Collectively, rare diseases impact approximately 8% of the Australian population, or around 2 million people. Orphan drugs are pharmaceutical products developed to treat rare diseases, however with each drug involving small patient populations and high development costs, these therapies require carefully crafted patent and regulatory strategies to be commercially viable.
In the first of our two part series on orphan drug development, we look at some of the key patenting considerations. In the second article, we examine how orphan drugs are defined and the regulatory considerations for them.
Patent strategies for orphan drugs: Start early, think long
A robust patent strategy for orphan drugs, as with other drugs, generally involves both primary patents, covering the substance, and often including claims to method of manufacture, formulation and the like, and secondary patents covering other key aspects of the substance, such as newer methods of manufacture, medical uses for lead indications or improved formulations.
Additional patent filings can be critical for orphan drugs, as it can take at least 10 years, and often longer, to bring a drug to market. By the time an orphan drug receives marketing approval, there may be limited patent term remaining to provide exclusive rights. For this reason, sponsors often seek further patents covering aspects such as new medical uses, dosing regimens, formulations, delivery routes, combination therapies, or treatment of specific patient subgroups.
This approach is often referred to as "evergreening", a strategy in which pharmaceutical companies extend the effective life of their patent monopolies by filing multiple follow-on or secondary patents around an original invention. These patents may relate to relatively minor changes, such as new formulations, dosages, or methods of use, and may offer limited inventive advances. Evergreening is common for high-cost, high-selling drugs and is particularly relevant for orphan drugs.
While such follow-on patents can be a legitimate means of protecting the significant investment required to develop new therapies, they should be pursued transparently, grounded in scientific merit, and applied ethically to avoid delaying access to affordable medicines.
Examples of common claim types relevant to orphan drug development include:
1. Claims to the substance: Where available, these claims offer the strongest form of protection. If it is possible to patent the relevant class or subclass of compounds, that should also be considered at an early stage, as this would create a broader fence around the core IP.
2. Claims to medical uses: There are various forms in which claims to medical uses can take depending on the jurisdiction:
Method of treatment claims: These claims typically take the form of "A method of treating disease Y comprising administering compound X to a subject in need thereof." While this form is available in Australia and the United States, they are not acceptable in many other jurisdictions including Europe, Canada, China, India, and New Zealand. These claims are particularly useful where dosing regimens, treatment schedules, or routes of administration form part of the inventive contribution.
Swiss-style claims: These claims typically take the form of "Use of compound X in the manufacture of a medicament for treating disease Y". These are designed to capture infringement by manufacturers or suppliers who produce or market a medicament for the patented therapeutic use. These claims may also be, and often are, used in Australia, in addition to the above method of treatment claims since they can capture infringement under different circumstances. Other countries that accept these claims include New Zealand, Japan and Canada.
The 'purpose limited' EPC 2000 format: Noted for completeness, this claim type is in the form of "Compound X for use in treating disease Y", and is the preferred form under the current European Patent Convention.
3. Formulation and delivery claims: These claims can cover the formulation per se, modifications thereof, such as sustained-release mechanisms, liposomal carriers, or targeted delivery. This claim format can be a valuable source of additional protection. These claims can under certain circumstances sidestep some of the prior art issues affecting use claims.
4. Biomarker-based claims: When a drug is particularly effective in patients with a specific biomarker, claims directed to methods of treatment for those biomarker-defined subpopulations can be pursued. This is especially relevant for personalised medicine approaches in rare diseases with genetic causes.
5. Method of manufacture/process claims: If the drug involves a novel or improved method of synthesis, these claims can offer added value, albeit with narrower prospects for enforcement. In some cases, scalable or green synthesis methods may offer additional leverage in partnering discussions.
6. Combination therapy claims: Many orphan drugs are used in combination with other agents. Where possible, securing claims to synergistic combinations or dosage regimens can extend exclusivity, especially when the individual components are off-patent.
Patent Term Extension: a crucial window
In Australia, patent term extension (PTE) provides a mechanism whereby a patentee may apply for an extension of up to five years for a standard patent that claims a pharmaceutical substance, in recognition of the long development timelines and regulatory burdens associated with bringing new medicines to market.
This mechanism may be relevant where the orphan drug is a new drug, and has not previously been included on the Australian Register of Therapeutic Goods (ARTG). Clinical development of these drugs may be particularly prolonged by funding constraints, recruitment challenges and limited trial populations.
To qualify, the patent must claim: (i) one or more pharmaceutical substances per se, and/ or (ii) pharmaceutical substance(s) produced by recombinant DNA technology. Goods containing, or consisting of, the substance must also be included on ARTG. The PTE is calculated based on the first regulatory approval date of a product containing that substance.
An important consideration arises when a patent covers more than one pharmaceutical substance that ultimately receives regulatory approval. Under Australian law, any extension of term must be based on the product that first obtains registration on the ARTG, even if that product is owned by a third party.
This can be particularly significant for orphan drugs, where the patentee may be relying on a later-approved product for commercialisation. If an earlier-approved product encompassed by the same patent has already triggered the calculation of the extension period, it may substantially reduce, or entirely eliminate, the available term extension for the orphan drug.
In other words, the patentee has no discretion to nominate a different, later-approved product to maximise the extension period. Furthermore, it is also important to note that if a product is registered less than five years after the patent's filing date, no effective extension will be available, regardless of when the second product receives approval.
In Australia, divisional filings may offer a strategic workaround where a patent covers multiple pharmaceutical substances. By filing a divisional for each individual substance, particularly where separate commercial products are expected to receive ARTG registration at different times, applicants may preserve the ability to obtain separate and potentially longer PTEs provided that each divisional patent meets the eligibility criteria.
This strategy can be especially important in the orphan drug context, where market sizes are small, and delays in approval can have a disproportionate impact on commercial viability.
How we can help
Navigating the complex landscape of orphan drug protection requires careful planning and tailored IP strategies. If you are developing treatments for rare diseases and would like guidance on maximising exclusivity and managing regulatory challenges in Australia, please reach out to the team to discuss how we can help.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
