ProQR Therapeutics N.V. has successfully defended against two oppositions that were filed against a key patent for its ADAR-mediated RNA editing platform Axiomer(R). The oppositions were filed in February 2021 with the European Patent Office (EPO) by two separate strawmen against ProQR's granted patent EP 3234134 B1, which is related to targeted RNA editing using endogenous ADARs and is part of ProQR's intellectual property estate surrounding its Axiomer RNA editing platform. The Opposition Division of the EPO held a public hearing on March 7 and 8, 2023 and ruled in favor of ProQR's position, after a minor amendment of the main claim and one dependent claim.

ProQR invented the use of endogenous ADAR in RNA editing in 2014 and filed a first patent application in that same year. Since then, ProQR has filed multiple additional patent applications on further improvements to form a leading patent estate that supports ProQR's ADAR-mediated RNA editing platform Axiomer. ProQR has extensive patent protection related to Axiomer, including 10 published patent families, that currently comprise a total of 22 patents.

Beyond this, ProQR has several unpublished patent applications and continuously invests in expanding its IP estate around ADAR-mediated RNA editing.