Challenging the validity of a patent based on unasserted claims
Update: For more current commentary please refer to our article (click here) on the more recent decision in Sun Electric Pte Ltd v Sunseap Group Pte Ltd and others  SGHC 232.
Sun Electric Pte Ltd (Plaintiff) is the proprietor of the Singapore Patent (based on Application No. 10201405341Y) (Patent), which comprises 12 claims. The Plaintiff alleged that Sunseap Group Pte Ltd (Defendant) infringed Claims 1, 3, 4, 5, 7, 9, 10 and 11 of the Patent. The Defendant denied any infringement, and counterclaimed for an order to revoke the Patent, and to seek remedies for groundless threats. In this suit, the Plaintiff challenged the Defendant's position of placing the validity of all claims (asserted and unasserted) in issue.
This ruling provides clarity in relation to counterclaiming against unasserted claims during patent related legal proceedings.
Validity of a Patent
Section 82(1) of the Singapore Patents Act (Act) sets out five instances where the validity of a patent may be put in issue:
- by way of defence, in proceedings for infringement of the patent (Section 67) or proceedings for infringement of rights conferred by the publication of an application (Section 76);
- in groundless threat of infringement proceedings (Section 77);
- in proceedings in which a declaration in relation to the patent is sought (Section 78);
- in proceedings before the Registrar for the revocation of the patent (Section 80); or
- in proceedings where the use of a patented invention by Government and authorised parties is disputed (Section 56 and 58).
Section 82(2) of the Act further states that the validity of a patent may not be put in issue in any other proceedings.
Issue 1: Is the Defendant entitled to include unasserted claims by way of defence under s 82(1)(a)?
Based on the reasoning given in Astrazeneca AB v Ranbaxy (Malaysia) Sdn Bhd  SGHC 7, the Court found that the Defendant is not entitled to include unasserted claims under S 82(1)(a). The Court highlighted the following points:
1. Infringement is tied to specific independent patent claims; i.e. the allegedly infringing product must fall squarely within the claim of the patent. In addition, as a matter of logic, questioning the validity of an unasserted claim does not function as a defence to infringement of an asserted claim.
2. The current procedure allows the Plaintiff to subsequently assert these unasserted claims. Such is dealt with by the court when the situation arises, and in consideration, should be struck out if is found to be an abuse of court process.
3. Allowing the Defendant to put in issue unasserted claims would be "putting the cart before the horse", and would result in expending unnecessary costs and time.
4. In the alternative, the Defendant needs to provide compelling reason to justify adding the unasserted claims in issue by way of defence.
Issue 2: Is the Defendant entitled to include unasserted claims by way of counterclaim for groundless threat of infringement under s 82(1)(b)?
The Court held that the Defendant is not entitled to put the unasserted claims in issue under this provision. In the context of groundless threat proceedings, it would be entirely futile for an aggrieved person to put the validity of unasserted claims in issue as they would not assist the groundless threat claim. As such, the issue of validity of patent claims ought to be limited to the claims for which actual or potential infringement is alleged.
Issue 3: Is the Defendant entitled to include unasserted claims by way of counterclaim for revocation under s 82(1)(d)?
The plain wordings of S 80(1) and S 82(1)(d) makes express reference to "the Registrar" and not "the Court" for revocation proceedings, in which a party is entitled to put the validity of all claims in issue. However, s 82(7) provides that where proceedings with regard to a patent are pending in the Court under any provision mentioned in S 82(1), revocation proceedings cannot be instituted before the Registrar except with the leave of the Court. Additionally, S 91(1) empowers the Court to make any order or exercise any other power which the Registrar could have made or exercised.
In this regard, the Court held that the Defendant is entitled to put the unasserted claims in issue by way of counterclaim for revocation of the patent. Such an action should be brought before the Court at first instance, unless the Court grants leave for the matter to go before the Registrar.
Points to Note
- The validity of a patent will always be at risk during infringement proceedings before a Court. In this regard, one should always consider if alternate dispute resolution (ADR) options are available and should only pursue legal proceedings after the ADR options are exhausted. While the validity of a patent may be questioned by way of counterclaim to infringement, the validity is usually only assessed in relation to the alleged infringed claims.
- All claims may be challenged by way of revocation proceedings. However, a challenger, on the basis of pre-empting infringement, should be prudent when initiating revocation proceedings at the patent office, as the initiation of the proceedings at the patent office may still lead to legal proceedings before a Court. S 80(6) states that proceedings at the patent office "shall not estop any party to any civil proceedings in which infringement of a patent is in issue".
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