Latitude in Admitting Hearsay Evidence Contained Within Facially Reliable Scientific References

Takeda Canada Inc v Mylan Pharmaceuticals ULC / pantoprazole (NOC) 2015 FC 751 Barnes J
             2,341,031 / pantoprazole magnesium dihydrate / TECTA

In this NOC proceeding Takeda’s 031 patent claiming pantoprazole magnesium dihydrate was found to be not infringed and invalid for anticipation. Both aspects of the decision turned entirely on the facts. The most interesting aspect of the decision is Barnes J’s discussion of hearsay evidence in NOC proceedings, and in particular his statement that “some latitude should be extended to the reliance by expert witnesses upon hearsay contained within authenticated and facially reliable scientific references” [92].

Pantoprazole magnesium is a known gastric acid inhibitor, and the dihydrate form was the inventive concept of the 031 patent [3]. The relevant prior art was Example 10 of an international patent application [27]. As Barnes J noted, the test for anticipation is strict and requires that following the directions in Example 10 would “inevitably or necessarily” produce pantoprazole magnesium dihydrate. “If the evidence discloses on a balance of probabilities only that a dihydrate will sometimes be the result,” the attack based on anticipation will fail [39]. The only direct evidence was provided by Mylan’s expert, who testified that by following the directions in Example 10 he had produced pantoprazole magnesium dihydrate [40]. Takeda’s expert suggested that different choices might have produced a different result, but those concerns were all “theoretical” and Barnes J was not persuaded [48]. The fact that Takeda did not conduct any tests to determine whether Example 10 would produce the dihydrate form substantially undermined its case [49] (though of course, if Takeda had carried out such tests and they had all produced the dihydrate form, that would not have helped either).

Mylan argued its pantoprazole magnesium product did not infringe because it was the hemipentahydrate, not the dihydrate. The issue turned entirely on whether Mylan’s product was indeed the hemipentahydrate. Barnes J took into account the fact that Mylan’s ANDS submitted to the Minister of Health reports that its product was characterized by various testing methods and found to be a hemipentahydrate [15]. He held that the fact that the Mylan’s product specification allowed for a range of water content that encompassed both the dihydrate and hemipentahydrate, “says very little about what is actually produced” [60], and “it would take far stronger evidence than this to support an inference that Mylan’s disclosure about its product to the Minister was deceitful” [62]. Barnes J also considered evidence related to various tests used to characterize Mylan’s product, and he concluded that Takeda had not carried its burden of showing that Mylan’s product was the dihydrate, particularly in light of the imprecision of many of the tests [79]. [104]. Again, Takeda’s failure to carry out its own characterization tests weighed against it [103].

A significant piece of evidence relied upon by Mylan to characterize its product as a hemipentahydrate was the fact that the XRPD pattern obtained by Mylan for its product matches the XRPD pattern reported in US patent application 623 for a product characterized by the US 623 inventors as pantoprazole magnesium hemipentahydrate [88]. Takeda attempted to block the introduction of this evidence as hearsay [90]. Barnes J held it was indeed hearsay [90] and it did not fall clearly into one of the previously recognized exceptions to the hearsay rule [91]. Nonetheless, he considered it:

[91] In particular, there is no evidence before me to show that the admission of this evidence was justified on the basis of its necessity. That said, the opinions expressed by expert witnesses in patent litigation frequently rest on their acceptance of the accuracy of hearsay references concerning scientific issues or for the interpretation of prior art. In some cases, this is justified on the ground that experts in a particular field are permitted to rely on the accuracy of widely accepted and publicly reported data.

[92] Given the summary nature of NOC proceedings, I am of the view that some latitude should be extended to the reliance by expert witnesses upon hearsay contained within authenticated and facially reliable scientific references. The contents of US 623 were disclosed in Mylan’s NOA and its expert witnesses relied on the reported findings in support of their own analysis. Where such a reference contains sufficient information to allow the opposite party to replicate the work and assess the accuracy of the reported data, that party suffers no material prejudice by the admission of hearsay in support of an expert’s opinion. It was open to Takeda to run the same tests reported in US 623 and to fully characterize the resulting compounds. Despite the significance of this evidence, Takeda chose not to make that effort.