Sun Pharma ANZ Pty Ltd v Otsuka Pharmaceutical Co Ltd [2025] FCA 44
Background
Otsuka Pharmaceutical Co. Ltd holds Australian Patent No. 2004285448 for a controlled-release injectable aripiprazole formulation used in treating schizophrenia and bipolar disorder. In August 2014, Otsuka sought a patent extension based on two products containing aripiprazole listed on the Australian Register of Therapeutic Goods (ARTG). However, IP Australia initially rejected the request, citing that aripiprazole had already been included in the ARTG for an earlier product (ABILIFY tablets). After further correspondence, Otsuka's request was granted, extending the patent's expiration to 25 July 2029.
Sun Pharma ANZ Pty Ltd challenged this extension, arguing that it was wrongly granted and should be removed from the Patent Register. Sun Pharma, as a "person aggrieved", has standing to seek the rectification of the register. Otsuka defended the extension by asserting the legitimacy of the patent claims and the products listed on the ARTG. The case centres on whether the extension was validly granted under the Patents Act 1990 (Cth) and whether it should remain in effect.
Expert evidence
Sun Pharma adduced expert evidence from Prof. GJW, a Professor
and former Chair of the Pharmaceutical Technology and
Biopharmaceutics' group of the Department of Pharmacy at Ludwig
Maximillian's University of Munich and Prof. GMG, psychiatrist
and Emeritus Professor in the Department of Psychiatry at the
University of Oxford and the Chief Medical Officer at Compass
Pathways.
Otsuka adduced expert evidence from Prof. AME, a pharmaceutical
scientist and a clinical pharmacologist and an Adjunct Professor at
the University of South Australia.
The experts prepared a joint expert report, but only. Prof GJW and Prof. AME were cross-examined.
Where Prof. GJW and Prof. AME disagreed, the court preferred the evidence of Prof. GJW.[31] This is based on the following:
- Prof. GJW's evidence was direct and relevant, showing his extensive experience in drug formulation, including lyophilised products. By contrast, Prof. AME's testimony often avoided addressing key issues directly and appeared somewhat unclear, especially when responding to Prof. GJW's evidence, which lacked clear explanations or disagreements.[24]
- Prof. GJW's testimony was well-reasoned, consistent and logical. His responses were calm, measured and he made reasonable concessions when appropriate. Otsuka criticised Prof. GJW for allegedly misinterpreting the Patent, but these criticisms were rejected because Prof. GJW raised valid concerns about missing data in the Patent, concerns that Prof. AME failed to adequately address.[25]-[26]
- Prof. AME, at times, became defensive and his testimony seemed aimed at protecting the PTE Claims. His affidavit evidence did not provide a full account of his work or reasons for his opinions. His analysis of Example 4 and Figure 3 in the Patent was not as limited as he claimed and it was later revealed that he had used a 28-day dosing interval and performed calculations with multiple doses that were not disclosed in his affidavits. This was contrary to clauses 3(d) and 3(e) of the Harmonised Expert Witness Code of Conduct, which is Annexure A to the Expert Evidence Practice Note (GPN-EXPT).[27]-[30]
The court disagreed with Otsuka's claim that Prof. GJW approached the Patent as a "scepticaltical expert" who doubted the information presented. Nor did he fail to apply the practical, commonsense approach of someone skilled in the art. Rather, it was clear to the court that Prof. GJW carefully examined the limited information in the Patent's Examples and the simplified blood plasma concentration data in Figure 3, which used 20-day time increments and only four subjects. His goal was to understand how a skilled person in the field could determine whether a formulation that met the PTE Claims would fall within the specified release boundaries. Given that the invention involves formulations designed for human injection to treat serious psychiatric conditions, the court held that Prof. GJW's critique of the Patent's lack of sufficient information was reasonable and not overly sceptical.[262]
Regarding Prof. AME's disagreement with Prof. GJW in the JER, Prof. AME admitted that he had improperly answered a key question, focusing only on whether a single product met the requirements, when the question actually required determining if all aripiprazole formulations under the PTE Claims met those criteria. Therefore, Prof. AME's evidence was not considered by the court on this point.[263]
Ultimately, the PTE Claims were declared invalid and were revoked.[298] It was ruled that the asserted pharmaceutical substances per se do not meet the requirements of s 70 of the Patents Act 1990 (Cth).[299]
Key takeaways:
- Expert evidence should be logical, consistent and well-reasoned in order to be compelling. Conclusions must be consistent with the expert's experience and directly tied to the evidence.
- Experts should ensure their evidence is clear, direct and directly addresses the issues at hand, not only in their reports but also in their testimonies. Experts should avoid defensive or antagonistic responses, as these can undermine their credibility.
- Experts should fully address all aspects of the questions put to them and must fully disclose the scope of their analysis and any assumptions made. A complete account of work, particularly use of calculations and assumptions, must be included in the expert reports.
Read the full decision here.
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