Cwengile Cwele | Patent Candidate Attorney | Spoor & Fisher | mail me |
with oversight by Chyreene Truluck | Partner | Spoor & Fisher | mail me |
As gene therapy technologies continue to reshape modern medicine, patent law increasingly faces a difficult task. Courts must distinguish products of nature from genuine biological engineering. They frequently decide whether inventions involving genetic material represent technological innovation or merely identify naturally occurring biological features.
This issue sat at the heart of the recent United States gene therapy patent dispute between REGENXBIO and Sarepta Therapeutics. On 20 February 2026, the United States Court of Appeals for the Federal Circuit reversed a District Court ruling.
The lower court had concluded that REGENXBIO’s claims related to a natural phenomenon and therefore fell outside patent protection. Although the decision arose under US law, it offers useful guidance for patent practitioners in other jurisdictions, including South Africa. It also contributes to the broader conversation around patenting genetic innovation.
The dispute and the ruling
The dispute concerns a patent licensed by REGENXBIO. The patent covers recombinant host cells used to manufacture Adeno-Associated Virus (AAV) vectors. These vectors serve as key delivery vehicles for therapeutic genetic material in gene therapy.
Sarepta Therapeutics developed a treatment for Duchenne muscular dystrophy using an AAV-based delivery system. REGENXBIO alleged that Sarepta’s manufacturing process infringed its licensed patent. Specifically, it argued that Sarepta used engineered host cells covered by the patent to produce these vectors.
The United States District Court ruled in favour of Sarepta. It found that the patent claims related to naturally occurring biological materials. Consequently, the court concluded that the claims did not qualify for patent protection. However, the Federal Circuit unanimously rejected this reasoning. It determined that the claimed host cells “do not and cannot exist in nature”.
These cells contain modified DNA produced through deliberate human intervention. They also combine genetic material from different species in ways that natural processes do not replicate. This reasoning strengthens the legal framework surrounding patenting genetic innovation. In reaching this conclusion, the court drew parallels with the earlier Myriad Genetics case. In that matter, the court held that naturally occurring DNA does not qualify for patent protection. By contrast, synthetic DNA created in a laboratory may qualify because it does not exist in nature.
Accordingly, this decision reaffirms an important principle. Human-engineered biological products may qualify for patent protection when they demonstrate meaningful differences from naturally occurring systems. This distinction remains central to patenting genetic innovation.
Implications for South African patent law
Although the REGENXBIO decision arose under US law, it highlights important structural differences between the United States and South African patent systems. These differences carry particular significance for biotechnology inventions.
South African patent law operates under the Patents Act 57 of 1978. Unlike the United States, South Africa does not apply an extensive “natural phenomenon” doctrine.
While the South African Patents Act excludes discoveries and certain abstract subject matter from patentability, it does not contain a judicial doctrine equivalent to the US restrictions on natural phenomena. Consequently, South African law generally regards engineered biological constructs as patentable subject matter. Examples include recombinant viral vectors, host cells and nucleic acid constructs. However, these inventions must still satisfy the traditional requirements of novelty, inventive step, and industrial applicability.
In practice, inventions resembling those in the REGENXBIO dispute are less likely to encounter patent eligibility challenges in South Africa. This position provides a more predictable environment for patenting genetic innovation.
Another important distinction involves the procedural framework governing patent grants. South Africa currently follows a formalities-based, non-substantive examination system. Patent authorities, therefore, assess applications only for compliance with formal requirements before granting patents. As a result, authorities do not evaluate patents involving recombinant DNA technologies or engineered host cells for inventive step or patent eligibility before grant. Instead, these issues typically arise during infringement litigation or revocation proceedings. However, the REGENXBIO case highlights the extent to which technical questions about molecular engineering can dominate patent disputes.
If similar matters arise locally, South African courts will likely engage with comparable issues. They will need to determine whether an invention reflects genuine technological advancement rather than a simple discovery.
Lessons for biotechnology innovators
For biotechnology innovators and patent attorneys in South Africa, the REGENXBIO decision offers several practical lessons. Patent specifications should clearly demonstrate that engineered biological inventions possess “markedly different characteristics” from natural systems.
Drafters should describe both structural modifications and functional differences from natural biological processes. They should also highlight non-natural combinations of genetic elements. In addition, they should emphasise the role of human intervention in producing the claimed invention. These strategies strengthen arguments supporting patenting genetic innovation.
Biotechnology innovation also operates within a global legal environment. South African innovators frequently seek patent protection across multiple jurisdictions, including the United States and Europe. As a result, developments in international case law can shape filing strategies. They can also influence patent claim drafting and freedom-to-operate analyses.
Finally, South Africa currently maintains a deposit system. However, the government has signalled a long-term intention to transition toward substantive examination. Once these reforms take effect, questions similar to those raised in the REGENXBIO case may become relevant to local examination practices. Future developments could therefore reshape how practitioners approach patenting genetic innovation in South Africa.
In conclusion
The Federal Circuit’s decision in REGENXBIO v Sarepta marks an important development in biotechnology patent law. By recognising the patent eligibility of engineered host cells containing modified genetic material, the court reaffirmed that modern genetic engineering can produce inventions fundamentally distinct from the natural biological systems on which they build.
For South Africa, where many high-value life sciences inventions receive protection, the case highlights several priorities. Practitioners must draft robust and technically detailed patent specifications. They must frame biotechnology inventions as engineered innovations rather than discoveries. They must also anticipate potential validity challenges during litigation, even within a non-examining patent system.
As gene therapy and plant biotechnology continue to grow in importance, decisions such as REGENXBIO will increasingly shape legal and professional thinking. They will inform how courts and practitioners assess the patentability of complex biological technologies. In doing so, they will continue influencing the evolving landscape of patenting genetic innovation.
