The Relevant Principles
18 Section 102(2)(a) requires the Court to ask whether any proposed amended claim would not in substance fall within the scope of the existing claims. This will usually involve asking whether the proposed amendment if allowed would make anything an infringement that was not an infringement before the amendment: Bristol-Myers Squibb Co v Apotex Pty Ltd (2010) 87 IPR 516 at [40], Fina Research SA v Halliburton Energy Services Inc (2003) 127 FCR 561 at [29]. If the answer is yes, subject to the operation of s 102(3), the amendment will not be allowable.
19 As mentioned, ToolGen says that the proposed amendment is to correct an "obvious mistake" in the complete specification within the meaning of s 103(a). What constitutes an obvious mistake was considered by Mr Blanco White QC in Patents for Inventions, 5th ed. Stevens & Sons, London, 1983. The learned author states at para 6-008:
For there to be an "obvious mistake" it must be apparent, on the face of specification when read by an instructed reader, not only that "something has gone wrong" but also what the mistake is and what is the correction needed. By "mistake" here is meant, it would seem, a failure to express the real intention of the writer of the specification. The correction does not cease to be "obvious" because there is more than one way of expressing it. But if extraneous evidence, beyond what is required to put the court in the position of an instructed reader, is needed to show the mistake, it is not an "obvious" one.
(Citations omitted)
20 In Holtite Ltd v Jost (Great Britain) Ltd [1979] RPC 81 Lord Diplock (with whom the remainder of the House of Lords agreed) when considering s 31(1) of the Patents Act 1949 (UK) (which relevantly provided "no amendment thereof shall be allowed, except for the purpose of correcting an obvious mistake") said at 91:
The policy of the section is clear. A major purpose of a patent specification is to define the scope of the invention claimed (section 4(3)(c)), so as to give public notice of the limits of the monopoly claimed. An amendment, if allowed, is retrospective to the date of filing the complete specification. So, with one exception, an amendment which enlarged the limits of the scope of the invention claimed would make actionable, ex post facto, what at the time when it was done the doer had no reason to suppose amounted to an infringement of the patentee's rights. An amendment that would have this effect is what is forbidden by the section. The one exception is where the amendment is for the purpose of correcting an "obvious mistake"; but this exception is not in conflict with the policy disclosed by the remainder of the section, since if the mistake was obvious, it cannot have misled. In the context of correcting it, the natural meaning of the expression "obvious mistake" is that: what must be obvious is not simply that there has been some mistake but also what the mistake is and what is the correction needed. But the correction needed does not fail to be obvious merely because, as a matter of drafting, there is more than one way of expressing it without affecting its meaning. Furthermore, having regard to the function of the specification as a warning to the public of the limits of the monopoly claimed, the mistake must be apparent on the face of the specification itself to an instructed reader versed in the particular art to which the invention relates. If beyond such evidence of the relevant art as may be needed to equip the court with the knowledge that would be possessed by the instructed reader, some other evidence extraneous to the specification is required to show that there has been a mistake in expressing the real intention of the inventor, the mistake is not an "obvious mistake" within the meaning of the section. The words of the section are clear and simple without the need for judicial exegisis. I note, however, that this interpretation of the section conforms with that adopted by Graham, J. in General Tire and Rubber Company (Frost's) Patent [1972] R.P.C. 259 in which several of the previous cases are also referred to.
(Emphasis in the original)
21 The need for both the error itself and the necessary correction to be obvious to the instructed reader (which is merely another way of describing the person skilled in the art) is aimed at ensuring that relevant members of the public are not misled as to the scope of the monopoly.
22 The power to direct the amendment of a complete specification under s 105(1A) of the Act is discretionary: Meat & Livestock Australia Ltd v Cargill, Inc (No 2) (2019) 139 IPR 47 ("Cargill") at [342]. The discretion is exercised by reference to guiding principles that seek to balance the right of the patent applicant to apply to amend claims and the public interest in ensuring that an amendment application is made promptly and for proper purposes, and that any amendment made does not confer on the patentee an unfair advantage: see in the context of the discretion under s 105(1) of the Act, Neurim Pharmaceuticals (1991) Ltd v Generic Partners Pty Ltd (No 2) (2019) 139 IPR 424 at [107].
23 In Cargill, Beach J referred to various cases concerned with the exercise of discretion under s 105(1) of the Act including Les Laboratoires Servier v Apotex Pty Ltd (2016) 247 FCR 61 in which the Full Court (Bennett, Besanko and Beach JJ) said at [242]:
While the power to amend should in appropriate circumstances be exercised in favour of the patentee, it bears mentioning that it will not always be possible to overcome a ground of revocation by an amendment. Accordingly, the ground of revocation sought to be overcome is also relevant to the way in which the discretion should be exercised. In the case of a failure to comply with the best method requirement, it would be necessary to take into account, in the exercise of the discretion, the reason for that obligation and the time at which it is meant to be fulfilled.
24 The Full Court went on at [243] to identify various considerations relevant to the exercise of the discretion as follows:
• The discretion exists for the benefit of the patentee.
• The onus to establish that amendment should be allowed is on the patentee.
• Generally, a permissible amendment (ie one which is permitted under the Act) will be allowed unless there are circumstances which would lead the court to refuse amendment.
• The patentee must make full disclosure of all relevant matters.
• The Court's focus is on a patentee's conduct, not the merit of an invention.
• Amendment should be sought promptly and where a patentee delays for an unreasonable period, the patentee has the onus of showing that it delayed on reasonable grounds, such as a belief, on reasonable grounds, that an amendment was not necessary.
• Unreasonable delay is a circumstance likely to lead to refusal of the amendment.
• In assessing delay, the time when the patentee was unaware and reasonably did not know of the need for amendment is not taken into account. The relevant delay is from when the patentee knows of the likely invalidity, or has its attention drawn to a defect in the patent, or is advised to strengthen the patent by amendment. That is, amendment will not be permitted in cases where a patentee knows or ought to know that amendment should be sought and fails to do so for a substantial period of time. Thus the reasonableness of the conduct of the patentee is a relevant consideration when assessing delay.
• Mere delay is not, of itself, sufficient to refuse to exercise the discretion to amend. The fact of delay is, however, relevant to whether the respondent or the general public have suffered detriment.
• If a patentee seeks to take unfair advantage of the unamended patent, knowing that it requires amendment, then refusal of the amendment is likely.
• The proportionality of the asserted culpability of the patentee as compared with the effect of loss of protection for the invention should be considered.