AstraZeneca AB v Pharmacor Pty Ltd (No 3)

This decision came out of a live pharmaceutical patent dispute between AstraZeneca and Pharmacor. The case was already moving on an expedited timetable. AstraZeneca had obtained an interlocutory injunction earlier in the proceeding, and the Court had listed the matter for trial starting on 31 August 2026.

The judge emphasised that timing was commercially important for everyone involved. AstraZeneca had given an undertaking as to damages as the price of the injunction, and that undertaking extended to third parties such as the Commonwealth. AstraZeneca therefore had an interest in getting to trial and judgment as soon as reasonably practicable so its exposure under that undertaking did not continue longer than necessary. Pharmacor, as the party wanting to launch a generic product, also had a strong interest in a prompt final hearing. The patent itself was due to expire on 22 October 2027, which added another commercial deadline to the dispute.

Against that background, Pharmacor sought leave to amend several key documents in the case, including its cross-claim, defence and particulars of invalidity. In practical terms, it wanted to broaden the grounds on which it said certain patent claims were invalid. The Court had to decide whether those changes should be allowed so close to trial, and whether the proposed new cases were properly framed.

The asserted claims were claims 1, 2, 3 and 16 of the patent. The Court described Pharmacor's application as an attempt to expand the grounds on which it alleged those claims were invalid.

Three proposed amendments were the real focus of the dispute.

First, Pharmacor wanted to add a classical obviousness case. The proposed pleading said, in substance, that the alleged invention in each asserted claim did not involve an inventive step when compared with the prior art base and common general knowledge, together with a particular prior art document referred to as WO 128.

Secondly, Pharmacor wanted to advance what the judgment calls the PTE allegation, meaning a challenge to the patent term extension under s 70(3)(a) of the Patents Act. In substance, Pharmacor alleged that in the request to extend the patent term, Bristol-Myers Squibb had asserted that FORXIGA contained dapagliflozin, but FORXIGA in fact contained dapagliflozin propanediol monohydrate, said to be a different substance. On that basis, Pharmacor argued that s 70(3)(a) had not been satisfied and the extension had been wrongly granted.

Thirdly, Pharmacor sought to add an alternative best method case. It alleged, in substance, that if the claimed compound included a complex of dapagliflozin, then before the filing date the patent applicant knew of a method involving such a complex and that this was the best method of performing the invention, but the specification did not disclose it.

This was not a ruling on the ultimate merits of the patent. It was a procedural decision about leave to amend. Even so, the Court's reasoning is commercially important because it shows the factors that matter when a party tries to reshape its case close to trial.

The judge had to balance several competing considerations. Courts generally prefer disputes to be decided on their real issues, which can support allowing amendments. But that preference is not unlimited. The Court also has to protect procedural fairness, make sure the other side has fair notice of the case it must meet, and manage the proceeding so it is resolved justly, quickly and efficiently.

Timing mattered here because the trial had been listed on an expedited basis using the pleadings as they stood earlier in the case. The Court recorded that AstraZeneca contended, and Pharmacor accepted, that a trial commencing on 31 August 2026 was no longer feasible if the amendments were allowed. That meant the amendment application had direct consequences for launch timing, injunction exposure and the overall commercial pressure of the litigation.

The Court also looked closely at the quality of the proposed amendments themselves. A late amendment is more likely to be allowed if it is coherent, sufficiently identified, and supported by a reasonable explanation for why it was not pleaded earlier. It is less likely to be allowed if it is vague, speculative, or effectively asks the Court to let a party search through discovery for a case it cannot yet articulate.

The Court split the result.

On obviousness, the amendment was allowed. A key point was that before the first hearing date Pharmacor had reserved the right to run a classical obviousness case at trial. That meant AstraZeneca had early notice that such a case might be advanced. The judge also found that the delay in formally applying to make those amendments was not significant. Although the amendment would add to the issues for experts and for trial preparation, the Court was satisfied it should be permitted.

On the patent term extension challenge, the amendment was also allowed. AstraZeneca argued that Pharmacor had enough information earlier and had delayed too long. The Court examined the evidence carefully. It showed that in May 2025 an employee within Pharmacor's corporate group had considered the alleged mismatch between the substance in FORXIGA and the patent claims, and that Pharmacor's solicitors had internally referred to a Novartis decision discussing s 70(3). But the Court accepted unchallenged evidence from the relevant witnesses that, before 6 February 2026, no one at Pharmacor or its legal representatives had really recognised the specific s 70(3)(a) argument now sought to be advanced. Once the argument was recognised as tenable, Pharmacor acted promptly. On that basis, the Court allowed the amendment.

On best method, the amendment was refused. The Court found that the proposed plea was not sufficiently precise and did not identify a clear case fit for trial. The judge pressed Pharmacor's counsel on which alleged complex was said to be the best method. Counsel responded, in substance, that until discovery was obtained, Pharmacor did not know and expected the case to be narrowed later. The Court treated that as a serious defect. Pleadings are meant to identify the issues, not operate as a broad net to search for a better theory through discovery.

The Court also found a more fundamental problem. The proposed best method case did not align with the inventions actually claimed in the asserted claims. Claims 1 and 2 were to a compound, claim 3 was to a pharmaceutical composition comprising the compound and a carrier, and claim 16 was to a treatment method involving administration of the compound. None of those claims referred in terms to a complex. Because of that mismatch, the proposed plea did not give AstraZeneca fair notice of the case it had to meet and would have been liable to be struck out.

One of the most useful parts of the judgment is how it deals with evidence about delay and internal consideration of possible arguments. The Court did not simply ask whether some relevant facts were known earlier. It asked whether the specific legal argument had actually been recognised as available and tenable.

That distinction mattered for the patent term extension challenge. The evidence showed that some underlying facts had been considered earlier, and that a Novartis decision referring to s 70(3) had been discussed internally by Pharmacor's solicitors. But the Court still accepted that there had been no real recognition before 6 February 2026 of the specific s 70(3)(a) argument now being advanced. That was enough to support a finding that Pharmacor acted promptly once the point was identified.

By contrast, Pharmacor's conduct on the best method issue worked against it. At the resumed hearing, it sought to rely on additional particulars based on three documents totalling more than 100 pages. There was no evidence explaining why those documents could not have been identified earlier with due diligence. The judge inferred that Pharmacor had decided to improve its proposed best method case after seeing AstraZeneca's submissions. The Court refused that attempt, saying it was not in the interests of justice and would impede the just, quick and efficient resolution of the proceeding.

For businesses, this is a practical lesson in litigation discipline. If you want to add a new case late, you need more than a broad assertion that the material became useful later. You need evidence explaining timing, diligence and why the point could not reasonably have been raised earlier.

This ruling is especially relevant for businesses in high-stakes intellectual property disputes where product launch timing matters. It shows that courts will often distinguish between a late amendment that sharpens a real, identifiable issue and a late amendment that is still looking for its own shape.

If your business is enforcing a patent, this case is useful because it confirms that the other side cannot simply plead a vague theory and hope discovery will later reveal a stronger version of it. The Court insisted on fair notice and a clear connection between the proposed invalidity case and the actual claims in issue.

If your business is defending a patent claim or trying to clear the way for market entry, the case shows that late amendments are still possible, but only if they are properly formulated and supported by evidence. Pharmacor succeeded on obviousness and the patent term extension challenge because those amendments were sufficiently identified and the Court accepted the explanation for timing. It failed on best method because the case was too uncertain and did not match the claim structure.

The costs outcome is also commercially important. Pharmacor obtained leave for some amendments, but still had to pay AstraZeneca's costs thrown away by those amendments. The costs of the amendment application itself were ordered to be AstraZeneca's costs in the cause. That means a partly successful amendment application can still carry a real financial downside.

The judgment was delivered on 6 May 2026 by Downes J in the Federal Court of Australia. The hearing dates referred to in the reasons were 2 April 2026 and 4 May 2026 for the amendment application, with the earlier interlocutory injunction hearing having taken place on 6 February 2026. The orders required any amended documents allowed by the reasons to be filed and served by 8 May 2026.

This was an interlocutory procedural ruling. It decided what Pharmacor could plead before trial. It did not finally determine whether the patent was valid, whether it was infringed, or whether the patent term extension challenge would ultimately succeed on the merits.