Gene therapy is revolutionising the field of molecular medicine and the capabilities of therapeutic approaches. Recent developments demonstrate the potential for gene therapy to address some of mankind’s most devastating diseases, unlocking previously unfathomable solutions which could transform people’s lives. As innovation accelerates, strong patent protection is essential to navigate rising IP disputes and safeguard gene therapy advances.
Introduction to gene therapy
Gene therapy is a medical technology which mitigates or eradicates the symptoms of diseases by transferring genetic material to a patient or correcting genetic defects. It can be achieved in several ways.
- Gene replacement delivers a functional copy of a gene to compensate for a defective one, making it especially useful for recessive monogenic diseases.
- Gene silencing reduces the expression of harmful genes, often through RNA interference or CRISPR–Cas13 targeting of pathogenic mRNA.
- Gene editing directly modifies endogenous DNA using tools like CRISPR-Cas9, zinc-finger nucleases, TALENs, or newer base and prime editors. These technologies allow targeted correction or disruption of disease-causing genes with increasing precision.
The genetic material can be delivered to the patient via viral and non-viral systems. For example, viral vectors such as adeno-associated virus (AAV) are preferable for in vivo use due to their safety and tissue specificity. Non-viral systems (such as lipid nanoparticles and polymer-based carriers) usually offer improved safety and flexibility but typically lower delivery efficiency.
Today, gene therapy is applied to an increasingly wide set of diseases. An analysis of patent activity shows that oncology accounts for roughly 32% of the gene therapy market, followed by rare genetic disorders (27%), cardiovascular diseases (15%), and neurological disorders (12%).
Recent innovation in the field
Whilst gene therapy is still predominantly limited to research and clinical trials, with over 250 clinical trials running in Europe and only around 20 therapies on the market, broader clinical adoption is getting closer.
The UK’s Medicine and Healthcare products Regulatory Agency (MHRA) approved the world’s first CRISPR-gene therapy in November 2023 and it is now available on the NHS in England. Named CASGEVY®, the drug (exagamglogene autotemcel) uses CRISPR-Cas9 to alter human stem cells to produce functional rather than defective haemoglobin, treating sickle cell disease and beta thalassemia.
Other advances are also setting the field into motion, such as innovations in delivery methods. Among these, AAVs are emerging as a major force in the gene therapy market. In June this year, Barcelona-based startup, SpliceBio, secured €118 million in a series B finance round to fund their development of AAVs with refined capabilities, able to carry longer genes.
The rapid rise of AI in biomedical research is also transforming how scientists design and test new therapies, including in gene editing. Stanford Medicine researchers have introduced CRISPR-GPT, an AI “copilot” that draws on extensive scientific literature and lab records to propose experimental designs, predict off-target risks, and justify its recommendations.
The patent wars
There are currently over 14,000 patent families related to gene therapy worldwide. Early patents mainly targeted basic delivery mechanisms and methodological approaches, but the focus has grown more specific over time, covering specific disease indications, vector designs and genetic modification techniques.
CRISPR-Cas9 in particular has been the topic of a major dispute over the last decade and the contest for the foundational patent rights is still ongoing. CRISPR-Cas9 was introduced as a programmable gene-editing tool in 2012 by Jennifer Doudna and Emmanuelle Charpentier, a discovery that later earned them the 2020 Nobel Prize in Chemistry. Around the same time, Feng Zhang and the Broad Institute demonstrated its use in mammalian cells, triggering a long-running patent battle. This leads to uncertainty and legal risks which impede those who wish to use CRISPR.
CVC
In Europe, one of the two leading CRISPR patent portfolios is held by the team behind the Nobel-winning discovery, collectively known as “CVC” (the University of California, the University of Vienna and Emmanuelle Charpentier). Their core rights are based on the fundamental patent family originating from parent application EP2800811, along with a series of divisional filings. The patents EP2800811 and EP3401400 (one of the divisional applications in the family) were originally maintained by the EPO Opposition Division, but these decisions were appealed. In its preliminary opinions, the Board of Appeal found that neither patent could rely on the earliest priority date because the earliest priority document failed to disclose the essential PAM sequence required by the CRISPR-Cas9 technology, rendering the claims not novel over the Science publication from the same inventors.
CVC decided to withdraw their approval of the granted texts in 2024, effectively revoking both patents to possibly avoid an adverse final decision that could negatively affect their broader CRISPR portfolio (see our relevant article here). The patent family still includes other active members including EP3597749, EP4289948 and EP4570908, with EP3597749 and EP4289948 already facing opposition. We can expect further disputes as the CRISPR patent landscape continues to evolve.
The Broad Institute
On the other hand, the Broad Institute (together with the Massachusetts Institute of Technology and Harvard College as co-applicants) also obtained early patent rights in Europe based on the patent family originating from parent application EP2771468. The patent was revoked in 2020 on the basis of intervening art that only became citeable due to invalid priority (in which one of the opponents was represented by Mathys & Squire). In this regard, the Board of Appeal held that a priority claim was deemed invalid if a proprietor was unable to show, when challenged, that the applicants for the subsequent application included all of the applicants for the priority application or their successor(s) in title at the time the subsequent application was filed (see our earlier articles here and here).
Interestingly, the recent decision G1/22 issued by the Enlarged Board of Appeal has significantly relaxed the EPO’s approach to “same applicant” priority. The EBA decided that there is a “rebuttable presumption” that the priority applicants approve of the subsequent applicants’ entitlement to priority, regardless of any difference in names (see our earlier article here). The divisional patents EP2784162 and EP2896697, and the relevant patent EP2764103 were originally revoked by the Opposition Division under similar reasons as with EP2771468, but the Board of Appeal have decided to return these cases back to the Opposition Division as the priority entitlement is now considered valid. Opposition proceedings are ongoing, and it will be interesting to see how these cases ultimately unfold.
Recent developments
Other companies have also been entering the legal battlefield in recent years. ToolGen, for example, filed an infringement suit against Vertex’s CASGEVY® therapy in April 2025 in the UK. The ongoing wave of disputes illustrates that the CRISPR and gene therapy patent landscape remains highly competitive. Thus, securing robust patent protection is crucial for companies seeking to commercialise their technologies.
How to protect innovation in gene therapy
Protecting gene therapy technology in Europe requires an early, well-structured patent strategy.
The foundation of any successful patent strategy is a comprehensive freedom-to-operate (FTO) analysis, which should be conducted as early as reasonably possible in the development pipeline. FTO searching allows innovators to identify third-party patents that may block research or manufacture of a gene therapy product. This is especially important in fields such as CRISPR-Cas systems, where multiple parties hold overlapping rights. An FTO review not only helps avoid infringement but can also inform strategic design-arounds, licensing decisions, and the scope of future patent filings.
Equally critical is the issue of valid priority filing, an area that has been at the centre of some of the most high-profile European disputes in gene editing as discussed above. The EPO is well known to be very strict on added matter, and it extends to the assessment of priority validity. The priority filing should include all essential features of the invention and the way for performing the invention that are later claimed. Omissions can result in the loss of the earliest filing date and, consequently, exposure to intervening prior art. Although the recent decision G 1/22 appears to have relaxed the “same applicant” priority rule in Europe, the underlying requirement of adequate technical disclosure remains stringent and fundamental.
Patent drafting
When drafting the patent application itself, a successful strategy typically involves pursuing multiple categories of claims. For gene therapy inventions, this may include:
- Composition of matter claims for the drug product, which might include specific nucleic acid, Cas enzymes, engineered cells, viral vectors, lipid nanoparticles or other delivery vehicles
- Sequence-specific claims for novel nucleic acid sequences
- Medical use claims for using the gene therapy product as a medicament or to treat specific diseases.
- Formulation claims for the specific solutions, buffers or excipients used to stabilise and deliver gene therapy components
- Dosage regimen and administration-route claims for optimised therapeutic windows and dosing approaches
- Manufacturing and process claims for nucleic acid production, cell-expansion protocols, vector-production methods, or purification steps involved in the production of the gene therapy product.
In view of the complexity of gene therapy patents, it is important to seek professional support. The application must be drafted effectively to secure appropriate breadth of protection, while also facilitating a smoother path to grant.
SPCs
Finally, as products approach regulatory approval, innovators might also consider Supplementary Protection Certificates (SPCs). SPCs extend protection for medicinal products beyond the standard 20-year patent term. This compensates for the time lost during regulatory review. Gene therapy products authorised in the EU may be eligible for SPC protection, provided they meet the regulatory and patent linkage criteria. Our professional team can guide applicants through SPC strategy and the application process (see here for further information).
Gene therapy is advancing rapidly, but its patent landscape remains complex and highly competitive. Careful strategy including strong priority filings, thoughtful claim drafting and early FTO analysis is essential. Robust IP protection allows innovators to focus on advancing therapies rather than defending their inventions.
