The Current Issues on Development and Clinical Use of Companion Diagnostics and Prospects of Personalized Medicine for the Future

Recently companion diagnostics (CoDx) have been getting more importance to promote personalized medicine which can improve not only the efficacy and safety of treatments but also increase the cost-effectiveness of medication. In July 2011, the U.S. Food and Drug Administration (FDA) notified the draft guidance for development of CoDx that recommends co-development of CoDx and a new drug as the best practice. The Ministry of Health, Labour and Welfare in Japan also issued on July 1, 2013, their official notification regarding considerable items on co-development of CoDx if the drug needs its dedicate diagnostics test or medical device to predict the efficacy or adverse reaction to the drug. However, since many useful and predictive biomarkers may be discovered after commercial launch of the drug, the validation process and regulatory criteria of CoDx including Laboratory Developed Test (LDT) should be changed in order to avoid biomarker test lag. The reimbursement system, moreover, is not always suitable to assess the clinical and technological values of CoDx and those systems need to be reformed for encouraging personalized medicine with co-developed CoDx.