The impact of stronger drug dosing patents on Canadian drug access

Canadians have long been proud of our universal healthcare system, and rightly so, even though confidence in the system’s performance and sustainability has waned in recent years, exacerbated by the weaknesses that were exposed during the COVID-19 pandemic. However, one consistent pain point and focus of reform within the system is the high cost of prescription drugs. Drug-related expenses rapidly outpace other healthcare costs and are the second-highest healthcare expenditure, even exceeding physician remuneration, and trailing only behind hospitals. High drug costs and restricted access to pharmaceuticals were the key impetus for the federal government’s proposed national pharmacare program.

One constant tension in Canadian and global pharmaceutical debates arises from the need to achieve a balance between encouraging drug research and development through patent protection, on the one hand, and the need to enable access to affordable generic and biosimilar drugs, on the other hand. There have been a number of notable developments in patent law over the last year that have shifted the balance further in favour of patent enforcement.

These developments enhance the ability of patent holders to assert patents related to dosage regimens of previously known medicines for previously known medical uses. The result is a prevention or delay of generic and biosimilar competition. These developments are likely to have meaningful impacts on the ability of generic and biosimilar manufacturers to market their products. The implication is therefore that generic and biosimilar manufacturers will need to carefully evaluate whether their product monographs might induce patent infringement and to explore innovative regulatory strategies to minimize such risk.

The balance between brand products and generic or biosimilar alternatives

For decades, reliance on generic drugs has been a proven strategy for reducing overall prescription drug costs. However, brand manufacturers can delay or prevent the introduction of generics and biosimilars to the Canadian market, including by securing multiple patents that extend protection to components beyond the drug’s active ingredient. These follow-on patents often extend to new or more specific uses, such as treatment for different diseases or dosing regimens or for new patient demographics. Given that each patent confers a 20-year exclusivity period, these use patents can effectively postpone accessibility to more affordable follow-on alternatives for significant periods of time. This delay in follow-on market entry necessarily maintains higher drug prices for a corresponding period of time and can impede cost savings.

Canadian pharmaceutical patent policy rightly seeks to support effective patent enforcement, while still enabling timely access to affordable generic and biosimilar drugs. The balance is a delicate one, intended to properly reward medical innovation while managing healthcare costs. When the balance tips too far in either direction, Canadians pay the price.

Dosage regimen patents as a new tool for brand manufacturers

It is well understood that patents are available for medicinal ingredients. Although once controversial, it is also now well settled that new patents are specifically available in Canada for novel uses of known medicinal ingredients. For example, if a drug was known to be useful for cancer and was patented on that basis, a patent may still be available if it is unexpectedly found that the drug is useful for treating diabetes as well.

Although not as well understood, it is also possible to obtain a patent on a dosing regimen for a known drug for a known use. Such a patent may be obtainable, for example, where a new regimen for prescribing the drug — such as revised dosage amounts, frequency and duration — achieves better patient outcomes. These benefits could be demonstrated through increased efficacy or fewer or less severe side effects. These latter patents are particularly valuable to pharmaceutical companies as their expiry dates are often significantly later than the patents on a medicinal ingredient or novel use.

There is significant risk that recent jurisprudence has shifted the balance between patent protection and drug accessibility in a manner that will materially challenge the potential for timely access to affordable generic alternatives.

In Canada, if a drug manufacturer wishes to launch a generic or biosimilar product, they are required to notify the brand manufacturer. The brand manufacturer then has an opportunity to assert, within 45 days, certain patents through a lawsuit and prevent or delay approval of the generic product for 24 months or until the lawsuit is resolved. During this period, dosage regimen patents are among the patents that can be asserted and, if asserted successfully, they can delay generic or biosimilar entry for many years.

To avoid having their market entry blocked by dosage regimen patents, generic and biosimilar manufacturers have long taken the view that, as long as they are not directing physicians to carry out a patented dosage regimen (i.e., through their approved product monograph), they do not induce infringement of a dosage regimen patent and should therefore be permitted to market their product. Canadian law has traditionally aligned with this view, requiring that acts of infringement be so influenced by the acts of the generic or biosimilar manufacturer that, without the influence, direct infringement would not occur. This standard is difficult for brand manufacturers to meet in circumstances where generic and biosimilar manufacturers are not actually influencing physicians through dosage instructions in the product monograph.

The Federal Court of Appeal strengthens dosage regimen patents

Canada’s Federal Court of Appeal (FCA) has issued several decisions this year signalling that the threshold for a generic manufacturer’s infringement of a dosage regimen is not as high a hurdle to meet as previously understood.

In one case, a generic manufacturer sought to bring to market a drug, macitentan, as a monotherapy. A patent existed for therapeutic use of the drug in combination with another drug. Although combination therapy was not expressly referenced in the generic manufacturer’s product literature for the monotherapy, their product monograph referenced a clinical study indicating that both the combined therapy and the monotherapy were safe and efficacious. The Federal Court of Appeal upheld, on appeal, the Federal Court’s determination that this reference was sufficient to induce infringement of the patented combination therapy. The FCA clarified that the generic manufacturer was not shielded from an infringement claim due to the fact that physicians exercise their professional judgment in prescribing drugs. On the contrary, the FCA found it was open to the Federal Court to find that the manufacturer knew or ought to have known that its product monograph would influence physician decisions.

In a separate dosage regimen case involving a different drug, paliperidone, the FCA further clarified that a finding of infringement does not depend on showing that the prescribing practices of physicians had changed due to the generic manufacturer’s activities. The FCA reasoned that although activities by patients and prescribers had previously been non-infringing because the drug was sourced from the brand manufacturer, they would become infringing once the drug was sourced from the generic manufacturer. As a result, the generic manufacturer would induce infringement.

The Supreme Court of Canada denied leave to appeal in each of these dosage regimen cases, as well as several others, leaving the FCA’s latest rulings as the current state of the law.

As a result of these decisions, dosage regimen patents have become more challenging for generic and biosimilar manufacturers to work around. If these patents cannot be avoided despite a generic or biosimilar manufacturer’s intent to do so, they will have the effect of preventing market entry of the generic or biosimilar drug altogether, even for unpatented uses. There is significant risk that recent jurisprudence has shifted the balance between patent protection and drug accessibility in a manner that will materially challenge the potential for timely access to affordable alternatives. Where legitimate unpatented use is prevented, Canadians will be denied the potential for low-cost alternatives in circumstances where access could be facilitated.

The Supreme Court of Canada is poised to weigh in on dosage regimen patents

Although the Supreme Court of Canada refused to review the cases addressing infringement of dosage regimen patents, the Supreme Court recently granted leave to appeal on the issue of whether a dosage regimen itself is unpatentable on the basis that it is a method of medical treatment that interferes with the exercise of skill and judgment by a physician. For 50 years, methods of medical treatment that interfere with the exercise of medical skill and judgment have been ineligible for patents in Canada. This case will evaluate whether and when dosage regimens may constitute unpatentable methods of medical treatment, potentially obviating the FCA’s recent infringement decisions.

In the case on appeal to the Supreme Court, the FCA ruled that a dosage regimen or other method of medical treatment is not patentable when use of the invention — namely, how to use the invention rather than whether to use it — requires the exercise of skill and judgment. The ruling provides a broader exception to patentability than some earlier decisions that restricted the exception to dosage regimens directed to a range of doses rather than to a fixed dose. Prior decisions found claims unpatentable where the decision about whether, in addition to how, to use the invention would interfere with a physician’s skill and judgment. The FCA’s ruling provides for a narrower exception.

Impact on pharmaceutical policy in 2025

In light of the recent decisions upholding the effectiveness of dosage regimen patents, the Supreme Court of Canada’s forthcoming decision will have a significant impact on the balance between patent enforcement and access to affordable generic and biosimilar alternatives. Although not yet scheduled, the hearing of this case is likely to occur toward late 2025. While the FCA decisions provide clear statements of law in relation to which the Supreme Court elected not to allow an appeal, the pending appeal that the Court has determined to hear will hopefully provide clear direction regarding the availability of dosage regimen patents.

The outcome will determine whether drug costs are likely to become more of a pain point over the coming years or whether the pain is likely to subside. Either way, the decision has the potential for a dramatic impact on pharmaceutical policy, including the planned national pharmacare program. Brand, generic and biosimilar manufacturers are well advised to monitor these developments closely as we move into 2025.