When it comes to filing patent applications, timing is everything: applications must be filed before any disclosures of the technology are made, as prior disclosures could undermine the validity of any subsequent patents. Although some countries, notably the US, operate a short grace period for inventor disclosures, key jurisdictions, including Europe, do not. A single filing (as an international application) will usually be made to eventually cover all territories of commercial interest, so the lack of a grace period in Europe will often determine when the application is filed.

Therefore, it is important that your patent attorneys are alerted before any disclosure so they can file an application if necessary. However, it is not necessarily best to file simply as early as possible. Provided that disclosures are controlled, it can be advantageous to wait as long as possible before filing any applications. In the vast majority of countries, patent term is 20 years from filing – not a huge amount of time when considering it takes roughly 10-15 years for a drug to be brought to market.
 
Thankfully, there are various ways in which the overall protection for therapeutic products can be extended. These require close coordination between in-house or external patent attorneys and researchers at every stage of drug development.

Screening in the lead generation phase gives rise to a wealth of in vitro data that can support broad patent filings before a clinical lead and any back-up compounds emerge. Clinical data is unlikely to be necessary for these filings and typically a rationale for why the demonstrated in vitro activity or animal data is relevant to treating disease will be sufficient. Filing patent applications at this stage without any data is generally unwise and the absence of data has led to unfavourable litigation outcomes in recent years for some of Europe’s top-selling medicines, for example the decision to uphold the revocation of AstraZeneca’s patent covering the active ingredient dapagliflozin (Forxiga) by the Court of Appeal in the UK.

In competitive areas of research, these filings can secure a broad footprint in the chemical or biological space that excludes third parties. If lead compounds are identified after the initial broad application is filed, a subsequent narrower application will restart the 20-year timeline, resulting in valuable additional exclusivity. The patents filed at this stage on the drug candidate itself – if well drafted and filed before any disclosures have been made – are often very difficult for generic companies to challenge, so companies can usually plan on the basis of the exclusivity they provide.

In addition, other inventions adjacent to the drug candidate can also arise in this phase, such as analytical methods, expression and purification methods, cell culture methods and media.

The opportunities for patent applications do not stop with new active substances. Pre-clinical development is challenging and can result in additional inventions. In particular, it is often possible to patent crystalline forms and co-crystals, where those forms have specific advantageous properties or – less frequently – a surprisingly advantageous salt form. These developments can add significant value to the IP protection for the eventual commercial product, if captured in a timely manner.

Straddling the preclinical and clinical phases is the development of a dosage form, which can range from entirely routine to extremely challenging, depending on factors such as loading, aqueous solubility of the drug, and delivery and release requirements. Where two drugs are being co-formulated, the challenges can multiply if their properties and requirements differ from each other. The sensitivity of biologics during manufacturing, shipping and storage adds additional complexity to formulation.

Formulators can work with patent attorneys to ensure that formulation patents are suitably broad to exclude future potential generic or biosimilar formulations that may be developed once the initial drug patents have expired; narrow formulation patents can be easily worked around to avoid infringement. These patents can be very valuable. For example, in 2025, Regeneron and Bayer successfully asserted a patent relating to a formulation of Eylea (aflibercept) against Formycon in a judgment spanning over 20 EU Member States: this led to Formycon agreeing a licence to market its biosimilar product.

Finally, medical devices such as features of auto-injectors and pre-filled syringes can give rise to patents and design rights.

Patent law in many jurisdictions, including Europe, is flexible in recognising novelty (one of the requirements for granting a patent) for medical use features, whether these relate to a new disease or condition for which the active has not previously been used, to dosing or dosage regimen features, to features arising from a newly identified drug-drug interaction, or to new subgroups of patients or new clinical applications. Significant value can be added by identifying and capturing these clinical stage inventions, especially when the IP can be aligned strategically with information that potential infringers will be required to include on the drug label, meaning that the patentee can readily show that the generic product infringes the patent. Generic companies may attempt to avoid infringement by omitting a patented indication from their drug label (‘skinny labelling’), but this strategy is not always successful. Skinny labels have been at issue in recent years in patent cases relating to empagliflozin (Jardiance), nilotinib (Tasigna) and fulvestrant (Faslodex), among other examples.

However, for these types of inventions, there is additional complexity due to the requirement to publish details of clinical trials before they commence and this publication requirement has only been extended in recent years under the new EU Clinical Trial Regulation. For patent applications filed after the publication of details of a clinical trial but relying on the results of that trial, it may be more difficult to establish inventive step (another requirement for granting a patent), because the patent might be considered obvious in view of the prior publication.

However, patent applications filed before publication of clinical trial details can also face challenges, because they will not include any data arising from the trial and may fall foul of rules introduced to avoid ‘armchair patent applications’. It is here, especially, where good communication between patent and regulatory teams is crucial to make sure that the maximum value is recognised for these developments from an IP perspective.

Once approved, most therapeutics will be eligible for patent term extension (known as supplementary protection certificates or SPCs in Europe), which allows for key patents to be extended for several years, often driving exclusivity for products.
 
Eligibility for SPC extension is a complex area of the law that is constantly evolving and early engagement with patent attorneys is important to make sure that companies can take advantage of the protection that may be available. Decisions taken by technical and regulatory colleagues can have implications for the availability of the SPC extensions and the type of patent that will be most valuable in this scenario is something that should be considered earlier rather than later in the development timeline.

All the IP rights discussed so far interplay with regulatory exclusivity – data and market exclusivity – that arises automatically when a drug is approved. The timing of approval determines the expiry of regulatory exclusivity and so can often determine the relative importance of the different patents relating to a drug that all have different expiry dates. With the new system of regulatory exclusivity being introduced with the EU’s Pharma Package, the considerations will only become more complex.

Strong patent portfolios deliver significant value to biopharma companies, and patents may arise from early stage research up to approval and beyond. The choices from the suite of options available will depend on the development path of the specific drug. Close communication between research and clinical teams and internal or external legal counsel is essential to ensure maximum advantage is taken of the available opportunities.

Carpmaels & Ransford is a European intellectual property firm, with a long-standing focus on the life sciences sector. The firm advises pharmaceutical and biotechnology companies on patent strategy, prosecution and enforcement across Europe.