Correlation of genotypes for thiopurine methyltransferase and inosine triphosphate pyrophosphatase with long term clinical outcomes in Korean patients with inflammatory bowel diseases during treatment with thiopurine drugs

Abstract

[한글]

[영문]Background and Aims: There is a lack of research describing associations between thiopurine methyltransferase (TPMT)/inosine triphosphate pyrophosphatase (ITPA) genotypes or phenotypes and long-term clinical outcomes after thiopurine treatment. We investigated whether TPMT/ITPA genotypes and TPMT activity would predict long-term clinical response in Korean patients with inflammatory bowel diseases (IBD) undergoing thiopurine treatment.Methods: A total of 113 patients with IBD in whom thiopurine treatment was indicated were enrolled and categorized by TPMT and ITPA genotypes and TPMT enzyme activity. Long-term follow-up clinical data for these patients were analyzed with specific focus on disease relapse.Results: Seventy-eight of 113 patients (69.0%) using thiopurines achieved remission and were included in the analysis. There were no significant differences in disease relapse-free survival between wild and mutant types of TPMT (p=0.690) or ITPA (p=0.403) according to the results of log rank analysis. The mean TPMT activity in the ‘non-relapsers’ (n=27) was significantly higher than in ‘relapsers’ (n=51) (p = 0.001).Conclusions: Our study suggests that TPMT and ITPA genotypes or TPMT activity may not affect rates of disease relapse in Korean IBD patients treated with thiopurines. Further studies are indicated to appropriately guide clinicians formulating individualized treatments for IBD patients requiring thiopurine therapy.