Health Canada’s proposal to streamline approvals may accelerate biosimilar patent litigation

Health Canada has proposed a major change to the regulation of biosimilar drugs that may accelerate biologic patent litigation in Canada. Following the lead of other jurisdictions, Health Canada has proposed that biosimilar manufacturers no longer be required to conduct phase 3 clinical trials to enter the Canadian market. Removing this requirement may lead to earlier biosimilar submissions to Health Canada and earlier litigation under Canada’s patent-linkage regime.

Background on biosimilars

Biosimilar and generic drugs are both follow-ons of an innovator’s originator drug. However, they have fundamental differences that have led to different regulatory standards for market entry in Canada and other jurisdictions.

• The active ingredient in a generic drug is a chemically synthesized small molecule with identical molecular structure to the active ingredient in the originator drug. Generic drugs are authorized for sale through the Abbreviated New Drug Submission (ANDS) pathway.
• By contrast, the active ingredient in a biosimilar drug is a biologically manufactured large molecule that is highly similar – but not identical – to the active ingredient in the originator drug. Biosimilar drugs are authorized for sale through the New Drug Submission (NDS) pathway.

An NDS for a biosimilar drug generally requires substantially more data than an ANDS for a generic drug, including, in “most cases” under Health Canada’s current guidance, clinical trial data “to rule out clinically meaningful differences in efficacy and safety between the biosimilar and the reference biologic drug” (i.e., the originator drug). This clinical trial data has typically come from large phase 3 trials. According to a 2021 report in JAMA Internal Medicine, a typical phase 3 trial for a biosimilar drug enrolled 538 patients, treated them for 55 weeks, and cost an estimated $28 million USD (median values from 29 trials). 

Proposal to eliminate phase 3 clinical trial requirement

Health Canada has now proposed, in a draft guidance, to reduce the data required for a biosimilar NDS. The draft guidance was released June 10, 2025, and public consultation closed on September 8, 2025.  Under the draft guidance, in “most cases” Health Canada would no longer require “a comparative clinical efficacy and safety trial” (i.e., a phase 3 trial).  While Health Canada would still require data comparing the safety and immunogenicity of the biosimilar drug to the originator drug, that data can be collected during comparative pharmacokinetic (PK) studies.  Such PK studies are already required, can often be conducted in healthy volunteers (rather than patients), and are generally much less onerous than phase 3 clinical trials.  

Health Canada’s draft guidance follows the lead of regulatory authorities and politicians in other jurisdictions. The United Kingdom’s Medicines and Healthcare products Regulatory Agency stopped requiring clinical evidence of efficacy for biosimilars in a 2021 guidance. The European Medicines Agency (EMA) released a reflection paper on April 1, 2025, stating that clinical evidence of efficacy “may no longer be required for approval of biosimilars.”  A bill (the Expedited Access to Biosimilars Act) was introduced in the United States Senate on April 10, 2025, that would no longer require comparative clinical efficacy data to approve a biosimilar.  A table below compares Health Canada’s draft guidance to these initiatives from the UK, EMA, and United States Senate. 

Potential effect on biosimilar patent litigation

In Canada, litigation under the Patented Medicines (Notice of Compliance) Regulations (Regulations) determines patent rights prior to generic or biosimilar market entry. A generic or biosimilar manufacturer cannot receive marketing authorization until it addresses any patents listed against the originator’s product. Unless willing to wait for those patents to expire, the manufacturer must obtain the patent owner’s consent or challenge the patents (e.g., as non-infringed or invalid). In that latter case, the patent owner can commence patent infringement proceedings. 

If Health Canada adopts the draft guidance, the reduced data requirements for biosimilar NDSs may lead to earlier filings in Canada. This would likely, in turn, cue earlier litigation under the Regulations. Innovators may need to consider preparing for biosimilar litigation in Canada earlier than they had previously expected.