Biosimilar drugs: Phase 3 clinical trials no longer required for approval in Canada

• Overview
• Background on biosimilars
• Proposed changes and consultation
• Key changes implemented in the updated Biosimilar Guidance
• International alignment
• Effects on biosimilar availability and litigation

Overview

Health Canada has made important changes to how it authorizes biosimilar drugs for sale in Canada. Notably, clinical efficacy studies (i.e. phase 3 studies) comparing the efficacy of the biosimilar candidate drug to the innovative drug it copies "are not typically required." This change aligns with those being made by US and European regulatory authorities. Health Canada's changes may lead to more biosimilar drugs coming to Canada and earlier litigation under the Patented Medicines (Notice of Compliance) Regulations.

Background on biosimilars

Biosimilar and generic drugs are both copies of an approved innovative 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 innovative 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 innovative drug. Biosimilar drugs are authorized for sale through the New Drug Submission (NDS) pathway.

Proposed changes and consultation

Health Canada's standard practices for approving biosimilar drugs are set out in its Guidance on Information and Submission Requirements for Biosimilar Biologic Drugs (Biosimilar Guidance). On June 10, 2025, Health Canada launched a consultation on proposed revisions to the Biosimilar Guidance (our report here). Health Canada received comments from 15 stakeholders, representing biopharmaceutical companies, industry associations, patient organizations, and the general public. On May 19, 2026, Health Canada published its final, updated Biosimilar Guidance.

Key changes implemented in the updated Biosimilar Guidance

Clinical efficacy studies not typically required: Comparative clinical efficacy studies (i.e. phase 3 trials) comparing a biosimilar candidate to the innovative drug "are not typically required." In fact, if such efficacy studies are included in the NDS, "the sponsor should explain the role of the studies and the value of the results." The clinical studies now required to approve a biosimilar drug are "generally limited to a comparative pharmacokinetic trial" that should also "collect data on safety and immunogenicity."

Quality information expanded: Quality sections of the guidance were expanded to emphasize that quality data must be robust and comprehensive to demonstrate biosimilarity. The Biosimilar Guidance states, "For consideration as a biosimilar, similarity should be deduced primarily from comprehensive and appropriately designed comparative analytical studies."

Indications: A detailed scientific rationale is no longer required to justify authorization of the biosimilar candidate for each of the innovative drug's approved indications (i.e. uses). However, the biosimilar must be able to deliver the same dosage as the innovative drug for each indication being sought.

Short polypeptide drugs: For short polypeptide drugs, the copycat drug is considered either a biosimilar candidate or a generic drug depending upon how the copy is manufactured. If manufactured by recombinant DNA procedures, the copy is considered a biosimilar candidate and authorized via an NDS. If manufactured by chemical synthesis, the copy can be eligible for authorization as a generic drug via an ANDS (even if the innovative drug is manufactured with recombinant DNA procedures).

International alignment

The changes to Health Canada's Biosimilar Guidance align with those being made in other jurisdictions:

• United States: On March 9, 2026, the US Food and Drug Administration (FDA) announced its latest steps to streamline biosimilar development. A draft FDA guidance from October 2025 states that a comparative efficacy study "may not be necessary to support a demonstration of biosimilarity."

• Europe: On March 16, 2026, the European Medicines Agency's Committee for Medicinal Products for Human Use adopted a reflection paper on biosimilar development. The paper states it is expected clinical efficacy studies "are no longer expected to be required for approval of biosimilars that can be thoroughly characterised using state-of-the-art analytical methods and have demonstrated similarity in physicochemical and functional properties." This finding is consistent with earlier guidance from the United Kingdom.

Effects on biosimilar availability and litigation

In practical terms, the changes in the Biosimilar Guidance may make it faster and cheaper to bring biosimilar drugs to market in Canada. This in turn may trigger earlier patent infringement proceedings against biosimilar manufacturers under the Patented Medicines (Notice of Compliance) Regulations, which link innovator patent rights to regulatory approval of biosimilar and generic drugs.