 5. Subjects with breast cancer must have been treated with at least two FDA-approved anti-HER2 directed therapies more than two is also permissible, and subjects with gastric and gastroesophageal junction cancers must have been treated with at least one FDA-approved anti-HER2 directed therapy more than one is also permissible; and all subjects must have refractory or relapsedprogressive disease during or following their last prior anti-HER2 directed therapy. 