Compositions, combinations and methods comprising the administration of a CDK4/6 inhibitor of Formula D with a selective estrogen receptor downregulator of Formula A, B or C that are advantageous for the treatment of abnormal cellular proliferation, including a cancer or a tumor.本發明提供組合物、組合及方法,其包括投與式D之CDK4/6抑制劑與式A、B或C之選擇性雌激素受體下調節劑,該投與可有利於治療異常細胞增殖(包括癌症或腫瘤)。