Novel selective estrogen receptor degraders (SERDs) according to the formula:,pharmaceutically acceptable salts thereof, and pharmaceutical compositions thereof, wherein either R1or R2is independently selected from Cl, F, -CF3, or -CH3, and the other is hydrogen, and methods for their use are provided.本發明提供根據下式之新穎選擇性雌激素受體降解劑(SERDs):、其醫藥上可接受之鹽,及其醫藥組合物,其中R1或R2係獨立地選自Cl、F、-CF3或-CH3,及另一者係氫,及其使用方法。