The present invention relates to 7-(4,7-diazaspiro[2.5]octan-7-yl)-2-(2,8-dimethylimidazo[1,2-b]pyridazin-6-yl)pyrido[1,2-a]pyrimidin-4-one for use in the treatment of spinal muscular atrophy (SMA), its pharmaceutical composition to be used in the treatment of SMA, its methods of treatment thereof.本發明係關於用於治療脊髓性肌萎縮(SMA)之7-(4,7-二氮雜螺[2.5]辛-7-基)-2-(2,8-二甲基咪唑并[1,2-b]嗒嗪-6-基)吡啶并[1,2-a]嘧啶-4-酮、用於治療SMA之其醫藥組合物、其治療方法。