Intellectual Property

Reversing the burden of proof in patent infringement proceedings

May 29, 2023

The recent case of Calix Limited v Grenof Pty Ltd & Aquadex Pty Ltd1 (Calix v Grenof) marks the first time the Federal Court of Australia has analysed section 121A of the Patents Act 1990 (Cth) (Act), a provision that reverses the burden of proof in patent infringement proceedings under specific circumstances.

Section 121A

The general rule in Australian civil litigation is the party who asserts a certain fact has the burden of proving it on the balance of probabilities. In claims of patent infringement, this burden typically rests on the patentee or an exclusive licensee.

Where a patent claims a process for making a product, a patentee who suspects infringement will often face difficulties in obtaining sufficient evidence of what process the alleged infringer is actually using to be able to prove infringement.

In such claims, the burden of proof is reversed under section 121A in the following circumstances:

     a)   Where the defendant/respondent alleges that it has used a process different from the patented            process to manufacture a product identical to the plaintiff/applicant; and

     b)   The court is satisfied that:

          i.   it is very likely the defendant's/respondent's product was made by the patented process; and

          ii.  the patentee or exclusive licensee has taken reasonable steps to find out the                defendant's/respondent's process but has not been able to do so.

Where these circumstances operate, it is up to the defendant/respondent to prove that its process was not obtained by the patented process.

The analysis in Calix v Grenof

On 28 April 2023, Justice Nicholas handed down his decision in Calix v Grenof. We have previously written about it here.

The case concerned an Australian patent for a process of producing hydroxide slurries owned by Calix (Applicant). Calix alleged that Grenof and Aquadex (Respondents) had infringed its patent by manufacturing their respective products using Calix's patented process. Amongst other things, claim 1 of the patented process included the following integer:

"allowing steam to evaporate from the reaction mixture as hydration proceeds, to remove excess heat and control the maximum reaction temperature to near the boiling point".

Section 121A of the Act was relied upon by Calix to attempt to shift the burden of proof with respect to infringement onto the Respondents. His Honour briefly considered the application of the provision at [86] – [88], noting:

  1. The structure of s 121A indicates it is concerned with the drawing of inferences with respect to a process based upon an examination of a product of that process.
  2. The provision can only apply if the Court is satisfied that it is "very likely" that a respondent's product was made by the patented process.
  3. The provision is primarily aimed at circumstances in which a plaintiff/applicant has access to the defendant's/respondent's product, but not the defendant's/respondent's process, such as in instances where the process is used by a third-party to the proceedings located overseas and is thus unavailable for inspection by the plaintiff/applicant (this was notably not the case here, as an inspection of the Respondents' process had been previously carried out by Calix)2.

His Honour relevantly found that:3  

  1. There was no evidence that the making of the Respondents' products could not be done by raising the temperature of the reaction mixture to its boiling point (as opposed to "near the boiling point" per the patented process); and
  2. There was nothing about the products made by the Respondents that made it unlikely the reaction mixture was allowed to boil during the production of the products.

Therefore, there was no evidence, nor anything inherent, about the Respondents' products that made it likely they were made by the patented method. In such circumstances, s 121A of the Act could not apply.

Significance of the decision

Section 121A of the Act has the potential to be a powerful tool in patent infringement proceedings. Where it applies, the defendant's/respondent's process is taken to have infringed the patented process, and the burden is on the defendant/respondent to prove otherwise.

Justice Nicholas' analysis marks the first time the Federal Court has considered the application of this section. His Honour's clarification of the circumstances in which s 121A of the Act applies provides importance guidance to patentees or exclusive licensees facing difficulties in obtaining sufficient evidence of what process an alleged infringer is using to be able to prove infringement.

Patentees or exclusive licensees should also be aware, notwithstanding the application of s 121A, that the Federal Court has wide powers to make orders regarding the obtaining of evidence about a process that is alleged to be an infringing one.

Further Information

For more information on this provision, or enforcing or defending the enforcement of patents generally, please contact a member of Thomson Geer’s Intellectual Property Team.


Ben Coogan | Partner | +61 7 3338 7503 |

Lachlan Ball | Law Graduate

1 [2023]FCA 378

2 At[34].

3 At[88].

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