. The extract indicates that the court considered multiple prior art documents (WO 506, WO 507, and US 079) in relation to novelty and inventive step. It also addressed whether technical prejudice existed against the claimed convergent synthesis approach for large-scale manufacture. The court’s conclusion that SG 29P lacked inventive step suggests that the claimed solution did not involve an inventive leap over the prior art when assessed from the perspective of the skilled person.
Infringement of SG 322 required a process-focused evidential analysis. The court considered whether the burden of proof shifted to the defendant. In process infringement cases, plaintiffs often face a practical difficulty: the defendant’s manufacturing process may be known only to the manufacturer. Singapore law recognises that in appropriate circumstances the evidential burden may shift, but the plaintiffs still must establish a prima facie case that the alleged infringing product is made by the patented process.
The extract indicates that the court examined two main aspects of the defendant’s alleged process: (i) moisture presence in DRL’s process, including moisture in reagents used in synthesis of intermediates (referred to as BZM-1 and BZM-2), and (ii) the use of anhydrous THF, zinc chloride and a nitrogen atmosphere. The court also considered whether the defendant used excess zinc chloride. These factors are consistent with the technical theme of SG 322, which emphasises solvent coordination and low miscibility with water, and which likely depends on controlled reaction conditions to achieve the claimed improvements.
The court also addressed whether the plaintiffs were unable to determine the process actually used to manufacture the alleged infringing product through reasonable efforts. This is a key question in process infringement litigation because it affects whether the plaintiffs can rely on presumptions or shifted burdens. Ultimately, the court concluded that the plaintiffs did not prove infringement of SG 322, even though the patent was valid.
What Was the Outcome?
The High Court held that SG 322 was valid but not infringed. This means the plaintiffs’ patent rights were upheld against invalidity challenges, but the defendant’s manufacturing and supply activities were not found to fall within the scope of the patented process as construed and assessed on the evidence.
As for SG 29P, the court held it invalid for lack of inventive step. The practical effect is that the plaintiffs could not rely on SG 29P to restrain the defendant (or others) from manufacturing or supplying bortezomib using processes that fall within the general area of convergent synthesis for large-scale production, because the patent could not stand.
Why Does This Case Matter?
This case is a useful reference for practitioners dealing with process patents in the pharmaceutical sector. First, it demonstrates the court’s careful approach to claim construction and the mapping of chemical process features to prior art. Inventions that hinge on solvent systems, reaction conditions, and moisture control can be highly fact-sensitive, and the decision underscores the importance of precise claim drafting and rigorous expert evidence.
Second, the decision illustrates how courts handle validity challenges in chemical patents. The court’s finding that SG 322 was valid but not infringed, while SG 29P was invalid for inventive step, shows that validity and infringement are distinct inquiries. A patent may survive novelty and sufficiency scrutiny yet still fail on infringement due to differences in the defendant’s actual process.
Third, the case provides guidance on evidential burdens in process infringement. Where plaintiffs allege that a defendant’s product was made using a patented process, the court will examine whether the plaintiffs have shown a substantial likelihood that the patented process was used, and whether the plaintiffs could not determine the process through reasonable efforts. For litigators, this emphasises the need to develop a strong evidential foundation early, including through regulatory records, technical documentation, and expert analysis.
Legislation Referenced
Cases Cited
- Not specified in the provided extract
Source Documents
This article analyses [2023] SGHC 360 for legal research and educational purposes. It does not constitute legal advice. Readers should consult the full judgment for the Court's complete reasoning.