The specification generally relates to the compound of Formula (I), i.e. to N,N-dimethyl-3-[[5-(3-methyl-2-oxo-l-tetrahydropyran-4-yl-imidazo[4,5-c]quinolin-8-yl)-2-pyridyl]oxy]propan-l-amine oxide as ATM (ataxia telangiectasia mutated) kinase modulator for treating cancer.La présente invention concerne généralement le composé de formule (I), cest-à-dire loxyde de N,N-diméthyl-3-[[5-(3-méthyl-2-oxo-1-tétrahydropyran-4-yl-imidazo[4,5-c]quinolin-8-yl)-2-pyridyl]oxy]propan-1-amine utilisé comme modulateur de la protéine kinase ATM (ataxia telangiectasia mutated) pour traiter le cancer.