Hydrogels: a broader interpretation for medical use patent protection in Europe

Dr. Heather West and Dr. Nicholas Watermeyer, patent attorneys at European intellectual property firm Withers & Rogers, both specialising in the firm’s Life Sciences and Chemistry Group, discuss the growing opportunity to patent hydrogels and explore emerging applications in the field.

Securing medical use patent protection in Europe may now be possible for a broader range of hydrogel products following a decision from the European Patent Office’s (EPO) Board of Appeal earlier this year. 

Whilst patenting novel hydrogels tends to be more straightforward, securing patent protection in Europe for new medical uses of existing hydrogels has been challenging. This is because, in Europe, medical use protection is not available for medical devices and is only available for “substances or compositions” for use in surgical, therapeutic or diagnostic methods. 

So, when is a hydrogel a “medical device”, and when is it a “substance or composition”? This has been an active area of EPO case law, and previously it was considered that a hydrogel must have a chemical mechanism of action, rather than a physical one, in order to qualify as a “substance or composition” and thus be eligible for medical use protection. This meant that hydrogels that acted in a physical way, such as a cement-like hydrogel filler material for a tooth, were classed as medical devices and could not be protected with medical use claims. This has posed a challenge for hydrogel innovators, faced with the rising cost of R&D without being able to secure medical use patent protection to help recoup their investment. 

The EPO has changed its approach in this recent decision, in a manner welcome for hydrogel innovators. The technology at the centre of the case related to self-assembling peptides for use in cancer treatment, that can be administered into a blood vessel where they aggregate to form a solid hydrogel, blocking the blood supply to a tumour. The patent application was initially refused under the previous approach of the EPO, because the blocking action of the peptide hydrogel was considered to be a purely physical mode of action, and the hydrogel was therefore classed as a medical device. However, this decision was overturned by the Board of Appeal, which came to the conclusion that there was no legal basis for the separation of medicinal products into the distinct categories of “medical devices” and “substances or compositions” based entirely on their mode of action being physical versus chemical.

Instead, the Board clarified that a product, such as a hydrogel, can be considered as a “substance or composition” for the purpose of a medical use claim if the claim clearly defines the chemical composition of the product and does not define device-like features of the product (such as shape). With regard to the peptide hydrogel of the present case, the Board found that the peptide solution was chemically defined by its amino acid sequence and was a shapeless liquid without any device-like features. The product was therefore considered a “substance or composition” and entitled to medical use protection.

Innovators in the hydrogel space will welcome this rebalanced approach, which opens up the possibility of medical use patent protection for a broader range of hydrogel products. European patent law is now catching up with the need to provide a complementary form of protection for useful hydrogel inventions in a field where technical development is highly desirable and beneficial.

Significant innovation is happening in the hydrogel space, with novel hydrogels continually being developed and new applications being tested. As an example of innovation taking place in the field of therapeutic hydrogels, researchers from Queen’s University Belfast have developed a long-acting, peptide hydrogel, drug delivery implant for the treatment of HIV/AIDs. The group has linked the established anti-HIV drug, zidovudine, to a short peptide which interacts with enzymes in the body to form a protease-resistant hydrogel. The hydrogel is long-lasting and allows sustained release of the anti-HIV drug, making this innovation particularly useful to address medication-adherence issues. It can also be easily and stably transported as a powder in areas with limited transport capabilities and inadequate storage conditions.

Another exciting innovation is a peptide-based hydrogel therapydeveloped by a multi-university team led by the New Jersey Institute of Technology. The peptides self-assemble into nanoscale fibrous hydrogels which form a multi-layer fibre on top of viruses, such as SARS-CoV-2, and are thought to mask the surface proteins of the virus to prevent the virus from attaching to and entering cells. 

The EPO’s decision is a positive step forward for hydrogel innovators, particularly those working with “shapeless” compositions. It is noted that this area of European case law is still developing, and there is no guarantee that this more lenient approach will be generally adopted, or that European national courts will follow suit. There is hope, however, that further research into new therapeutic uses of existing hydrogels will be driven by the refreshed approach of the EPO, and that innovators will be fairly compensated for their R&D investment. 

Dr Heather West and Dr Nicholas Watermeyer are patent attorneys at European intellectual property firm, Withers & Rogers. Both specialise in the firm’s Life Sciences and Chemistry group.