[Exploratory studies on genetic biomarkers related to serious drug adverse reactions]

Serious adverse events (SAEs) induced by drugs occur rarely, but the symptoms are very critical and generally not related to their pharmacological activities. Although SAEs should be avoided wherever possible, their occurrence is unpredictable at this time. In this article, we describe the clinical condition, figures on reported occurrence in Japan and studies on genetic markers related to serious cutaneous adverse reactions (SCARs), drug induced liver injury (DILI and rhabdomyolysis among SAEs. Then we introduce our last 3 years' approach of exploratory study on genetic markers for Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN), two of SCARs, useful for Japanese patients, including construction of a new case collection system, study methodology and progress. As the result at this moment, no Japanese SJS/TEN patients including 12 carbamazepine-related and 23 aromatic anti-epileptic agent-related ones carried HLA-B 1502 that was reported to have a strong association with carbamazepine-induced SJS/TEN in Han Chinese patients. On the other hand, 5 in 15 allopurinol-related SJS/TEN patients were found to have HLA-B 5801 that was detected as a genetic marker for allopurinol-induced SCARs in Han Chinese and Caucasians. Hereafter, we have a plan to begin the new exploratory studies on genetic markers for DILI and rhabdomyolysis, in addition to SJS/TEN patients.