Pharmacogenomic researches have been performed in high levels also in Asia, especially in association analyses with severe cutaneous adverse reactions. Association of an HLA type, HLA-B*15:02 with carbamazepine-related Stevens-Johnson syndrome and toxic epidermal necrolysis was first reported from Taiwanese and its association is specific to Asian populations since HLA-B*15:02 is frequent in South-East Asians and Chinese. In addition, HLA-B*58:01, HLA-B*51:01, HLA-A*02:06, HLA-A*02:07 and CYP2C9*3 were associated with severe cutaneous adverse reactions related to allopurinol, phenobarbital, cold medicine such as acetaminophen, zonisamide and phenytoin, respectively, which were first reported from Asian researchers. Other examples of functional genetic polymorphisms in relatively high frequencies for Asian populations are UGT1A1*6 with reduced enzymatic activities and CYP2C19*2 and *3 with null activities. UGT1A1 is a metabolic enzyme for active metabolite of irinotecan, SN-38, and UGT1A1*6 in addition to UGT1A1*28 are associated with severe neutropenia. CYP2C19 is involved in the metabolism of omeprazole and the patients with the null allele (*2 and/or *3) show higher success rates of Helicobacter pylori eradication. Helicobacter pylori infection is one of the major factors for gastric cancer in East Asians.

On the other hand, their implementation is still limited. In Taiwan, prior testing of HLA-B*15:02 for the carbamazepine-administred patients should be considered in patients with ancestry in Asian populations and the test is reimbursed by the national health insurance. But in Japan, only the description of its association is on the package inserts, probably due to the low allele frequency in Japanese. UGT1A1*6 and *28 testing is reimbursed by national health insurance, but the test is not mandatory.

Issues on collaboration among Asian countries are 1) differences in used drugs between developing countries and advanced countries, 2) poverty of cold chain in sampling and storage processes in some countries, 3) difficulty in exporting genomic DNA to the other countries at least in a few countries/regions.

In this presentation, major achievements of Asian pharmacogenomic researchers and their implementation are summarized.