The European Patent Office (EPO) has revoked Tarrytown, New York–based Regeneron's patent on VelociMab, a mouse expression system for generating monoclonal antibodies, saying it lacked an inventive step as required by European patent law. Though the opposition procedure requested by European companies Kymab, Novo Nordisk and Merus renders the patent invalid, it remains in force as Regeneron has signaled its intention to appeal the decision to the EPO's Technical Board of Appeal.