On Weeks 1-24 you will take lapatinib every day by mouth with water (about 8 ounces). It should be taken at least 1 hour before or at least 2 hours after eating. It is important that you take the study drug at about the same time every day. You should not eat pamelo fruit, grapefruit, star fruit, pawpaw, and/or drink their juices while on study.