Die Erfindung betrifft (5s,8s)-3-(4-Chlor-3-fluor-4-methylbiphenyl-3-yl)-4-hydroxy-8-methoxy-1-azaspiro[4.5]dec-3-en-2-on zu therapeutischen Zwecken, Pharmazeutische Mittel und deren Verwendung in der Therapie, insbesondere zur Prophylaxe und Therapie von Tumorerkrankungen.The present invention relates to (5s, 8s) - 3 - (4 - chlorine - 3 - fluorine - 4 - methyl biphenyl - 3 - y) - 4 - hydroxy - 8 - methoxy - 1 - azaspiro- [4.5] dec - 3 - s - 2 - on for therapeutic purposes, to pharmaceutical compositions and their use in therapy, in particular for the prophylaxis and treatment of tumour diseases.