Aasen has participated in about twenty lawsuits dealing with drugs and patent infringements either as an expert co-judge of Borgarting Court of Appeal,Co-judge in Borgarting Court of Appeal (in Norwegian) the District Courts of Asker and Bærum, Follo, and Oslo, or an expert for one of the parties in Norway and in New York, USA. He has since 2000 been consultant for the Norwegian registries of drugs used in humanStated in the introduction of Felleskatalogen over Farmasøytiske Spesialpreparater markedsført i Norge e.g. in the 2009-edition and veterinaryStated in the introduction of Felleskatalogen over Farmasøytiske Preparater markedsført i Norge til bruk i veterinærmedisinen e.g. in the 2014 - 2015-edition medicine.
