Cipo's March 2026 Practice Notice: What It Means for Patentable Subject‑matter in Pharma & Biotech Litigation

On March 24, 2026, the Canadian Intellectual Property Office (CIPO) published a practice notice that materially changes how patentable subject matter in Canada is assessed for pharmaceutical and biotechnology claims. The notice introduces a structured, multi‑step framework that CIPO examiners must now apply when determining whether a claimed invention falls within the definition of “invention” under section 2 of the Patent Act. For innovator companies, generic manufacturers and their litigation counsel, this guidance reshapes claim construction arguments, patent validity Canada strategies and PM(NOC) litigation risk calculations.

This article provides a litigation‑first playbook, covering the notice’s substance, its impact on biotech patent eligibility, concrete claim drafting biotech examples, Federal Court patent strategy considerations and immediate action steps for both sides of the courtroom.

Executive Summary, Key Takeaways

• What changed. CIPO’s March 24, 2026 practice notice replaces earlier piecemeal guidance with a consolidated multi‑step framework for assessing patentable subject‑matter. Examiners must now purposively construe claims, identify the “actual contribution” or “inventive concept,” and then determine whether that contribution falls within the statutory categories of invention.
• Who is affected. Every holder of a pharmaceutical patent in Canada, every generic company evaluating a Notice of Allegation (NOA), and every patent prosecutor with pending biotech applications at CIPO.
• Immediate tactical choices. Patentees should audit existing claims for subject‑matter vulnerability. Generics should reassess invalidity grounds in upcoming PM(NOC) proceedings. Both sides must recalibrate expert evidence strategies.
• Recommended next steps. Conduct a portfolio‑wide claim audit within 30 days, commission targeted experimental evidence within 90 days, and revise PM(NOC) readiness plans before the next round of NOA deadlines.

What the CIPO March 24, 2026 Practice Notice Says, Legal Summary

The CIPO practice notice consolidates and updates the guidance previously scattered across the Manual of Patent Office Practice (MOPOP) and earlier practice notices. It instructs examiners to apply a structured framework when evaluating whether claims define patentable subject‑matter under section 2 of the Patent Act, which defines “invention” as “any new and useful art, process, machine, manufacture or composition of matter, or any new and useful improvement in any art, process, machine, manufacture or composition of matter.” The notice brings CIPO’s internal practice into closer alignment with the analytical approach emerging from recent Federal Court jurisprudence.

The framework requires examiners to: (1) purposively construe the claims to identify their essential elements; (2) determine the “actual contribution” or “inventive concept” of the claimed invention; and (3) assess whether that contribution constitutes subject‑matter that falls within the statutory definition, excluding, for example, mere abstract ideas, scientific principles, methods of medical treatment (where applicable) or disembodied discoveries. The Canadian Bar Association’s prior MOPOP submissions had advocated for greater clarity in precisely this area, and the notice can be read as CIPO’s response to those professional‑body concerns.

Key Excerpts From the Practice Notice

The notice states that examiners must look beyond the “form of the claim” to its “substance and inventive concept” when assessing eligibility. This language signals a shift toward a more rigorous analysis that does not accept at face value the structural elements recited in a claim if the true contribution lies outside patentable categories. It also clarifies that the presence of physical or tangible elements in a claim does not automatically render the subject‑matter patentable, the inventive concept itself must be patent‑eligible.

A critical point for litigators: the notice is guidance to CIPO examiners and is not, by itself, binding on the Federal Court. However, industry observers expect that courts will treat the framework as persuasive, particularly where it reflects or codifies principles already articulated in Federal Court and Supreme Court of Canada decisions. Patent prosecutors and litigators alike must therefore anticipate that this framework will be cited in validity challenges.

How the Notice Changes Patentable Subject‑Matter Analysis for Biotech

For biotech patent eligibility, the March 2026 practice notice represents the most significant recalibration of CIPO’s approach in over a decade. Biological inventions, from novel protein compositions to diagnostic methods and gene‑therapy delivery systems, now face a more granular “inventive concept” inquiry that can strip away claim elements the examiner considers non‑inventive and examine whether the residual contribution is truly patentable.

This analytical approach has direct consequences for pharmaceutical patents in Canada. A composition claim that recites a known protein in combination with a novel formulation, for example, must demonstrate that the inventive concept resides in the formulation (a manufacture or composition of matter) rather than in the mere discovery of a biological property of the protein. Similarly, claims directed to methods of treatment face renewed scrutiny, as the notice reinforces the principle that methods of medical treatment may not constitute patentable subject‑matter where the inventive concept is the therapeutic application itself, rather than a novel process or manufacture.

Differences Between Pre‑2026 Practice and New Guidance

• Claim construction. Previously, CIPO applied a relatively generous reading of claim elements. Under the new guidance, purposive construction focuses squarely on isolating the “actual contribution.”
• Inventive concept identification. The notice formalises a step that was implicit but inconsistently applied, examiners must now explicitly identify and articulate the inventive concept before assessing its subject‑matter eligibility.
• Methods of treatment. The notice reinforces that claims whose inventive concept is a method of medical treatment remain problematic, even if the claim is drafted in “use” or “composition adapted for” format.
• Diagnostic and personalized‑medicine claims. Claims to diagnostic methods face heightened scrutiny where the contribution is the correlation between a biomarker and a condition, rather than a tangible process step.

Early Court Reactions and Signals

Early 2026 Federal Court activity suggests that the judiciary is already engaging with the subject‑matter framework in ways that parallel the CIPO notice. Commentary on CanLII Connects regarding recent decisions has highlighted that Federal Court judges are independently applying a purposive, “inventive concept”‑centred analysis to patentable subject‑matter challenges. The likely practical effect will be that CIPO’s framework and the Court’s emerging approach converge, giving generic challengers a unified analytical toolkit and requiring patentees to mount evidence‑intensive defences.

Practical Implications for PM(NOC) Litigation, Playbook

PM(NOC) litigation is the front line where patentable subject matter in Canada will be tested under the new framework. Both innovator and generic counsel must reassess their strategies immediately. The practice notice provides generic companies with a strengthened analytical foundation for subject‑matter‑based invalidity attacks, while patentees must prepare evidence and arguments that anticipate the three‑step inquiry.

For Generic Manufacturers, Evaluating Freedom‑to‑Operate and Invalidity Risk

Generic manufacturers evaluating freedom to operate in Canada should now re‑examine each listed patent against the CIPO framework. Where a patent’s claims rest on an inventive concept that arguably falls outside statutory subject‑matter, for example, a method of medical treatment disguised as a “use” claim, or a diagnostic claim whose contribution is a biomarker correlation, the generic has a stronger basis for including subject‑matter invalidity as a ground in its Notice of Allegation. This reassessment should be completed before the next scheduled NOA deadline.

Tactically, generics should consider whether subject‑matter invalidity can be raised alongside or in place of traditional grounds such as obviousness or anticipation. Industry observers expect that subject‑matter arguments will be increasingly prominent in PM(NOC) proceedings because they go to the root eligibility of the patent, if the inventive concept is not patentable, no amount of novelty or inventive step analysis can save the claim.

For Patentees, How to Shore Up Claims and Prioritise Defence Evidence

Patentees should not wait for a challenge. An internal simulation exercise, applying the CIPO three‑step framework to each patent on the register, will identify vulnerable claims before a generic does. Where claims are vulnerable, patentees have two options: (a) seek to amend claims during prosecution (for pending applications) or reissue proceedings (for granted patents, where available); or (b) prepare robust evidence packages that frame the inventive concept as squarely within patentable categories.

Evidence preparation is critical. Patentees should commission expert affidavits that explicitly articulate the inventive concept in terms of a tangible process, manufacture or composition of matter, supported by comparative experimental data demonstrating that the contribution is not merely an abstract idea or a correlation but a concrete, practical and patent‑eligible advance.

Timeline, Key Dates and How They Matter

For PM(NOC) readiness, the recommended evidence production schedule is: within 0–30 days, complete a claim‑by‑claim subject‑matter audit of all registered patents; within 31–60 days, instruct experts and commission affidavits addressing inventive concept characterisation; and within 61–90 days, finalise litigation strategy and NOA drafting (for generics) or pre‑emptive evidence packages (for patentees).

Claim Drafting and Prosecution Tactics for Biotech After CIPO

The March 2026 practice notice demands a fundamental rethink of claim drafting biotech strategies for pending applications and future filings in Canada. The “inventive concept” inquiry means that claims must be drafted so the contribution is unambiguously located in a patent‑eligible category. Below are two concrete redraft examples illustrating how claims can be restructured to reduce exposure under the new framework.

Example 1, Composition claim (monoclonal antibody formulation):

• Before: “A composition comprising antibody X for use in treating disease Y.”, Risk: the inventive concept may be characterised as the method of treatment (use of antibody X against disease Y), an excluded category.
• After: “A stable liquid pharmaceutical composition comprising antibody X at a concentration of 10–50 mg/mL, a buffer system maintaining pH 5.5–6.5, and a surfactant selected from polysorbate 20 or polysorbate 80, wherein the composition exhibits less than 5% aggregation after 24 months at 2–8°C.”, Rationale: the inventive concept is now anchored in the novel formulation (composition of matter) with measurable stability parameters, rather than in the therapeutic application.

Example 2, Method of treatment claim (gene therapy):

• Before: “A method of treating condition Z comprising administering to a patient an effective amount of vector V encoding gene G.”, Risk: the inventive concept is the method of medical treatment itself.
• After: “A process for producing a gene‑therapy‑ready viral vector comprising: (a) transfecting host cells with plasmid P encoding gene G; (b) harvesting vector V from the cell supernatant; and (c) purifying vector V by tangential flow filtration to achieve a titre of at least 1 × 10¹² vg/mL.”, Rationale: the inventive concept is a manufacturing process (an art or process) with defined technical parameters, removing the claim from the excluded “method of treatment” category.

Functional Language Versus Structural Elements

Under the new framework, claims that rely heavily on functional language (e.g., “a compound that inhibits enzyme X”) without structural definition are at higher risk. Examiners, and, industry observers expect, courts, will look through functional language to the underlying contribution. Where that contribution is a biological effect or correlation rather than a defined structure or process, the claim is vulnerable. Best practice now is to anchor claims in structural features (molecular weight, amino acid sequences, formulation parameters) supported by enabling disclosure and experimental data.

When to Amend Versus When to Litigate

The decision between amending claims and defending their validity as‑is depends on several factors. For pending applications, amendment is usually preferable where it can be accomplished without narrowing commercial coverage beyond acceptable limits. For granted patents, the calculus is different: reissue proceedings are limited in scope, and any amendment could be used against the patentee in subsequent litigation as an admission of the original claim’s weakness. A cost‑benefit analysis should weigh: (a) the likelihood of a subject‑matter challenge succeeding under the new framework; (b) the commercial value of the claims at risk; (c) the availability of evidence to defend the inventive concept as patent‑eligible; and (d) the strategic signal that an amendment sends to generic competitors.

Evidence, Expert Strategy and Validity Defences in Federal Court

Patent validity in Canada now turns, more than ever, on the quality of technical evidence presented to the Federal Court. Under the CIPO framework, the “inventive concept” step requires judges to look beyond claim language to the substance of what the inventor actually contributed. This makes expert evidence the decisive battleground.

For patentees defending biotech claims, the expert report must accomplish three things: (1) articulate the inventive concept in terms of a tangible, patent‑eligible category; (2) provide comparative experimental data demonstrating that the contribution produces a concrete, measurable improvement over the prior art; and (3) explain why the contribution is not merely the discovery of a naturally occurring phenomenon or a correlation, but rather a practical application embodied in a process, manufacture or composition of matter.

How to Defend Inventive Step Versus Subject‑Matter Objections

A critical distinction for Federal Court patent strategy is that subject‑matter and inventive step (obviousness) are legally separate inquiries, but evidentially they overlap. An expert who has prepared a strong inventive‑step defence, showing unexpected results, long‑felt need or teaching away, can often repurpose elements of that evidence to characterise the inventive concept as patent‑eligible. Cross‑examination should be anticipated on the precise boundary between what the inventor discovered (potentially non‑patentable) and what the inventor made or did with that discovery (potentially patentable).

Immediate Action Checklist for Patentees and Generics

The following parallel checklists set out time‑bound tasks for both patent owners and generic manufacturers responding to the new patentable subject matter Canada framework.

For Patent Owners

1. 0–30 days: Conduct a claim‑by‑claim audit of all Canadian patents and pending applications in the portfolio. Flag any claim whose inventive concept could be characterised as a method of treatment, an abstract idea or a biomarker correlation.
2. 0–30 days: Identify the three to five most commercially critical patents and prioritise them for detailed analysis.
3. 31–60 days: Instruct technical experts to prepare affidavits that articulate the inventive concept for priority patents in patent‑eligible terms, supported by experimental data.
4. 31–90 days: For pending applications, evaluate whether claim amendments can reposition the inventive concept without unacceptable scope narrowing.
5. 90+ days: Update PM(NOC) readiness plans, including pre‑prepared evidence binders and litigation strategy memoranda addressing subject‑matter arguments.

For Generic Manufacturers

1. 0–30 days: Reassess each target patent on the register under the three‑step framework. Run an internal simulation of a subject‑matter validity attack.
2. 0–30 days: Evaluate whether subject‑matter invalidity should be added as a ground in upcoming NOAs, either alongside or replacing traditional grounds.
3. 31–60 days: Commission freedom to operate Canada assessments for priority products, incorporating the updated eligibility analysis.
4. 31–90 days: Identify and instruct experts capable of testifying on the “inventive concept” characterisation from the perspective of the person skilled in the art.
5. 90+ days: Finalise NOA drafting with updated subject‑matter grounds and supporting evidence strategy.

Both sides should monitor Federal Court decisions through mid‑2026 for further judicial engagement with the framework. Early indications suggest that the Court is receptive to subject‑matter challenges framed in the “inventive concept” terminology, which means the window for proactive preparation is now, not after the first adverse ruling.

Conclusion

CIPO’s March 24, 2026 practice notice marks a pivotal moment for patentable subject matter in Canada. For pharmaceutical and biotech stakeholders, the notice is not merely a prosecution‑stage concern, it reshapes the validity landscape in Federal Court and PM(NOC) proceedings. Patentees who act now to audit claims, reframe inventive concepts and prepare targeted evidence will be in the strongest position to defend their portfolios. Generics who incorporate subject‑matter invalidity into their NOA strategy, supported by expert evidence aligned with the three‑step framework, stand to gain a powerful additional tool. The guidance is new, but the window for preparation is finite. Counsel on both sides should treat the next 90 days as critical.

For tailored advice on PM(NOC) readiness, claim redrafting or patent validity strategy under the updated framework, explore the Global Law Experts lawyer directory to connect with experienced IP litigation practitioners in Canada. Additional resources on cross‑border IP strategy are available in our guides on how to protect your intellectual property across borders and international intellectual property.

Sources

1. CIPO / ISED, March 24, 2026 Practice Notice
2. CIPO, Patentable Subject‑Matter under the Patent Act (general guidance)
3. Smart & Biggar, Technical Commentary
4. Gowling WLG, The Canadian Patent Eligibility Landscape (2025)
5. CanLII Connects, Dusome Commentary (Early 2026)
6. Canadian Bar Association, MOPOP Update on Patentable Subject‑Matter
7. ROBIC, Patentability and Ineligibility in Canada