The present invention relates generally to the field of anti-cancer therapy. More particularly, it provides novel crystalline forms of organic arsenic compounds and methods for their use in treating cancers such as leukemia and solid tumors.本發明主要係有關於抗癌症治療的領域,更特別地,係提供有機砷化合物的新穎結晶體以及使用這類化合物在癌症例如白血病和實性腫瘤的治療上的方法。