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Foolish Consistency is the Hobgoblin of Little Minds

Is an adjuvant an excipient or an active ingredient?  This was the central question in the Federal Court’s decision in GSK’s application for judicial review challenging the Minister of Health’s refusal to grant a Certificate of Supplementary Protection (“CSP”) in respect of Canadian Patent No. 2,600,905 (the “905 Patent”) and the Shingrix vaccine under the Certificate of Supplementary Protection Regulations (“CSPR”). The CSPR were promulgated following the ratification of the Canada-European Union Comprehensive Economic and Trade Agreement (“CETA”).

The issue arose because Shingrix is comprised of Varicella Zoster Virus (VZV) glycoprotein E (“VZV gE”) together with an adjuvant known as AS0B.  The Minister noted that in its dealings with Health Canada GSK had repeatedly referred to Shingrix as containing a single medicinal ingredient (VZV gE). The 905 Patent, though, claimed the combination of VZV gE and an adjuvant referred to as AS0B.  The Minister characterized the adjuvant as a nonmedicinal ingredient and because the 905 Patent had no claims to VZV gE on its own, the Minister denied GSK’s application for a CSP.

The Court expressed the Minister’s position as follows

At the core of the Minister’s decision is the position that, to be eligible for a CSP, a patent must include at least one claim limited to one or more medicinal ingredients, or to their use. According to this view, the 905 Patent is not so limited because each of the claims includes a non-medicinal ingredient (an adjuvant). The Minister says that because the 905 Patent claims are not limited to only medicinal ingredients, they amount to claims for a CSP-ineligible formulation.

The Court also noted:

In order to assess the reasonableness of the Minister’s decision, consideration must be given to the patent eligibility requirements found in the Patent Act and in the CSPR as informed by CETA. [underlining added]

The question, then, was whether the adjuvant was an excipient or an active ingredient.
On the evidence, it was apparent that the vaccine would not have any therapeutic effect unless the adjuvant were included.  It was also clear that while the adjuvant on its own had biological activity, it does not independently initiate an immunological reaction and so cannot be considered to be a medicinal ingredient. Only the co-administered antigen fits that requirement because it triggers an immune response.

The Court held that the relevant statutory and regulatory provisions had to be interpreted “harmoniously” with CETA and “and not necessarily with Health Canada’s drug licensing guidelines” (which characterize adjuvants as excipients).

The effect of this decision is that the provisions of CETA  appear to have paramountcy over domestic statutes and regulations and Ministerial guidance. This is apparent from the Court’s observation that “[i]nasmuch as the term “medicinal ingredient” was open to interpretation, the Minister was … required to consider and apply the language of CETA.”

While it remains open to the Minister to continue to characterize “adjuvants” as excipients for licensing and regulatory purposes, in the CSP context, having regard to the provisions of CETA, a different characterization is required.

In the result, the decision was set aside, and the matter returned to the Minister for redetermination.  The Minister has appealed.

The decision can be found here.