Canada: Federal Court Of Appeal Upholds Invalidity Of Fampridine Patent

The Federal Court of Appeal (FCA) dismissed an appeal by Biogen and a cross-appeal by Taro from a decision of the Federal Court (see our previous article) dismissing two actions by Biogen under the Patented Medicines (Notice of Compliance) Regulations (PMNOC Regulations): Biogen Canada Inc v Pharmascience Inc, 2022 FCA 143. The Federal Court had found Canadian Patent No. 2,562,277 (277 Patent) invalid but would have been infringed by Taro's proposed fampridine product (Biogen's FAMPYRA). The infringement portion of the Pharmascience action was to take place at a later date.

Background

The 277 Patent pertains to uses of fampridine sustained release (SR) compositions to treat multiple sclerosis (MS). The claims at issue were construed by the Federal Court to relate to the use of a fampridine SR composition (or use of a fampridine SR composition in the manufacture of a medicament) for improving walking in a statistically significant way in a subject with MS in need thereof (i.e., who experiences some form of walking disability) for a period of at least two weeks at a unit dose of 10 mg twice a day.

In the Federal Court, Taro and Pharmascience denied infringement and alleged invalidity on the grounds of anticipation, obviousness and lack of patentable subject matter. While the trial judge rejected the argument that the claims were directed to unpatentable methods of medical treatment, certain claims were held to be anticipated by a registration statement (Acorda S-1) submitted to the US Securities and Exchange Commission and all of the asserted claims were found to be invalid for obviousness.

FCA Decision

Biogen argued that the Federal Court should have dismissed the attack on the validity of the 277 Patent because the only expert evidence presented by the respondent was inadmissible and thus, the respondents could not have met their burden of proof. The objection was based on the fact that the section entitled "State of the art" consisted mostly of paragraphs found in Taro's Notice of Allegation (NOA), a document the expert had never reviewed. The Federal Court gave little weight to much of the evidence of the expert in respect of the prior art and obviousness, but it did accept and refer to some of his evidence in respect of the common general knowledge and claim construction. The FCA held there was no reviewable error that would justify intervention. The Federal Court was satisfied that the expert was entirely aware of all of the prior art listed before referring to it in his report. The part of the report that mirrored the NOA essentially consisted of citations of various passages from documents attached to his report, and there were paragraphs in this section of the report that were clearly added to reflect the expert's personal knowledge. This was therefore not an egregious case or one of those rare and very clear cases the trier of fact should conclude the proposed expert is unable or unwilling to meet his duty to the court and should strike the report.

Biogen also argued that the Federal Court erred in failing to adopt the perspective of the person skilled in the art (POSITA) in construing the claimed terms "improving walking" and "increasing walking speed". The Federal Court had construed the words "improving" and "increasing" as referring only to a meaningful quantitative improvement or increase, i.e., one that would be statistically significant so as to take into account the variability of symptoms and the prevalence of placebo effect in MS patients. Biogen argued that these words would rather be understood as directed only to "clinically meaningful" improvement or increase and therefore require two essential elements: a meaningful quantitatively measured improvement or increase that is also subjectively assessed as meaningful by the "subject with MS in need thereof". The FCA disagreed and held that it was not appropriate to read into the claims a subjective assessment of the efficacy of the treatment. The FCA found no basis to intervene.

Biogen further argued that the Federal Court erred in declaring the claims at issue invalid by failing to adopt the perspective of the POSITA when assessing the 277 Patent and the prior art for obviousness and anticipation. The FCA concluded that the Federal Court did not make a reviewable error in its assessment of the evidence that would justify intervention and that there was sufficient evidence before it to support its obviousness finding. The FCA declined to endorse the conclusion of the Federal Court on anticipation but found it was not necessary to deal with anticipation given the findings on obviousness.

Finally, the FCA held that Taro's cross-appeal on infringement did not need to be addressed in light of the dismissal of Biogen's appeal.

Leave from the Supreme Court of Canada would be required to appeal this decision.

Should you have any questions, please do not hesitate to contact a member of the  Pharmaceutical Litigation Group.

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