OBJECTIVE: To determine whether the presence of polymorphisms associated with reduced or absent activity of thiopurine methyltransferase (TPMT), an enzyme involved in azathioprine metabolism, can predict side-effects, particularly myelosuppression, in patients taking this drug. METHODS: The TPMT genotype was determined in 120 patients with systemic lupus erythematosus (SLE) together with 15 patients with inflammatory bowel disease (IBD) and correlated with the effects of clinical exposure to azathioprine. RESULTS: TPMT polymorphisms were detected in eight patients. Severe marrow toxicity occurred in the single homozygote identified. Azathioprine was generally well tolerated, but 11 drug-associated neutropenias were detected. In only one of the 11 cases was a TPMT polymorphism identified. CONCLUSION: Homozygous TPMT deficiency was associated with severe marrow suppression. In the majority of cases, however, TPMT genotyping prior to azathioprine therapy would not have predicted myelosuppressive events and may augment, but not replace, regular blood monitoring.
OBJECTIVE: To determine whether the presence of polymorphisms associated with reduced or absent activity of thiopurine methyltransferase (TPMT), an enzyme involved in azathioprine metabolism, can predict side-effects, particularly myelosuppression, in patients taking this drug. METHODS: The TPMT genotype was determined in 120 patients with systemic lupus erythematosus (SLE) together with 15 patients with inflammatory bowel disease (IBD) and correlated with the effects of clinical exposure to azathioprine. RESULTS:TPMT polymorphisms were detected in eight patients. Severe marrow toxicity occurred in the single homozygote identified. Azathioprine was generally well tolerated, but 11 drug-associated neutropenias were detected. In only one of the 11 cases was a TPMT polymorphism identified. CONCLUSION: Homozygous TPMT deficiency was associated with severe marrow suppression. In the majority of cases, however, TPMT genotyping prior to azathioprine therapy would not have predicted myelosuppressive events and may augment, but not replace, regular blood monitoring.
Authors: Partha Krishnamurthy; Matthias Schwab; Kazumasa Takenaka; Deepa Nachagari; Jessica Morgan; Mark Leslie; Weinan Du; Kelli Boyd; Meyling Cheok; Hiromitsu Nakauchi; Catia Marzolini; Richard B Kim; Balasubramanian Poonkuzhali; Erin Schuetz; William Evans; Mary Relling; John D Schuetz Journal: Cancer Res Date: 2008-07-01 Impact factor: 12.701
Authors: Elizabeth D Ferucci; Kathy J Hurlburt; Marlyn J Mayo; Stephen Livingston; Heike Deubner; James Gove; Julia Plotnik; Brian J McMahon Journal: Can J Gastroenterol Date: 2011-01 Impact factor: 3.522