Personalized Medicine and the Ocular Surface

Abstract

again I am having thoughts flying home from the ASCPT convention. The most dominant theme I heard this year was “personalized medicine,” 4 in which pharmacotherapy is individualized based upon the individual’s genetic and other characteristics. There are several examples of personalized medicine already in use in systemic medicine. Trastuzumab is indicated for the treatment of patients with metastatic breast cancer whose tumors overexpress the HER2 protein (Herceptin ® package insert, Genentech, South San Francisco, CA). A genetic test is performed on each patient’s tumor, and trastuzumab is administered only to patients with the HER2 protein overexpression. Warfarin, a drug used for its anticoagulant effects since 1954, has always been challenging to titrate, given its relatively low therapeutic index. Recently, it has been shown that better prediction of optimal dose was attained with additional incorporation of genetic information on CYP2C9, which metabolizes the more active form (S-) of warfarin, and VKORC1, the enzyme responsible for vitamin K metabolism and the target for warfarin action, rather than clinical data (eg, age and weight) alone. The FDA recently modified the package insert for warfarin to include evaluation of both CYP2C9 and VKORC1 genetic information in the “Dosage and Administration” section. 5