The novel compound 8-Cyclopentyl-7-oxo-2-(4-piperazin-1-yl-phenyl amino)-7,8-dihydro-pyrido[2,3-d]pyrimidine-6-carbonitrileand pharmaceutically acceptable salts thereof are described as well as methods of their use in the treatment of cellular proliferative disorders including cancer.本文描述了新穎的化合物8-環戊基-7-側氧基-2-(4-哌嗪-1-基-苯基胺基)-7,8-二氫-吡啶[2,3-d]嘧啶-6-氰基及其藥學上可接受的鹽,以及使用它們治療包括癌症在內的細胞增生性疾病的方法。