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Defence of key patent related to Hunter syndrome at EPO Opposition

REGENXBIO is a leading clinical-stage biotechnology company developing pioneering gene therapy candidates for the treatment of retinal, metabolic and neurodegenerative diseases.  Their product candidates utilise AAV viral vectors from their proprietary NAV® Technology Platform for gene delivery.

We have handled some of the REGENXBIO European patent portfolio for a number of years, particularly their portfolio concerning the use of AAV viral vectors in treating lysosomal storage disorders, which are a group of genetic conditions caused by a biological enzyme deficiency.  These conditions are life-limiting, multi-systemic and usually progressive.

We successfully prosecuted one of REGENXBIO’s key European patent applications to grant coving their RGX-121 product candidate for the treatment of Mucopolysaccharidosis Type II (MPS II), also known as Hunter syndrome (EP3294323).  Following grant, their patent was opposed centrally at the European patent office (EPO) by an anonymous opponent through their European representative.

Working closely with the team at REGENXBIO and their US attorneys Schwegman Lundberg & Woessner, Life Sciences partner Charlotte Teall successfully defended this key European patent during the opposition proceedings resulting in rejection of the opposition.  This means that this patent was upheld as granted.

How we helped

In July 2022, an anonymous opponent filed an opposition against EP3294323 through their European representative. Their main allegations were that the claims were not novel or inventive over a conference abstract and/or various other documents concerning therapies using AAV vectors.

In their preliminary opinion, the opposition division at the EPO questioned the availability of the conference abstract as prior art and alluded to a find that the claims would not be novel and inventive if the document was prior art. They also referenced other prior art as potentially anticipating the claims.

We filed detailed technical and legal submissions, which convinced the opposition division that none of the cited prior art disclosed or prompted the skilled person to the use of the claimed AAV viral vectors in treating MPS II with a reasonable expectation of success. We submitted declarations confirming that the testing done by the inventors, as corroborated by the subsequent clinical trial data, shows that the claimed invention enhances neurocognition in MPS II patients, which has not been successfully achieved before.

Results

Charlotte Teall was able to overcome the preliminary opinion and the opponent’s reply and successfully persuaded the opposition division to reject the opposition.

This was a resounding success for REGENXBIO which is focusing its efforts on commercial development and enhancing the quality of the lives of MPS II patients.